Electrical connection to process fluid pressure sensor

Abstract

A process variable transmitter configured to sense a process pressure of a process fluid in an industrial process. The transmitter includes a pressure sensor and measurement circuitry carried on a circuit board, the measurement circuitry electrically coupled to the pressure sensor and measuring the process pressure. At least one through hole is formed in the printed circuit board, which is electrically coupled to the measurement circuitry. A slot extends from the through hole to an edge of the circuit board. A wire is soldered to the through hole and electrically connects the through hole to an electrical connection on the pressure sensor, thereby completing an electrical connection between the pressure sensor and the measurement circuitry. A method is also provided.

Description

Technical Field

[0001] This invention relates to pressure transmitters used in industrial processes for monitoring the pressure of process fluids. More specifically, this invention relates to pressure sensors electrically connected to this device. Background Technology

[0002] Process transmitters typically consist of transducers or sensors that respond to process variables. Process variables generally refer to the chemical or physical state or energy conversion of a substance. Examples of process variables include pressure, temperature, flow rate, conductivity, pH, and other properties. Pressure is considered a fundamental process variable because it can be used to measure flow rate, level, and even temperature.

[0003] Pressure transmitters are commonly used in industrial processes to measure and monitor the pressure of various industrial process fluids, such as slurries, liquids, steam, and gases from chemical, pulp, petroleum, gas, pharmaceutical, food, and other fluid-type processing equipment. Differential pressure transmitters typically include a pair of process pressure fluid inputs operatively coupled to a differential pressure sensor (within the transmitter), which responds to the pressure difference between the two inputs. Differential pressure transmitters typically include a differential pressure sensor operatively coupled to a pair of isolator diaphragms. The isolator diaphragms are located at the process fluid inlet and isolate the differential pressure sensor from the harsh process fluid being sensed. Pressure is transmitted from the process fluid to the differential pressure sensor via a generally incompressible filler fluid carried in a passage extending from the isolator diaphragms to the differential pressure sensor.

[0004] Process fluid pressure transmitters are typically considered field devices and are designed for field installation. "Field" is generally an external area within a process installation that can withstand extreme weather conditions, vibration, humidity variations, electromagnetic or radio frequency interfaces, or other environmental challenges. Therefore, the robust physical package of a process fluid pressure transmitter provides it with the ability to operate in the "field" for extended periods (e.g., years). Summary of the Invention

[0005] A process variable transmitter is configured to sense the process pressure of a process fluid in an industrial process. The transmitter includes a housing and a pressure sensor configured to sense an applied pressure. The pressure sensor has electrical characteristics that change in response to the applied pressure. A measurement circuitry system carried on a circuit board is electrically coupled to the pressure sensor and measures the process pressure based on the change in the electrical characteristics of the pressure sensor. At least one through-hole is formed in the printed circuit board, electrically coupled to the measurement circuitry system. A slot extends from the through-hole to the edge of the circuit board. Wires are soldered to the through-hole and electrically connect the through-hole to an electrical connection on the pressure sensor, thereby completing the electrical connection between the pressure sensor and the measurement circuitry system for sensing electrical parameters of the pressure sensor via the measurement circuitry system. A method is also provided.

[0006] This summary is provided to introduce, in a simplified form, a series of concepts further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter. The claimed subject matter is not limited to embodiments that address any or all the shortcomings pointed out in the background art. Attached Figure Description

[0007] Figure 1 A front view of an exemplary pressure transmitter is shown.

[0008] Figure 2 Show Figure 1 An inclined cross-sectional view of the transmitter module housing, which includes a pressure sensor and a measurement circuit system.

[0009] Figure 3 yes Figure 2 A cross-sectional view of the sensor module shows the wires connecting the pressure sensor to the measurement circuitry carried on the circuit board.

[0010] Figure 4 is a perspective view of a prior art configuration in which connecting wires are routed through through-holes in the circuit board.

[0011] Figure 5 is a perspective view of a prior art configuration in which connecting wires are laid around the edge of the circuit board and wound around the posts of the circuit board.

[0012] Figure 6 It is a plan view of a circuit board, in which slots are used to place connecting wires in through holes in the circuit board.

[0013] Figure 7 yes Figure 6 A close-up perspective view of the slots and through-holes in the circuit board.

[0014] Figure 8 This is a perspective view of a circuit board located in a sensor module, which uses slots to place wires in through holes.

[0015] Figure 9 This is a close-up perspective view of another example embodiment of a slot with a certain angle for placing wires in a through hole.

[0016] Figure 10 This is a close-up perspective view of another example embodiment of a spiral groove for placing wires in a through-hole.

[0017] Figure 11 This is a close-up perspective view of another example embodiment of a tapered groove for placing wires in a through-hole. Detailed Implementation

[0018] As discussed in the Background section, process variable transmitters must operate reliably under harsh environmental conditions. Components within the transmitter must be sealed from the external environment and withstand extreme conditions, including vibration, physical shock, and extreme temperatures. Even under these conditions, the electrical components within the device must maintain their electrical connections. In current pressure transmitter configurations, such as Rosemount's 3051C and 3051S_C, making electrical connections from the pressure sensor to the circuit board carrying the measurement circuitry can be challenging. Blind through-hole connections (“through holes”) are used to connect leads from the pressure sensor to the measurement circuitry. This arrangement provides robust electrical connections. However, this is only feasible for a small number of interconnects and requires manual assembly. In another configuration, wire-wound posts are used for electrical connections. This configuration allows for higher wire density but requires significant assembly precision to make the connections without creating weaknesses in the leads or damaging the strain relief components.

[0019] In one aspect, the present invention provides a novel conical groove geometry that can be implemented to enable higher-density connections from the pressure sensor to the circuit board carrying the measurement circuitry. This facilitates the formation of robust and reliable connections in automated assembly processes and allows the pressure transmitter to achieve higher vibration levels than existing configurations.

[0020] Embodiments of this disclosure are described more fully below with reference to the accompanying drawings. Elements identified using the same or similar reference numerals refer to the same or similar elements. For simplicity of illustration, some elements may not be shown in every figure.

[0021] However, the various embodiments of this disclosure may be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0022] Figure 1A front view of an exemplary process fluid pressure transmitter 100 is shown. The pressure transmitter 100 includes an electronics housing 101 enclosing an electronic circuitry system, and a pressure sensor module housing 102 housing an isolator diaphragm, a pressure sensor, and associated sensor measurement circuitry. The pressure sensor module housing 102 is bolted to a pressure flange (not shown) by bolts 105. The pressure flange provides one or more process fluid pressures to the transmitter 100 for pressure measurement. The pressure transmitter 100 is connected to a process control loop 103, which actuates the pressure transmitter 100 and provides bidirectional communication for use in a process control system. The process control loop 103 can be configured according to any suitable process control communication standard. For example, loop 103 may carry a 4-20 mA current that carries information and provides power to the device. Digital signals may also be transmitted on loop 103. In another embodiment, loop 103 is a wireless embodiment, where the loop provides wireless communication between the process variable transmitter 101 and a remote location, such as a control room.

[0023] The pressure sensor module housing 102 (which measures differential pressure in this embodiment) includes an isolator diaphragm 110 (e.g., [missing information]) directly welded to the pressure sensor module housing 102. Figure 2 (As shown). The housing 102 also includes bolt holes 112 in a standard pattern surrounding the isolator diaphragm 110.

[0024] Figure 2 An inclined cross-sectional view of the pressure sensor module housing 102 is shown. The differential pressure sensor 140 is located inside the pressure sensor module housing 102 and is connected to the isolator diaphragm 110 via fittings (pulse tubes) 142 and 144. The isolator diaphragm 110 is directly welded to the pressure sensor module housing 102. Figure 2 In this configuration, pressure sensor 140 is configured as a capacitance-based sensor. A differential pressure is applied to sensor 140 via filling fluid carried in fittings 142, 144, and an internal diaphragm deflects in response to the applied pressure. This causes the capacitance between the inner wall of sensor 140 and the sensor diaphragm to change according to the applied pressure. Circuit board 146 provides a measurement circuitry associated with processing the electrical signal from differential pressure sensor 140. The differential pressure can be used to measure the flow rate of process fluid through process piping, the fill level of process fluid in a tank, or other process variables. An optional flat cable reel 148 houses a flat cable that provides access from circuit board 146 to an electronics housing (e.g., Figure 1 Electrical connections of the circuitry within the housing 101 shown. In another configuration, module 102 operates independently and transmits information related to sensed pressure via, for example, process control loop 103.

[0025] As discussed above, in the pressure transmitter, lead 200 from pressure sensor 140 is connected to the measurement circuitry carried on circuit board 146. This is in Figure 3 The sensor module 102 is shown in a cross-sectional view. Some configurations of the coplanar sensor module 102 have between three and five pins 200 that must be connected to the circuit board 146.

[0026] In a prior art configuration shown in Figure 4, three wires 200 are pulled through through-holes 202 in a circuit board 146 and soldered into place. The through-holes have electrical traces connecting the wires 200 to a measurement circuitry carried on the circuit board 146. This configuration provides a robust arrangement capable of withstanding the harsh environments common in industrial processes. However, this technique is only suitable for a small number of electrical connections. Furthermore, this technique requires manual assembly and soldering of the connections.

[0027] Another example of a prior art configuration uses five conductors 200 laid around the edge 206 of the plate 146. The conductors 200 are then manually wound around a square turntable or post 204 and soldered in place, as shown in the perspective view of Figure 5. The assembly process requires a high level of operator skill to achieve these joints without creating weaknesses in the conductors 200. Furthermore, strain relief elements are preferably carried on the conductors 200 and serve to protect them from forces applied along the edge 206 of the plate 146. Care must be taken during the assembly process to ensure that these strain relief elements are not damaged. Additionally, the turntable 204 requires considerable space on the plate 146, and winding it is time-consuming.

[0028] This invention provides a novel lead connector geometry for industrial process pressure transmitters to address the aforementioned challenges. Figure 6 An example of this configuration is shown in the figure. Figure 6 This is a plan view of printed circuit board 146. Figure 6 In the plan view shown, circuit board 146 includes a plurality of through holes 220. The through holes 220 are coupled to slots 222, which extend from the through holes 220 to the edge 206 of circuit board 146. Figure 6 A measurement circuit system 226 mounted on circuit board 146 is also shown. The measurement circuit system 226 is electrically connected to via through-hole 220 via trace connection 228. Figure 6 The configuration shows seven through holes 220 and slots 222; however, any number can be used as needed.

[0029] Figure 7 This is an enlarged perspective view of the through hole 220 shown in Figure 5. (As shown...) Figure 7As shown, the through-hole 220 is surrounded by metal pads 230. The opening provided by the through-hole 220 extends to the edge 206 of the printed circuit board 146 by means of a groove 222. The metal pads 230 are adapted to provide solder connections and electrical connections, for example... Figure 6 The trace connection 228 is shown. The wire 200 can be slid into place by sliding it through the slot 222 and into the position in the through hole 220. Once the wire 200 is in place, it can be soldered to the metal pad 230 to secure the wire within the through hole 220 and provide an electrical connection to the measurement circuitry 226 via the trace connection 228. Figure 8 This is a perspective view of module 102, showing a circuit board 146 fixed in place by wires 200 soldered to metal pads 230.

[0030] The slotted configuration is ideal for automated assembly, where the wire 200 is automatically placed into the through-hole 220 by pulling it through the slot 222. The wire 200 can then be soldered to the metal pad 230 using an automated soldering station. This configuration provides a robust design that can withstand high levels of G-forces and vibration. In one configuration, the slot 222 has a helical or angled shape to facilitate the placement and / or securing of the wires 200 in their correct positions during assembly. This configuration, for example... Figure 9 As shown in the plan view. Figure 9 In this configuration, the slot 222 includes at least one angle. The action of pulling the wire 200 through the slot 222 causes a springback force to push the wire 200 toward the edge 206 of the plate 146. After the wire 200 has been moved around the bend in the slot 222, this force holds the wire 200 in place until it is soldered into place. Figure 10 Another example configuration using spiral groove 220 is shown. Figure 11 The conical groove 220 configuration is shown in the figure.

[0031] In one configuration, the wire 200 is soldered to the circuit board 146 before being connected to the sensor 140. A strain relief feature can also be provided on the wire 200 to improve reliability. A feature can also be provided to help guide the wire 200 to the correct position during assembly.

[0032] Although the invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes in form and detail may be made without departing from the spirit and scope of the invention. With this configuration, the wire 200 can slide through the slot 222 into place and be soldered to the metal pad 230. After soldering, excess wire can be trimmed so that the wire 200 is substantially flush with the surface of the circuit board 146. Although a capacitive pressure sensor has been described herein, the invention is applicable to any type of pressure sensing technology. Although three and five wires are shown, any number of wires can be used. Although a pressure transmitter has been discussed, the invention can be used with any type of process variable transmitter.

Claims

1. A process variable transmitter configured to sense the process pressure of a process fluid in an industrial process, comprising: case; A pressure sensor configured to sense applied pressure and having electrical characteristics that change in response to said applied pressure; A measurement circuit system, carried on a circuit board, is configured to be electrically coupled to the pressure sensor and to measure the process pressure based on changes in the electrical characteristics of the pressure sensor. At least one through-hole is formed in the printed circuit board and electrically coupled to the measurement circuit system; A groove that extends from the through-hole to the edge of the circuit board; as well as A wire, soldered in the through-hole and electrically connected to the pressure sensor, thereby completing the electrical connection between the pressure sensor and the measurement circuit system for sensing the electrical parameters of the pressure sensor via the measurement circuit system.

2. The process variable transmitter according to claim 1, wherein the groove is straight.

3. The process variable transmitter according to claim 1, wherein the slot includes at least one angle.

4. The process variable transmitter according to claim 1, wherein the slot is conical.

5. The process variable transmitter of claim 1, comprising a metal pad surrounding the through-hole and electrically coupled to the measurement circuitry.

6. The process variable transmitter according to claim 5, wherein the wire is soldered to the metal pad.

7. The process variable transmitter of claim 1, comprising a total of three wires welded to the through-hole, the three wires connecting the pressure sensor to the measurement circuit system.

8. The process variable transmitter of claim 1, comprising a total of five wires welded to the through-hole, the five wires connecting the pressure sensor to the measurement circuit system.

9. The process variable transmitter of claim 1, wherein the process variable transmitter is coupled to a process control loop and information related to the sensed pressure is transmitted on the process control loop.

10. The process variable transmitter according to claim 1, wherein the slot is angled or helical.

11. The process variable transmitter according to claim 1, wherein the pressure sensor comprises a differential pressure sensor.

12. A method for manufacturing a process variable transmitter configured to sense the process pressure of a process fluid in an industrial process, comprising: Set the casing; A pressure sensor is provided, the pressure sensor being configured to sense the applied pressure and having electrical characteristics that change in response to the applied pressure; A measurement circuit system is provided, which is carried on a circuit board and configured to be electrically coupled to the pressure sensor and to measure the process pressure based on the change in the electrical characteristics of the pressure sensor; At least one through-hole is formed in the printed circuit board, and the at least one through-hole is electrically coupled to the measurement circuit system; A groove is formed extending from the through-hole to the edge of the circuit board; A sliding wire passes through the groove and enters the through hole, the wire electrically connecting the through hole to an electrical connection on the pressure sensor, thereby completing the electrical connection between the pressure sensor and the measurement circuit system for sensing the electrical parameters of the pressure sensor through the measurement circuit system; as well as The wire is soldered to the through hole.

13. The method of claim 12, wherein the groove is straight.

14. The method of claim 12, wherein the groove includes at least one angle.

15. The method of claim 12, wherein the groove is conical.

16. The method of claim 12, further comprising providing metal pads surrounding the via and electrically coupled to the measurement circuitry.

17. The method of claim 16, wherein the wire is soldered to the metal pad.

18. The method of claim 12, further comprising connecting the pressure sensor to the measurement circuit system using a total of three wires welded to the through-hole.

19. The method of claim 12, further comprising connecting the pressure sensor to the measurement circuitry using a total of five or more wires welded to the through-hole.

20. The method of claim 1, wherein the groove is angled or helical.

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