Surge protection device, transmitter, surge protection system and mutual communication transmitter

Abstract

The invention relates to a surge protection device, a transmitter, a surge protection system and a mutual communication transmitter. A surge protection device (1) is mounted on a transmitter. The terminal block screw portions (12, 13) are connected to a cable that transmits a signal from an external device. The connector is detachable with respect to a connector member of the transmitter, and outputs an input signal from the terminal block threaded portions (12, 13) to the connector member. The surge protection element absorbs a surge current when a surge voltage is applied to the connector member from the terminal block screw portions (12, 13). The terminal connector part (11) is connected to the terminal block screw parts (12, 13) via a surge protection element.

Description

Technical Field

[0001] This invention relates to a surge protection device, a transmitter, a surge protection system, and a mutually communicating transmitter. Background Technology

[0002] In the past, in process control of various workshops using petroleum, petrochemicals, chemicals, gases, etc., field devices such as pressure transmitters were used to ensure stable process control by the controller. Based on the information obtained from the field devices, the workshop control system controlled and managed the workshop.

[0003] Typically, field devices have power terminals, which are connected to the power cable to receive the power required for operation. Additionally, for two-wire transmitters, the power cable also serves as a current output signal cable with a variable current range of 4-20mA.

[0004] Due to lightning strikes, high-voltage facilities, and other factors, power cables can sometimes be subjected to instantaneous, large, abnormal voltages known as surge voltages. To protect field equipment from these surge voltages, surge protection devices (also known as lightning arresters, overvoltage fuses, surge absorbers, overvoltage protection devices, etc.) are used.

[0005] Surge protection devices are sometimes installed on the circuit board of field equipment, and sometimes mounted on field equipment as surge protection modules. Surge protection devices used as surge protection modules have a pair of positive and negative terminals for connection to the power supply terminals of the field equipment to be protected, and have a structure in which a surge protection element is connected between the terminals.

[0006] Surge protection components include metal oxide varistors, avalanche diodes, gas discharge tubes, and surge protection thyristors. Additionally, filtering functions for noise reduction are sometimes incorporated into surge protection devices. In some cases, surge protection devices are welded to the frame of the field equipment, making replacement difficult.

[0007] Furthermore, for lighting fixtures, there are devices with replaceable surge protection modules. Additionally, for centrifugal compressors, there are devices with surge detection capabilities. Furthermore, as devices equipped with temperature sensors, there are devices with replaceable surge protection devices.

[0008] Patent Document 1: U.S. Patent Application Publication No. 2010 / 0127625

[0009] Patent Document 2: U.S. Patent Application Publication No. 2017 / 0284410

[0010] Patent Document 3: Chinese Utility Model No. 203385492 Specification

[0011] However, in the event of a surge voltage, the surge protection device blocks the leakage of the surge voltage to the field equipment. At this point, the surge protection element is damaged and gradually deteriorates. For conventional surge protection devices in field equipment, it is difficult to detect the deterioration of the surge protection element and to appropriately determine when to replace it. Similarly, it is difficult to detect the deterioration of the surge protection element in any of the following: lighting fixtures equipped with surge protection modules, centrifugal compressors with compressor surge detection capabilities, or temperature sensors with replaceable surge protection devices. Therefore, it is difficult to improve the reliability of field equipment such as transmitters.

[0012] Furthermore, in the case of surge protection devices welded to the frame of field equipment, if the surge protection device deteriorates, the entire frame of the field equipment needs to be replaced. Therefore, replacement is not easy and it is difficult to improve the reliability of field equipment such as transmitters. In addition, replacing the entire frame of the field equipment increases operating costs. Moreover, the construction of lighting fixtures and centrifugal compressors differs from that of field equipment, making it difficult to directly apply their mechanisms to the surge protection devices of the field equipment. Summary of the Invention

[0013] One aspect of the present invention is to detect the deterioration of surge protection devices and improve the reliability of transmitters.

[0014] One aspect relates to a surge protection device mounted on a transmitter, comprising the following components: a signal terminal connected to a cable for transmitting signals from an external device; a connector detachable from a connector assembly of the transmitter, outputting an input signal from the signal terminal to the connector assembly; a surge protection element absorbing surge current when a surge voltage is applied from the signal terminal to the connector assembly; and a terminal connector connected to the signal terminal via the surge protection element.

[0015] The effects of the invention

[0016] According to the present invention, it is possible to detect the deterioration of surge protection devices and improve the reliability of transmitters. Attached Figure Description

[0017] Figure 1 This is a perspective view of a differential pressure / pressure transmitter.

[0018] Figure 2 This is a perspective view of the surge protection device.

[0019] Figure 3 This is a front view of the terminal block side of the surge protection device.

[0020] Figure 4 This is a front view of the circuit board side of the surge protection device.

[0021] Figure 5 This is a diagram showing the surge protection device after the circuit board has been removed.

[0022] Figure 6 This is a diagram showing a portion of the wiring for a surge protection device.

[0023] Figure 7 This is a diagram illustrating the measurement principle of the tester.

[0024] Figure 8 This is a diagram showing the self-diagnostic circuitry mounted on the surge protection device according to the second embodiment.

[0025] Figure 9 This is a schematic structural diagram showing the mutual communication type transmitter according to the fifth embodiment. Detailed Implementation

[0026] Hereinafter, embodiments of the transmitter will be described with reference to the accompanying drawings. Furthermore, the same reference numerals will be used for the same elements, and repeated descriptions will be omitted where appropriate. Additionally, the various embodiments can be appropriately combined without contradiction.

[0027] (First Embodiment)

[0028] (Overall structure)

[0029] Figure 1 This is a perspective view of a differential pressure / pressure transmitter. The differential pressure / pressure transmitter 100 is an example of a field device (transmitter). The housing 2 of the differential pressure / pressure transmitter 100 has a terminal compartment and a circuit compartment separated by walls. The terminal compartment is... Figure 1 The space is open to the outside and can be visually confirmed. In the differential pressure / pressure transmitter 100, the surge protection device 1 is disposed in one of the internally partitioned spaces, the terminal chamber.

[0030] An internal circuit, including a resistor and an amplifier for differential pressure / pressure transmission, is configured on the circuit chamber side. On the terminal chamber side of the wall separating the terminal chamber and the circuit chamber of the differential pressure / pressure transmitter 100, a connector component (not shown) for transmitting signals to the internal circuit is provided.

[0031] The differential pressure / pressure transmitter 100 receives input signals from the upstream process control equipment via the surge protection device 1. Then, based on the received signals, the differential pressure / pressure transmitter 100 sends a signal representing the measurement result generated by its internal circuitry to an external device, thereby notifying the external device of the control instructions from the upstream process control equipment.

[0032] The surge protection device 1 has a shape that falls inside the differential pressure / pressure transmitter 100. Furthermore, the surge protection device 1 has screws 14 to 16 that secure input / output terminals to threaded portions. These input / output terminals are used to receive input signals to the differential pressure / pressure transmitter 100 and to transmit output signals from the differential pressure / pressure transmitter 100. Wiring extending from upstream process control equipment is connected via the screws 14 to 16 and the threaded portions.

[0033] Furthermore, the surge protection device 1 has a circuit board 20 facing the internal space of the differential pressure / pressure transmitter 100. A grounding terminal 19 is provided on the circuit board 20 at a position separate from the threaded portion for connection by screws 14 to 16. Additionally, the connection terminals on the circuit board 20 and the connector component provided in the wall inside the differential pressure / pressure transmitter 100 are detachable. By connecting the connection terminals on the circuit board 20 and the connector component, the input / output terminals of the surge protection device 1 are connected to the internal circuitry of the differential pressure / pressure transmitter 100.

[0034] The surge protection device 1 receives power supplied from the upstream process control equipment and field communication signals sent from the upstream process control equipment via its input / output terminals. Furthermore, the surge protection device 1 transmits signals from the upstream process control equipment to the internal circuitry of the differential pressure / pressure transmitter 100 via connection terminals on the circuit board 20 and connector components connected to those connection terminals.

[0035] Furthermore, when a surge occurs and a surge current input is received, the surge protection device 1 absorbs the surge current through the surge protection element and allows the surge current to flow to the grounding element via the grounding terminal 19. Thus, the surge current does not flow into the internal wiring of the differential pressure / pressure transmitter 100, protecting the circuitry of the differential pressure / pressure transmitter 100 from the influence of the surge current.

[0036] (Details of surge protection device)

[0037] Figure 2 This is a perspective view of the surge protection device. Figure 2 Indicates that it will be in Figure 1 The surge protection device 1 is removed from the partitioned space inside the differential pressure / pressure transmitter 100, and screws 14 to 16 are removed. Additionally, Figure 3 This is a front view of the terminal block side of the surge protection device.

[0038] like Figure 2As shown in Figure 3, the surge protection device 1 has a main housing 10. Additionally, the surge protection device 1 has detachable screws 14 to 16, a grounding terminal 19, and a circuit board 20. The main housing 10 and the circuit board 20 constitute the frame of the surge protection device 1.

[0039] The surge protection device 1 has terminal block threaded portions 12 and 13 on the main housing 10. For example... Figure 2 As shown, there are actually two threaded portions in the terminal block threaded portion 13, but they are collectively referred to as terminal block threaded portion 13 here. Sometimes, depending on the type of equipment equipped with the surge protection device 1, the terminal block threaded portion 13 is not used. Furthermore, the surge protection device 1 has a terminal connector portion 11. In addition, the surge protection device 1 has threaded fixing portions 17 and 18 on the main body housing 10.

[0040] Screw 14 is screwed into and fixed to the terminal block threaded portion 12, clamping the wiring extending from the external device. Additionally, screws 15 and 16 are respectively screwed into the two threaded portions of the terminal block threaded portion 13, clamping the wiring extending from the external device. Here, depending on the type of equipment equipped with the surge protection device 1, screw 16 and the screw 16 side of the terminal block threaded portion 13 are sometimes not used. Furthermore, the main housing 10 is fixed to the terminal chamber portion of the differential pressure / pressure transmitter 100's frame 2 via threaded fixing portions 17 and 18.

[0041] Here, the combination of terminal block thread 12 and screw 14, and the combination of terminal block thread 13 and screws 15 and 16, respectively correspond to examples of "signal terminals". Furthermore, these signal terminals are connected to cables that transmit signals from external devices such as upstream process equipment. The combinations of terminal block thread 12 and screw 14, and the combinations of terminal block thread 13 and screws 15 and 16, are both disposed on the main housing 10 in an exposed manner. Moreover, the signal terminals transmit signals from external devices such as upstream process equipment to the internal circuitry of the differential pressure / pressure transmitter 100 via connector 23 and the connector components of the differential pressure / pressure transmitter 100.

[0042] Figure 4 This is a front view of the circuit board side of the surge protection device. Figure 5 This is a diagram showing the surge protection device after the circuit board has been removed.

[0043] like Figure 4As shown, the surge protection device 1 has a positive-side varistor 21 and a negative-side varistor 22 on the circuit board 20, as well as connection terminals (i.e., connectors) 23, positioning holes 24 and 25 on the circuit board 20. The connector 23 is disposed on the outward-facing surface of the circuit board 20 and protrudes outward from the main body shell 10, which serves as the frame. Furthermore, the circuit board 20 is mounted and fixed to the main body shell 10 by self-tapping screws 26 and 27.

[0044] When the applied voltage is positive and less than or equal to a specified value, the positive-side varistor 21 does not conduct current. When the applied voltage is positive and greater than the specified value, a large current flows through the positive-side varistor 21. Conversely, when the applied voltage is negative and its absolute value is less than or equal to the specified value, the resistance of the negative-side varistor 22 is high. Conversely, when the absolute value of the voltage is greater than the specified value, a large current flows through the negative-side varistor 22. In the event of a large voltage surge on the positive side, the positive-side varistor 21 absorbs the surge current. Similarly, in the event of a large voltage surge on the negative side, the negative-side varistor 22 absorbs the surge current. Both the positive-side varistor 21 and the negative-side varistor 22 deteriorate depending on the duration of application if a voltage greater than or equal to the maximum permissible voltage is applied.

[0045] Here, the positive-side varistor 21 and the negative-side varistor 22 are positioned on the circuit board 20 opposite to the differential pressure / pressure transmitter 100, but their placement is not limited to this. For example, the positive-side varistor 21 and the negative-side varistor 22 can be positioned on the inward-facing side of the circuit board 20 opposite to the side facing the differential pressure / pressure transmitter 100.

[0046] The positive-side varistor 21 and the negative-side varistor 22 are examples of a "surge protection element." That is, the surge protection element has a positive-side varistor 21 that absorbs surge current when a surge voltage is applied to the positive side, and a negative-side varistor 22 that absorbs surge current when a surge voltage is applied to the negative side. Furthermore, the surge protection element absorbs surge current when a surge voltage is applied from the signal terminal to the connector component. The positive-side varistor 21 and the negative-side varistor 22 are disposed inside or on the surface of the main body housing 10, which serves as the frame.

[0047] like Figure 5 As shown, positioning portions 28 and 29, provided on the inner side of the main body housing 10, are inserted into positioning holes 24 and 25 of the circuit board 20, thereby positioning the circuit board 20 at a predetermined position relative to the main body housing 10. Furthermore, the circuit board 20 is fixed by screwing self-tapping screws 26 and 27 into the main body housing 10.

[0048] When the main housing 10 is mounted on the frame 2 of the differential pressure / pressure transmitter 100, the connector 23 on the circuit board 20 is positioned opposite to the connector component disposed on the wall separating the terminal chamber and the circuit chamber of the differential pressure / pressure transmitter 100. Furthermore, when the main housing 10 is mounted on the frame 2 of the differential pressure / pressure transmitter 100, the connector 23 on the circuit board 20 is connected to the connector component of the differential pressure / pressure transmitter 100.

[0049] Here, the connector 23 on the circuit board 20 and the connector component of the differential pressure / pressure transmitter 100 are detachable, thereby allowing the main housing 10 on which the circuit board 20 is mounted to be detached from the frame 2 of the differential pressure / pressure transmitter 100. That is, the surge protection device 1 can be easily installed and removed from the differential pressure / pressure transmitter 100.

[0050] As described above, connector 23 is connected to the internal circuitry built into the differential pressure / pressure transmitter 100. Furthermore, connector 23 is detachable from the connector component of the differential pressure / pressure transmitter 100, allowing input signals from the signal terminals to be output to the connector component. Additionally, if the main housing 10, which serves as the frame, is mounted on the differential pressure / pressure transmitter 100, connector 23 is connected to the connector component; if the main housing 10, which serves as the frame, is removed from the differential pressure / pressure transmitter 100, connector 23 is removed from the connector component.

[0051] The terminal connector section 11 is arranged to be exposed to the outside from the main body housing 10. The terminal connector section 11 is connected to the signal terminal via a positive side varistor 21 and a negative side varistor 22, which are surge protection elements.

[0052] Figure 6 This diagram shows a portion of the wiring for a surge protection device. The terminal block threaded portion 12 connects to the internal circuitry of the differential pressure / pressure transmitter 100 via a connector 23 mounted on the circuit board 20 and a connector component connected to the differential pressure / pressure transmitter 100 side of the connector 23. The wiring extending from the terminal block threaded portion 12 branches midway and connects to one end of the positive-side varistor 21. The other end of the positive-side varistor 21 connects to the terminal connector portion 11. A grounding terminal 19 is positioned midway along the path connecting the positive-side varistor 21 and the terminal connector portion 11.

[0053] Similarly, the terminal block threaded portion 13 is connected to the internal circuitry of the differential pressure / pressure transmitter 100 via a connector 23 provided on the circuit board 20 and a connector component connected to the differential pressure / pressure transmitter 100 side of the connector 23. A wiring extending from the terminal block threaded portion 13 branches midway and connects to one end of the negative-side varistor 22. The other end of the negative-side varistor 22 is connected to the terminal connector portion 11. A grounding terminal 19 is disposed midway along the path connecting the negative-side varistor 22 and the terminal connector portion 11.

[0054] As described above, the positive-side varistor 21 and the negative-side varistor 22, which serve as signal terminals, are connected to the terminal connector 11 so that the resistance values ​​of the positive-side varistor 21 and the negative-side varistor 22 can be measured using a terminal measurement method of a tester. Furthermore, one end of the positive-side varistor 21 and the negative-side varistor 22 is connected to the signal terminal, and the other end is connected to a grounding element via the grounding terminal 19 mounted on the overvoltage fuse. Additionally, the terminal connector 11 is connected to a wiring branching off from the wiring that connects the positive-side varistor 21 and the negative-side varistor 22 to the grounding element.

[0055] Through this wiring, when a surge voltage is applied to the terminal block thread 12 or 13, the surge current is absorbed by the positive-side varistor 21 or the negative-side varistor 22 according to its polarity, and the influence on the internal circuit of the differential pressure / pressure transmitter 100 is suppressed.

[0056] (Deterioration detection method)

[0057] The deterioration of surge protection device 1 is caused by the deterioration of the positive-side varistor 21 and the negative-side varistor 22. Therefore, in the surge protection device 1 according to this embodiment, the user detects the deterioration of surge protection device 1 by determining the deterioration of the positive-side varistor 21 and the negative-side varistor 22 through the following process.

[0058] The user performs the following process using a tester that has a constant current power supply and a voltmeter that measures the voltage based on the potential difference that occurs at the load when the current flows through it.

[0059] The user connects one end of the tester to Figure 3 The terminal connector 11 shown is connected at one end to the terminal block thread 12, allowing a constant current to flow between the terminal connector 11 and the terminal block thread 12. The user then uses a tester to measure the voltage between the terminal connector 11 and the terminal block thread 12.

[0060] Figure 7This diagram illustrates the measurement principle of the tester. Here, we will use the degradation determination of the positive-side varistor 21 as an example. Resistor R represents the resistance of the positive-side varistor 21. Additionally, resistors r1 and r2 represent the wiring resistances.

[0061] The user performs a standard two-terminal measurement using the tester. That is, a constant current I is generated in the constant current source 101 of the tester and flows through it as shown in the figure. Figure 7 The load shown includes a resistor R with a positive-side varistor 21 and resistors r1 and r2 as wiring resistors. The user then reads the voltage between the terminal connector portion 11 and the terminal block thread portion 12 using the voltmeter 102 of the tester. In this case, the load resistance includes not only the varistor's resistance R but also the wiring resistors r1 and r2. However, the influence of resistors r1 and r2 is smaller than that of resistance R. Therefore, the user can determine the degradation of the positive-side varistor 21 using this two-terminal measurement method.

[0062] Here, the case using the two-terminal measurement method in this embodiment has been described, but the four-terminal measurement method can also be used for degradation detection. In this case, the influence of wiring resistance can be eliminated, and degradation detection with higher accuracy can be performed.

[0063] When the positive-side varistor 21 fails due to deterioration, it enters a short-circuit mode, and its resistance value decreases. Therefore, if the resistance value calculated based on the measured voltage is less than the specified value, the user determines that the positive-side varistor 21 has deteriorated. Thus, the user can detect the deterioration of the surge protection device 1.

[0064] In addition, the user connects one end of the tester to Figure 3 The terminal connector 11 shown is connected at one end to the terminal block thread 13, allowing a constant current to flow between the terminal connector 11 and the terminal block thread 13. The user then uses a tester to measure the voltage between the terminal connector 11 and the terminal block thread 13. From this, the user can determine the deterioration of the negative-side varistor 22 by calculating the resistance value based on the measured voltage.

[0065] Similarly, the negative-side varistor 22, when it fails due to deterioration, enters a short-circuit mode, and its resistance value decreases. Therefore, if the resistance value calculated based on the measured voltage is less than the specified value, the user determines that the negative-side varistor 22 has deteriorated. Thus, the user can detect the deterioration of the surge protection device 1.

[0066] Here, a system having a differential pressure / pressure transmitter 100, a surge protection device 1, and a tester used by the user is equivalent to an example of a "surge protection system".

[0067] (Alternative method)

[0068] As described above, the surge protection device 1 can be easily installed and removed from the differential pressure / pressure transmitter 100. Therefore, if the user detects deterioration of the surge protection device 1, they can loosen the threaded fasteners 17 and 18 to remove the surge protection device 1 from the housing 2 of the differential pressure / pressure transmitter 100. Then, the user places a new surge protection device 1 in the partitioned space inside the differential pressure / pressure transmitter 100 and secures it to the housing 2 using the threaded fasteners 17 and 18. As described above, the surge protection device 1 can be easily replaced if it deteriorates.

[0069] In the above description, a two-wire differential pressure / pressure transmitter 100 was used as an example of a transmitting device. However, the application of the surge protection device 1 involved in this embodiment is not limited to the two-wire differential pressure / pressure transmitter 100. For example, it can be applied to two-wire field devices such as temperature transmitters, vortex flow meters, and pH meters, or to four-wire field devices such as electromagnetic flow meters, Coriolis flow meters, and ultrasonic flow meters that are powered by commercial power supplies.

[0070] (Effect)

[0071] As explained above, the surge protection device 1 according to this embodiment has a terminal connector portion 11 for deterioration determination. Furthermore, the user can use a tester to determine the deterioration of the surge protection device 1 for the terminal connector portion 11 and the terminal block thread portions 12 and 13.

[0072] Furthermore, the housing 2 of the differential pressure / pressure transmitter 100 has a terminal compartment and a circuit compartment separated by a wall. In conventional field equipment, surge protection devices are sometimes installed on the circuit compartment side. Additionally, in conventional field equipment, connecting the terminal compartment and the circuit compartment requires a connection through the housing wall. Therefore, inexpensive soldering is used, taking into account waterproofing and noise performance. Since the circuit compartment is located inside the terminal compartment, direct contact is difficult, making it difficult to replace the surge protection device when it is located in the circuit compartment. Furthermore, even when the surge protection device is located in the terminal compartment, in conventional field equipment, the wiring for the surge protection device is mostly soldered, making replacement of these surge protection devices difficult.

[0073] In contrast, the surge protection device 1 involved in this embodiment is disposed on the terminal chamber side of the differential pressure / pressure transmitter 100, and the surge protection device 1 can be plugged into the internal circuit via the connector 23, thereby allowing for easy replacement in the event of deterioration.

[0074] As described above, by utilizing the surge protection device 1 involved in this embodiment, the user can easily determine the replacement timing, which was previously difficult to ascertain, and can replace the surge protection device 1 at the appropriate time. That is, the user can replace the surge protection device 1 before it is completely damaged, thereby improving the reliability of the transmitter. Furthermore, as a whole, cost reduction in the use of the transmitter can be achieved.

[0075] (Second Implementation)

[0076] Next, the second embodiment will be described. The surge protection device 1 according to this embodiment automatically performs impedance measurement of the circuit including the terminal block threaded portion 13 and the terminal connector portion 11, and performs self-diagnosis of deterioration by detecting leakage current. In the following description, the functions of the parts that are the same as those in the first embodiment will be omitted.

[0077] Figure 8 This is a diagram showing the self-diagnostic circuitry mounted on the surge protection device according to the second embodiment. (Example) Figure 8 As shown, the surge protection device 1 involved in this embodiment has an AD (Analog Digital) converter 31 and an MCU (Micro Controller Unit) 32.

[0078] The AD converter 31 is connected, for example, across the resistor between the terminal block threaded portion 12 and the terminal connector portion 11. More specifically, the AD converter 31 is connected to... Figure 6 The two ends of the positive side varistor 21.

[0079] By from Figure 8 Leakage current flows through the resistor between the terminal block threaded portion 12 and the terminal connector portion 11, so that the AD converter 31 can obtain the voltage across the resistor. The AD converter 31 converts the voltage across the resistor between the terminal block threaded portion 12 and the terminal connector portion 11 into a digital signal and outputs it to the MCU 32.

[0080] The MCU32 is connected to the AD converter 31. The MCU32 receives the voltage across the resistor between the terminal block thread portion 12 and the terminal connector portion 11, which is converted into a digital signal, from the AD converter 31. Next, the MCU32 measures the impedance of the resistor between the terminal block thread portion 12 and the terminal connector portion 11 to determine the leakage current. Then, the MCU32 measures the resistance value between the terminal block thread portion 12 and the terminal connector portion 11 based on the leakage current and the impedance.

[0081] The MCU32 determines the degradation of the positive-side varistor 21 based on the measured resistance value. Based on the degradation determination of the positive-side varistor 21, the MCU32 detects the degradation of the surge protection device 1. If degradation of the surge protection device 1 is detected, the MCU32 notifies the user of the degradation detection. For example, the MCU32 can notify the user of the degradation detection by illuminating a warning light (not shown) installed on the surge protection device 1, or it can send a message indicating degradation detection to the user's terminal device.

[0082] In this embodiment, the resistance between the terminal block threaded portion 12 and the terminal connector portion 11, i.e., the resistance of the positive side varistor 21, is described as an example. However, the resistance between the terminal block threaded portion 13 and the terminal connector portion 11, i.e., the resistance of the negative side varistor 22, is the same.

[0083] The MCU32 is equivalent to an example of a control unit. The MCU32 measures the resistance value of the surge protection element based on the leakage current between the signal terminal and the terminal connector 11, and detects the deterioration of the surge protection element based on the measured resistance value.

[0084] (Effect)

[0085] As explained above, the surge protection device 1 of this embodiment can automatically detect its own deterioration by utilizing the leakage current between the terminal block thread portion 13 and the terminal connector portion 11. Therefore, the user can quickly determine the replacement time and replace the surge protection device 1 at the appropriate time. This improves the reliability of field equipment.

[0086] (Third Implementation)

[0087] Next, the third embodiment will be described. The surge protection device 1 according to this embodiment utilizes the MCU 32 of the second embodiment to estimate the remaining service life of each based on the resistance values ​​of the positive-side varistor 21 and the negative-side varistor 22. The remaining service life refers to information indicating how many more times the device can absorb surge current and protect the differential pressure / pressure transmitter 100. In the following description, the functions of parts identical to those in the second embodiment will be omitted. Hereinafter, the positive-side varistor 21 will be used as an example for explanation.

[0088] The MCU32 has prior information on the extent to which the resistance value of the positive-side varistor 21 changes during a surge. In reality, the extent to which it changes during a surge depends on the energy of the surge, but in this embodiment, it is determined, for example, based on the typical voltage and current required by specifications.

[0089] The MCU32 calculates the resistance value of the positive-side varistor 21 based on the resistance value between the terminal block thread portion 12 and the terminal connector portion 11. Then, based on the current resistance value of the positive-side varistor 21 and information about the degree of change during a single lightning surge, the MCU32 estimates how many surges the positive-side varistor 21 can withstand, i.e., its remaining lifespan. The MCU32 then informs the user of the remaining lifespan of the positive-side varistor 21.

[0090] In this embodiment, the positive-side varistor 21 is used as an example for explanation, but the MCU 32 can similarly estimate the remaining service life based on the resistance of the negative-side varistor 22. As described above, the MCU 32, as the control unit, has prior information on the change in resistance value of the surge protection element caused by one surge, and estimates the remaining service life of the surge protection element based on the measured resistance value and the change in resistance value.

[0091] (Effect)

[0092] As explained above, the surge protection device 1 of this embodiment can automatically detect the remaining service life of the positive-side varistor 21 and the negative-side varistor 22 by utilizing the leakage current between the terminal block thread portion 13 and the terminal connector portion 11. Therefore, the user can quickly determine the replacement time and replace the surge protection device 1 at the appropriate time. This improves the reliability of the field equipment.

[0093] (Fourth implementation)

[0094] Next, the fourth embodiment will be described. The surge protection device 1 according to this embodiment utilizes the MCU 32 of the third embodiment to predict future deterioration opportunities and automatically determine the timing of purchasing replacement spare parts. Hereinafter, the positive-side varistor 21 will be used as an example for description. In the following description, the functions of parts that are the same as in the third embodiment will be omitted. Hereinafter, the positive-side varistor 21 will be used as an example for description.

[0095] The MCU32 has pre-defined information on the extent to which the resistance value of the positive-side varistor 21 changes during a surge, as well as the operating time of the surge protection device 1. Additionally, the MCU32 counts the number of surges flowing through the positive-side varistor 21 and stores the current number of surges experienced by the positive-side varistor 21.

[0096] Based on the current resistance value of the positive-side varistor 21 and the extent to which it changes during a single surge, the MCU32 estimates the remaining lifespan of the positive-side varistor 21. Next, the MCU32 calculates the surge frequency based on the operating time of the surge protection device 1 and the number of surges experienced by the positive-side varistor 21.

[0097] Next, the MCU32 calculates the timing of degradation of the positive-side varistor 21 using the surge occurrence frequency and the remaining service life of the positive-side varistor 21. Based on the calculated degradation timing, the MCU32 determines when to purchase a spare positive-side varistor 21 for replacement. Furthermore, the MCU32 notifies the user of the purchase timing of the spare positive-side varistor 21. Alternatively, the MCU32 can be connected via a network to a server or similar provider of the component, allowing the MCU32 to automatically purchase the spare positive-side varistor 21 from the provider when the purchase timing is reached.

[0098] As described above, the MCU32, acting as the control unit, counts the number of surge occurrences and predicts the deterioration timing of the surge protection component based on the number of occurrences, operating time, and remaining service life. Furthermore, the MCU32 determines the timing for purchasing spare parts for the surge protection component based on the predicted deterioration timing.

[0099] (Effect)

[0100] As explained above, the surge protection device 1 involved in this embodiment can predict the timing of degradation and determine when to purchase spare parts. Therefore, the user can pre-allocate spare parts and replace the surge protection device 1 at the appropriate time. This improves the reliability of field equipment.

[0101] (Fifth Embodiment)

[0102] Next, the fifth embodiment will be described. Figure 9 This is a schematic structural diagram showing the mutual communication type transmitter according to the fifth embodiment. The surge protection device 1 according to this embodiment is mounted on the mutual communication transmitter 200.

[0103] like Figure 9 As shown, the mutual communication transmitter 200 includes a primary transmitter 100A and a secondary transmitter 100B. The mutual communication transmitter 200 is capable of handling various physical quantities of the object being measured. For example, the mutual communication transmitter 200 is a differential pressure transmitter. Hereinafter, the mutual communication transmitter 200 will be described using a differential pressure transmitter as an example.

[0104] Primary transmitter 100A and secondary transmitter 100B are connected by a communication cable. Primary transmitter 100A and secondary transmitter 100B can transmit and receive data from each other via the communication cable. Primary transmitter 100A is positioned on the high-pressure side, where the pressure generated by the measured object is measured. Secondary transmitter 100B is positioned on the low-pressure side, where the pressure generated by the measured object is measured.

[0105] The primary transmitter 100A acquires the pressure measured by the secondary transmitter 100B and outputs a signal corresponding to the differential pressure between the pressure measured by the primary transmitter 100A and the pressure measured by the secondary transmitter 100B.

[0106] A surge protection device 1A is installed in the primary transmitter 100A. The surge protection device 1A, like the surge protection device 1 described above, is provided with terminal block threaded portions 12 and 13 and a terminal connector portion 11.

[0107] The user connects one end of the tester to the terminal connector 11 of the surge protection device 1A and the other end to the terminal block thread 12. Then, the user performs a two-terminal measurement using the tester to read the voltage between the terminal connector 11 and the terminal block thread 12. Based on the read voltage, the user determines the degradation of the positive-side varistor 21.

[0108] Additionally, the user connects one end of the tester to the terminal connector 11 of the surge protection device 1A and the other end to the terminal block thread 13. Then, the user performs a two-terminal measurement using the tester to read the voltage between the terminal connector 11 and the terminal block thread 13. Based on the read voltage, the user determines the degradation of the negative-side varistor 22.

[0109] In addition, users can calculate the number of surges based on the deterioration status of the positive side varistor 21 and the negative side varistor 22 of the surge protection device 1A, and determine the deterioration status of the surge protection device 1A based on the calculated number of surges.

[0110] Furthermore, in the structure of this mutual communication transmitter 200, a surge protection device 1A can also be mounted. Figure 8 The AD converter 31 and MCU 32 shown can be automatically determined to be degraded. In this case, the MCU 32 can also be made to estimate the remaining service life, predict the timing of future degrades, and automatically determine when to purchase replacement parts.

[0111] Here, primary transmitter 100A is equivalent to an example of "first transmitter", and secondary transmitter 100B is equivalent to an example of "second transmitter". Additionally, surge protection device 1A is equivalent to an example of "surge protection device".

[0112] In this embodiment, the case where the secondary transmitter 100B is not equipped with a surge protection device is described, but a surge protection device may also be equipped on the secondary transmitter 100B. In this case, the surge protection device equipped on the secondary transmitter 100B may not have a structure for detecting degradation. In this case, the degradation of surge protection device 1A and the degradation of surge protection device 1B equipped on the secondary transmitter 100B can be considered the same. Therefore, the user can detect the degradation of surge protection device 1A and surge protection device 1B based on the degradation determination results of the positive side varistor 21 and the negative side varistor 22.

[0113] Surge protection device 1A, as a first surge protection device, has signal terminals, which are combinations of terminal block threaded portion 12 and screw 14 connected to a cable transmitting signals from an external device, and combinations of terminal block threaded portion 13 and screws 15 and 16. Additionally, surge protection device 1A has a connector 23, which is detachable from the connector component of the primary transmitter 100A, which is the first transmitter, and outputs the input signal from the signal terminals to the connector component. Furthermore, surge protection device 1A has a positive-side varistor 21 and a negative-side varistor 22, which are surge protection elements that absorb surge current when a surge voltage is applied from the signal terminals to the connector component. Finally, surge protection device 1A has a terminal connector portion 11 connected to the signal terminals via the surge protection elements.

[0114] (Effect)

[0115] As explained above, even the interconnected transmitter 200, which includes a primary transmitter 100A and a secondary transmitter 100B, can be equipped with a surge protection device 1A. Furthermore, by utilizing the surge protection device 1A installed in the interconnected transmitter 200, the timing of potential degradation can be predicted, allowing for the timely purchase of spare parts. This enables the user to pre-allocate spare parts and replace the surge protection device 1A installed in the interconnected transmitter 200 at the appropriate time. Therefore, the reliability of the primary transmitter 100A can be improved.

[0116] (system)

[0117] Information including the processing flow, control flow, specific names, various data, and parameters shown in the above documents and figures can be arbitrarily changed, except where specifically stated.

[0118] Furthermore, the structural elements of each device illustrated are functional concepts and do not necessarily have to be physically arranged as shown. That is, the specific ways in which the devices are distributed and integrated are not limited to the illustrated representation. In other words, all or part of each device can be functionally or physically distributed and integrated in any unit according to various loads, usage conditions, etc.

[0119] The following are some examples of combinations of publicly disclosed technical features. (1)

[0121] A surge protection device mounted on a transmitter,

[0122] The surge protection device is characterized by having:

[0123] Signal terminals, which are connected to cables that transmit signals from external devices;

[0124] A connector, which is detachable from the connector component of the transmitter, outputs the input signal from the signal terminal to the connector component;

[0125] A surge protection element that absorbs surge current when a surge voltage is applied from the signal terminal to the connector component; and

[0126] The terminal connector is connected to the signal terminal via the surge protection element. (2)

[0128] According to the surge protection device described in (1), the characteristic is that,

[0129] It has a frame that can be detachably mounted on the transmitter.

[0130] The signal terminal, the connector, and the terminal connector portion are configured to protrude from the frame to the outside.

[0131] The surge protection element is disposed inside the frame or on its surface. (3)

[0133] According to the surge protection device described in (2), the characteristic is that,

[0134] If the housing is mounted on the transmitter, the connector is connected to the connector assembly; if the housing is removed from the transmitter, the connector is removed from the connector assembly. (4)

[0136] The surge protection device according to any one of (1) to (3) is characterized in that,

[0137] The signal terminal and the terminal connector are connected such that the resistance value of the surge protection element can be measured using a terminal measurement method of a tester. (5)

[0139] The surge protection device according to any one of (1) to (4) is characterized in that,

[0140] The connector component is connected to the internal circuitry built into the transmitter.

[0141] The signal terminal transmits signals from the external device to the internal circuit via the connector and the connector components. (6)

[0143] The surge protection device according to any one of (1) to (5) is characterized in that,

[0144] One end of the surge protection element is connected to the signal terminal, and the other end is connected to the grounding component.

[0145] The terminal connector is connected to a wiring branching off from the wiring that connects the surge protection element and the grounding element. (7)

[0147] The surge protection device according to any one of (1) to (6) is characterized in that,

[0148] The surge protection element has:

[0149] A positive-side varistor that absorbs surge current when a surge voltage is applied to the positive side; and

[0150] The negative-side varistor absorbs surge current when a surge voltage is applied to the negative side. (8)

[0152] The surge protection device according to any one of (1) to (7) is characterized in that,

[0153] It also includes a control unit that measures the resistance value of the surge protection element based on the leakage current between the signal terminal and the terminal connector, and detects the deterioration of the surge protection element based on the measured resistance value. (9)

[0155] According to the surge protection device described in (8), the characteristic is that,

[0156] The control unit has information in advance about the change in resistance value of the surge protection element caused by one surge, and based on the measured resistance value of the surge protection element and the change, it estimates the remaining service life of the surge protection element. (10)

[0158] According to the surge protection device described in (9), the characteristic is that,

[0159] The control unit counts the number of surges that occur and predicts the timing of the deterioration of the surge protection element based on the number of occurrences, operating time, and remaining service life. (11)

[0161] According to the surge protection device described in (10), the characteristic is that,

[0162] The control unit determines when to purchase spare parts for the surge protection component based on the predicted timing of the degradation. (12)

[0164] A transmitter, characterized in that,

[0165] It is equipped with the surge protection device described in (1). (13)

[0167] A surge protection system comprising the transmitter and tester described in (12),

[0168] The surge protection system is characterized in that...

[0169] The tester has:

[0170] The first terminal is connected to the signal terminal of the surge protection device;

[0171] The second terminal is connected to the terminal connector portion of the surge protection device;

[0172] A constant current circuit, which causes a constant current to flow between the first terminal and the second terminal; and

[0173] A measuring circuit that measures the resistance between the first terminal and the second terminal when a constant current flows through the constant current circuit. (14)

[0175] A transmitter, characterized in that,

[0176] The first transmitter and the second transmitter are respectively equipped with the surge protection device described in (1), and the first transmitter and the second transmitter are connected by a cable for mutual communication.

[0177] Explanation of the label

[0178] 1, 1A, 1B surge protection devices

[0179] 2. Frame

[0180] 11-Terminal Connector Section

[0181] 12, 13 Terminal block threaded section

[0182] 14, 15, 16 screws

[0183] 17, 18 Threaded fixing parts

[0184] 19 Grounding terminal

[0185] 20 Circuit board

[0186] 21 Positive side varistor

[0187] 22 Negative-side varistor

[0188] 23 Connectors

[0189] 24, 25 positioning holes

[0190] 26, 27 self-tapping screws

[0191] Positioning Departments 28 and 29

[0192] 31AD converter

[0193] 32MCU

[0194] 100 Differential Pressure / Pressure Transmitter

[0195] 100A Primary Transmitter

[0196] 100B Secondary Transmitter

[0197] 200 Interconnected Transmitter

Claims

1. A surge protection device mounted on a transmitter, The surge protection device is characterized by having: Signal terminals, which are connected to cables that transmit signals from external devices; A connector, which is detachable from the connector component of the transmitter, outputs the input signal from the signal terminal to the connector component; A surge protection element that absorbs surge current when a surge voltage is applied from the signal terminal to the connector component; as well as The terminal connector is connected to the signal terminal via the surge protection element.

2. The surge protection device according to claim 1, characterized in that, It has a frame that can be detachably mounted on the transmitter. The signal terminal, the connector, and the terminal connector portion are configured to protrude from the frame to the outside. The surge protection element is disposed inside the frame or on its surface.

3. The surge protection device according to claim 2, characterized in that, If the housing is mounted on the transmitter, the connector is connected to the connector assembly; if the housing is removed from the transmitter, the connector is removed from the connector assembly.

4. The surge protection device according to claim 1, characterized in that, The signal terminal and the terminal connector are connected such that the resistance value of the surge protection element can be measured using a terminal measurement method of a tester.

5. The surge protection device according to claim 1, wherein, The connector component is connected to the internal circuitry built into the transmitter. The signal terminal transmits signals from the external device to the internal circuit via the connector and the connector components.

6. The surge protection device according to claim 1, characterized in that, One end of the surge protection element is connected to the signal terminal, and the other end is connected to the grounding component. The terminal connector is connected to a wiring branching off from the wiring that connects the surge protection element and the grounding element.

7. The surge protection device according to claim 1, characterized in that, The surge protection element has: A positive-side varistor that absorbs surge current when a surge voltage is applied to the positive side; and The negative-side varistor absorbs surge current when a surge voltage is applied to the negative side.

8. The surge protection device according to any one of claims 1 to 7, characterized in that, It also includes a control unit that measures the resistance value of the surge protection element based on the leakage current between the signal terminal and the terminal connector, and detects the deterioration of the surge protection element based on the measured resistance value.

9. The surge protection device according to claim 8, characterized in that, The control unit has information in advance about the change in resistance value of the surge protection element caused by one surge, and based on the measured resistance value of the surge protection element and the change, it estimates the remaining service life of the surge protection element.

10. The surge protection device according to claim 9, characterized in that, The control unit counts the number of surges that occur and predicts the timing of the deterioration of the surge protection element based on the number of occurrences, operating time, and remaining service life.

11. The surge protection device according to claim 10, characterized in that, The control unit determines when to purchase spare parts for the surge protection component based on the predicted timing of the degradation.

12. A transmitter, characterized in that, It is equipped with the surge protection device as described in claim 1.

13. A surge protection system comprising the transmitter and tester as described in claim 12, The surge protection system is characterized in that... The tester has: The first terminal is connected to the signal terminal of the surge protection device; The second terminal is connected to the terminal connector portion of the surge protection device; A constant current circuit that allows a constant current to flow between the first terminal and the second terminal; and A measuring circuit that measures the resistance between the first terminal and the second terminal when a constant current flows through the constant current circuit.

14. A mutually communicating transmitter, characterized in that, The device comprises a first transmitter and a second transmitter respectively equipped with the surge protection device of claim 1, the first transmitter and the second transmitter being connected by a cable for communication with each other.

Images