HK1119765B - Method of monitoring and/or determining the condition of a force-measuring device, and force-measuring device - Google Patents

Description

Method for monitoring and/or determining the condition of a force-measuring device and force-measuring device

Technical Field

The invention relates to a method for monitoring and/or determining the condition of a force-measuring device, wherein the force-measuring device has at least one housing with an interior space and at least one force-measuring cell mounted in the interior space of the at least one housing, and also has an electronics section for measuring and/or estimating signals; the invention also relates to a force-measuring device operable to implement the method.

Background

In view of the fact that in the environment in which force-measuring devices are used, these can in some cases be made very difficult to control, a variety of force-measuring devices, in particular gravimetric measuring instruments (instruments), (for example balances or retail scales used in particular in laboratories or in manufacturing plants), thermogravimetric measuring instruments, gravimetric measuring instruments for moisture, weighing modules for storage tank installations (storage tank installations) and reaction vessels, weighing modules and weighing module installations of tank lines and packaging lines, and similar torque-measuring devices and accelerometers, are protected by taking effective measures against non-ionising types of radiation, in particular electromagnetic fields. These protective measures include: the force-measuring device is adapted to the environment in which it is used, and meets the requirements of specific regulations in terms of radiation resistance and the like, such as different exposure levels described in the specification standard EN45501 or IEC 61326.

For example, a force-measuring cell for a weighing module is mounted in a metal housing made of steel. The operation of a force-measuring cell enclosed in a housing of this type will not present problems as long as the housing is such that the radiation effects impairing the measurement signal remain sufficiently far away from the force-measuring cell and the measurement electronics, or in other words, the penetration of high-frequency electromagnetic fields into the interior of the housing is prevented.

However, in environments where the gravimetric measuring instrument, the weighing module or the balance is exposed to unusually high magnetic field strengths, it may also occur in certain cases that certain high-frequency electromagnetic fields are able to penetrate through the smallest openings and gaps into the interior of the housing and reduce the measurement accuracy of the weighing module to an interesting extent.

Errors in the measurement results can lead to inaccurate weighing processes. If such measuring devices are integrated in industrial installations with a high degree of automation, a misalignment of the measuring devices may even lead to the production of a defective product.

In the case of retail scales (retail store scale) used to sell goods, the cost to the consumer is made higher or lower if the product is weighed inaccurately or with a completely wrong weighing result.

As a result of operational errors and/or negligence of the telecommunications equipment, it can occur that the high-frequency electromagnetic field penetrates the interior of the housing and increases the radiation density in the interior space of the housing, so that the measurement accuracy of a part of the force-measuring cell or of the components of the signal processing section or of the measurement electronics is reduced. The term "telecommunication device" here comprises a multitude of possible devices based on the principle of electromagnetic radio transmission, such as mobile phones, cordless phones, radio communication devices, wireless data communication, RFID devices, etc.

It is also conceivable that one wishes to vary the measurement result of the force-measuring device by means of intentional control of the high-frequency radiation.

Disclosure of Invention

It is therefore an object of the present invention to propose an improved method of monitoring and/or determining the condition of a force-measuring device, and to propose a force-measuring device capable of operating under such an improved method.

In a method for monitoring and/or determining the condition of a force-measuring device having at least one housing with an interior space and at least one force-measuring cell mounted in the interior space of the at least one housing, the device also has an electronic measuring and/or signal processing section which can also be located outside the housing, and has at least one sensor for high-frequency electromagnetic field detection arranged in the interior space of the housing and/or at least one sensor for high-frequency electromagnetic field detection arranged outside the housing. Determining, by the sensor, at least one parameter characteristic of the high frequency electromagnetic field when the magnetic field is present; comparing at least one value of said determined parameter with at least one threshold value; and in case the value of the parameter exceeds a threshold value, a responsive operation of the force-measuring device is triggered.

The term "electromagnetic field" as used herein has a general meaning and also includes electromagnetic radiation, in particular of the type as emitted by a telecommunication device.

For the user of the force-measuring device, this method offers the advantage that in the presence of high-frequency electromagnetic fields of very high magnetic field strength or in particular of potentially disturbing frequencies, factors influencing the force-measuring device can be identified and the output of erroneous measurement results prevented and in some cases information can be given about the presence of a fault. Thus, in the case of weighing, in particular weighing, it is possible to prevent force measurements from being carried out which would lead to erroneous measurement results. In particular, the device is applied in the case of a measurement parameter value (in particular the magnetic field strength) exceeding a predeterminable threshold value. The user of the force-measuring device is provided with the possibility of identifying a problem, which can be eliminated if necessary, in order to achieve a correct measurement result. In the method according to the invention, an electromagnetic field in a frequency range of the telecommunication device is determined using at least one sensor, wherein the measurable parameters comprise the frequency, the frequency range and/or the magnetic field strength of the high-frequency electromagnetic field.

In a preferred embodiment, the force measuring device comprises: a computer unit and a storage unit; and the computer unit executes a program which compares the measured value of the magnetic field strength with at least one threshold value which can be preset and changed in the memory unit and/or the computer unit. The measured values can in particular be stored in a memory unit for further processing in a computer unit. The force-measuring device preferably comprises a clock which is accessible by the computer unit, wherein the program assigns a time value to each measurement value and stores the measurement value and the time value in pairs in the memory unit. So that the stored values can generally be tracked in a timely manner for potentially problematic events. If, for example, a service technician estimates a time series of values of the magnetic field strength or studies out how the measured strength values depend on the frequency or frequency range of the electromagnetic field, the trackable range can be widened, so that information about the environment of the force-measuring device can be obtained and, if necessary, the measurement can be initiated to eliminate problematic factors.

The term "computer unit" includes all signal processing elements, such as analog circuits, digital circuits, integrated circuits, processors, computers, etc., which can compare the sensor signal generated by the sensor with values stored or set in advance in the computer unit. These values, such as in particular the maximum values, the threshold values and the usage limits, can be based on adjustment criteria determined by comparative measurements or specified by the manufacturer of the force-measuring cell, for example national or international code standards. If necessary, the force-measuring device can also have a plurality of computer units, for example, a dedicated computer unit which can be used independently for each sensor installed.

If the force-measuring device comprises an output unit, in particular a display screen and/or at least one light-emitting diode and/or a printer, as an indication and operating unit, the method preferably comprises the following steps: the output unit emits a signal depending on the measured value of the parameter characterizing the high-frequency electromagnetic field. The user of the force-measuring device is therefore always informed about the environmental conditions of the high-frequency electromagnetic field.

The term "output unit" denotes a transmission, reporting and alarm system based on an analog or digital working principle capable of representing the sensor signals generated by the sensor and/or the sensor signals generated by the output signal of the computer unit by a suitable means (e.g. sound, light, vibration, electronic signals, electromagnetic pulses, digital output, etc.) or of transmitting such signals to other instruments, such as another output unit, a higher level system, a terminal, etc. Thus, the output unit may also be a transponder or a transmitter that transmits the sensor signal and/or the output signal to e.g. a portable instrument. The output unit may issue an alarm to the user, send an event to the storage unit, or even send an alarm message directly to the vendor or its service representative, e.g. via the internet.

In the case of a parameter value exceeding the at least one threshold value, one or more repeated measurements can then be carried out, in particular if the force-measuring device or a computer unit connected thereto classifies the parameter value characterizing the high-frequency magnetic field as being sufficient to influence the stability of the measurement signal. Alternatively or simultaneously, an alarm may be activated and/or a measurement process may be terminated and/or prevented. As a possible further response of the measuring electronics or force-measuring device, it is also possible to switch off the operational readiness indicator. In terms of traceability, it is advantageous if the parameter values characterizing the high-frequency electromagnetic field are stored in a log file of the storage unit together with the time values.

If, in a force-measuring device capable of calibration, in particular in a balance, a threshold value is exceeded at this time, no definitive calibration is carried out, which is carried out only after the value in question subsequently returns to a range below the threshold value.

In an advantageous step of the method for the functional checking of at least one sensor, the sensor signal transmitted by the sensor to the computer unit is checked at least periodically in the computer unit by comparing it with a verification value or a verification tolerance value stored in the memory unit. If the sensor signal is found to differ from these verification values or deviate from predetermined verification tolerance values, an event is registered and transmitted to the output unit as an error measurement. Thereby increasing the safety of the method.

If a high-frequency electromagnetic field is present, various solutions are conceivable for determining at least one parameter characterizing such a field. In particular, the signal may be tapped from an electronic measuring part and/or the electromagnetic field strength inside or outside the housing is measured and/or preferably the signal may be tapped from a cable connection of a power supply cable or a data transmission cable.

In a preferred further development of the method, there is available at least one additional sensor, such as in particular a temperature sensor, in addition to the at least one sensor for the detection of the high-frequency electromagnetic field. In this way, the values determined by the additional sensors can be correlated with parameter values characterizing the high-frequency electromagnetic field and can be taken into account together with a crossing (crossing) or deviation value from a threshold value for the evaluation of the operation to be carried out in the electronic measuring section.

In a particular solution, the force-measuring device, or any signal or signals of the measuring and/or processing electronics, can also be used independently to detect the high-frequency electromagnetic field, since in most cases in the presence of disturbances the high-frequency electromagnetic field will be superposed on the signal of the force-measuring device, so that no dedicated physical sensor is required. In view of this possibility, the sensor for high-frequency electromagnetic field detection should be understood in the ordinary meaning of terms.

In a further embodiment of the invention, the time profile (profile) of the force measurement signal over the past time period can also be registered, and the intersection of the parameter values determined therefrom with threshold values can be taken into account for the evaluation of the operation to be carried out in the electronic measuring unit.

Preferably, in addition to the threshold value triggering the operation of the measuring electronics, a lower, second threshold value can also be stored in the computer unit as a modified value, wherein an alarm signal is emitted in the output unit when the second threshold value is exceeded.

The invention also relates to a force-measuring device suitable for implementing the method of the invention, the device comprising: at least one housing having an interior space, and at least one force cell mounted in the interior space of the at least one housing, and the apparatus further comprises: an electronic measurement and/or processing section. The force-measuring device is equipped with at least one sensor for high-frequency electromagnetic field detection mounted in the interior space of the housing and/or at least one sensor for high-frequency electromagnetic field detection arranged outside the housing.

Preferably, the sensor is connected to measurement and/or processing electronics, wherein a responsive operation of the force-measuring device can be initiated if the sensor for high-frequency electromagnetic field detection detects a value exceeding at least one predetermined threshold value.

In a preferred embodiment of the force-measuring device, the force-measuring device is equipped with a computer unit and a memory unit, wherein the computer unit is operable to execute a program, to initiate a responsive operation of the force-measuring device if the sensor for high-frequency electromagnetic field detection detects a value exceeding at least one predetermined threshold value, and/or to store the measured value in the memory unit for further processing.

The sensor for high-frequency electromagnetic field detection may be configured as a circuit for tapping signals of the electronic measuring and/or processing section and/or in the form of a broadband and/or narrowband electromagnetic field sensor and/or an antenna and/or in the form of an inductive and/or capacitive coupling loop and/or an antenna arranged near a cable, in particular a power supply cable for supplying power to the force-measuring cell and/or the electronic measuring section or near a connector cable.

The sensor can be mounted inside the housing, in particular on the inner wall of the force-measuring cell housing or on the force-measuring cell, but also, for example, on a circuit board of the signal processing circuit. Preferably, the sensor is placed in the vicinity of an element sensitive to electromagnetic radiation. For example, in the case of a system based on electromagnetic force compensation, the sensor may be located close to the coil, or may be a part of the coil or the coil itself, or may also be a position sensor element of a device based on electromagnetic force compensation.

In a further preferred embodiment of the force-measuring device, it can be seen that, in addition to the at least one sensor for high-frequency electromagnetic field detection, a further sensor is arranged in the interior space of the housing or on a housing wall for detecting a line power peak occurring in a power supply which supplies the force-measuring cell. In addition to the at least one sensor for high-frequency electromagnetic field detection, further sensors are arranged in the interior space of the housing or on the housing wall for other parameter detection, in particular temperature.

In other preferred embodiments of the invention, the computer unit and/or the output unit are connected to the at least one sensor by means of a wireless connection or wire bonding.

In a further preferred embodiment of the invention, the at least one sensor for high-frequency electromagnetic field detection is of the type comprising a memory module and/or a measuring transducer.

The sensors of the force-measuring device for high-frequency electromagnetic field detection can be of a construction in which a memory module and/or a measuring transducer and/or a transmitter are integrated in each sensor.

Drawings

The details of the method according to the invention and of the force-measuring device according to the invention are made clear from the description of the embodiments shown in the simply illustrated drawings, in which:

FIG. 1 shows the principle of a force-measuring cell based on electromagnetic force compensation from the side;

FIG. 2 shows schematically in a sectional view a force-measuring device in the form of a balance having a housing with an interior space and a force-measuring cell arranged in the housing, wherein the interior space comprises at least one sensor operable to perform the method according to the invention;

FIG. 3 schematically shows, in cross-section, a force-measuring device in the form of a weighing module for an oil reservoir, said force-measuring device having a housing with an interior space and a force-measuring cell arranged in the housing, wherein the interior space comprises at least one sensor operable to perform the method according to the invention, which sensor is connected to an output unit arranged outside the housing by means of a connecting device;

FIG. 4 shows, in a first configuration, a block diagram of a force-measuring device with at least one sensor for detecting high-frequency electromagnetic fields;

FIG. 5 shows, in a second configuration, a block diagram of a force-measuring device with at least one sensor for detecting high-frequency electromagnetic fields;

FIG. 6 shows, in a third configuration, a block diagram of a force-measuring device with at least one sensor for detecting high-frequency electromagnetic fields;

FIG. 7 shows, in a fourth configuration, a block diagram of a force-measuring device with at least one sensor for detecting high-frequency electromagnetic fields; and

FIG. 8 shows, in a fifth configuration, a block diagram of a force-measuring device with at least one sensor for detecting high-frequency electromagnetic fields.

Wherein the reference numbers are as follows:

1, 11 fixed part

2, 12 load receiving part

4 guide part

5 Flexible shaft

6 lever

7 Flexible fulcrum

8, 18 lever arms

9 connecting element

10, 110, 210 force cell

13 middle part

14 force transmission rod

15 cantilever

16 permanent magnet

17 air gap

19 coil

20, 120, 220 casing

21 casing mounting support part

22 transition hole

23 photoelectric measuring device

24 broadband sensor for detecting high frequency electromagnetic field

30 load receiver

40 force measuring cell

41 analog electronic module

42 digital electronic module

43 computer unit

44 interface

45 output unit

46, 146 sensor for detecting high frequency electromagnetic field

47, 147 electronic processing module

48 load receiver

50 sensor

51 computer unit connection

52 output connection

53 estimation program

56, 156 sensors for tapping high frequency signals

57, 157 electronic processing module

60 computer unit

62 connection from computer unit to output unit

70 light emitting diode used as output unit

80, 280 inner space

100, 200 force measuring device

202 transmitter

203 measurement converter

204-segment coupler

205 bus system

206 computer unit/host computer (lead computer)

207 output unit/host computer output unit

208 operating program

230 container feet

231 base

250 sensor for electromagnetic radiation

251 other sensors for electromagnetic radiation

252 wire connection

253 radio connection

254 weighing signal connection

290 stable sensor

Detailed Description

In a very simplified schematic representation, fig. 1 shows a force-measuring cell 10 of a type suitable for use in the field of weighing technology, in particular in balances, operating according to the principle of electromagnetic force compensation. The force-measuring cell 10 comprises a force-transmitting mechanism with a parallel-guiding system having a stationary part 1 and a vertically movable load-receiving part 2, wherein the stationary part 1 and the load-receiving part 2 are connected to a pair of guiding members 4 by means of flexible shafts 5 to limit the stationary part 1 and the load-receiving part 2 to a directed movement relative to each other. The load-receiving part 2 has a cantilever 15 for receiving a load to be measured. The vertical component of the force generated by the load is transmitted from the load-receiving portion 2 to the short arm 8 of the lever 6 through the connecting member 9. The lever 6 is supported on a part of the fixed portion 1 through a flexible fulcrum 7. The force-measuring cell 10 further comprises a cup-shaped permanent magnet system 16, which is rigidly connected to the stationary part 1 and has an air gap (airgap) 17. The coil 19 is located in the air gap 17 and is held by the long arm 18 of the lever 6. An equal amount of compensation current, determined by the force acting on the lever 6, flows into the coil 19. The position of the lever 6 is measured by an opto-electronic measuring device 23 connected to a feedback servo circuit which adjusts the compensation current in response to the arriving measurement signal so that the lever 6 always remains in the same position or returns to the same position after a load change. A broadband sensor 24 for detecting high-frequency electromagnetic fields is arranged on the force-measuring cell 10 for the purpose of measuring high-frequency electromagnetic fields that can penetrate from the outside and reach this location. If an excessive magnetic field strength is detected, i.e. if the magnetic field strength exceeds a predetermined threshold value, a responsive operation of the balance can be triggered thereby.

Fig. 2 schematically shows a force-measuring device 100, such as a balance in particular, in cross-section. The load cell 110 comprises a fixing portion 11 and a load receiving portion 12 connected to each other by an intermediate portion 13. The force-measuring cell 110 is arranged in the interior space 80 of the housing 20 and its fixing portion 11 is rigidly connected to the housing 20 by means of a support 21 which is firmly attached to the housing. The load receiver 30 is in the form of a weighing pan arranged outside the housing 20, connected to the load receiving portion 12 of the force-measuring cell 110 in the inner space 80 by means of the force-transmitting rod 14. The force-transmitting lever 14 enters the housing 20 through the transition hole 22 with free-space contact. The transition holes 22 are configured in such a way that penetration of as much high frequency electromagnetic radiation as possible can be prevented or at least greatly reduced. Furthermore, at least one sensor 50 is arranged in the interior 80 for high-frequency electromagnetic field detection, wherein the sensor 50 measures at least one parameter of the high-frequency electromagnetic field. In particular, the parameter can be indicative of the strength and/or frequency of the electromagnetic field. The sensor signals corresponding to the measured values are sent via a computer unit connection 51 to a computer unit 60 for further processing and/or via an output connection 52 to an output unit 70, here shown as a light emitting diode. The computer unit 60 is connected to the output unit 70 via a computer unit output connection 62, transmitting the output signal generated by the computer unit 60 to the output unit 70. The output unit 70 may be disposed directly on an outer surface of the housing 20, or may be separate from the housing 20, or the output unit 70 may be mounted inside the housing if the housing 20 is designed (acoustically transparent, transparent) so that the output signal can be heard or seen. Symbols or alarm signals that are particularly suitable for the communication characteristics or the alarm to be issued can enhance the communication with the person. It is therefore conceivable to use well-known pictures (for example graphical road signs or symbols specially created to represent the alarm to be conveyed). The importance of the alarm or communication can be changed by changing the flashing frequency of the visible indicia or also by changing the volume and the note frequency of the audible output device. Each connection 51, 52, 62 in the embodiment of fig. 2 may be a cable connection (e.g. a signal cable, a bus system, etc.) or a wireless connection.

In the case of magnetic field strength of high-frequency electromagnetic radiation, the responsive operation of the balance is triggered as soon as a parameter of the interior space 80 changes or exceeds a predetermined permissible threshold value. This operation can be carried out by the computer unit 60 or else directly in the electronic measuring and/or processing section of the balance containing the computer unit. In the case of weighing results to be registered, when the electronic measurement system of the balance finds an instability or a large underload or load associated with a previously determined measurement value, the operation in response to exceeding the predetermined threshold value makes it necessary to repeat the measurement. The measurement may also be repeated a number of times, at least over some acceptable length of time, but the repeated measurement is stopped only when the measured magnetic field strength falls below a threshold value. If the above-mentioned acceptable length of time is exceeded or the measurement parameter value is too high, the measurement process may be interrupted and/or prevented and/or the operational readiness indicator is turned off. The measured values of the magnetic field strength, in particular the distribution of the magnetic field strength as a function of frequency, are stored together with time values in a log file in a memory unit of the computer unit. This enables the data to be tracked in a timely manner.

As a further operation of the balance, in particular as an electronic measuring and/or processing section, the sensor signal or the output signal is transmitted to the output unit 70, in which output unit 70 the signal is displayed correctly. The display may take the form of an audible signal, an optical signal (e.g., a flashing light), or an alarm or attention that is indicated on the display panel.

Fig. 3 shows a force-measuring device 200 in the form of a tank-weighing module which is monitored according to the method of the invention. Bucket weighing modules are used in particular in industrial installations for weighing the volume of basins, tanks, reaction vessels, etc. Generally, in order to weigh one container, several weighing modules are required to be arranged between the container foot 230 and the base 231. Thus, each foot 230 of the container rests on the force-measuring device 200. In order to determine the weight of the container and/or its capacity, it is necessary to add these signals to each other, since each signal generated by the force-measuring device 200 represents a fraction of the total quantity. Thus, the force-measuring device 200, which is represented in the form of a weighing module, does not normally emit a separate output. For example, the weighing signals of the individual load cells 200 of the container are transmitted to a computer unit 206 in the form of a master computer (lead computer), in which these signals are processed and displayed on an output unit 207 contained in the master computer, in most cases as part of the display of a forecasting system.

The force-measuring device 200 comprises a force-measuring cell 210 which is enclosed by a housing 220. Typically, the housing 220 is welded to the force-measuring cell and sealed against the surrounding environment of the force-measuring device 200. When the force measuring device 200 is in place for measurement, the force measuring cell 210 and the housing 220 are elastically compressed. The effect of the rigidity of the housing on the weighing signal can be partially compensated, the hysteresis of the weighing module being negligible in proportion to the measuring range. For the case of such a relatively unlikely penetration of the high-frequency electromagnetic field into the interior space of the force-measuring cell, sensors 250, 251 are arranged in the interior space for detecting the high-frequency electromagnetic field, wherein one sensor is of broadband design and the second sensor is designed as a narrowband sensor to cover a specific frequency range, for example the range of public telecommunication equipment. These sensors 250, 251 are connected via a physical connection 252 and/or a radio connection 253 to the computer unit 206 via the transmitter 202, the measurement converter 203, the segment coupler 204 and the bus system 205. The weighing signal of the force-measuring cell 210 can be transmitted to the computer unit 206 via these connections or via a dedicated weighing signal connection 254.

The force-measuring device 200 shown in fig. 3 further comprises a temperature sensor 290 located in the interior space 280 of the housing 220. The sensors 250, 251, which can operate independently of each other, are used to transmit measured values representing parameters of the interior space to the computer unit 206. The computer unit 206 in fig. 3 is a host computer of, for example, a process control system. Depending on the configuration of the force-measuring device 200 and the computer unit 206, the sensors 250, 251 send their sensor signals to the computer unit 206 continuously or periodically and/or at arbitrary time intervals or automatically after a change has been detected. Of course, the computer unit 206 may also obtain the sensor signal by interrogating the sensors 250, 251 continuously, periodically or in any way. Since several force-measuring devices 200 are used for one container, the sensor signals of the sensors in one force-measuring device 200 for detecting the high-frequency electromagnetic field can be verified by comparing the sensor signals from the other force-measuring devices 200. However, it is also possible that a verification value is already stored in the sensor 250, 251 or in the computer unit 206. For example, the verification value may be based on a published table of values obtained from other instruments or from data published on the internet. For example, data specific to the location where the force-measuring device is installed (e.g. atmospheric pressure, temperature, and range of radiation) or data relating to seismic vibrations are known and can be used for verification of the sensor signal. In the sense of a device history, if a part of the sensor signals is stored in the computer unit 206, an analysis of this history can be used to obtain additional information about the state of the force-measuring cell 210 and the sensors 251, 252.

Sensors that may be used for high frequency electromagnetic radiation include any known prior art sensor capable of forming a sensor signal indicative of a change or a measurement to be determined.

The block diagrams in fig. 4 to 8 show sensors for detecting high-frequency electromagnetic radiation in or on a force-measuring device having different structures and different configurations. Elements of the same structure are denoted by the same reference numerals in fig. 4 to 8, and are not described again in each drawing.

Fig. 4 shows a block diagram of a force-measuring device in the form of a balance with a force-measuring cell 40 connected to a load receiver 48. The measurement signals of the force-measuring cell 40 are processed by an electronic measuring section with an analog section 41 and a digital section 42, and the resulting values are created in a computer unit 43. The resulting value of the measurement signal is displayed as the quality value of the load by the output unit 45. The result value can also be derived for further use via an interface connection 44 (which can be a hardware or software interface), or the result value can trigger further operation of the balance. One or more sensors 46 for detecting high frequency electromagnetic fields may be arranged outside the housing 120 to measure parameters characteristic of the high frequency electromagnetic fields in the presence thereof by means of the electromagnetic processing module 47. The parameter values to be measured and to be sent to the computer unit 43 are in particular electromagnetic field intensity values and/or frequencies. The threshold value, which can be predetermined and stored in the memory unit of the computer unit 43, is then compared with the electromagnetic field strength, in particular at comparable frequencies, and in the event of the threshold value being exceeded, the operation of the balance is triggered to enable repeated measurements, and/or an alarm is triggered, and/or the measurement process is interrupted and/or prevented, and/or the operational readiness indicator is switched off, and/or this value is stored together with the time value in a log file of the memory unit.

Fig. 5 also shows a balance in a manner similar to the block diagram of fig. 4. One or more sensors 146 for detecting the high-frequency electromagnetic field are arranged in the housing 120, determining, by means of an electronic processing module 147, a parameter characterizing the current high-frequency electromagnetic field, in particular a value of the electromagnetic field strength. The parameter values thus determined are sent to the computer unit 43. The value may be determined as a function of frequency or a range of frequencies. A threshold value, which can be predetermined and stored in the memory unit of the computer unit 43, is compared with the electromagnetic field strength and, if a deviation greater than the threshold value is found, the operation of the balance is triggered as described above.

In the embodiment shown in the block diagram of fig. 6, the function of the sensor 56 for detecting high-frequency electromagnetic fields is achieved by tapping the high-frequency signals from the measurement signals of the force-measuring cell 40 via inductive and/or capacitive coupling and/or via an antenna, and the tapped signals are directed to the computer unit 43 by means of the electronic processing module 57. Such high-frequency signals, which are superimposed on the actual measurement signals, can be characteristic of the high-frequency electromagnetic fields that may be present in the interior space and which have an excessive and harmful effect on the balance from the outside.

The tapping of high frequency signals can also take place from an analog electronics module 41 as shown in the block diagram of fig. 7. Furthermore, such signals can also be tapped from the supply line or the connecting line of the balance.

The block diagram of fig. 8 shows: how it is checked whether a deviation of the parameter value representing the characteristic of the existing high-frequency electromagnetic field from the threshold value is likely to be caused by the high-frequency electromagnetic field penetrating into the inner space is based on the correlation of the measured values of other sensors (e.g., temperature sensors) or even the measured values of the force-measuring device itself. This requires an estimation program 53, by which the estimation program 53 compares such a parameter value with a threshold value of the high-frequency electromagnetic field predetermined at a variable level (variable level). The correct responsive operation of the balance can also be triggered by this dedicated evaluation program 53.

The appropriate sensor signal generated by the at least one sensor can also be used to correct the measurement results as a possible way of avoiding the installation of other types of measurement sensors, which can be used according to the state of the art, for example, to compensate for hysteresis and/or drift phenomena. However, such means for correcting the measurement and/or compensating or error are fully encompassed and will not be discussed herein.

The embodiments presented in the description should not be understood as limiting the invention to the configuration of only one force-measuring cell in one housing. It will be readily understood by those of ordinary skill in the relevant art that the present invention is equally applicable to configurations that include at least two weighing cells in one housing. Furthermore, the way in which the measurements cooperate with the respective alarm signals is not relevant to the subject matter of the present invention. The notification or alarm may occur in real time, i.e., at the time of each measurement, or may occur at a different time than each measurement.

Claims (26)

1. A method of monitoring and/or determining the condition of a force-measuring device (100, 200) comprising at least one housing (20, 120, 220) containing an interior space (80, 280) and at least one force-measuring cell (10, 40, 110, 210) mounted in the interior space (80, 280) of said at least one housing (20, 120, 220), and further comprising an electronic measuring part (41, 42, 43, 60, 206) for measuring and/or estimating a measurement signal of said force-measuring cell, characterized in that the method comprises the steps of:

determining at least one parameter characterizing an existing high-frequency electromagnetic field by means of at least one sensor for high-frequency electromagnetic field detection arranged in an interior space (80, 280) of the housing (20, 120, 220) and/or at least one sensor for high-frequency electromagnetic field detection (24, 46, 50, 56, 146, 156, 250, 251) arranged outside the housing (20, 120, 220), the at least one sensor being connected to the electronic measuring section;

comparing at least one value of said determined parameter with at least one threshold value; and

triggering a responsive operation of the force measuring device (100, 200) in case the parameter value exceeds the threshold value.

2. Method according to claim 1, characterized in that at least one parameter characterizing the electromagnetic field in the frequency range of the telecommunication device is determined by means of the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251).

3. The method of claim 2, wherein the at least one parameter to be determined comprises one or more of a frequency, a frequency range, and a magnetic field strength of the electromagnetic field.

4. Method according to claim 3, characterized in that the force-measuring device (100, 200) comprises a computer unit (43, 60, 206) and a memory unit, and in that a program is executed in the computer unit (43, 60, 206), wherein the program compares the measured magnetic field strength values with at least one threshold value predetermined by a changeable value and stores the measured magnetic field strength values in the memory unit and/or the computer unit (43, 60, 206).

5. Method according to claim 3 or 4, characterized in that the force-measuring device (100, 200) comprises a memory unit and that the measured magnetic field strength values are stored in the memory unit for further processing.

6. Method according to claim 4, characterized in that a clock is present in the force-measuring device (100, 200), wherein the clock is accessible to the computer unit, and that the program assigns a time value to each measured magnetic field strength value and stores the measured magnetic field strength values and time values in pairs in the memory unit.

7. A method according to claim 4, characterized in that the measured value of the magnetic field strength is determined as a function of the frequency or frequency range of the electromagnetic field.

8. Method according to claim 7, characterized in that the above-determined function between the value of the measured magnetic field strength and the frequency or frequency range of the electromagnetic field is stored in the memory unit.

9. Method according to claim 1 or 3, characterized in that the force-measuring device (100, 200) comprises an output unit (45, 70, 207) being a display screen and/or at least one light-emitting diode and/or a printer of an indication and operating unit, wherein a signal depending on a parameter value characterizing the high-frequency electromagnetic field is transmitted to the output unit (45, 70, 207).

10. Method according to claim 6, characterized in that in case the determined parameter value exceeds the at least one threshold value, a repeated measurement is performed, and/or an alarm is triggered, and/or an interruption and/or a blocking of the measurement process, and/or an operation readiness indicator is turned off, and/or the determined parameter value is stored together with a time value in a log file of the storage unit.

11. A method according to claim 1 or 3, characterized in that in case a determined parameter value exceeds the threshold value, the calibration is pending and not performed at this point, and is not performed until after the subsequently determined parameter value returns to a range below the threshold value.

12. Method according to claim 4, characterized in that, for monitoring the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251), the sensor signal sent from the sensor to the computer unit (43, 60, 206) is verified at least at periodic time intervals in the computer unit (43, 60, 206) by comparing it with verification values and verification tolerance values stored in the memory unit, and in that if it is detected that the sensor signal deviates from these verification values or from predetermined verification tolerance values, an error is registered and an error signal is sent to an output unit (45, 70, 207).

13. Method according to claim 1 or 3, characterized in that for determining the at least one parameter characterizing the existing high-frequency electromagnetic field, a signal is tapped from an electronic measuring section (40, 41, 42, 43, 47, 57, 147, 157) and/or the electromagnetic field strength inside and/or outside the housing (20, 120, 220) is measured and/or a signal is tapped from a cable connection, wherein the cable connection is a power supply cable and/or a connection cable connection.

14. A method according to claim 1 or 3, characterized in that in addition to the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) for determining a high-frequency electromagnetic field, a further sensor (24, 46, 50, 56, 146, 156, 250, 251) is provided, which is a temperature sensor (290), and that the parameter values determined by means of the further sensor are used together with the difference values deviating from the threshold value as a criterion for determining the response operation occurring in the electronic measuring part (41, 42, 43, 60, 206).

15. A method according to claim 1 or 3, characterized in that the time distribution of the force measurement signals over the past period of time is also registered, and the resulting parameter values are used as a criterion, together with the difference values deviating from the threshold values, to determine the response operations taking place in the electronic measuring part (41, 42, 43, 60, 206).

16. Method according to claim 4, characterized in that in addition to the threshold value triggering the operation of the electronic measuring part (41, 42, 43, 60, 206), a lower second threshold value is stored in the computer unit (43, 60, 206) as a modifiable value, and that when the second threshold value is exceeded, an alarm signal is issued in an output unit (45, 70, 207).

17. Force-measuring device (100, 200) operable to carry out a method according to any one of claims 1 to 16, the device comprising at least one housing (20, 120, 220) containing an interior space (80, 280) and at least one force-measuring cell (10, 40, 110, 210) mounted in the interior space (80, 280) of said at least one housing (20, 120, 220), and the device further comprising an electronic measuring section (41, 42, 43, 60, 206) for measuring and/or estimating a measurement signal of said force-measuring cell, characterized in that the device is provided with at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection in the interior space (80, 280) of said housing (20, 120, 220) and/or with at least one sensor (24) for high-frequency electromagnetic field detection outside said housing (20, 120, 220), 46, 50, 56, 146, 156, 250, 251) coupled to the electronic measurement portion.

18. Force measuring device (100, 200) according to claim 17, characterized in that a sensor (24, 46, 50, 56, 146, 156, 250, 251) for high frequency electromagnetic field detection is connected to the electronic measuring section (41, 42, 43, 60, 206), wherein a responsive operation of the force measuring device (100, 200) is triggered if the sensor (24, 46, 50, 56, 146, 156, 250, 251) for high frequency electromagnetic field detection detects a value exceeding at least one predeterminable threshold value.

19. Force measuring device (100, 200) according to claim 17 or 18, characterized in that the device is further provided with a computer unit (43, 60, 206) and a memory unit, wherein the computer unit (43, 60, 206) is operable to execute a program which triggers a responsive operation of the force measuring device (100, 200) and/or stores the detected values in the memory unit for further processing if the sensor for high frequency electromagnetic field detection (24, 46, 50, 56, 146, 156, 250, 251) detects a value exceeding at least one predeterminable threshold value.

20. Force measuring device (100, 200) according to claim 17 or 18, characterized in that the sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection is configured as a circuit for tapping a signal of an electronic measuring section (41, 42, 43, 60, 206).

21. Force measuring device (100, 200) according to claim 17 or 18, characterized in that the sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection is configured in the form of a broadband and/or narrowband electromagnetic field sensor (24, 46, 50, 56, 146, 156, 250, 251) and/or an antenna.

22. Force measuring device (100, 200) according to claim 17 or 18, characterized in that the sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection is configured in the form of an inductive and/or capacitive coupling loop and/or an antenna arranged in the vicinity of a cable, which is a power supply cable supplying power to the force measuring cell (10, 40, 110, 210) and/or the electronic measuring section (41, 42, 43, 60, 206).

23. Force measuring device (100, 200) according to claim 19, characterized in that the computer unit and/or the output unit (45, 70, 207) is connected to the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) by means of a wireless connection or wire bonding.

24. Force measuring device (100, 200) according to claim 17 or 18, characterized in that a memory module and/or a measuring transducer is integrated in the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection.

25. Force measuring device (100, 200) according to claim 17 or 18, characterized in that in addition to the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection, further sensors (24, 46, 50, 56, 146, 156, 250, 251) for detecting line power peaks of a power supply supplying the force measuring cell (10, 40, 110, 210) are arranged in the interior space (80, 280) of the housing (20, 120, 220) or on the housing (20, 120, 220).

26. Force measuring device (100, 200) according to claim 17 or 18, characterized in that in addition to the at least one sensor (24, 46, 50, 56, 146, 156, 250, 251) for high-frequency electromagnetic field detection, at least one further sensor (24, 46, 50, 56, 146, 156, 250, 251) for detecting a further parameter, which is temperature, is arranged in the interior space (80, 280) of the housing (20, 120, 220) or on the housing (20, 120, 220).