HK1087175A - Wireless transmitting pressure measurement device - Google Patents

Description

Wireless transmission pressure measuring device

Cross reference to previous application

This application claims rights to U.S. provisional application filed on 10.12.2002 under the designation "wireless transmission pressure gauge", U.S. provisional application No. 60/432,416, 31.1.2003 under the designation "wireless transmission pressure gauge", U.S. provisional application No. 60/444,314, and U.S. utility model application filed on 26.11.2003 under the designation "wireless transmission pressure measuring device".

Technical Field

The following description relates generally to pressure measurement devices and, more particularly, to providing information from pressure measurement devices.

Background

Pressure gauges are widely used in a myriad of different environments in commerce and industry. Typically, pressure gauges measure pressure and provide an indication. Pressure values are typically displayed in analog form (e.g., with a pointer) or in digital form (e.g., with an LED reading). Gauges that display values in analog form often include a mechanical pressure transducer, such as a Bourdon tube, that moves a predictable amount in response to the pressure to which the transducer is subjected. This displacement is transmitted by the movement to a rotatable pointer which oscillates in relation to the dial on which the pressure values are inscribed. Watches that display numerical values in digital form often use an electronic pressure transducer, such as a piezoelectric transducer, that generates an electrical signal in response to the pressure experienced by the transducer. The electrical signal is then converted to a symbol for display on a display.

Summary of The Invention

In one general aspect, an apparatus for measuring pressure includes a housing, a transducer, and a data transmission device. The housing has an inlet, and the transducer is connected to the inlet within the housing to produce an electrical signal indicative of the pressure at the inlet. The transducer may be, for example, a piezoelectric type sensor that generates an electrical signal in response to inlet pressure. The data transmission device is coupled to the transducer within the housing to transmit a wireless signal corresponding to the electrical signal to provide the pressure information remotely. The data transmission device may be, for example, an infrared transmitter.

In some embodiments, the device includes a visual indicator coupled to the inlet in the housing to indicate the inlet pressure. In this manner, pressure information can be provided both locally and remotely. The visual indicator may be, for example, a digital display.

In some particular embodiments, the housing includes a stem extending to the inlet, and the sensor includes a Bourdon tube coupled to the inlet to accurately move in response to pressure at the inlet. The device also includes a visual indicator having a shaft coupled to the Bourdon tube for rotation in response to displacement of the Bourdon tube, and a pointer coupled to the shaft for indicating the pressure value.

In certain embodiments, the transducer comprises: an inductive target coupled to a Bourdon tube, the target being movable in response to displacement of the Bourdon tube; and an eddy current sensor positioned to sense movement of the inductive target and generate an electrical signal indicative of an inlet pressure in response to the movement.

In some embodiments, the pressure measurement device includes a processor coupled between the transducer and the transceiver. The processor may have a variety of operations. For example, the processor may generate pressure characterization data based on the signal indicative of the inlet pressure. The characterization data may be transmitted as part of a wireless signal and may include an alarm based on the inlet pressure. As another example, the processor may control the frequency at which the pressure information is sent. The processor may control the pressure information transmission frequency based on the pressure data set point, the frequency varying in response to pressure crossing a pressure data set point. As yet another example, the processor may place itself and other electronic components in a power saving mode. As yet another example, the processor may compensate for non-linearities and/or temperature coefficients of the sensed pressure.

Some particular embodiments may include an infrared data association interface coupled to the processor, wherein the processor may be remotely programmed via the interface. For example, the processor may be programmed to change the pressure data set point.

Some embodiments may include externally accessible terminals coupled to the processor. The processor is operable to receive a discrete status input via the terminals. In addition, the processor is operable to output pulse accumulation information (pulse accumulation information) through the terminals.

In some embodiments, the pressure measurement device includes a visual indicator on the housing to indicate the mode of operation. A pressure measurement device may also include a transceiver on/off switch.

In another general aspect, a method performed by a pressure measurement device includes sensing a pressure at an inlet of a housing and converting the sensed pressure to a visual pressure indication representative of the pressure at the housing. The method also includes converting the sensed pressure to an electrical signal representative of the pressure at the housing and transmitting a wireless signal corresponding to the electrical signal from the housing to provide pressure information locally and remotely.

In some embodiments, the transformation from the sensed pressure to a visual indication of pressure may include transforming the sensed pressure to a mechanical displacement and transmitting the mechanical displacement to a pointer. Additionally, the transformation from the sensed pressure to an electrical signal may include imparting mechanical displacement to an inductive target, and sensing eddy currents generated in response to the displacement of the target. Additionally, transmitting a wireless signal may include transmitting pulses of infrared radiation.

Some particular embodiments may include many additional operations. For example, some embodiments may include generating characterization data for the sensed pressure based on the electrical signal, and sending the characterization data as part of the wireless signal. As another example, certain embodiments may include controlling the frequency at which pressure information is sent. As yet another example, some particular embodiments may include placing electronic components in a power saving mode. As another example, some embodiments may include receiving a wireless signal specifying an operational adjustment and adjusting operation of the pressure measurement device. As yet another example, some embodiments may include receiving externally generated data and transmitting the data as part of a wireless signal. As yet another example, certain embodiments may include providing a visual indication of an operating mode on the housing.

In another specific aspect, a device for measuring pressure includes a housing, a Bourdon tube, a shaft, and a pointer. The housing has a stem with an inlet, and the Bourdon tube is connected to the inlet for precise displacement in response to inlet pressure. The shaft is mechanically coupled to the Bourdon tube for rotation in response to displacement of the tube, and the pointer is attached to the shaft for indicating a pressure value. The apparatus also includes an inductive target coupled to the Bourdon tube, the target moving in response to displacement of the Bourdon tube, and an eddy current sensor positioned to sense movement of the target and generate an electrical signal in response to movement of the inductive target. The apparatus also includes an analog-to-digital converter coupled to the sensor. The transducer is operable to receive the electrical signal and to generate a digitized version of the signal. The apparatus also includes a microprocessor coupled to the converter. The microprocessor is operable to receive the digital signal, compensate for non-linearities in the sensed pressure, compensate for temperature coefficients and generate pressure characterization data based on the compensated signal. The microprocessor is also operable to determine whether the frequency at which the pressure information is transmitted should be adjusted and, if the frequency must be adjusted, adjust the frequency. The microprocessor is also operable to determine whether it is time to transmit pressure information, generate a signal including the pressure information if it is time to transmit pressure information, and place the microprocessor itself and other electronics in a power conservation mode. The apparatus additionally includes an infrared data association interface coupled to the microprocessor such that the microprocessor can be remotely programmed via the interface, and an infrared transceiver coupled to the microprocessor for transmitting a wireless signal representative of the microprocessor signal to provide pressure information both locally and remotely.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other structural features will be apparent from the description and drawings, and from the claims.

Brief description of the drawings

FIG. 1 illustrates a perspective view of an exemplary pressure measurement device;

FIG. 2 shows a cross-sectional view of the pressure measurement device of FIG. 1;

FIGS. 3A-E illustrate another pressure measurement device;

FIGS. 4A-D illustrate an example of a printed circuit board assembly;

FIG. 5 shows a perspective view of an example of a pressure measurement device;

FIGS. 6A-B illustrate perspective views of an example of a pressure measurement device;

FIG. 7 illustrates the operation of a pressure measurement device;

FIG. 8 is a block diagram showing components of an example of a pressure measurement device;

FIG. 9 shows a system for programming a pressure measurement device.

Detailed Description

Fig. 1 shows an example of a pressure measurement device 10. As shown, the pressure measuring device 10 is a pressure gauge; however, other types of pressure measurement devices may be used. The device 10 includes a housing 20 having a rear cover 22 and a front cover (not shown to help show the internal components of the device). A dial face including pressure values is also not shown to assist in displaying the internal components of the device.

In the device 10, a pressure sensor 30 is in fluid communication with an inlet 26 of the housing 20. Pressure sensor 30 is responsive to the pressure at inlet 26 to produce an electrical output indicative of the pressure at inlet 26. Pressure sensor 30 may be a piezoelectric type pressure sensor, a capacitive type pressure sensor, a strain gauge type pressure sensor, or any other suitable pressure-to-electrical signal transducer. The electrical signal output by the sensor 30 may be indicative of pressure by voltage, current, frequency, pulse width, or any other suitable electrical signal characteristic. The apparatus 10 also includes a second transducer, a Bourdon tube 40. However, the Bourdon tube produces an output that is different from the output of the pressure sensor 30.

An end 42 of Bourdon tube 40 is precisely displaced in response to the pressure at inlet 26. By displacement, the tip 42 actuates a hinge plate 52 of a moving member 50. The moving member 50 further includes an amplifying member to amplify the displacement of the hinge plate 52. The movement 50 mechanically links the displacement of the tip 42 to the rotation of a pointer 58, an indicator. Thus, the pointer 58 rotates in response to changes in pressure at the inlet 26. When the device 10 is fully assembled, the pointer 58 is opposite a pressure-dividing dial face.

As described above, the device 10 has two transducers, one that converts pressure to an electrical signal and the other that converts pressure to mechanical motion. In other embodiments, a pressure measurement device may have any number of transducers. Additionally, in some embodiments, a transducer may provide multiple outputs.

Fig. 2 again shows a pressure measuring device 10. As shown, the pressure sensor 30, Bourdon tube 40, and motion piece 50 of FIG. 1 are removed to reveal a Printed Circuit Board (PCB) 60. The PCB 60 is electrically connected to the pressure sensor 30 of fig. 1 via a sensor connector 62. The PCB 60 also includes an analog-to-digital (a/D) converter 64 to digitize the sensor output and a processor 66, and a processor 66 to process pressure data indicated by the sensor output. In some embodiments, the output from the sensor is amplified before being digitized by the A/D converter 64. However, not all embodiments require magnification.

The a/D converter 64 and processor 66 are operably mounted to, and preferably soldered to, the PCB 60. Processor 66, which may be a microprocessor for example, receives a digital signal from transducer 64 indicative of the inlet pressure and generates an output signal including pressure data corresponding to the digital signal, and thus the sensor output. The pressure data may, for example, include an indication of the sensed pressure.

In many particular embodiments, the processor output may include characteristic data related to the measured pressure at the inlet 26 in the form of pressure data. The characteristic data may include, for example, exception reporting (exceptingreventing) or pressure set points. Table 1 lists the anomaly data.

TABLE 1

Pressure value (P)	Feature(s)
		P＜＜X	Low pressure dangerous ground
P＜X	Low pressure
		X＜P＜Y	Calibrating pressure
P＞Y	High pressure
		P＞＞Y	High pressure dangerous ground

The processor output is connected to a transmitter PCB 70 located between PCB 60 and housing 20. The transmitter PCB 70 includes a transmitter, which is a data transfer device for transmitting pressure data via a wireless signal to a remote location separate from the device 10. Acceptable forms of wireless signals include Radio Frequency (RF), Infrared (IR), or any other suitable electromagnetic means (regime). Additionally, data may be transmitted by amplitude modulation, frequency modulation, phase modulation, pulse modulation, or any other suitable communication technique. The transmitter PCB 70 may include its own processor to control the wireless transmission function. In certain embodiments, transmitter PVB 70 may also wirelessly receive data from a remote source, perhaps using a transceiver, which is another type of data communication device. A radio transceiver may be used in conjunction with or in place of the transmitter.

The PCB 60 includes a battery to serve as a power source. In certain embodiments, the battery 68 may be a lithium battery or other long-lasting power source to facilitate long-life, maintenance-free operation. The use of a long-lasting power source in conjunction with remote reporting provides significant benefits in applications involving hazardous or inaccessible locations. Note that: the battery 68 may be mounted in a number of locations within the housing 20.

The device 10 has a number of features. For example, the pressure data may be provided on the pressure device and remotely from the pressure device. Thus, the field crew can measure pressure data on the pressure device and the pressure data can also be sent to a remote location. This allows for convenient inspection and monitoring of pressure data. In addition, remote monitoring can be important for hazardous or difficult to reach locations. In certain embodiments, the device 100 may be CE approved for EMI/RFI compatibility and may be suitable for class 1, segment 1 (Div) hazardous location use. Furthermore, pressure measurements by two different transducers facilitate validation of pressure data and allow for redundancy after failure of one transducer. As yet another example, wireless transmitting elements may be incorporated into a standard form factor of a pressure measurement device, which may provide manufacturing efficiencies. In addition, it may provide commercial advantages, such as cost savings through inventory control.

Fig. 3A-E illustrate a pressure measurement device 100. Fig. 3A shows a perspective view of the device 100, and fig. 3B shows a side view of the device 100. Fig. 3C-D are end views of the device 100 and fig. 3E is a cross-sectional view taken along section line E-E in fig. 3D. The device 100 is CE approved for EMI/RFI compatibility and is suitable for class 1, division 1 (Div) hazardous location use (i.e., truly secure).

The device 100 includes a housing 110 having a first end 112 and a second end 114. First end 112 includes a pressure sensing inlet 113 and second end 114 includes a translucent window 119 to facilitate an infrared link 160. In a particular embodiment, the housing 110 is approximately 5 inches long and 3 inches in diameter; in other embodiments, it may have any suitable dimensions.

At the first end 112, a fitting 115 is attached (e.g., by welding) to a fitting flange 116. The flange 116 contains methodology designed to interface with the support of the electronics (discussed below). The flange is then attached to the housing 110, which may be non-metallic, by a flat gasket 117, or an O-ring and screw 118. In another embodiment, a threaded flange may be used that mates with the housing threads.

The inlet 113 is in fluid communication with a pressure sensor 120 within the housing 110. The pressure sensor 120 is secured (e.g., by threaded connection or welding) to the pressure fitting 115 and outputs an electrical signal indicative of the pressure applied to the sensor through the inlet 113 in the pressure fitting 115. Thus, pressure sensor 120 converts the pressure at inlet 113 into an electrical output, similar to pressure sensor 30 of FIG. 1.

The pressure sensor 120 is connected to a main (host) PCB 130. Attached to the main PCB 130 is a transmitter PCB 140. An infrared LED 150, which may be of any suitable type, is located at second end 114 of housing 110 and is electrically connected to transmitter PCB 140.

The PCB 130 includes a processor 132 that processes signals indicative of the magnitude of the pressure. The processor may, for example, generate a code corresponding to the pressure and/or include second pressure data, such as an exception report. Predetermined abnormal conditions, such as "low pressure" and "high pressure", may be associated with a predefined pulse code. The processor may be programmed to indicate the abnormal condition, such as setting or clearing a target. The pressure data (e.g., pressure readings and secondary data) can then be wirelessly transmitted by a series of pulses using LEDs. The main PCB 130 also includes a long-life power source 134, such as a lithium battery.

In certain embodiments, the main PCB 130 receives a low level or a high level output (e.g., 300 millivolts to about 2 volts) from the pressure sensor 120, performs analog-to-digital conversion of the signal, and then processes the digitized signal before sending the signal to an appropriate receiver via electromagnetic waves. The receiver then passes the data to a Remote Transmitting Unit (RTU) for upload to an established system or directly to a computer or local system via serial transfer. Yet another alternative is to indicate the pressure locally at the device 100, for example in the form of a digital display.

To transmit a pulse (e.g., a series of long and short blinks), transmitter PCB 140 includes a processor 142 that may be controlled by programming stored in memory. The programming may, for example, search a database, which may also be stored in memory, for a pulse frequency corresponding to a detected pressure. For example, the programming can search a database for a code received from a microprocessor. The code will have an associated pulse frequency and the processor 142 will cause the LED 150 to send an infrared signal in the sequence of pulses. Infrared link 160 then carries this pressure data to a conventional infrared receiver for decoding.

In particular embodiments, transmitter PCB 140 may include an infrared data association (IrDA) interface. The IrDA interface may allow data to be wirelessly transmitted in both directions between device 100 and an external, separate computer. The IrDA interface may, for example, determine the pulse frequency associated with the pressure data from processor 132. Alternatively, an external computer may be used to program device 100 through link 160. The IrDA interface is advantageous because it can be implemented without having to have a hole in the housing, which would be required for an external connector for another type of interface, such as an RS-232 interface. In addition, alignment issues are mitigated by locating a programming device adjacent to the receiving aperture, allowing the programming device and the interface to communicate with each other. Note that: an RF transceiver can be used to program the processor 132 in some embodiments.

Fig. 4A-4D illustrate an example of a PCB assembly 400. Fig. 4A is a front view of PCB assembly 400. Fig. 4B is a rear view of PCB assembly 400. Fig. 4C is an end view of PCB assembly 400. Fig. 4D is a side view of PCB assembly 400. PCB assembly 400 may be used with the pressure measurement device of fig. 1, PCB assembly 400 of fig. 3, or any other suitable pressure measurement device.

The PCB assembly 400 includes a main PCB 410 and a transmitter PCB 420. The assembly 400 is powered by a lithium battery 430 mounted on the main PCB420, which may last for 6 months to 2 years with a transmission frequency of once per minute. Thus, maintenance-free operation in a hazardous environment can extend the useful life. Therefore, the assembly, and perhaps the entire pressure measurement device of which the assembly is a part, does not require an external power source.

The main PCB 410 includes an a/D converter 412 and a microprocessor 414. The a/D converter 412 is operable to receive and digitize a signal from a pressure transducer. The signal may be filtered and protected from EMI/RFI interference. The operating characteristics of the a/D converter 412, such as the rate of modification and input selection when appropriate, may be programmed through a serial interface. For example, the A/D converter 412 may be adjusted from the microprocessor 414 via a serial interface to accommodate different output voltage values from different types of pressure transducers, which may be energized from a constant voltage or constant current source.

Microprocessor 414 may have a variety of functions. For example, the microprocessor may read the raw digitized pressure signal from the A/D converter 412 and also control the A/D converter 412. In addition, microprocessor 414 may compensate the digitized signal to modify non-linearities and temperature coefficients.

Microprocessor 414 also controls the power supplied to a/D converter 412 and most (if not all) of the other electronics of a pressure measurement device. Thus, microprocessor 414 may conserve power by placing PCB assembly 400, or possibly even the entire pressure measurement device, to sleep or in a low power mode and waking the components at programmable intervals.

Microprocessor 414 may additionally control the frequency of wireless transmission of pressure data according to a programmable pressure set point. For example, the device may transmit pressure data at a nominal frequency until such time as the sensed pressure exceeds or falls below a programmable warning pressure value. At that moment, the transmission frequency is increased or decreased according to the program. If the sensed pressure exceeds or falls below these warning values, a warning condition is reached in which the transmission frequency is increased or decreased again. When the sensed pressure returns to its calibrated value, the transmit frequencies return to their previous set points. Table 2 shows a typical transmit frequency scheme. In general, the processor output may include any suitable type of pressure-related data and/or any suitable information regarding the pressure measurement device.

TABLE 1

Pressure value (P)	Transmitting frequency (Hertz)
		P＜＜X	1.000
P＜X	0.100
		X＜P＜Y	0.017
P＞Y	0.100
		P＞＞Y	1.000

Microprocessor 414 may also monitor and communicate over a serial IrDA link. In addition, microprocessor 414 may "data-record" the pressure data to an onboard memory, which may include, for example, Random Access Memory (RAM), electrically erasable, programmable read-only memory (EEPROM), compact disk read-only memory (CD-ROM), and/or any other suitable volatile or non-volatile information storage device.

Microprocessor 414 may further send the pressure data to a digital display for local pressure indication. The pressure data may be sent in a serial manner and the display may operate in a low power mode.

Control of various aspects of assembly 400 and a pressure measurement device of which assembly 400 is a part may be maintained and programmed via an infrared data association (IrDA) interface 419. The IrDA interface 419 provides a two-way, serial communication link between the microprocessor 414 and an external computer loaded with a software application (software utility).

An external computer, which may be connected to an IrDA converter through an RS-232 link, may use this software application to create multiple functions. These functions may include polling a pressure measurement device for information, varying the transmission frequency based on the sensed pressure, and/or COM port selection. There are also a number of warning ranges and alarm ranges, each established with its own programmable transmission interval and a calibrated transmission frequency. Each warning range and alarm range is an example of an exception report. In addition, functions can establish stress check, transmit, and IrDA wake-up rates. In addition, the application program can perform diagnosis of each element. The functions may be built upon and/or in conjunction with existing functions at IrDA interface 419.

IrDA interface 419 may also be used by the software application to control calibration and verification of the device of which assembly 400 is a part. For example, a full scale pressure value may be entered, zero pressure introduced to the pressure sensor, and a zero button clicked on a utility screen. This action causes the readings to be corrected to zero and causes the microprocessor 414 to respond that the unit (unit) has been zeroed. The pressure sensor is then brought to full scale pressure and a full scale button on a utility screen is clicked. The full scale value is displayed and the microprocessor responds that the unit has been checked at full scale.

a/D converter 412 may also be established via IrDA interface 419. Through the interface, a user can program which inputs of the a/D converter can be used, the required internal gain (gain) depending on the sensor technology used, the conversion time of the converter and/or other technical aspects of the a/D converter operation. Additionally, a calibration factor for the pressure data and an engineering unit for the selected pressure reading may be set.

Transmitter PCB420 includes any suitable components for wirelessly transmitting and/or receiving information. One suitable transmitter PCB is available from AXONN corporation of new orleans, louisiana, usa.

Fig. 5 illustrates an exemplary pressure measurement device 500. The apparatus is similar to the apparatus 10 of fig. 1. However, rather than using a piezoelectric sensor to generate an electrical output, the device 500 uses motion-responsive current generation/detection receiving technology. One example of such a technique is eddy current sensing. Suitable eddy current sensing components are available from LZT Technology, Inc. of San Bernadino, Calif., USA.

As shown, pressure measurement device 500 includes a Bourdon tube 504 that is responsive to changes in pressure at inlet 502. An inductive target 506 is coupled to Bourdon tube 502, possibly by a motion that displaces Bourdon tube 504 causing target 506 to translate in proportion to changes in pressure sensed at inlet 502. As shown, the target 506 is a U-shaped, metallic, molded piece sized to wrap around the edge of a PCB 508. However, the target 506 may have any other suitable configuration. The PCB 508 is supported in a fixed position relative to the housing of the pressure measurement device by screws 510 and includes a pair of induction coils 509 and other traces. The movement of the target 506 relative to the pair of induction coils affects the induction balance in the circuit. In this manner, the pressure change at the inlet 502 is converted into an electrical output. In some embodiments, the output may be 4-20 milliamps. As with device 10, the electrical output is then processed and wirelessly transmitted to a remote location.

The device 500 has a number of features. For example, the device provides an efficient structure to convert pressure into an electrical output that can be transmitted to a remote location. In addition, the structure can be easily implemented on a standard pressure gauge, can reduce manufacturing costs and can allow for retrofitting. Additionally, the device 500 may be CE approved for EMI/RFI compatibility and may be suitable for class 1, division 1 (Div) hazardous location use (i.e., truly safe).

Fig. 6A-B illustrate an exemplary pressure measurement device 600. As shown, the pressure measurement device 600 is a digital pressure gauge. Fig. 6A shows a perspective view of pressure measurement device 600, and fig. 6B shows a cross-sectional view of device 600.

The device 600 includes a housing 610 that supports a pressure connector 620 that allows the pressure to be measured to be introduced into the device. The device 600 further includes a PCB 630 that includes a processor 632 for processing a signal indicative of the pressure introduced at the junction 620 and a transceiver 634 for generating a wireless transmission corresponding to the signal. That is, transceiver 634 may generate a wireless transmission representing the pressure introduced at junction 620 and other pressure-related data. PCB 630 may be similar to PCB assembly 400 of fig. 4, and the signal may be formed by a piezoelectric sensor.

The device 600 additionally includes a display to show pressure related data for the device. Display 600 may also display device status information (e.g., on/off, generate/receive, etc.). The display 640 may be, for example, a Liquid Crystal Display (LCD).

The device 600 also includes a number of components that can interact with the processor 632. Located adjacent to the display 640 are a plurality of function keys 650. Using function keys 650, a user may query processor 632 for additional pressure-related data, such as pressure set points or exception reports, device status, or any other suitable information. In some embodiments, a user may even program processor 632 using keys 650. Information relating to these interactions may be displayed on display 640. Keys 650 may also be used to turn the display on and off. Power may be saved when a user is not viewing the device 600. In some embodiments, keys 650 may be buttons, dials, a touchpad, or any other suitable user input device. The apparatus 600 may be safe for use in hazardous level 1, section 1 locations, such as upstream gas well heads.

The device 600 further includes an electrical connector 660, which may be, for example, a Heyco connector. Processor 632 may accept discrete states of input and/or output pulse accumulation information through electrical connection 660. For example, the discrete state input may be a contact closure input that detects a switch closure from an external source, such as a magnetic switch contact closure that signals the presence of a "Plunger Event" at a gas well head. As another example, the connector and processor may count pulses received from an external source, such as a gas meter. In addition, other information can be input to processor 632 for transmission by transceiver 634. For example, information from another measurement device (e.g., a temperature measurement device such as a resistance temperature device or a thermocouple) may be input and transmitted. These measurements may also be truly secure.

The device 600 also includes a switch 670. Switch 670 controls the power state of transceiver 634. Thus, the apparatus 600 may prevent wireless transmission of information. Switch 670 is useful when a user is programming processor 632 using function keys 650. In other embodiments, switch 670 may be a button, a dial, or any other suitable user input device.

Note that: switch 670 and function keys 650 allow independent control of the on/off function of the components providing local and wireless pressure data. As such, the device 600 may provide pressure data from a local, remote location, or both. However, in other embodiments, independent control may be achieved through an input element or class of input elements.

In certain embodiments, apparatus 600 may include more, less, and/or a different arrangement of elements. For example, device 600 may include a dedicated visual indicator (e.g., an LED) and/or an audible indicator (e.g., a speaker) to indicate the status of the device. As another example, device 600 may include an IrDA interface for programming processor 632. As yet another example, device 600 does not include display 640, buttons 650, electrical connector 660, and/or switch 670. The device 600 is CE approved for EMI/RFI compatibility and would be suitable for class 1, division 1 (Div) hazardous location use (i.e., truly safe).

Fig. 7 illustrates an operational process 700 of the pressure measurement device. This process 700 may be performed by a pressure measurement device similar to device 10 in fig. 1, pressure measurement device 100 in fig. 3, pressure measurement device 500 in fig. 5, pressure measurement device 600 in fig. 6, or any other suitable pressure measurement device.

The process begins by waiting to sense the pressure of an inlet (decision block 704). Once pressure is sensed, the process continues by converting the sensed pressure to an electrical signal (function block 708). The pressure is converted into an electrical signal by, for example, a piezo-resistive device. The process also calls for converting the sensed pressure to a visual indication (function block 712). Such a conversion may be performed, for example, by: 1) a Bourdon tube with a rotatably connected pointer; 2) determining a value of an electrical signal, representing the value by a symbol and displaying the symbol; or 3) any other suitable technique. The visual indication may be displayed on the pressure measurement device.

The process continues at functional block 716 to generate characterization data from the electrical signal. These feature data may be generated, for example, by comparing an attribute of the signal to a table of signal attributes and determining a feature associated with the attribute. Table 1 provides an example of this.

The process continues to determine if a change in pressure range has occurred (decision block 720). This determination can be made, for example, by comparing the magnitude of the signal to certain set points. Column 1 of table 1 provides an example of pressure settings. If the pressure changes range, the process calls for adjusting the pressure data transmission frequency (function block 724). For example, if the pressure has changed from a nominal value to a high pressure value, the frequency of delivery is adjusted from 1 time per minute to 1 time per ten seconds. In addition, if the pressure reaches a very high value, the transmission frequency is adjusted to 1 time per second. Other pressure ranges and transmission frequencies may also be used.

After adjusting the transmit frequency or if the pressure range has not changed, the process continues to determine if it is time to transmit pressure data (decision block 728). The transmission time is determined in part by the transmission frequency. If the send time is not reached, the process returns to check for additional pressure sensing (decision block 704).

If, however, it is time to transmit pressure data, the process calls for transmitting a wireless signal representing the pressure data (function block 732). The wireless signal may be transmitted by IR or other electromagnetic means and the data may be sent by pulse modulation or other suitable techniques. The data may include a representation of the magnitude of the electrical signal, characterization data, new transmission frequency, or any other suitable pressure-related information.

The process also calls for determining whether a transmission containing an operational adjustment has been received at decision block 736. The adjustment may be related to, for example, a pressure set point, a transmission frequency, and/or any other suitable operating parameter. If the one transmission has been received, the process calls for adjusting the operation at function block 740. The adjustment operation may, for example, include changing instructions to a processor or data in a table. After the operation is adjusted, or if this transmission has not been received, the process calls for returning to check for additional pressure sensing (decision block 704).

Although fig. 7 illustrates a process for a pressure measurement device, other processes for a pressure measurement device may include more or less and/or a different set of operations. For example, some processes may not require transforming the sensed pressure into a visual indication, generating characteristic data, adjusting the transmission frequency, and/or receiving an operational adjustment transmission. As another example, a process may require that pressure data be saved until the send time is reached. As yet another example, generating the characterization data occurs at any time after the electrical signal is formed but before the wireless signal is transmitted. As yet another example, the determination of whether an operation adjustment transmission has been received may be done at any time. As yet another example, a process may require providing a visual indication of an operating mode. This can be achieved using an LED indicator with two LEDs, one indicating on/off and the other indicating transmit/receive. As yet another example, a process may require entering a power saving mode. As yet another example, a process may include receiving externally generated data and transmitting the data as part of a wireless signal.

Fig. 8 shows elements 800 of an example of a pressure measurement device. Element 800 includes a pressure transducer 810, a processor 820, and a transceiver 830. The pressure transducer 810 is operable to sense pressure and generate an electrical signal indicative of the pressure. The pressure transducer 810 may be, for example, a piezoelectric sensor. The processor 820 is operable to receive the signal, analyze the signal, and generate a signal representative of the pressure transducer signal. Processor 820 may do this, for example, by determining a set of pulses representing the pressure transducer signal. Processor 820 may also determine other pressure related data, such as an exception report. To perform this operation, the processor 820 may have instructions encoded therein and stored in memory associated therewith. The transceiver 830 is responsive to wirelessly transmitting processor signals. The transmission may represent the pressure sensed by the pressure transducer as well as other pressure-related data.

The element 800 also includes a number of user interface devices-a user output device 840 and a user input device 850. User output device 840 is operable to present information (regarding pressure, device, or otherwise) to a user of the pressure measurement device. The information may be presented in a visual, audible, tactile, or other suitable format. The user input device 850 is operable to detect commands from a user of the device. User input device 850 may include a button, a keyboard, a touch screen, a pen, a microphone, and/or any other suitable device. The processor 820 is generally responsible for responding to instructions.

Although FIG. 8 illustrates the components of a pressure measurement device, other pressure measurement devices may include more, less, and/or a different arrangement of components. For example, a pressure measurement device may not include a user input device and/or a user output device. As another example, a pressure measurement device may include an a/D converter between pressure transducer 810 and processor 820 and/or a memory coupled to processor 820.

Fig. 9 shows a system 900 for programming a pressure measurement device. To program a pressure measurement device, the system 900 uses IR signals. The system 900 may be particularly useful for programming a pressure gauge.

System 900 includes an IrDA adapter 910 and a holder 920 for the adapter. The adapter 910 and holder 920 include a plurality of holes, a plurality of IR transmission windows, and/or other structures through which signals may be transmitted. Holder 920 also includes an aperture 922 through which an LED status light of adapter 910 may flash when transmitting so that a user may determine the status of the adapter. Adapter 920 may be any suitable IrDA adapter, and in particular embodiments may be an IrDA serial COM port (port) manufactured by ActiSys, Calif., U.S.A. The holder 920 may be molded, for example, from a suitable plastic such as polycarbonate.

The system 900 also includes a vacuum cup 930 assembly secured with integral studs/nuts. The component 930 may be of the type provided by Adams, Pa.

In operation, a user assembles the holder 920 and the vacuum cap assembly 930 and inserts the adapter 920 into the holder 920. The holder 920 may include a means for gripping the adapter 910. The gripping device may be, for example, a strip of Velcro in an opening to further secure the adapter 910 when it is fully inserted into the holder 920. The user positions the transfer structure (holder) of the holder 920 near the receiving structure (receiving structure) of the pressure measurement device. In particular embodiments, the receiving structure may be a through hole in a dial and the positioning of the transmitting structure is accomplished by pressing the assembly 930 against the housing window, which may be a transparent window that serves as a standard outlet on a pressure gauge. Since the user typically breaks the vacuum grip of the assembly 930 and stores the assembly for future reuse, the assembly 930 may be attached to the housing on a temporary basis (e.g., as long as it configures the conveyor).

Once in place, the IR pulse is transmitted through the adapter 910 and the transmitting structure of the assembly 930 to the receiving structure of the housing. The signals may reach the IrDA transceiver located on the front side of the main PCB 60 in fig. 2 after passing through a plurality of aligned holes on the middle of the housing.

The pressure measurement device discussed above is particularly useful in a variety of different applications. For example, they may be used in well heads (well heads). As another example, they may be used in hazardous environments or locations that are difficult to access.

While particular embodiments and uses have been illustrated and discussed, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various additions, deletions, substitutions and/or modifications may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (60)

1. An apparatus for measuring pressure, the apparatus comprising:

a housing including an inlet;

a transducer connected to the inlet on the housing to generate an electrical signal indicative of the pressure at the inlet;

a visual indicator coupled to the inlet on the housing to indicate pressure at the inlet; and

a data transfer device coupled to the transducer in the housing to transmit a wireless signal corresponding to the electrical signal to provide pressure information both locally and remotely.

2. The apparatus of claim 1,

the housing includes a stem extending to the inlet;

the transducer includes a Bourdon tube connected to the inlet for precise movement in response to inlet pressure; and

the visual indicator includes:

a shaft connected to the Bourdon tube for rotation in response to displacement of the Bourdon tube;

and

a pointer connected to the rotary shaft to indicate a pressure value.

3. The apparatus of claim 2, wherein the transducer further comprises:

an inductive target coupled to the Bourdon tube, the target being movable in response to displacement of the Bourdon tube; and

an eddy current sensor positioned to sense motion of the inductive target and generate an electrical signal in response to the motion of the target.

4. The apparatus of claim 1, wherein the transducer comprises a piezoelectric type sensor coupled to the inlet to generate an electrical signal in response to inlet pressure.

5. The device of claim 1, wherein the visual indicator comprises a digital display.

6. The apparatus of claim 1, wherein the data transfer means comprises an infrared transmitter.

7. The apparatus of claim 1, further comprising a processor coupled between the transmitter and the data transfer device.

8. The apparatus of claim 7, wherein the processor is operable to generate pressure characterization data based on the signal indicative of the inlet pressure, wherein the characterization data is sent as part of the wireless signal.

9. The apparatus of claim 8, wherein the characterization data includes an alert based on the inlet pressure.

10. The apparatus of claim 7, wherein the processor is operable to control the frequency at which the pressure information is transmitted.

11. The apparatus of claim 10, wherein the processor is operable to control the pressure information transmission frequency based on pressure data set points, the frequency being varied in response to pressure crossing a pressure data set point.

12. The apparatus of claim 7, wherein the processor is operable to place itself and other electronic components in a power saving mode.

13. The apparatus of claim 7, wherein the processor is operable to compensate for non-linearities in the sensed pressure.

14. The apparatus of claim 7 wherein the processor is operable to compensate for the temperature coefficient.

15. The apparatus of claim 7, further comprising an infrared data association interface coupled to the processor, wherein the processor is remotely programmable through the interface.

16. The device of claim 15, wherein the processor is programmable to change the pressure data set points.

17. The apparatus of claim 7, further comprising a plurality of externally accessible terminals connected to the processor.

18. The apparatus of claim 17, wherein the processor is operable to receive a discrete status input via the terminals.

19. The apparatus of claim 17, wherein the processor is operable to output pulse accumulation information via the terminals.

20. The device of claim 1, further comprising a visual indicator on the housing to indicate the mode of operation.

21. The apparatus of claim 1, further comprising a data transfer means on/off switch.

22. An apparatus for measuring pressure, the apparatus comprising:

a housing including an inlet;

a transducer connected to the inlet on the housing to generate an electrical signal indicative of the pressure at the inlet;

a processor coupled to the transducer on the housing, the processor operable to receive the electrical signal and generate a signal, the signal including pressure information corresponding to the signal; and

a data transfer device connected to the processor in the housing for transmitting a wireless signal representative of the signal generated by the processor to provide pressure information remotely.

23. The apparatus of claim 22, further comprising a visual indicator coupled to the inlet on the housing to indicate inlet pressure.

24. The apparatus of claim 22, wherein the transducer comprises:

a Bourdon tube connected to the inlet for precise movement in response to inlet pressure;

an inductive target coupled to the Bourdon tube, the target being movable in response to displacement of the Bourdon tube; and

an eddy current sensor positioned to sense motion of the inductive target and generate an electrical signal in response to the motion of the target.

25. The apparatus of claim 22, wherein the processor is further operable to generate pressure characterization data based on the electrical signal, wherein the characterization data is transmitted as part of the wireless signal.

26. The apparatus of claim 22, wherein the processor is further operable to control a frequency at which the pressure information is transmitted.

27. The apparatus of claim 22, wherein the processor is further operable to place itself and other electronic components in a power saving mode.

28. The apparatus of claim 22, wherein the processor is further operable to compensate for non-linearities in the sensed pressure.

29. The apparatus of claim 22, wherein the processor is further operable to compensate for a temperature coefficient.

30. The apparatus of claim 22, further comprising an infrared data access interface coupled to the processor, wherein the processor is remotely programmable via the interface.

31. The apparatus of claim 22, further comprising a plurality of externally accessible terminals connected to the processor.

32. An apparatus for measuring pressure, the apparatus comprising:

a housing including an inlet;

a Bourdon tube connected to the inlet in the housing for movement in response to inlet pressure;

a shaft connected to the Bourdon tube for rotation in response to displacement of the Bourdon tube;

a pointer connected to the rotary shaft to indicate an inlet pressure value;

an inductive target coupled to the Bourdon tube for movement in response to displacement of the Bourdon tube;

an eddy current sensor positioned to sense motion of the inductive target and generate an electrical signal in response to the motion of the target;

a data transfer device is connected to the sensor in the housing to transmit a wireless signal corresponding to the electrical signal to provide pressure information both locally and remotely.

33. The apparatus of claim 32, further comprising a processor coupled between the eddy current sensor and the data transfer device.

34. The apparatus of claim 33, wherein the processor is operable to generate pressure characterization data based on the electrical signal, wherein the characterization data is transmitted as part of the wireless signal.

35. The apparatus of claim 33, wherein the processor is operable to control the frequency at which the pressure information is transmitted.

36. The apparatus of claim 35, wherein the processor is operable to control the pressure information transmission frequency based on pressure data set points, the frequency being varied in response to pressure crossing a pressure data set point.

37. The apparatus of claim 33, wherein the processor is operable to place itself and other electronic components in a power saving mode.

38. The apparatus of claim 33, wherein the processor is operable to compensate for non-linearities in the sensed pressure.

39. The apparatus of claim 33 wherein the processor is operable to compensate for temperature coefficients.

40. The apparatus of claim 33, further comprising an infrared data access interface coupled to the processor, wherein the processor is remotely programmable via the interface.

41. A method of operation on a pressure measurement device, the method comprising:

sensing a pressure at an inlet of a housing;

converting the sensed pressure to a visual indication of pressure on the housing;

converting the sensed pressure into an electrical signal on the housing; and

a wireless signal corresponding to the electrical signal is transmitted from the housing to provide pressure information both locally and remotely.

42. The method of claim 41, wherein transforming the sensed pressure into a visual pressure indication comprises:

converting the sensed pressure into a mechanical displacement; and

the mechanical displacement translation is transmitted to a pointer.

43. The method of claim 42, wherein converting the sensed pressure into an electrical signal comprises:

translating the mechanical displacement to an inductive target; and

the generated eddy current is transmitted in response to displacement of the target.

44. The method of claim 41, wherein transmitting a wireless signal comprises emitting pulses of infrared radiation.

45. The method of claim 41, further comprising:

generating characteristic data for the sensed pressure from the electrical signal; and

the characteristic data is sent out as part of the wireless signal.

46. The method of claim 41, further comprising: the frequency at which the pressure information is sent is controlled.

47. The method of claim 41, further comprising placing the electronic components in a power saving mode.

48. The method of claim 41, further comprising:

receiving a wireless signal indicative of an operational adjustment; and

the operation of the pressure measurement device is adjusted.

49. The method of claim 41, further comprising:

receiving externally generated data; and

these data are sent as part of the wireless signal.

50. The method of claim 41, further comprising providing a visual indication of the mode of operation on the housing.

51. An apparatus for measuring pressure, the apparatus comprising:

means for sensing pressure at an inlet of a housing;

means for converting the sensed pressure into a pressure indication visible on the housing;

means for converting the sensed pressure into an electrical signal on the housing; and

means for transmitting a wireless signal corresponding to the electrical signal from the housing to provide pressure information both locally and remotely.

52. The apparatus of claim 51, wherein transforming the sensed pressure into a visual pressure indication comprises:

converting the sensed pressure into a mechanical displacement; and

the mechanical displacement translation is transmitted to a pointer.

53. The apparatus of claim 52, wherein converting the sensed pressure into an electrical signal comprises:

transmitting the mechanical displacement to an inductive target; and

eddy currents generated in response to displacement of the target are sensed.

54. The apparatus of claim 51, wherein transmitting a wireless signal comprises transmitting pulses of infrared radiation.

55. The apparatus of claim 51, further comprising generating characteristic data of the sensed pressure based on the electrical signal, wherein the characteristic data is transmitted as part of the wireless signal.

56. The apparatus of claim 51, further comprising means for controlling the frequency at which pressure information is transmitted.

57. The apparatus of claim 51 further comprising means for adjusting operation in response to received wireless signals.

58. The apparatus of claim 51, further comprising means for receiving externally generated data, wherein the data is transmitted as part of a wireless signal.

59. The device of claim 51 further comprising means for providing a visual indication of an operating mode on the housing.

60. An apparatus for measuring pressure, the apparatus comprising:

a housing including a stem including an inlet;

a Bourdon tube connected to the inlet for precise movement in response to inlet pressure;

a shaft mechanically coupled to the Bourdon tube for rotation in response to displacement of the Bourdon tube;

a pointer connected to the rotary shaft to indicate a pressure value;

an inductive target coupled to the Bourdon tube for movement in response to displacement of the Bourdon tube;

an eddy current sensor positioned to sense motion of the inductive target and generate an electrical signal in response to the motion of the target;

an analog-to-digital converter coupled to the sensor, the converter being operable to receive the electrical signal and generate a digital signal;

a microprocessor coupled to the transducer, the microprocessor operable to:

receiving a digital signal;

compensating for non-linearity of the sensed pressure;

compensating the temperature coefficient;

generating pressure characterization data from the compensated signal;

determining whether a frequency at which the pressure signal is transmitted should be adjusted;

if the frequency should be adjusted, adjusting the frequency;

determining whether it is time to transmit pressure information;

generating a signal including pressure information if it is time to transmit the pressure information;

putting itself and other electronic components into a power saving mode;

an infrared data association interface connected to the microprocessor, wherein the microprocessor can be remotely programmed through the interface; and

an infrared transceiver is connected to the microprocessor for transmitting a wireless signal representative of the microprocessor signal to provide pressure information both locally and remotely.