WO2025068198A1 - Measuring system - Google Patents

Abstract

The measuring system is used to sense two temporally variable primary measured variables (x1, x2) and/or a secondary measured variable (y1) derived therefrom. It comprises measurement electronics, an active sensor element (C1), a passive sensor element (R1) and electrical connecting lines. The sensor element (C1) generates a voltage dependent on x1, while the sensor element (R1) changes its resistance depending on x2. For a defined interval (t1), the measurement electronics drive a measurement current through R1 and interrupt this before (t2) and after (t3) this interval, with the result that rising and falling current flanks arise in the transitional intervals (t-4, t5). Moreover, the measurement electronics temporarily sense and analyse the voltages (u1, u2) and implement this measurement in particular time intervals in order to allow failure-free and precise evaluation.

Description

measuring system

The invention relates to a measuring system for measuring two (time-varying) primary (process) measured variables of a fluid medium and/or for measuring a (time-varying) secondary (process) measured variable of the medium derived from at least one of the primary (process) measured variables.

In US-A 2003/0061887, US-A 2004/0216532, US-A 2009/0038406, US-A 2022/0057240, WO-A 2004/023081, WO-A 2022/128418 or the (not pre-published) German patent application 102022127160.9, measuring systems are each described for measuring a time-varying primary first (process) measured variable, here namely a time-varying, in particular at least temporarily periodic, static pressure and/or a time-varying change or rate of change of the same pressure, of a fluid measuring medium flowing in a (process) line and/or for measuring a time-varying pressure derived from the same primary (process) measured variable. variable) secondary (process) measured variable, here namely a flow velocity and/or a volume flow of a fluid medium conveyed in a (process) line.

Each of the measuring systems—here embodied as a vortex flowmeter (in a compact design)—includes measuring system electronics, at least one first sensor element for detecting the first primary (process) measured variable, and at least one passive second sensor element for detecting a second primary (process) measured variable that is different from the first primary (process) measured variable (serving as an auxiliary measured variable), in this case a time-varying temperature. The first and second sensor elements are each electrically connected to the respective measuring system electronics by means of electrical connecting lines (forming first and second measuring channels of the respective measuring system, respectively). In addition, the first sensor element is configured (in conjunction with the measuring system electronics) to generate or set a first electrical (measurement) voltage dependent on the first primary measured variable, and the second sensor element is configured (in conjunction with the measuring system electronics) to generate or set a second electrical (measurement) voltage dependent on the second primary measured variable.

The measuring system electronics of each of the aforementioned measuring systems is housed in an, for example, impact- and/or weather-resistant, electronic (protective) housing and is also each set up to generate one or more (digital) measured values for the primary and/or secondary To determine a (process) measured variable and to output it as qualified measured values of the measuring system. In the measuring systems shown here, the measuring system electronics are also particularly designed to determine, based on at least the first electrical (measurement) voltage, measured values for a frequency serving as a secondary (process) measured variable of at least temporarily periodic pressure fluctuations within the flowing medium - in this case, pressure fluctuations within a Karman vortex street formed in a flow of the medium - and to determine, based on the same (vortex) frequency and the (temperature-dependent) second electrical (measurement) voltage, measured values for a volume and/or mass flow of the medium serving as a secondary (process) measured variable. The measuring system electronics can, for example, also be configured to determine, based on the first and second electrical (measurement) voltages, measured values for a (static) pressure of a (flowing) fluid medium, which serves as the first primary (process) measured variable. Typically, measuring systems of the type in question are mostly designed as low-power measuring systems, for example, such that the respective measuring system electronics are at least temporarily operated with an electrical (nominal) power of less than 100 mW (milliwatts); this is particularly true if the measuring system electronics or the measuring system formed thereby is connected via a current loop interface to a (4-20 mA) two-wire line used to transmit electrical power and measured values.

As shown in US-A 2003/0061887, US-A 2004/0216532, US-A 2009/0038406, US-A 2022/0057240, the first sensor element can be designed, for example, as a capacitive (passive) sensor element, such that the same sensor element has an electrical (sensor) capacitance and is configured to follow a change in the first primary (process) measured variable with a change in the same capacitance, and accordingly be formed by means of a (measuring) capacitor, for example with a (capacitor) electrode geometry that changes depending on the first primary measured variable. In addition, the measuring system electronics can be configured accordingly to electrically charge or maintain the aforementioned (sensor) capacitance in order to generate the first electrical (measurement) voltage, for example by means of a corresponding charge-voltage converter (charge amplifier). In the aforementioned measuring systems, the first sensor element is formed by at least one (measurement) capacitor - here, for example, designed as a plate capacitor - for example with a (capacitor) electrode geometry that changes depending on the first primary measurement variable. The first sensor element can, for example, also be formed by a (plate) capacitor having a dielectric that changes depending on the first primary measurement variable, or can also be a piezoelectric or galvanic (active) sensor element. The second sensor element, in turn, can typically be a resistive passive (temperature) sensor element, such that the same sensor element has a temperature dependent electrical (sensor) resistance, for example a platinum measuring resistor (standardized according to EN IEC 60751), and is configured to follow a change in the second primary measured variable with a change in the same resistance. To effect the second electrical (measurement) voltage, the measuring system electronics can also be configured to energize the second sensor element, namely to drive an (impressed) electrical (measurement) current with a current intensity typically between approximately 0.05 mA and 0.5 mA through the second sensor element and connecting lines electrically connecting it to the measuring system electronics, for example in order to establish a corresponding voltage drop (proportional to the resistance) across the second sensor element.

In order to connect the first and second sensor elements or the measuring system formed thereby to the respective process or its respective measuring medium, measuring systems of the type in question typically also have a metallic (process) coupling element, formed for example by means of a membrane and/or a sleeve and/or a plate, which is designed to be contacted by the respective measuring medium (during operation of the measuring system), for example to be flowed against and/or around, in particular in such a way that the (process) coupling element has a (coupling element) temperature that is dependent on a (measured medium) temperature of the measured medium and/or that the (process) coupling element has an (elastic) expansion that is dependent on a (measured medium) pressure.

In the measuring systems shown in US-A 2003/0061887, US-A 2004/0216532, US-A 2009/0038406, US-A 2022/0057240, WO-A 2022/128418, the (process) coupling element is arranged proportionately within a (housing) connecting piece which serves to hold the aforementioned electronics (protective) housing on the (process) line or a measuring tube of the measuring system incorporated therein, for example, detachably connected to the electronics (protective) housing by means of a flange connection and/or is tubular, and/or is (mechanically) connected to it at a connecting piece end distal to the electronics housing, and the aforementioned Connecting lines are routed at least partially within the (housing) connection piece. In addition, the (process) coupling element shown here is formed by means of a membrane-like deformation body and a paddle-shaped sensor vane formed thereon and is in particular designed to be inserted at least partially into a lumen of a pipe (used to convey a fluid medium), for example in such a way that the (process) coupling element is inserted into the lumen through an opening in a pipe wall surrounding the lumen and is (removably) fixed to the same pipe wall. The coupling element can, for example, also be formed by means of a tuning fork or a tuning rod and be designed to be inserted at least partially into a lumen of a container (used to convey a fluid medium), for example a tank or a silo. The coupling element is further mechanically coupled to the first sensor element in such a way that the first electrical (measurement) voltage depends on an elongation of the coupling element or such that a change in an elongation of the coupling element causes a change in the first electrical (measurement) voltage, for example, by rigidly connecting at least one (movable) capacitor electrode of the (measurement) capacitor to the coupling element. Last but not least, in the aforementioned case where the first sensor element is formed by at least one (measurement) capacitor, the first sensor element can also be an (integral) component of the coupling element, for example, such that at least one (movable) capacitor electrode of the (measurement) capacitor is formed by the coupling element. Furthermore, the coupling element and the second sensor element are coupled to one another at least thermally, in particular both thermally and mechanically, in such a way that the second electrical (measurement) voltage is dependent on a (coupling element) temperature of the coupling element or that a change in a (coupling element) temperature of the coupling element causes a change in the electrical (sensor) resistance of the second sensor element.

One disadvantage of measuring systems of the type in question is, among other things, that the aforementioned connecting lines, not least in the case of their at least partial installation within the connecting piece, have small distances of less than 5 mm from one another and can therefore be capacitively (signal) coupled to a considerable extent. Due to this (signal) coupling, the (measurement) current through the second sensor element, which serves to generate the second electrical (measurement) voltage, can also cause a disturbance in the first measuring channel that influences the first electrical (measurement) voltage and thus the measuring accuracy of the measuring system as a whole; this is particularly the case if the (measurement) current is changed abruptly, for example, when it is switched on or off. To avoid resulting measurement errors, switching operations that influence the respective measuring current are avoided in such measuring systems during the determination of the measured values or, conversely, the measuring current is kept as constant as possible for the determination of the measured values. In conjunction with this, the total electrical power required for the operation of the aforementioned first and second measuring channels alone can be approximately 0.5 to 2 mW, which in the case of a low-power measuring system can (occasionally) amount to more than 1% of the total available, albeit already low, electrical power (<100 mW). Based on the aforementioned prior art, it is an object of the invention to improve the measuring system of the type in question in such a way that the electrical power required to determine the measured values can be regularly reduced from a (maximum) electrical power required overall for the operation of the first and second measuring channels to a comparatively lower (minimum) electrical power, while still maintaining a sufficiently high measurement accuracy or a sufficiently high update rate of the measured values determined thereby.

To achieve this object, the invention consists in a measuring system for measuring a (time-varying) first primary (process) measured variable, for example a (static) pressure of a fluid medium (conducted in a line and/or held in a container) and/or a temporal change in the same pressure, as well as a (time-varying) second primary (process) measured variable different from the first primary (process) measured variable, for example a temperature of a fluid medium (conducted in a line), and/or for measuring a (time-varying) secondary (process) measured variable derived from at least one of the first and second primary (process) measured variables, for example a mass flow of a fluid medium conveyed in a line or a fill level of a fluid medium held in a container, which measuring system comprises:

• a measuring system electronics, for example, operated with a maximum electrical power of less than 1 W (watt) and/or connected to a (4-20 mA) 2-wire line,

• at least one, for example capacitive and/or passive, first sensor element (C1) for detecting the first primary (process) measured variable,

• at least one, for example resistive, passive second sensor element (R1) for detecting the second primary (process) measurement variable,

• and first, second, third and fourth, for example each (at least) partially unshielded and/or not twisted together, electrical connecting lines, wherein the first sensor element is electrically connected to the measuring system electronics by means of the first and second connecting lines (forming a first measuring channel of the measuring system), for example with the interposition of a feedthrough, • wherein the second sensor element is electrically connected to the measuring system electronics by means of the third and fourth connecting lines (forming a second measuring channel of the measuring system), for example with the interposition of a feedthrough,

• and wherein at least one, for example each, of the first and second connecting lines is (signal-)coupled to at least one, for example each, of the third and fourth connecting lines, for example capacitively, for example by a smallest distance between at least one of the first and second connecting lines and at least one of the third and fourth connecting lines being less than 5 mm,

• wherein the first sensor element is configured, for example in conjunction with the measuring system electronics, to generate and/or adjust a first electrical (measurement) voltage dependent on the first primary (process) measurement variable,

• and wherein the second sensor element has an electrical (sensor) resistance, for example at a temperature of 20°C not less than 90 Ω and/or not more than 1.1 kΩ, and is arranged to follow a change in the second primary measured variable with a change in the same resistance,

• wherein the measuring system electronics are configured to temporarily record and evaluate the first electrical (measurement) voltage, for example, to digitize it and/or to determine (digital) first (voltage) measured values representing the (measurement) voltage,

• the measuring system electronics are set up,

• to temporarily cause a voltage drop across the second sensor element, to temporarily energize the second sensor element, namely during a predetermined first (energization) time interval t1, for example lasting not less than 10 ms, to drive an electrical (measurement) current, for example impressed and/or constant and/or having a maximum current of not less than 0.1 mA and/or converting a maximum electrical power of not less than 0.4 mW in the second sensor element, through the second sensor element and the third and fourth connecting lines and during a second time interval t2 preceding the first time interval and a third time interval t3 following the first (energization) time interval, not to energize the second sensor element or to drive no (measurement) current through the second sensor element and the third and fourth connecting lines, such that the (measurement) current at least during a time interval (immediately) following the second time interval and the first (Power supply) time interval temporal (immediate) preceding, for example, not less than 1 s (microsecond), fourth (transition) time interval has a (rising) first current edge, for example with a current rise rate that is not less than 0.1 mA/ps at least temporarily and/or on average over time (arithmetic), and that the (measurement) current has a (falling) second current edge, for example with a current fall rate that is not less than 0.1 mA/ps at least temporarily and/or on average over time (arithmetic), at least during a fifth (transition) time interval that (immediately) follows the first (energization) time interval and (immediately) precedes the third time interval, for example, not less than 1 ps (microsecond),

• and wherein the measuring system electronics are configured to detect and evaluate a second electrical (measurement) voltage dependent on the voltage drop across the second sensor element during the first (energization) time interval t1, for example to digitize it and/or to determine (digital) second (voltage) measured values representing the (measurement) voltage;

• wherein the measuring system electronics are configured to determine, based on at least the first electrical (measurement) voltage, for example based on both the first electrical (measurement) voltage and the second electrical (measurement) voltage, one or more (digital) measured values for the first primary (process) measured variable and/or one or more (digital) measured values for the secondary (process) measured variable, for example to determine them and output them as qualified measured values of the measuring system,

• and wherein the measuring system electronics, for example to avoid measurement errors in measured values determined for the first measured variable caused by (signal) coupling from the third and/or fourth connecting lines into the first and/or second connecting lines, are configured: not to output a (qualified) measured value for the first primary (process) measured variable determined based on the first (measurement) voltage detected during the fourth and fifth (transition) time intervals, and/or not to output a measured value for the first primary (process) measured variable based on the first electrical (measurement) voltage present during the fourth and fifth (transition) time intervals, and/or not to output a (qualified) measured value for the secondary (process) measured variable determined based on the first (measurement) voltage detected during the fourth and fifth (transition) time intervals, and/or not to determine any measured value for the secondary (process) measured variable based on the first electrical (measurement) voltage present during the fourth and fifth (transition) time intervals, and/or to determine (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable during the fourth (transition) time interval based on a first (measurement) voltage previously recorded during the second time interval, and/or to determine (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable during the fifth (transition) time interval based on a first (measurement) voltage previously recorded during the first time interval.

Furthermore, the invention also consists in using such a measuring system for measuring both a first primary (process) measured variable, for example a time-varying (static) pressure, and a second primary (process) measured variable (different from the first measured variable), for example a time-varying temperature, of a fluid medium (conducted in a line or held in a container).

According to a first embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured: not to output a (qualified) measured value for the first primary (process) measured variable determined on the basis of the first (measurement) voltage detected during the (current supply) time interval, and/or not to determine a measured value for the first primary (process) measured variable based on the first electrical (measurement) voltage present during the (current supply) time interval, and/or not to output a (qualified) measured value for the secondary (process) measured variable determined on the basis of the first (measurement) voltage detected during the (current supply) time interval, and/or not to determine a measured value for the secondary (process) measured variable based on the first electrical (measurement) voltage present during the (current supply) time interval. Developing this embodiment of the invention, the measuring system electronics is further configured to determine (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable based on a first (measurement) voltage detected during the first time interval, and/or to output (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable determined based on a first (measurement) voltage detected during the (energization) time interval. According to a second embodiment of the measuring system of the invention, it is further provided that the first sensor element has an electrical (sensor) capacitance, for example, at a temperature of 20°C, of not less than 10 pF and/or not more than 100 pF, and is configured to follow a change in the first primary (process) measured variable with a change in the same (sensor) capacitance, and that the measuring system electronics are configured to electrically charge or keep charged the capacitance of the first sensor element, for example, at least during the second and third time intervals, in order to effect the first electrical (measurement) voltage. Further developing this embodiment of the invention, the measuring system electronics are further configured such that the first electrical (measurement) voltage is (substantially) proportional to an electrical charge of the (sensor) capacitance of the first sensor element.

According to a third embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured to determine (voltage) measured values representing the first (measurement) voltage, for example, to determine them and store them in a (volatile) digital data memory. Further developing this embodiment of the invention, the measuring system electronics are further configured to determine one or more measured values for the second primary (process) measured variable using one or more (voltage) measured values representing the first (measurement) voltage.

According to a fourth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured to determine (voltage) measured values representing the second (measurement) voltage, for example, to determine them and store them in a (volatile) digital data memory. Further developing this embodiment of the invention, the measuring system electronics are further configured to determine one or more measured values for the first primary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage and/or to determine one or more measured values for the first secondary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage and/or to determine one or more measured values for the second primary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage. According to a fifth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured to determine, based on the second electrical (measurement) voltage, one or more (digital) measured values for the second primary (process) measured variable, for example, for determining at least one measured value for the first primary (process) measured variable and/or the secondary (process) measured variable, each serving as an auxiliary measured value, for example, to determine them and store them in a (volatile) digital data memory. Further developing this embodiment of the invention, the measuring system electronics are further configured to determine one or more measured values for the first primary (process) measured variable using one or more measured values for the second primary (process) measured variable.

According to a sixth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured to determine, for example, namely to determine and output as qualified measured values of the measuring system, one or more (digital) measured values for the second primary (process) measured variable based on at least the second electrical (measurement) voltage, for example based on both the second electrical (measurement) voltage and the first electrical (measurement) voltage.

According to a seventh embodiment of the measuring system of the invention, it is further provided that each of the first and second connecting lines is at least partially, for example completely, unshielded.

According to an eighth embodiment of the measuring system of the invention, it is further provided that each of the third and fourth connecting lines is at least partially, for example completely, unshielded.

According to a ninth embodiment of the invention, it is further provided that each of the first and second connecting lines is formed at least partially by means of a conductor track arranged on a (flexible) printed circuit board.

According to a tenth embodiment of the measuring system of the invention, it is further provided that each of the third and fourth connecting lines is formed at least partially by means of a conductor track arranged on a (flexible) printed circuit board.

According to an eleventh embodiment of the measuring system of the invention, it is further provided that each of the first, second, third and fourth connecting lines is formed at least partially by means of a respective conductor track arranged on one and the same (flexible) printed circuit board. According to a twelfth embodiment of the measuring system of the invention, it is further provided that the first and second connecting lines run parallel to each other at least in sections.

According to a thirteenth embodiment of the measuring system of the invention, it is further provided that the third and fourth connecting lines run parallel to each other at least in sections.

According to a fourteenth embodiment of the measuring system of the invention, it is further provided that the first and third connecting lines run parallel to each other at least in sections.

According to a fifteenth embodiment of the measuring system of the invention, it is further provided that the first and fourth connecting lines run parallel to each other at least in sections.

According to a sixteenth embodiment of the measuring system of the invention, it is further provided that the first, second, third and fourth connecting lines run parallel to one another at least in sections.

According to a seventeenth embodiment of the measuring system of the invention, the measuring system electronics comprises at least one operational amplifier, for example, an FET or a CMOS operational amplifier, wherein the first sensor element is electrically connected to a (high-impedance) (voltage) input of the operational amplifier by means of the first and second connecting lines, for example, forming a charge-to-voltage converter of the measuring system electronics, and wherein the operational amplifier is configured to supply the first electrical (measurement) voltage at a (voltage) output (when the measuring system electronics is operating in the first operating mode). Further developing this embodiment of the invention, the operational amplifier comprises a (feedback) capacitor (Cf) that feeds back its (voltage) output to its (voltage) input, for example, a switched (feedback) capacitor. Advantageously, the (feedback) capacitor (Cf) may have a (feedback) capacitance which is not less than 0.1 pF and/or not more than 100 pF.

According to an eighteenth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics has at least one, for example switchable, (electronic) current source, wherein the second sensor element is electrically connected to a (current) output of the current source by means of the third and fourth connecting lines and wherein the current source is configured to supply the (measurement) current. According to a nineteenth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics has at least one, for example switchable, (electronic) voltage source, wherein the second sensor element is electrically connected to an output of the voltage source by means of the third and fourth connecting lines and wherein the voltage source is configured to drive the (measurement) current.

According to a twentieth embodiment of the measuring system of the invention, it is further provided that the measuring system electronics are configured to determine the sensor resistance of the second sensor element based on the second (measurement) voltage.

According to a twenty-first embodiment of the invention, it is further provided that the measuring system electronics have at least one (reference) resistance element having an electrical (reference) resistance, for example, at a temperature of 20°C, not less than 90 Ω and/or not more than 1.1 kΩ, which is electrically connected to the second sensor element, for example, electrically connected in series with the second sensor element. Further developing this embodiment of the invention, the measuring system electronics are configured to detect and evaluate, for example, digitize and/or determine (digital) third voltage measurement values representing the reference voltage, a third electrical (reference) voltage dependent on a voltage drop across the (reference) resistance element during the first (energization) time interval. Advantageously, the measuring system electronics can also be configured to determine the (sensor) resistance of the second sensor element based on the third (reference) voltage, for example based on the second and third voltages as well as the (reference) resistance and/or ratiometrically.

According to a twenty-second embodiment of the invention, it is further provided that the measuring system electronics are configured to determine, based on at least the first electrical (measurement) voltage, measured values for a frequency (serving as a secondary measured variable) of at least temporarily periodic pressure fluctuations within a fluid measuring medium, for example of pressure fluctuations within a Karman vortex street formed in a flow of the measuring medium.

According to a twenty-third embodiment of the invention, it is further provided that the measuring system electronics are configured to determine measured values for a (measuring substance) temperature (serving as a second primary measured variable) of a, for example, flowing, fluid measuring substance based on at least the second electrical (measuring) voltage. According to a twenty-fourth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine measured values for a (static) pressure of a (flowing) fluid medium (serving as the first primary measured variable) based on the first and second electrical (measurement) voltages.

According to a twenty-fifth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine measured values for a volume flow of a flowing (fluid) medium (serving as a secondary measured variable) based on the first and second electrical (measurement) voltages.

According to a twenty-sixth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine measured values for a mass flow of a flowing (fluid) medium (serving as a secondary measured variable) based on the first and second electrical (measurement) voltages.

According to a twenty-seventh embodiment of the invention, it is further provided that the first sensor element is formed by means of at least one (measuring) capacitor, for example designed as a plate capacitor, for example with a (capacitor) electrode geometry changing as a function of the first primary measured variable and/or with a dielectric changing as a function of the first primary measured variable.

According to a twenty-eighth embodiment of the invention, it is further provided that the second sensor element (R1) is formed by means of at least one platinum measuring resistor, for example a Pt100 and/or a Pt1000.

According to a first development of the invention, the measuring system further comprises at least one (electrical) feedthrough, for example explosion-pressure-resistant (Ex-d) and/or compliant with the international standard IEC 60079-1:2014.

According to a first embodiment of the first further development of the invention, it is provided that the first, second, third and fourth connecting lines are guided in sections within the bushing.

According to a second embodiment of the first development of the invention, it is provided that the feedthrough is electrically connected to the first, second, third and fourth connecting lines, for example by means of unshielded (connecting) pins.

According to a third embodiment of the first further development of the invention, it is provided that the bushing is interposed between the first, second, third and fourth connecting lines. According to a second development of the invention, the measuring system further comprises an electronics (protective) housing for the measuring system electronics, for example one that is explosion-pressure-resistant (Ex-d) and/or conforms to the international standard IEC 60079-1:2014.

According to a third embodiment of the invention, the measuring system further comprises a (housing) connection piece, which is detachably connected to the electronics (protective) housing, for example, by means of a flange connection and/or is tubular. Advantageously, the first, second, third, and fourth connecting lines can also be routed at least partially within the (housing) connection piece, for example, in such a way that they run parallel to each other at least in sections.

According to a fourth development of the invention, the measuring system further comprises a (process) coupling element, formed for example by means of a membrane and/or a sleeve and/or a plate, which is designed to be contacted by a fluid medium (during operation of the measuring system), for example to be flowed against and/or around, for example in such a way that the (process) coupling element has a (coupling element) temperature dependent on a (measured medium) temperature of the measured medium and/or that the (process) coupling element has an (elastic) expansion dependent on a (measured medium) pressure.

According to a first embodiment of the fourth development of the invention, it is provided that the coupling element is configured to react to a change in a (measuring substance) temperature of the measuring substance with a change in a (coupling element) temperature, for example in such a way that the (coupling element) temperature of the coupling element deviates stationary from a stationary (measuring substance) temperature of the measuring substance by less than 2 K (Kelvin).

According to a second embodiment of the fourth development of the invention, it is provided that the coupling element is designed to react to a change in a (measuring medium) pressure of the measuring medium with an, for example, biaxial and/or elastic, expansion.

According to a third embodiment of the fourth development of the invention, it is provided that the coupling element is designed to be inserted at least partially into a lumen of a tube (serving to guide a fluid measuring substance), for example, namely through an opening in a tube wall enclosing the lumen into the lumen and to be fixed (removably) to the same tube wall.

According to a fourth embodiment of the fourth development of the invention, it is provided that the coupling element is designed to be inserted at least partially into a lumen of a container (serving to guide a fluid measuring substance), for example a tank, for example through an opening in a container wall enclosing the lumen into the lumen and to be fixed (removably) to the same container wall. According to a fifth embodiment of the fourth development of the invention, it is provided that the coupling element consists at least partially, for example completely, of metal, for example a (stainless) steel and/or a nickel-based alloy.

According to a sixth embodiment of the fourth development of the invention, it is provided that the coupling element and the first sensor element are at least mechanically coupled to one another, for example in such a way that the first electrical (measurement) voltage is dependent on the strain of the coupling element or that a change in the strain of the coupling element causes a change in the first electrical (measurement) voltage.

According to a seventh embodiment of the fourth development of the invention, it is provided that the first sensor element is an (integral) component of the coupling element, for example in such a way that the first electrical (measurement) voltage is dependent on the strain of the coupling element or that a change in the strain of the coupling element causes a change in the first electrical (measurement) voltage.

According to an eighth embodiment of the fourth development of the invention, it is further provided that the coupling element is arranged partially within a (housing) connecting piece of the measuring system, which is detachably connected, for example, by means of a flange connection to an electronics (protective) housing of the measuring system and/or is tubular, for example, namely (mechanically) connected (at a nozzle end distal to the electronics housing) to the connecting piece.

According to a ninth embodiment of the fourth development of the invention, it is further provided that the first sensor element is formed by means of at least one (measuring) capacitor, for example designed as a plate capacitor, for example with a (capacitor) electrode geometry that changes depending on the first primary measured variable and/or with a dielectric that changes depending on the first primary measured variable, wherein at least one, for example movable, (capacitor) electrode of the (measuring) capacitor is mechanically connected to the coupling element or is formed by means of the coupling element and/or wherein the coupling element and the second sensor element are at least thermally coupled to one another, for example both thermally and mechanically, for example in such a way that the second electrical (measuring) voltage is dependent on a (coupling element) temperature of the coupling element or that a change in a (coupling element) temperature of the coupling element causes a change in the electrical (sensor) resistance of the second sensor element causes.

According to a fifth development of the invention, the measuring system further comprises an electronics (protective) housing for the measuring system electronics, for example one that is explosion-pressure-resistant (Ex-d) and/or conforms to the international standard IEC 60079-1:2014. An advantage of the invention is that the measuring current required for determining the second primary measured variable can be switched on or off in a manner optimized for the operation of the measuring system electronics, without impairing the measuring accuracy of the measuring system or its (measured value) update rate.

The invention and advantageous embodiments thereof are explained in more detail below using exemplary embodiments illustrated in the figures of the drawing. Identical or equivalent or functioning parts are provided with the same reference numerals in all figures; where clarity requires it or it otherwise seems expedient, previously mentioned reference numerals have been omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of partial aspects of the invention initially explained only individually, will become apparent from the figures of the drawing and/or from the claims themselves.

In detail:

Fig. 1 shows a perspective side view of an embodiment of a measuring system according to the invention;

Fig. 2 shows schematically in a partially sectioned side view a measuring system according to Fig. 1;

Fig. 3 schematically shows an embodiment of a measuring system electronics suitable for a measuring system according to Fig. 1;

Fig. 4 and in a time diagram, curves of measuring voltages or currents in a measuring system electronics according to Fig. 3.

1, 2 and 3 show an embodiment of a measuring system for measuring a (time-varying) first primary (process) measured variable, in particular a (static) pressure of a fluid medium (conducted in a line and/or held in a container) and/or a temporal change in the same pressure, as well as a (time-varying) second primary (process) measured variable x2 different from the first primary (process) measured variable x1, in particular a (measured medium) temperature of a fluid medium (conducted in a line), and/or for measuring a (time-varying) secondary (process) measured variable y1 derived from at least one of the first and second primary (process) measured variables, in particular a volume or mass flow of a fluid medium conducted in a line or a fill level of a fluid medium held in a container. A schematic representation of a medium to be measured, for example a gas, a liquid or a dispersion. The aforementioned line and/or the aforementioned container can, for example, be designed as a system component of a heat supply network or a turbine cycle; thus, the medium to be measured can, for example, be steam, in particular saturated steam or superheated steam, or, for example, condensate discharged from a steam line. However, the medium can also be, for example, (compressed) natural gas or biogas or, for example, (drinking) water; thus, the pipeline and/or the container can, for example, also be a component of a natural gas or biogas plant or of a gas supply network or a water supply network. According to the exemplary embodiment shown in Fig. 1 or 2, the measuring system can, for example, comprise a (measuring) tube 3 which can be inserted into the course of the aforementioned line, for example also designed as a (rigid) pipeline, and has a lumen 3' enclosed by a (metallic) wall 3* of the tube, wherein the tube 3 or its lumen extends from an inlet end 3+ to an outlet end 3# and is designed to guide the measuring medium flowing (in the connected line) during operation of the measuring system or to be flowed through by the same measuring medium in the direction of a main flow direction of the measuring system. In the exemplary embodiment shown in Fig. 1 or 2, a flange is further provided at the inlet end 3+ as well as at the outlet end 3#, each serving to create a leak-free flange connection with a corresponding flange on an inlet-side or outlet-side line segment of the line. Furthermore, the tube 3, as shown in Fig. 1 or 2, can be designed to be substantially straight, for example as a hollow cylinder with at least partially circular cross-section, such that the tube 3 has an imaginary straight longitudinal axis L imaginarily connecting the inlet end 3+ and the outlet end 3#. The measuring system shown as an example in Fig. 1 or 2 is designed in particular as a (vortex counting) vortex flow meter and accordingly further comprises a bluff body 4 - for example prismatic or cylindrical - arranged within the lumen 3', which is designed to swirl the flowing medium in such a way that vortices with a vortex or shedding frequency fv (fv ~ u) dependent on a momentary flow velocity u of the same medium are generated in the medium flowing past it, or a Karman vortex street is formed in the medium flowing downstream of the bluff body 4. The measuring system according to the invention comprises at least one measuring system electronics 2, which can be operated or is operated, for example, with an energy flow of less than 360 Ws/h and/or with a maximum electrical power of less than 1 W (watt), in particular less than 0.1 W, at least one, for example capacitive and/or passive, first sensor element C1 for detecting the first primary (process) measured variable, at least one, for example resistive, passive second sensor element R1 for detecting the second primary (process) measured variable. Not least for the aforementioned case that the measuring system is designed as a vortex flow meter, the first and second sensor elements can, for example, be provided or set up to detect the first or second primary (process) measured variables of the medium (during operation of the measuring system) downstream of the aforementioned bluff body or from a Karman vortex street formed there, for example in such a way that the first primary (process) measured variable x1 is a (static) pressure fluctuating with a (vortex) shedding rate or frequency (fv), in particular proportional to a flow velocity u of the medium, or its change over time and/or the second primary (process) measured variable y1 is a (measured medium) temperature0 of the (swirled) medium.

The measuring system electronics 2 - which can be programmed, for example - can have an interface circuit, particularly designed as a TTY interface, for both wired power supply and wired signal or measurement data transmission, by means of which the measuring system (forming a current loop 2L) can be electrically connected to higher-level evaluation and supply electronics that provide the electrical energy required by the measuring system during operation. For example, the measuring system electronics 2 can be configured to draw electrical power from the aforementioned current loop 2L and to transmit (measurement) data to the evaluation and supply electronics by means of (load) modulation of an electrical (loop) current in the current loop 2L driven by the evaluation and supply electronics, carried out by the interface circuit, for example in the form of a (4-20 mA) standard signal compliant with DIN IEC 60381-1:1985-11. For temporarily storing digital (measurement) data, the measuring system electronics 2 may further comprise, for example, at least one (volatile) digital data memory (RAM). For electrically connecting the first and second sensor elements C1, R1 to the measuring system electronics 2, which may also be formed, for example, by means of at least one microprocessor (pC), the measuring system according to the invention further comprises first, second, third and fourth, in particular non-twisted, electrical connecting lines 401, 402, 403, 404. According to a further embodiment of the invention, each of the first and second connecting lines 401, 402 and/or each of the third and fourth connecting lines 403, 404 is at least partially, for example completely, unshielded, not least for cost reasons, and/or the connecting lines 401, 402, 403, 404 are arranged, not least for space reasons, such that a smallest distance between at least one of the first and second connecting lines 401, 402 and at least one of the third and fourth connecting lines 403, 404 is less than 5 mm. The first and second connecting lines 401, 402 and/or the third and fourth connecting lines 403, 404 can, for example, also be formed at least partially by means of a conductor track arranged on a (flexible) printed circuit board. According to a further embodiment of the invention, the first and second

Connecting lines 401, 402 and/or the third and fourth connecting lines 403, 404 and/or the first and third connecting lines 401, 403 and/or the first and fourth connecting lines 401, 404 run parallel to one another at least in sections, in particular in such a way that the first, second, third and fourth connecting lines 401, 402, 403, 404 run parallel to one another at least in sections.

According to a further embodiment of the invention, the measuring system comprises an electronics (protective) housing 20, for example one that is explosion-proof (Ex-d) and/or conforms to the international standard IEC 60079-1:2014, for accommodating the measuring system electronics. A mechanical connection of the electronics (protective) housing to the aforementioned cable or container or to a sensor (protective) housing of the measuring system can be established, for example, by means of a (housing) connection piece 30 of the measuring system, which itself is detachably connected to the electronics (protective) housing 20 by means of a flange connection and/or is tubular. In this case, the first, second, third and fourth connecting lines 401, 402, 403, 404 can also be routed at least partially within the (housing) connection piece 30, for example in such a way that they run parallel to one another at least in sections within the (housing) connection piece 30 and/or adjacent connecting lines 401, 402, 403, 404 have at least in sections only a small distance of less than 5 mm. Not least for the aforementioned case that the measuring system is housed in the aforementioned electronics (protective) housing 20 and/or that the first, second, third and fourth connecting lines are routed at least partially within the (housing) connection piece 30 connected to the same electronics (protective) housing 20, the measuring system according to a further embodiment of the invention further comprises at least one, for example, explosion-pressure-resistant (Ex-d) and/or (electrical) feedthrough 50 compliant with the international standard IEC 60079-1:2014. Advantageously, the first, second, third, and fourth connecting lines can be routed in sections within the feedthrough 50 and/or the feedthrough 50 can be interposed between the first, second, third, and fourth connecting lines 401, 402, 403, 404. According to a further embodiment of the invention, the feedthrough 50 has, for example, unshielded, (connection) pins, and the feedthrough 50 is electrically connected to the first, second, third, and fourth connecting lines 401, 402, 403, 404 by means of one of the (connection) pins each.

As also schematically shown in Fig. 2 or in Fig. 3, the first sensor element C1 is electrically connected to the measuring system electronics 2 by means of the first and second connecting lines 401, 402 (forming a first measuring channel of the measuring system) and the second sensor element R1 is electrically connected to the measuring system electronics 2 by means of the first and second connecting lines 403, 404 (forming a second measuring channel of the measuring system), for example also (in each case) with the interposition of the possibly required (housing) feedthrough 50. In addition, the first sensor element C1 of the measuring system according to the invention is in particular configured (in conjunction with the measuring system electronics) to generate and/or adjust a first electrical (measurement) voltage u1 dependent on the first primary (process) measured variable x1, and the measuring system electronics 2 is configured to temporarily detect and evaluate the same first electrical (measurement) voltage u1, for example to digitize it and/or to convert the first (Measurement) voltage u1 to determine (digital) first (voltage) measured values Xu1 representing. Not least for the aforementioned case in which the measuring system is designed as a vortex flow meter, the measuring system electronics 2 can also be configured, for example, to determine, based on at least the first electrical (measurement) voltage u1, measured values for a frequency (fv) (serving as a secondary measured variable) of at least temporarily periodic pressure fluctuations within the fluid measuring medium, in particular pressure fluctuations within the aforementioned Karman vortex street. According to a further embodiment of the invention, the first sensor element C1 is designed for this purpose as a capacitive sensor element (having at least one measuring capacitor). In particular, the first sensor element C1 has an electrical (sensor) capacitance, particularly at a temperature of 20°C, of not less than 10 pF (picofarads) and/or not more than 100 pF and/or composed of two or more partial capacitances, and the first sensor element is further configured to follow a change in the first primary (process) measured variable x1 with a change in the same (sensor) capacitance. Accordingly, the first sensor element C1 can, for example, also be formed by at least one plate capacitor, particularly with a (capacitor) electrode geometry that changes depending on the first primary measured variable x1 and/or with a dielectric that changes depending on the first primary measured variable x1. To effect the first electrical (measurement) voltage u1 The measuring system electronics are further configured to at least temporarily charge or keep charged the same capacitance of the first sensor element C1; for example, this also in such a way that the first electrical (measurement) voltage u1 is (essentially) proportional to an electrical charge of the (sensor) capacitance of the first sensor element C1. The second sensor element R1, in turn, has an electrical (sensor) resistance of not less than 90 Ω and/or not more than 1.1 kΩ, in particular at a temperature of 20°C, and is further configured to follow a change in the second primary measured variable x2 with a change in the same (sensor) resistance. According to a further embodiment of the invention, the second sensor element R1 is formed by means of at least one platinum measuring resistor, for example a Pt100 and/or a Pt1000.

In the measuring system according to the invention, the measuring system electronics 2 is further configured to temporarily energize the second sensor element R1 in order to temporarily cause a voltage drop across the second sensor element R1, namely, as also shown in Fig. 4, to drive an electrical (measurement) current through the second sensor element R1 and the third and fourth connecting lines 403, 404 during a predetermined first (energization) time interval t1, for example, lasting not less than 100 ms (milliseconds), in particular an impressed and/or constant and/or having a maximum current of not less than 0.1 mA (milliampere) and/or converting a maximum electrical power of not less than 0.4 mW (milliwatt) in the second sensor element R1, as well as during a second time interval t2 preceding the first time interval t1 and a third time interval following the first (energization) time interval t1 t3 not to energize the second sensor element R1, in particular to save electrical power or energy, or not to drive any (measuring) current through the second sensor element R1 and the third and fourth connecting lines 403, 404; this in particular in such a way that the (measurement) current i2, as also schematically shown in Fig. 4, has a (rising) first current edge, for example with a current rise rate that is at least temporarily and/or on average (arithmetic) terms not less than 0.1 mA/ps (milliamperes per microsecond), at least during a fourth (transition) time interval t4 that (immediately) follows the second time interval t2 and (immediately) precedes the first (current supply) time interval t1, for example (not less than 1 s (microsecond), and that the (measurement) current i2 has a (rising) first current edge, for example (not less than 0.1 mA/ps (milliamperes per microsecond), at least during a fifth (transition) time interval that (immediately) follows the first (current supply) time interval t1 and (immediately) precedes the third time interval t3, for example (not less than 1 ps (microsecond), t5 has a (falling) second current edge, for example with a current decay rate that is at least temporarily and/or on average (arithmetic) basis not less than 0.1 mA/ps. Furthermore, the measuring system electronics 2 is configured to, at least during the first (current supply) time interval t1 to detect and evaluate a second electrical (measurement) voltage u2 dependent on the voltage drop across the second sensor element R1, for example, namely to digitize it and/or to determine (digital) second (voltage) measured values Xu2 representing the second (measurement) voltage u2. In addition, the measuring system electronics 2 is further configured, based on at least the first electrical (measurement) voltage u1, for example also based on both the first electrical (measurement) voltage u1 and the second electrical (measurement) voltage u2, to determine one or more (digital) measured values for the first primary (process) measured variable x1 and/or one or more (digital) measured values for the secondary (process) measured variable y1, in particular to determine them and output them as (qualified) measured values XM of the measuring system. According to a further embodiment of the invention, the measuring system electronics 2 is in particular also configured to electrically charge or maintain the capacitance of the first sensor element C1 at least during the second and third time intervals in order to effect the first electrical (measurement) voltage u1, and/or the measuring system electronics 2 is configured to determine the sensor resistance of the second sensor element R1 based on the second (measurement) voltage u2. Advantageously, the measuring system electronics 2 can also be configured to (temporarily) store (voltage) measured values Xu1 representing the first (measurement) voltage u1, for example in order to (temporarily) store the same (voltage) measured values u1 in the aforementioned (volatile) digital data memory and/or to determine one or more measured values for the second primary (process) measured variable x2 using one or more of the same (voltage) measured values. Alternatively or in addition, the measuring system electronics 2 can also be configured to determine (voltage) measured values Xu2 representing the second (measurement) voltage u2, for example in order to (temporarily) store the same (voltage) measured values Xu2 in the aforementioned (volatile) digital data memory and/or to determine one or more measured values for the first and/or second primary (process) measured variables x2 and/or for the secondary (process) measured variable y1 using one or more of the same (voltage) measured values Xu2.

According to a further embodiment of the invention, the measuring system electronics 2 is also configured to determine one or more (digital) measured values for the second primary (process) measured variable x2 based on the second electrical (measurement) voltage u2, for example, in order to store the same measured values in the aforementioned (volatile) digital data memory and/or to serve as an auxiliary measured value for determining at least one measured value for the secondary and/or first primary (process) measured variables. Alternatively or additionally, the measuring system electronics 2 can advantageously also be configured to determine one or more measured values for the first primary (process) measured variable x1 using one or more measured values for the second primary (process) measured variable x2. Not least for the aforementioned case in which the measuring system is designed as a vortex flowmeter, the measuring system electronics 2 can, for example, be configured to determine one or more measured values for the first primary (process) measured variable x1 based on at least the second electrical (Measuring) voltage u2 to determine measured values for a (measuring material) temperature 0 of a (flowing) fluid measuring medium, which serves as a second primary measured variable x2, and/or the measuring system electronics 2 can be set up to determine, based on the first and second electrical (measuring) voltages, measured values for a volume flow v (serving as a secondary measured variable) and/or a mass flow m (serving as a secondary measured variable) of a flowing (fluid) measuring medium and/or measured values for a (static) pressure p (serving as a first primary measured variable x1) of a (flowing) fluid measuring medium.

To provide the first electrical (measurement) voltage u1, the measuring system electronics 2, according to a further embodiment of the invention, has at least one operational amplifier OP, for example, a FET or a CMOS operational amplifier. Furthermore, the first sensor element C1 is electrically connected to a (high-impedance) (voltage) input of the operational amplifier OP by means of the first and second connecting lines 401, 402, in particular forming a charge-to-voltage converter of the measuring system electronics 2, and the operational amplifier is configured to deliver the first electrical (measurement) voltage u1 at a (voltage) output (when the measuring system electronics is operating in the first operating mode). For this purpose, the operational amplifier OP can, for example, also have a (feedback) capacitor Cf which feeds back its (voltage) output to its (voltage) input, in particular a switched (feedback) capacitor, for example with a (feedback) capacitance which is not less than 0.1 pF and/or not more than 100 pF.

To provide the second electrical (measurement) voltage u2, the measuring system electronics 2, according to a further embodiment of the invention, has at least one (electronic) current source, for example, a switchable one. Furthermore, the second sensor element R1 is electrically connected to a (current) output of the current source via the third and fourth connecting lines 403, 404, and the current source is configured to supply the (measurement) current i2, in particular such that the (measurement) current is an impressed current or a current regulated to a setpoint. Instead of the aforementioned current source, the measuring system electronics 2 can, for example, also have at least one, possibly also switchable (electronic) voltage source VREF, which - as also schematically shown in Fig. 3 - is electrically connected to the second sensor element R1 via an output and by means of the third and fourth connecting lines 403, 404 and is configured to drive the (measurement) current i2 or to supply an (impressed) voltage driving the (measurement) current i2. Alternatively or additionally, the measuring system electronics 2 can further have at least one (reference) resistance element R2 having an electrical (reference) resistance, particularly at a temperature of 20°C, not less than 1000 Ω and/or not more than 10 kΩ, electrically connected to the second sensor element R1, particularly electrically connected in series with the second sensor element R1. In addition, the measuring system electronics 2 can be configured to detect and evaluate, during the first (current supply) time interval, an electrical third (reference) voltage u3 dependent on a voltage drop across the (reference) resistance element R2, in particular to digitize it and/or to determine (digital) third voltage measured values representing the reference voltage u3. Furthermore, the measuring system electronics can advantageously be configured to determine the (sensor) resistance of the second sensor element R1 based on the third (reference) voltage u3, for example based on the second and third voltages u2, u3 and the (reference) resistance and/or ratiometrically.

Not least for the aforementioned case that the connecting lines 401, 402, 403, 404 are at least partially unshielded and a smallest distance between at least one of the first and second connecting lines and at least one of the third and fourth connecting lines is less than 5 mm, at least one, in particular each, of the first and second connecting lines 401, 402 is (signal-)coupled to at least one, in particular each, of the third and fourth connecting lines 403, 404; this in particular capacitively and/or in such a way that the aforementioned, inter alia also by the third and fourth

The (measurement) current i2 flowing through the connecting lines 403, 404 or its temporal changes can or do cause (voltage) disturbances in the first and second measuring lines 401, 402, and thus in the first electrical (measurement) voltage u1. In order to minimize or avoid any interference voltages caused by such (signal) coupling from the third and/or fourth connecting lines 403, 404 into the first and/or second connecting lines 401, 402, in particular but also any associated measurement errors in measured values determined for the first measured variable x1, the measuring system electronics 2 in the measuring system according to the invention is further configured not to output a (qualified) measured value XM for the secondary and/or first primary (process) measured variables determined on the basis of the first (measurement) voltage detected during the fourth and fifth (transition) time intervals, or not to determine a measured value for the secondary and/or first primary (process) measured variables based on the first electrical (measurement) voltage present during the fourth and fifth (transition) time intervals. Alternatively or additionally, the measuring system electronics in the measuring system according to the invention can also be configured to determine (qualified) measured values for the secondary and/or first primary (process) measured variables during the fourth (transition) time interval based on a first (measurement) voltage u1 previously acquired during the second time interval and/or to determine (qualified) measured values for the secondary and/or first primary (process) measured variables during the fifth (transition) time interval based on a first (measurement) voltage u1 previously acquired during the first time interval t1. According to a further embodiment of the invention, the measuring system electronics 2 is also configured to determine (qualified) measured values XM for the secondary and/or first primary (process) measured variables based on a first (measurement) voltage u1 previously acquired during the first time interval t1. first (measurement) voltage u1, in particular to determine and output it. Alternatively, if necessary, for example in order to reduce the converted electrical power and/or to avoid measurement errors, the measuring system electronics 2 can also be configured, for example, not to output a (qualified) measured value for the secondary and/or first primary (process) measured variable x1 determined based on the first (measurement) voltage u1 detected during the (current supply) time interval t1 and/or not to determine a measured value for the secondary and/or first primary (process) measured variables based on the first electrical (measurement) voltage u1 present during the (current supply) time interval. Furthermore, the measuring system electronics 2 can advantageously also be configured to determine one or more (digital) measured values for the second primary (process) measured variable x2 based on at least the second electrical (measurement) voltage u2, in particular based on both the second electrical (measurement) voltage u2 and the first electrical (measurement) voltage u1 determined in the manner described above, in particular to output them as qualified measured values of the measuring system 2.

For the (leakage-free or fluid-tight) connection of the measuring system to a process containing or conducting the medium, in particular in such a way that an operative relationship (resulting in measuring effects) between the (fluid) medium and at least the first and second sensor elements can be established or is established during operation of the measuring system, the measuring system according to a further embodiment of the invention further comprises a (process) coupling element 11, formed for example by means of a membrane and/or a sleeve and/or a plate. According to a further embodiment of the invention, the coupling element consists at least partially, for example completely, of metal, in particular a (stainless) steel and/or a nickel-based alloy. The coupling element 11 is particularly designed to be contacted by the aforementioned medium (during operation of the measuring system), for example to be flowed against and/or around; This is particularly the case in such a way that the (process) coupling element 11 has a (coupling element) temperature dependent on a (measuring medium) temperature of the measuring medium and/or an (elastic) expansion dependent on a (measuring medium) pressure. Accordingly, according to a further embodiment, the aforementioned coupling element is also particularly configured to react to a change in a (measuring medium) pressure of the measuring medium with an expansion, for example, also biaxial and/or elastic, and to a change in a (measuring medium) temperature of the measuring medium with a change in a (coupling element) temperature, for example also in such a way that the (coupling element) temperature of the coupling element deviates from a stationary (measuring medium) temperature of the measuring medium by less than 2 K (Kelvin). For example, the coupling element 11 can be configured to be inserted at least partially into a lumen (3') of a tube (3) (serving to convey a fluid medium), in particular through an opening (3a) in a tube wall (3*) surrounding the lumen into the lumen and fixed (removably) to the same tube wall. Not least for the aforementioned case, that the measuring system is designed as a vortex flow meter, the coupling element 11 can, as also schematically shown in Fig. 2, be designed, for example, as a sensor flag protruding into the lumen 3' of the aforementioned tube 3. Alternatively, the coupling element 11 can, for example, also be configured to be inserted at least partially into a lumen of a container (used to guide a fluid measuring substance), in particular a tank, in particular through an opening in a container wall enclosing the lumen into the lumen and to be fixed (removably) to the same container wall. For the aforementioned case in which the measuring system has a connecting piece 30, the coupling element 11 can, for example, also be arranged partially within the connecting piece and/or be (mechanically) connected to the connecting piece, for example at a piece end distal to the aforementioned electronics housing 20. According to a further embodiment of the invention, the coupling element 11 and the first sensor element C1 are at least mechanically coupled to one another, or the first sensor element C1 is designed as an (integral) component of the coupling element 11; this is particularly the case in such a way that (during operation of the measuring system) the first electrical (measurement) voltage u1 is dependent at least on the strain of the coupling element 11, or that a change in the strain of the coupling element 11 causes a change in the first electrical (measurement) voltage u1. For the aforementioned case in which the first sensor element 11 is formed by means of at least one (measurement) capacitor designed as a plate capacitor, at least one (capacitor) electrode of the (measurement) capacitor, for example a movable (capacitor) electrode, can be mechanically connected to the coupling element or formed by means of the coupling element. According to a further advantageous embodiment of the invention, the coupling element 11 and the second sensor element R1 can also be coupled to one another at least thermally, in particular both thermally and mechanically; this in particular also in such a way that the second electrical (measurement) voltage u2 is dependent at least on a (coupling element) temperature of the coupling element or that a change in a (coupling element) temperature of the coupling element causes a change in the electrical (sensor) resistance of the second sensor element R1.

Claims

PATENT CLAIMS 1. A measuring system for measuring a (time-varying) first primary (process) measured variable (x1), in particular a (static) pressure of a fluid medium (conducted in a line and/or held in a container) and/or a temporal change in the same pressure, as well as a (time-varying) second primary (process) measured variable (x2) different from the first primary (process) measured variable, in particular a temperature of a fluid medium (conducted in a line), and/or for measuring a (time-varying) secondary (process) measured variable (y1) derived from at least one of the first and second primary (process) measured variables, in particular a mass flow of a fluid medium conveyed in a line or a fill level of a fluid medium held in a container, which measuring system comprises: - a measuring system electronics (2), in particular one operated with a maximum electrical power of less than 1 W (watt) and/or connected to a (4-20 mA) 2-wire line; - at least one, in particular capacitive and/or passive, first sensor element (C1) for detecting the first primary (process) measured variable; - at least one, in particular resistive, passive second sensor element (R1) for detecting the second primary (process) measured variable; - and first, second, third and fourth, in particular (at least) partially unshielded and/or not twisted together, electrical connecting lines (401, 402, 403, 404); - wherein the first sensor element is electrically connected to the measuring system electronics (2) by means of the first and second connecting lines (forming a first measuring channel of the measuring system), in particular with the interposition of a feedthrough (50); - wherein the second sensor element is electrically connected to the measuring system electronics by means of the third and fourth connecting lines (forming a second measuring channel of the measuring system), in particular with the interposition of a feedthrough (50), - and wherein at least one, in particular each, of the first and second connecting lines (401, 402) is (signal-)coupled to at least one, in particular each, of the third and fourth connecting lines (403, 404), in particular capacitively, in particular by a smallest distance between at least one of the first and second connecting lines and at least one of the third and fourth connecting lines being less than 5 mm; - wherein the first sensor element (C1) is configured, in particular in conjunction with the measuring system electronics, to generate and/or adjust a first electrical (measurement) voltage (u1) dependent on the first primary (process) measured variable (x1), - and wherein the second sensor element (R1) has an electrical (sensor) resistance, in particular at a temperature of 20°C, of not less than 90 Ω and/or not more than 1.1 kΩ, and is designed to follow a change in the second primary measured variable (x2) with a change in the same resistance; - wherein the measuring system electronics are configured to temporarily detect and evaluate the first electrical (measurement) voltage (u1), in particular to digitize it and/or to determine (digital) first (voltage) measured values (Xu1) representing the (measurement) voltage; - the measuring system electronics are set up, - temporarily energising the second sensor element to temporarily cause a voltage drop across the second sensor element, - namely, during a predetermined, in particular not less than 10 ms, first (energization) time interval (t1), to drive an electrical (measurement) current (i2) through the second sensor element and the third and fourth connecting lines, in particular an impressed and/or constant and/or having a maximum current of not less than 0.1 mA and/or converting a maximum electrical power of not less than 0.4 mW in the second sensor element - and during a second time interval (t2) preceding the first (energization) time interval and a third time interval (t3) following the first (energization) time interval, not to energize the second sensor element or to drive no (measurement) current through the second sensor element and the third and fourth connecting lines, such that the (measurement) current at least during a fourth time interval (immediately) following the second time interval and preceding the first (energization) time interval, in particular lasting not less than 1 ps (microsecond). (transition) time interval (t4) has a (rising) first current edge, in particular with a current rise rate that is at least temporarily and/or on average (arithmetic time) not less than 0.1 mA/ps, and that the (measurement) current has a (falling) second current edge, in particular with a current fall rate that is at least temporarily and/or on average (arithmetic time) not less than 0.1 mA/ps, at least during a fifth (transition) time interval (t5) that (immediately) follows the first (current supply) time interval and (immediately) precedes the third time interval, in particular lasting not less than 1 ps (microsecond), - and wherein the measuring system electronics are configured to detect and evaluate a second electrical (measurement) voltage (u2) dependent on the voltage drop across the second sensor element during the first (current supply) time interval (t1), in particular to digitize it and/or to determine (digital) second (voltage) measured values (Xu2) representing the (measurement) voltage; - wherein the measuring system electronics are configured to determine, based on at least the first electrical (measurement) voltage (u1), in particular based on both the first electrical (measurement) voltage and the second electrical (measurement) voltage (u2), one or more (digital) measured values for the first primary (process) measured variable (x1) and/or one or more (digital) measured values for the secondary (process) measured variable, in particular to determine them and output them as qualified measured values (XM) of the measuring system, - and wherein the measuring system electronics, in particular to avoid measurement errors caused by (signal) coupling from the third and/or fourth connecting lines into the first and/or second connecting lines in measured values determined for the first measured variable (x1), are configured: - not to output a (qualified) measured value for the first primary (process) measured variable based on the first (measurement) voltage (u1) recorded during the fourth and fifth (transition) time intervals, - and/or not to determine a measured value for the first primary (process) measured variable (x1) based on the first electrical (measurement) voltage (u1) applied during the fourth and fifth (transition) time intervals, - and/or not to output a (qualified) measured value for the secondary (process) measured variable (y1) based on the first (measurement) voltage (u1) recorded during the fourth and fifth (transition) time intervals, - and/or not to determine a measured value for the secondary (process) measured variable (y1) based on the first electrical (measurement) voltage (u1) present during the fourth and fifth (transition) time intervals, - and/or during the fourth (transition) time interval, to determine (qualified) measured values (XM) for the first primary (process) measured variable (x1) and/or for the secondary (process) measured variable (y1) based on a first (measurement) voltage previously recorded during the second time interval, - and/or during the fifth (transition) time interval to determine (qualified) measured values (XM) for the first primary (process) measured variable (x1) and/or for the secondary (process) measured variable (y1) based on a first (measurement) voltage (u1) previously recorded during the first time interval (t1). 2. Measuring system according to claim 1, wherein the measuring system electronics are arranged: - not to output a (qualified) measured value for the first primary (process) measured variable based on the first (measurement) voltage recorded during the (current supply) time interval, - and/or not to determine a measured value for the first primary (process) measured variable based on the first electrical (measurement) voltage applied during the (current supply) time interval, - and/or not to output a (qualified) measured value for the secondary (process) measured variable based on the first (measurement) voltage recorded during the (current supply) time interval, - and/or not to determine a measured value for the secondary (process) measured variable based on the first electrical (measurement) voltage applied during the (energization) time interval. 3. Measuring system according to claim 1, wherein the measuring system electronics is arranged: - to determine (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable based on a first (measurement) voltage recorded during the first time interval; - and/or to output (qualified) measured values for the first primary (process) measured variable and/or for the secondary (process) measured variable based on a first (measurement) voltage recorded during the (current supply) time interval. 4. Measuring system according to one of the preceding claims, - wherein the first sensor element has an electrical (sensor) capacitance, in particular at a temperature of 20°C, of not less than 10 pF and/or not more than 100 pF, and is configured to follow a change in the first primary (process) measured variable with a change in the same (sensor) capacitance, - and wherein the measuring system electronics are configured to electrically charge or keep charged the capacitance of the first sensor element, in particular at least during the second and third time intervals, in order to effect the first electrical (measurement) voltage. 5. Measuring system according to the preceding claim, wherein the first electrical (measurement) voltage is (substantially) proportional to an electrical charge of the (sensor) capacitance of the first sensor element. 6. Measuring system according to one of the preceding claims, wherein the measuring system electronics are configured to determine (voltage) measured values representing the first (measurement) voltage, in particular to determine them and to store them in a (volatile) digital data memory. 7. Measuring system according to the preceding claim, wherein the measuring system electronics are configured to determine one or more measured values for the second primary (process) measured variable using one or more (voltage) measured values representing the first (measurement) voltage. 8. Measuring system according to one of the preceding claims, wherein the measuring system electronics are configured to determine (voltage) measured values representing the second (measurement) voltage, in particular to determine them and to store them in a (volatile) digital data memory. 9. Measuring system according to the previous claim, - wherein the measuring system electronics are configured to determine one or more measured values for the first primary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage; and/or - wherein the measuring system electronics are configured to determine one or more measured values for the first secondary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage; and/or - wherein the measuring system electronics are configured to determine one or more measured values for the second primary (process) measured variable using one or more (voltage) measured values representing the second (measurement) voltage. 10. Measuring system according to one of the preceding claims, wherein the measuring system electronics are configured to determine, based on the second electrical (measurement) voltage, one or more (digital) measured values for the second primary (process) measured variable, in particular for determining at least one measured value for the first primary (process) measured variable and/or the secondary (process) measured variable, each serving as an auxiliary measured value, in particular to determine and store them in a (volatile) digital data memory. 11. Measuring system according to the preceding claim, wherein the measuring system electronics are configured to determine one or more measured values for the first primary (process) measured variable using one or more measured values for the second primary (process) measured variable. 12. Measuring system according to one of the preceding claims, wherein the measuring system electronics are configured to determine one or more (digital) measured values for the second primary (process) measured variable based on at least the second electrical (measurement) voltage, in particular based on both the second electrical (measurement) voltage and the first electrical (measurement) voltage, in particular to determine them and output them as qualified measured values of the measuring system. 13. Measuring system according to one of the preceding claims, - wherein each of the first and second connecting lines is at least partially, in particular completely, unshielded; and/or - wherein each of the third and fourth connecting lines is at least partially, in particular completely, unshielded; and/or - wherein each of the first and second connecting lines is formed at least partially by means of a conductor track arranged on a (flexible) printed circuit board; and/or - wherein each of the third and fourth connecting lines is formed at least partially by means of a conductor track arranged on a (flexible) printed circuit board; and/or - wherein each of the first, second, third and fourth connecting lines is formed at least partially by means of a conductor track arranged on one and the same (flexible) printed circuit board; and/or - wherein the first and second connecting lines run parallel to each other at least in sections; and/or - wherein the third and fourth connecting lines run parallel to each other at least in sections; and/or - wherein the first and third connecting lines run parallel to each other at least in sections; and/or - wherein the first and fourth connecting lines run parallel to each other at least in sections; and/or - wherein the first, second, third and fourth connecting lines run parallel to one another at least in sections. 14. Measuring system according to one of the preceding claims, - wherein the measuring system electronics comprises at least one operational amplifier, in particular a FET or a CMOS operational amplifier; - wherein the first sensor element is electrically connected to a (high-impedance) (voltage) input of the operational amplifier by means of the first and second connecting lines, in particular by forming a charge-voltage converter of the measuring system electronics; - and wherein the operational amplifier is configured to supply the first electrical (measurement) voltage at a (voltage) output (when the measuring system electronics are operating in the first operating mode). 15. Measuring system according to the preceding claim, wherein the operational amplifier has a (feedback) capacitor (Cf) which feeds back its (voltage) output to its (voltage) input, in particular a switched (feedback) capacitor. 16. Measuring system according to the preceding claim, wherein the (feedback) capacitor (Cf) has a (feedback) capacitance which is not less than 0.1 pF and/or not more than 100 pF. 17. Measuring system according to one of claims 1 to 16, - wherein the measuring system electronics comprises at least one, in particular switchable, (electronic) current source; - wherein the second sensor element is electrically connected to a (current) output of the current source by means of the third and fourth connecting lines; - and wherein the current source is arranged to supply the (measuring) current. 18. Measuring system according to one of claims 1 to 16, - wherein the measuring system electronics has at least one, in particular switchable, (electronic) voltage source; - wherein the second sensor element is electrically connected to an output of the voltage source by means of the third and fourth connecting lines; - and wherein the voltage source is arranged to drive the (measuring) current. 19. Measuring system according to one of the preceding claims, wherein the measuring system electronics are configured to determine the sensor resistance of the second sensor element based on the second (measurement) voltage. 20. Measuring system according to one of the preceding claims, wherein the measuring system electronics comprises at least one (reference) resistance element having an electrical (reference) resistance, in particular at a temperature of 20°C (degrees Celsius) not less than 90 Ω (ohms) and/or not more than 1.1 kΩ (kiloohms), which is electrically connected to the second sensor element, in particular electrically connected in series with the second sensor element. 21 . Measuring system according to the preceding claim, wherein the measuring system electronics are configured to detect and evaluate, in particular to digitize and/or to determine (digital) third voltage measurement values representing the reference voltage, an electrical third (reference) voltage dependent on a voltage drop across the (reference) resistance element during the first (current supply) time interval. 22. Measuring system according to the preceding claim, wherein the measuring system electronics are configured to determine the (sensor) resistance of the second sensor element based on the third (reference) voltage, in particular based on the second and third voltages and the (reference) resistance and/or ratiometrically. 23. Measuring system according to one of the preceding claims, further comprising: at least one (electrical) feedthrough (50), in particular explosion-pressure-resistant (Ex-d) and/or compliant with the international standard IEC 60079-1:2014. 24. Measuring system according to the previous claim, - wherein the first, second, third and fourth connecting lines are guided in sections within the bushing (50); and/or - wherein the feedthrough is electrically connected to the first, second, third and fourth connecting lines, in particular by means of unshielded (connecting) pins; and/or - wherein the bushing is connected between the first, second, third and fourth connecting lines. 25. Measuring system according to one of the preceding claims, further comprising: an electronics (protective) housing (20) for the measuring system electronics (2), in particular an electronics housing which is explosion-proof (Ex-d) and/or compliant with the international standard IEC 60079-1:2014. 26. Measuring system according to the preceding claim, further comprising: a (housing) connection piece (30), in particular detachably connected to the electronics (protective) housing by means of a flange connection and/or tubular. 27. Measuring system according to the preceding claim, wherein the first, second, third and fourth connecting lines are guided at least partially within the (housing) connection piece, in particular running parallel to one another at least in sections. 28. Measuring system according to one of the preceding claims, further comprising: a (process) coupling element (11), in particular formed by means of a membrane and/or a sleeve and/or a plate, which is designed to be contacted by a fluid medium (during operation of the measuring system), in particular to be flowed against and/or around, in particular in such a way that the (process) coupling element (11) has a (coupling element) temperature dependent on a (measured substance) temperature of the measured substance and/or that the (process) coupling element has an (elastic) expansion dependent on a (measured substance) pressure. 29. Measuring system according to the previous claim, - wherein the coupling element is configured to react to a change in the (measuring medium) temperature of the measuring medium with a change in the (coupling element) temperature, in particular such that the (coupling element) temperature of the coupling element deviates from a stationary (measuring medium) temperature of the measuring medium by less than 2 K (Kelvin); and/or - wherein the coupling element is configured to react to a change in the (measuring medium) pressure of the measuring medium with a, in particular biaxial and/or elastic, expansion; and/or - wherein the coupling element is designed to be inserted at least partially into a lumen of a tube (serving to guide a fluid measuring substance), in particular through an opening in a tube wall surrounding the lumen into the lumen and to be fixed (removably) to the same tube wall; and/or - wherein the coupling element is designed to be inserted at least partially into a lumen of a container (serving to convey a fluid measuring substance), in particular a tank, in particular through an opening in a container wall surrounding the lumen into the lumen and to be fixed (removably) to the same container wall; and/or - wherein the coupling element consists at least partially, in particular completely, of metal, in particular a (stainless) steel and/or a nickel-based alloy. 30. Measuring system according to claim 28 or 29, wherein the coupling element and the first sensor element are at least mechanically coupled to one another, in particular in such a way that the first electrical (measurement) voltage is dependent on the strain of the coupling element or that a change in the strain of the coupling element causes a change in the first electrical (measurement) voltage. 31. Measuring system according to claim 28 or 29, wherein the first sensor element is an (integral) component of the coupling element, in particular such that the first electrical (measurement) voltage is dependent on the strain of the coupling element or that a change in the strain of the coupling element causes a change in the first electrical (measurement) voltage. 32. Measuring system according to claim 26 in conjunction with one of claims 28 to 31, - wherein the coupling element, in particular at a nozzle end distal to the electronics housing, is (mechanically) connected to the connecting nozzle; and/or - wherein the coupling element (11) is arranged partially within the connecting piece (30). 33. Measuring system according to one of the preceding claims, wherein the first sensor element (C1) is formed by means of at least one (measuring) capacitor, in particular designed as a plate capacitor, in particular with a (capacitor) electrode geometry changing as a function of the first primary measured variable and/or with a dielectric changing as a function of the first primary measured variable. 34. Measuring system according to claim 33 in conjunction with one of claims 28 to 32, wherein at least one, in particular movable, (capacitor) electrode of the (measuring) capacitor is mechanically connected to the coupling element or is formed by means of the coupling element. 35. Measuring system according to one of claims 28 to 33, wherein the coupling element (11) and the second sensor element (R1) are coupled to one another at least thermally, in particular both thermally and mechanically, in particular in such a way that the second electrical (measurement) voltage is dependent on a (coupling element) temperature of the coupling element or that a change in a (coupling element) temperature of the coupling element causes a change in the electrical (sensor) resistance of the second sensor element. 36. Measuring system according to one of the preceding claims, wherein the second sensor element (R1) is formed by means of at least one platinum measuring resistor, in particular a Pt100 and/or a Pt1000. 37. Measuring system according to one of the preceding claims, - wherein the measuring system electronics are configured to determine, based on at least the first electrical (measurement) voltage, measured values for a frequency (serving as a secondary measured variable) of at least temporarily periodic pressure fluctuations within a fluid medium, in particular of pressure fluctuations within a Karman vortex street formed in a flow of the medium; and/or - wherein the measuring system electronics are configured to determine measured values for a (measuring medium) temperature (serving as a second primary measured variable) of a, in particular, flowing, fluid measuring medium based on at least the second electrical (measuring) voltage; and/or - wherein the measuring system electronics are configured to determine measured values for a (static) pressure of a (flowing) fluid medium (serving as the first primary measured variable) based on the first and second electrical (measurement) voltages; and/or - wherein the measuring system electronics are configured to determine measured values for a volume flow of a flowing (fluid) medium (serving as a secondary measured variable) based on the first and second electrical (measurement) voltages; and/or - wherein the measuring system electronics are configured to determine measured values for a mass flow of a flowing (fluid) medium (serving as a secondary measured variable) based on the first and second electrical (measurement) voltages. 38. Use of a measuring system according to one of the preceding claims for measuring both a first primary (process) measured variable, in particular a time-varying (static) pressure, and a second primary (process) measured variable (different from the first measured variable), in particular a time-varying temperature, of a fluid measuring substance (conducted in a line or held in a container).