Customizing a process variable transmitter with emi-protected electronics having a hermetic seal

Abstract

A process variable transmitter (102) includes a process variable sensor (110), and an electromagnetic interference (EMI) protection circuit (182) coupled to the process variable sensor (110). The process variable transmitter (102) also includes a hermetic module (104C) enclosing the EMI protection circuit (182), and electrical connectors (132A, 134A, 136A) coupled to the EMI protection circuit (182) within the hermetic module (104C). The EMI protection circuit is configurable from outside the hermetic module (104C) via the electrical connectors (132A, 134A, 136A) to interconnect electronic components of the EMI protection circuit (182) in one of two configurations, for example to provide or not provide transient protection.

Description

Background Technology

[0001] In the process control industry, process transmitters are often placed in or near corrosive / hazardous environments. Therefore, in some process transmitter architectures, the transmitter electronics are housed in a hermetically sealed package with a floating lead serving as a customer interface to simplify approval requirements. To achieve this hermetically sealed design, a limited number of electrical signals are transmitted through the sealed connector interface.

[0002] Industrial process transmitters typically offer standard or transient protection options. Transient protection options provide enhanced protection against lightning and other unexpected power surges, but also require additional transient suppression electronics to be protected against environmental conditions. Summary of the Invention

[0003] The embodiments disclosed herein provide a process variable transmitter architecture in which signals from a hermetically sealed manifold can be configured to output connectors upon final assembly, allowing a single, hermetically sealed module to offer both standard and transient protection options. This overcomes approval hurdles in hazardous locations and provides the ability for later customization, which reduces module inventory.

[0004] In one embodiment, a process variable transmitter is provided. The process variable transmitter includes a process variable sensor and electromagnetic interference (EMI) protection circuitry coupled to the process variable sensor. The process variable transmitter also includes a hermetically sealed module enclosing the EMI protection circuitry and an electrical connector coupled to the EMI protection circuitry within the hermetically sealed module. The electrical connector can be configured externally to the hermetically sealed module to connect the electronic components of the EMI protection circuitry in a configuration that provides transient protection.

[0005] In another embodiment, a method is provided. The method includes enclosing EMI protection circuitry coupled to a process variable sensor within a hermetically sealed module, wherein an electrical connector extends to the outside of the hermetically sealed module. The method also includes connecting electronic components of the EMI protection circuitry from outside the hermetically sealed module via the electrical connector in a configuration providing transient protection.

[0006] In yet another embodiment, a process variable transmitter is provided. The process variable transmitter includes a process variable sensor and EMI circuitry coupled to the process variable sensor. The process variable transmitter also includes a hermetically sealed module enclosing the EMI protection circuitry. The hermetically sealed module has a first end portion including a feedthrough and a plurality of feedthrough pins passing through and hermetically sealed to the feedthrough. The feedthrough pins are coupled to the EMI protection circuitry within the hermetically sealed module and can be configured from outside the hermetically sealed module to connect electronic components of the EMI protection circuitry in a configuration providing transient protection.

[0007] This invention is provided to introduce a series of concepts in a simplified form, which are further described in the detailed embodiments below. This invention 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

[0008] Figure 1 This is a partial cross-sectional view of an example process control system, which includes a pressure transmitter that can be utilized with embodiments of the present disclosure.

[0009] Figure 2 yes Figure 1 A simplified block diagram of a pressure transmitter.

[0010] Figure 3 This is a schematic diagram showing the electrical architecture, where components for transient protection or electromagnetic interference (EMI) protection are located outside the hermetic module of the process transmitter.

[0011] Figure 4 The image shows an airtight module that includes EMI protection circuitry and an output assembly without any EMI protection components.

[0012] Figure 5 This is a schematic diagram illustrating the configuration of an airtight module output component according to one embodiment, wherein an additional feedthrough is routed to electrical ground for transient protection.

[0013] Figure 6 This is a schematic diagram showing the configuration of the output components of the airtight module, where for units without transient protection, the additional feedthrough is routed back to its corresponding line. Detailed Implementation

[0014] Embodiments of this disclosure are described more fully below with reference to the accompanying drawings. Elements identified by 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. However, 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.

[0015] The embodiments of this disclosure generally relate to custom process variable transmitters with hermetically sealed electronics. More specifically, embodiments of this disclosure provide a common hermetically sealed module that can be reconfigured after assembly to provide standard or transient protection options while meeting hazardous location approval requirements. Before providing details about the different embodiments, a description of an example process control system including a process transmitter is provided below.

[0016] Figure 1 An example process control system that can be incorporated into certain specific implementations disclosed herein is shown. Figure 1 The process control system shown is for illustrative purposes only. Embodiments of this disclosure are not limited to any particular process control system, such as... Figure 1 The process control system shown is illustrated. Embodiments of this disclosure are illustratively practiced in any number of different types of process control systems.

[0017] Figure 1 The diagram shows a schematic and partial cross-sectional view of an example of a process control system 100, which includes a process variable transmitter (e.g., a pressure transmitter) 102 that can utilize embodiments of the present disclosure. Figure 2 yes Figure 1 A simplified block diagram of transmitter 102. System 100 can be used in the handling of materials (e.g., process media) to transform materials from a lower-value state into higher-value and more useful products, such as petroleum, chemicals, paper, food, etc. For example, system 100 can be used in facilities performing hygienic processes or other types of industrial processes.

[0018] The pressure transmitter 102 may include a housing 104, which can be coupled to an industrial process 106 via a process coupling 108. The housing 104 and the process coupling 108 may be formed of stainless steel or another suitable material. The transmitter 102 includes a pressure sensor assembly 110, which includes a pressure sensor 112 and measurement circuitry 114 within the housing 104. The measurement circuitry 114 may include processing / computing circuitry, communication circuitry, and electromagnetic interference (EMI) protection circuitry. In the transmitter 102, a first end 116 of the housing 104 surrounds and contacts the outer surface of a feedthrough 118 for electrical connections as described further below, and is hermetically sealed to the feedthrough 118 by brazing or welding or any other suitable technique. Similarly, a second end 120 of the housing 104 is hermetically sealed using any suitable technique to form a hermetically sealed chamber in which the pressure sensor assembly 110 and the measurement circuitry 114 are housed.

[0019] Process coupling 108 can be connected to pipe 121, which connects to process 106 and contains process material (e.g., fluid) at pressure P, which will be measured by pressure sensor 112. Pressure P is transmitted to pressure sensor 112 via fluid passage 122. Pressure sensor 112 includes a sensor element having electrical parameters indicating the applied pressure P. Measurement circuit 114 can detect and process the electrical parameters of the sensor element via suitable electrical connection 124 to establish the value of the sensed pressure P. The measured pressure value and any other information from measurement circuit 114 are transmitted via suitable output electrical connection 128 and through process control loop 130 to an external computer control unit 126 located in a remote control room 127, such as... Figure 1 As indicated in the document.

[0020] like Figure 2 As best seen, the output electrical connection 128 has three electrical connectors (e.g., wires), including a first active connector 132, a second active connector 134, and an electrical ground connector 136. More or fewer connectors may also be used. The first ends of connectors 132, 134, and 136 are coupled to feedthrough pins 138, 140, and 142, respectively, which pass through a feedthrough body 118 and are sealed to the feedthrough body 118 by a sealing material such as glass or ceramic. For example, pin 142 passes through an opening 144 in the feedthrough body 118 and is sealed to the feedthrough body 118 by a cylindrical glass sealing layer 156. The second ends of wires 132, 134, and 136 can be connected to pads on a printed circuit board, such as a transmitter measurement circuit 114. The feedthrough body 118, together with the feedthrough pins 138, 140, and 142, is sometimes referred to herein as a manifold.

[0021] As in Figures 1 to 2 As can be seen, transmitter 102 includes an output assembly 158 that is detachably coupled to housing 104. Output assembly 158 includes housing 160, output interface 162, and floating leads 164, 166, and 168 coupled to output interface 162. The portions of output interface 162 and floating leads 164, 166, and 168 within housing 160 are encapsulated using any suitable material 170. When output assembly 158 is as described... Figure 1 When coupled to housing 104 as shown, floating leads 164, 166, and 168 are electrically connected to connectors 132, 134, and 136 via output interface 162 and corresponding feedthrough pins 138, 140, and 142, respectively. Floating lead 168 is connected to electrical ground, and floating leads 164 and 166 are connected to process control loop 130.

[0022] Communication between the control unit 126 or another external computing device and the pressure transmitter 102 can be performed via the control loop 130 according to conventional analog and / or digital communication protocols. In some embodiments, the two-wire control loop 130 includes a 4 to 20 mA control loop, wherein the measured pressure value can be represented by the level of the loop current flowing through the two-wire control loop 130. Exemplary digital communication protocols include those based on… The communication standard modulates the digital signal onto the analog current level of the two-wire control loop 130. Other purely digital technologies, including FieldBus and Profibus communication protocols, can also be used.

[0023] In some implementations, wireless communication between the transmitter 102 and the control unit 130 may also be provided. Exemplary wireless versions of the process control loop 130 include, for example, wireless mesh network protocols, such as... (IEC62591) or ISA 100.11a (IEC 62734), or another wireless communication protocol, such as WiFi, LoRa, Sigfox, BLE or any other suitable protocol.

[0024] Power can be supplied to the pressure transmitter 102 from any suitable power source. For example, the pressure transmitter 102 can be powered entirely by the current flowing through the control loop 130. One or more power sources, such as internal or external batteries, can also be used to power the pressure transmitter 102. A generator (e.g., solar panels, wind turbines, etc.) can also be used to power the pressure transmitter or to charge the power source used by the pressure transmitter 102.

[0025] The goal is to manufacture industrial process variable transmitters (e.g., at a single location) Figure 1 and Figure 2 The pressure transmitter 102) has an airtight sealing module (e.g., with Figure 1 and Figure 2 The housing 104 of the internal components shown allows for later customization of standard or transient protection options at different final assembly locations. One technique for achieving this is to position the components providing transient protection on the printed circuit assembly (PCA) outside the hermetic-sealed module. If this method is used... Figure 1 and Figure 2 For the process transmitter 102, the output interface 162 will include a PCA. Here, the PCA will provide a connection between the hermetically sealed module 104 and the suspended leads 164, 166, and 168 for the user interface. The PCA and the suspended lead assembly 164, 166, and 168 will be immersed in encapsulation material 170 to meet hazardous location approval requirements.

[0026] Figure 3This is a schematic diagram showing the electrical architecture 180, where components for transient protection are located outside the hermetic module 104A of the process transmitter. The hermetic module 104A includes a first active electrical connector 132A, a second active electrical connector 134A, and an electrical grounding connector 136A. For simplicity, other circuitry and components within the hermetic module 104A (such as...) are not shown. Figure 1 The sensor assembly 110). The output assembly 158A, detachably coupled to the hermetic module 104A, includes an EMI protection circuit 182 electrically connected to connectors 132A, 134A, and 136A via electrical connectors 132B, 134B, and 136B, respectively. The EMI protection circuit 182 includes capacitors C1 and C2, transient voltage suppression (TVS) diodes D1 and D2, a gas discharge tube GT1, and resistors R1 and R2. (As shown in...) Figure 3 As can be seen, the first capacitor C1 is connected between the active electrical connector 132B and the grounding connector 136B, and the second capacitor C2 is connected between the active electrical connector 134B and the grounding connector 136B. Each capacitor C1, C2 has a capacitance value of 1500 picofarads (pF) or any other suitable capacitance value. Capacitors C1 and C2 mitigate any changes in voltage or current in circuit 182 caused by induced transients. In one embodiment, TVS diodes D1 and D2 are bidirectional TVS diodes, represented by two opposing avalanche diodes connected in series. The first TVS diode D1 is connected between the active electrical connector 132B and the grounding connector 136B, and the second TVS diode D2 is connected between the active electrical connector 134B and the grounding connector 136B. Each TVS diode D1, D2 may have a cutoff voltage or breakdown voltage of 70 volts (V) or any other suitable breakdown voltage value. TVS diodes D1 and D2 operate by cutting off excessive current when the induced voltage exceeds the breakdown voltage. TVS diodes D1 and D2 automatically reset when the overvoltage disappears. The gas discharge tube GT1 is a three-electrode gas discharge tube with a first electrode 1 connected to active electrical connector 132B, a second electrode 2 connected to electrical ground connector 136B, and a third electrode 3 connected to active electrical connector 134B. The three electrodes 1, 2, and 3 allow the use of a single gas discharge tube GT1 to protect circuit 182. When a voltage greater than its rated breakdown voltage is applied across the gas discharge tube GT1, the gas in the gas discharge tube GT1 begins to ionize and conduct electricity until the gas reaches its pulsed spark discharge voltage. At this time, the gas discharge tube GT1 is in its fully conducting state and maintains a low arc voltage regardless of the discharge current. After the transient passes, the gas discharge tube GT1 resets to its non-conducting state. The gas discharge tube GT1 can have a pulsed spark discharge voltage of 90V or any other suitable pulsed spark discharge voltage value.

[0027] Resistors R1 and R2 are included in the EMI protection circuit 182 to help provide protection from the time the transient is first sensed until the gas discharge tube GT1 reaches its pulsed spark discharge voltage. Figure 2 In this implementation, resistor R1 is connected in series with active electrical connector 132B, and resistor R2 is connected in series with active electrical connector 134B. Resistors R1 and R2 can be wire-wound, axial, etc., and can have any suitable resistance value. As described above... Figure 1 and Figure 2 As indicated, the PCA, including the EMI protection circuit 182 and the suspended wires 164, 166, 168, is immersed in the encapsulation material 170 to meet hazardous location approval requirements.

[0028] Additional types of protection may also be expected in the transmitter design, such as Ex mb (for providing a high level of safety encapsulation) or Ex eb (explosion protection according to the Increased Safety for Zone 1 standard). However, there are some additional safety requirements that make it difficult to meet approval. For example, these include capacitors (e.g. Figure 3 C1 and C2), gas discharge tube (e.g. Figure 3 GT1) and resistors (e.g. Figure 3 Components (R1 and R2) that may be considered to be at risk of ignition need to be immersed in the bonded joint before and after extended thermal aging and after passing a high-pressure hydrostatic test.

[0029] In one instance, testing revealed that water seeped into the output component / manifold interface during high-pressure testing and did not meet approval criteria for additional types of protection, such as Ex mb and Ex eb.

[0030] One technique for meeting approval requirements for additional types of protection involves moving all electrical components used for transient protection (e.g., EMI protection circuitry 182) inside the hermetically sealed module. This simplifies the approval process for output assembly 158, which only includes the suspended conductors 164, 166, 168 immersed in encapsulation material 170, allowing for a direct approach to accepting approval requirements. However, the number of hermetically sealed modules doubles because two versions are used, one for standard protection and the other for transient protection. Figure 4 An airtight module 104B is shown, including an EMI protection circuit 182 and an output assembly 158B without any EMI protection components. For simplicity, Figure 4 The suspended conductors 164, 166, and 168 are not shown. The hermetic sealing module for the standard option is not shown.

[0031] To address the complexity, cost, and early customization issues associated with having two different versions of the hermetic sealing module, an alternative solution is provided. The following section combines... Figure 5 and Figure 6 To describe the solution.

[0032] This article combines Figure 5 and Figure 6 The described embodiments of this disclosure provide an architecture in which the electronics within the hermetically sealed package can be reconfigured after assembly, while meeting hazardous location approval requirements. Post-assembly customization of standard and transient outputs is selected at the hub during the final assembly process. This avoids the need for association with the foregoing. Figure 4 The described architecture is associated with cost, complexity, and distribution challenges. Additionally, the lack of components within the encapsulation region of the output components simplifies security zone 1 approval.

[0033] As in Figure 4 In that architecture, Figure 5 and Figure 6 The architecture shown moves the electronic components inside the hermetically sealed module. However, the connections to the protection diodes D1 and D2, as well as the gas discharge tube GT1, pass outside the hermetically sealed module using an additional feedthrough on the existing header. Post-construction customization is achieved by attaching different wire interface boards during final assembly.

[0034] Figure 5 This is a schematic diagram illustrating a configuration of a first hermetic module 104C-output component 158C according to one embodiment, wherein additional feedthroughs 184 and 186 are routed to ground for transient protection. (See also...) Figure 5 As can be seen, the hermetic module 104C includes an EMI protection circuit 182 with transient protection elements, and additional feedthroughs 184 and 186 are connected to these transient protection elements. More specifically, feedthrough 184 is connected to a first TVS diode D1, and feedthrough 186 is connected to both a second TVS diode D1 and a gas discharge tube GT1. The output assembly 158C includes a wire interface board 188A, which includes connectors (e.g., traces) 190, 192, 194, 196, and 198. Trace 190 is connected to an active floating lead 164, trace 192 is connected to an active floating lead 166, and trace 194 is connected to a ground floating lead 168. Traces 196 and 198 are connected to the ground trace 194. When output component 158C is coupled to airtight module 104C, traces 190, 192, 194, 196, and 198 are connected to feedthroughs 138, 140, 142, 184, and 186, respectively. As in Figure 5As can be seen, in this connection configuration, the first TVS diode D1 is connected between the active electrical connector 132A and the electrical ground via trace 196, and the second TVS diode D2 is connected between the active electrical connector 134A and the electrical ground via trace 198. Additionally, the second electrode 2 of the gas discharge tube GT1 is connected to the electrical ground via trace 198. Therefore, transient protection is achieved in this connection configuration.

[0035] Figure 6 This is a schematic diagram showing the configuration of the second airtight module 104C - output component 158C, where, for units without transient protection, additional feedthroughs 184 and 186 are routed back to their respective lines 132A and 134A. Figure 6 In the wire interface board 188B, trace 196 is routed to trace 190, which is electrically connected to active electrical connector 132A via feedthrough 138. Similarly, trace 198 is routed to trace 192, which is electrically connected to active electrical connector 134A via feedthrough 140. Therefore, no transient protection is provided in this configuration. Besides the lack of transient protection in the routing, Figure 6 The rest of the circuit is similar to Figure 5 The circuit.

[0036] Figure 5 and Figure 6 The structure shown allows the same hermetic module to be used in units with and without transient protection. For example, customization can be done at the hub, possibly in units already designed for... Figure 4 The architecture was customized several weeks later. This avoided the additional costs of building extra modules and the larger annual costs of maintaining them. It should be noted that a single wire interface board with one or more switches to toggle between the two configurations can be used, instead of separate wire interface boards 188A and 188B for the two different connection configurations.

[0037] The approval process has also been simplified. Because the concept of Zone 1 increased safety approval is to reduce the risk of heat and spark hazards, many common electrical components are not permitted. Removing electrical components from the encapsulated conduit inlet area allows for seamless and direct analysis to obtain approval.

[0038] This method allows end users the flexibility to install the equipment for fire-resistant or increased safety purposes. Because all electronic components are moved inside a hermetically sealed package, the electronics are insensitive to humidity. Very late-stage customization is possible. Users can configure the equipment during commissioning. The equipment can be reconfigured long after customer ownership. For example, a customer can reconfigure the equipment in the field, perhaps years after the initial commissioning.

[0039] The architecture of the implementation plan can be extended to include other functionalities. For example:

[0040] a. The unit can be configured to communicate using HART, fieldbus, or Modbus protocols.

[0041] b. A unit can be configured for standard power or low power output protocols.

[0042] Figure 7 This is a simplified flowchart of an embodiment of method 200. At 202, the electromagnetic interference (EMI) protection circuit coupled to the process variable sensor is enclosed in a hermetically sealed module, wherein an electrical connector extends to the outside of the hermetically sealed module. At 204, the electronic components of the EMI protection circuit are connected from the outside of the hermetically sealed module via the electrical connector in a configuration that provides transient protection.

[0043] 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.

Claims

1. A process variable transmitter, comprising: Process variable sensors; An electromagnetic interference (EMI) protection circuit is coupled to the process variable sensor. An airtight module that encloses the EMI protection circuit; as well as An electrical connector, coupled to the EMI protection circuitry within the hermetic module, and configurable from outside the hermetic module to connect the electronic components of the EMI protection circuitry in a configuration providing transient protection. The electrical connector coupled to the EMI protection circuit within the hermetic module can be configured from outside the hermetic module to connect the electronic components of the EMI protection circuit in a standard configuration without the transient protection.

2. The process variable transmitter of claim 1, wherein the electrical connector comprises a first electrical connector electrically coupled to a first electronic component in the electronic components of the EMI protection circuit, and wherein the first electronic component is further coupled to an active electrical conductor.

3. The process variable transmitter of claim 2, wherein the first electrical connector is coupled to an external electrical grounding connector of the hermetic module so that the first electronic component can provide the transient protection.

4. The process variable transmitter of claim 2, wherein the first electrical connector is capable of coupling from outside the hermetic module to the active electrical conductor to prevent the first electronic component from providing the transient protection.

5. The process variable transmitter of claim 1, further comprising a feedthrough located at a first end of the hermetic module, and the electrical connector comprising a plurality of feedthrough pins passing through the feedthrough and hermetically sealed to the feedthrough, the feedthrough pins comprising: The first active conductor feed pin and the second active conductor feed pin enable the first active conductor and the second active conductor inside the hermetic module to be electrically coupled to the first active conductor and the second active conductor outside the hermetic module. An electrical grounding feedthrough pin, which enables the internal electrical grounding connector of the hermetic module to be electrically coupled to the external electrical grounding connector of the hermetic module; and A first additional feedthrough pin and a second additional feedthrough pin, the first additional feedthrough pin and the second additional feedthrough pin being coupled to different electronic components in the electronic components of the EMI protection circuit, wherein each different electronic component is also coupled to the first active conductor or the second active conductor in the hermetic module.

6. The process variable transmitter of claim 5, wherein the first additional feedthrough pin and the second additional feedthrough pin are coupled to the electrical grounding connector outside the hermetic module to provide transient protection from outside the hermetic module.

7. The process variable transmitter of claim 5, wherein, in order to disable the transient protection, the first additional feedthrough pin is coupled to the first active electrical conductor outside the hermetic module, and the second additional feedthrough pin is coupled to the second active electrical conductor outside the hermetic module.

8. The process variable transmitter of claim 5, wherein the electronic components include a first transient voltage suppression TVS diode, a second transient voltage suppression TVS diode, and a gas discharge tube.

9. The process variable transmitter as described in claim 8, wherein: The first transient voltage suppression TVS diode is coupled to the first active electrical conductor in the hermetic module and to the first additional feedthrough pin in the hermetic module; The second transient voltage suppression TVS diode is coupled to the second active conductor in the hermetic module and to the second additional feedthrough pin in the hermetic module; and The gas discharge tube is coupled to the first active conductor and the second active conductor in the airtight module, and is also coupled to the second additional feedthrough pin in the airtight module.

10. A method for a process variable transmitter, comprising: The electromagnetic interference (EMI) protection circuit coupled to the process variable sensor is enclosed in an airtight module, wherein the electrical connector extends to the outside of the airtight module; Electronic components of the EMI protection circuit are connected from outside the hermetic module via the electrical connector in a configuration that provides transient protection; as well as The electronic components of the EMI protection circuit are connected from outside the hermetic module via the electrical connector in a standard configuration without the transient protection.

11. The method of claim 10, further comprising electrically coupling a first electrical connector in the electrical connector to a first electronic component in the electronic components of the EMI protection circuit, wherein the first electronic component is further coupled to an active electrical conductor.

12. The method of claim 11, further comprising coupling the first electrical connector to an external electrical grounding connector for providing the transient protection by the first electronic component.

13. The method of claim 11, further comprising electrically coupling the first electrical connector to the active electrical conductor from outside the hermetic module to prevent the first electronic component from providing the transient protection.

14. A process variable transmitter, comprising: Process variable sensors; An electromagnetic interference (EMI) protection circuit is coupled to the process variable sensor. An airtight module that encloses the EMI protection circuit, the airtight module having a first end, the first end including a feedthrough and a plurality of feedthrough pins passing through the feedthrough and airtightly sealed to the feedthrough. The feedthrough pin is coupled to the EMI protection circuit within the hermetic module and can be configured from outside the hermetic module to connect the electronic components of the EMI protection circuit in a configuration that provides transient protection. The plurality of feedthrough pins include: The first active conductor feed pin and the second active conductor feed pin enable the first active conductor and the second active conductor inside the hermetic module to be electrically coupled to the first active conductor and the second active conductor outside the hermetic module. An electrical grounding feedthrough pin, which enables the internal electrical grounding connector of the hermetic module to be electrically coupled to the external electrical grounding connector of the hermetic module; and A first additional feedthrough pin and a second additional feedthrough pin, the first additional feedthrough pin and the second additional feedthrough pin being coupled to different electronic components in the circuit electronics of the EMI protection circuit, wherein each different electronic component is also coupled to the first active conductor or the second active conductor in the hermetic module.

15. The process variable transmitter of claim 14, wherein the first additional feedthrough pin and the second additional feedthrough pin are coupled to the electrical grounding connector outside the hermetic module to provide transient protection from outside the hermetic module.

16. The process variable transmitter of claim 14, wherein, in order to disable the transient protection, the first additional feedthrough pin is coupled to the first active electrical conductor outside the hermetic module, and the second additional feedthrough pin is coupled to the second active electrical conductor outside the hermetic module.

17. The process variable transmitter of claim 14, wherein the electronic components include a first transient voltage suppression TVS diode, a second transient voltage suppression TVS diode, and a gas discharge tube, and wherein: The first transient voltage suppression TVS diode is coupled to the first active electrical conductor in the hermetic module and to the first additional feedthrough pin in the hermetic module; The second transient voltage suppression TVS diode is coupled to the second active electrical conductor in the hermetic module and to the second additional feedthrough pin in the hermetic module; The gas discharge tube is coupled to the first active conductor and the second active conductor in the airtight module, and is also coupled to the second additional feedthrough pin in the airtight module.

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