Bidirectional transmission circuit for general-purpose signals

Abstract

A bidirectional transmission circuit for a general-purpose signal, comprising a power supply module (10) and a bidirectional transmission module (20), the bidirectional transmission module comprising an intrinsically safe energy limiting module (21), a first signal coupling module (22), an isolation transformer module (23), a second signal coupling module (24) and a control module (25), the first signal coupling module (22) being configured to condition a first DC signal (DC1) in the general-purpose signal into a first AC signal (AC1), the isolation transformer module (23) being configured to condition the first AC signal (AC1) into the second signal coupling module (24), the second signal combining module (24) is configured to adjust the first AC signal (AC1) to a second DC signal (DC2) and transmit the second DC signal (DC2) to the general-purpose signal receiving end (252), the second signal combining module (24) is further configured to adjust the third DC signal (DC3) in the control signal to the second AC signal (AC2), and the first signal combining module (22) is further configured to adjust the second AC signal (AC2) to a fourth DC signal (DC4) and transmit the fourth DC signal (DC4) to the control signal receiving end (215).

Description

[Technical field]

[0001] This application claims priority to a Chinese patent application bearing application number 202110120265.5, filed with the China Patent Office on January 28, 2021, the entire contents of which are incorporated herein by reference.

[0002] The embodiments of the present application relate to a technical field of isolated transmission of general-purpose signals, for example, to a bidirectional transmission circuit for general-purpose signals. [Background technology]

[0003] In industrial control systems, isolation technology is used in industrial control sites, where there are many types of signals that need to be detected and transmitted, and there are many pressure sensors, temperature sensors, positioning valves, solenoid valves, or proximity switches. The normal signals generated by field devices and the signals between the Programmable Logic Controller (PLC) / Distributed Control System (DCS) may interfere with each other in two-way transmission, causing the system to become unstable. Some special dangerous places require the use of safety barriers, and in order to ensure the stable and reliable operation of the system, most systems adopt isolators or isolating safety barriers to convert signals and enable mutual isolation between inputs and outputs, thereby improving the interference resistance. However, such signal division, isolation, and transmission by adopting multi-path circuits and arranging multiple types of safety barriers not only increases the cost of the industrial control system, but also affects the applicability of the control system. Summary of the Invention

[0004] The embodiments of the present application provide a general-purpose bidirectional signal transmission circuit that solves the technical problem in the related art that signal division, isolation, and transmission are costly and affect the applicability of control systems by adopting multi-path circuits and arranging multiple types of safety barriers.

[0005] An embodiment of the present application includes a power supply module, an intrinsically safe energy limiting module, a first signal coupling module, an isolation transformer module, a second signal coupling module, and a control module, the first signal coupling module is electrically connected to the intrinsically safe energy limiting module and the isolation transformer module, the second signal coupling module is electrically connected to the isolation transformer module and the control module, the power supply module is electrically connected to the intrinsically safe energy limiting module, the first signal coupling module, the second signal coupling module, and the control module, the intrinsically safe energy limiting module includes a control signal receiving end configured to receive a control signal, and at least one general-purpose signal input end, each of which is configured to receive a general-purpose signal, the control module includes a control signal output end configured to output the control signal, and a control signal output end configured to receive the general-purpose signal. the first signal coupling module is configured to adjust a first DC signal in the general-purpose signal to a first AC signal, the isolation transformer module is configured to isolate and transmit the first AC signal to the second signal coupling module, the second signal coupling module is configured to adjust the first AC signal to a second DC signal and transmit the second DC signal to the general-purpose signal receiving end, the second signal coupling module is further configured to adjust a third DC signal in the control signal to a second AC signal, the isolation transformer module is further configured to isolate and transmit the second AC signal to the first signal coupling module, and the first signal coupling module is further configured to adjust the second AC signal to a fourth DC signal and transmit the fourth DC signal to the control signal receiving end.

[0006] Preferably, the first signal combining module comprises a first filtering unit, a first AC-DC conversion unit and a DC-AC conversion unit, the second signal combining module comprises a second filtering unit, a second AC-DC conversion unit and the DC-AC conversion unit, the first filtering unit and the second filtering unit are all configured to filter the general-purpose signal and the control signal, the first AC-DC conversion unit is configured to adjust the second AC signal to a fourth DC signal and transmit the fourth DC signal to the control signal receiving end, the second AC-DC conversion unit is configured to adjust the first AC signal to a second DC signal and transmit the second DC signal to the general-purpose signal receiving end, and the DC-AC conversion unit is configured to adjust the first DC signal in the general-purpose signal to the first AC signal and adjust the third DC signal in the control signal to the second AC signal.

[0007] Preferably, the first filtering unit comprises a first capacitor and a second capacitor, a first end of the first capacitor is electrically connected to each general-purpose signal input terminal, a second end of the first capacitor is electrically connected to the control signal receiving terminal, a first end of the second capacitor is electrically connected to each general-purpose signal input terminal, and a second end of the second capacitor is electrically connected to the control signal receiving terminal; the first AC-DC conversion unit comprises a third capacitor and a fourth capacitor; the DC-AC conversion unit comprises a first inductor, a second inductor, a fifth capacitor, a first diode, a second diode, a first triode, and a second triode, a first end of the third capacitor is electrically connected to each general-purpose signal input terminal, a first end of the first triode, a control end of the first triode, and an anode of the first diode; a second end of the fourth capacitor electrically connected to the first end of the isolation transformer module, a second end of the fourth capacitor electrically connected to the control signal receiving end, the first end of the second triode, the control end of the second triode, the cathode of the second diode, the first end of the second inductor and the first end of the fifth capacitor, a first end of the first inductor electrically connected to the second end of the isolation transformer module, a second end of the first inductor electrically connected to the second end of the second inductor, the second end of the fifth capacitor, the second end of the first triode and the second end of the second triode, a cathode of the first diode electrically connected to the anode of the second diode, and the second filtering unit comprises a third inductor, a fourth inductor, a sixth capacitor and a seventh capacitor, and the first end of the third inductor is electrically connected to the first end of the control signal receiving end, the first end of the second triode, the control end of the second triode, the cathode of the first diode is electrically connected to the anode of the second diode, General-purpose signal receiving terminal and a first end of the sixth capacitor, a second end of the third inductor is electrically connected to a first end of the seventh capacitor, and a first end of the fourth inductor is electrically connected to the Control signal output terminaland a second end of the sixth capacitor, a second end of the fourth inductor electrically connected to the second end of the seventh capacitor, and the second end of the fourth inductor electrically connected to the second end of the seventh capacitor, the second AC-DC conversion unit comprises an eighth capacitor, a ninth capacitor, a third diode and a fourth diode, a first end of the eighth capacitor electrically connected to the second end of the third inductor and the cathode of the third diode, a second end of the eighth capacitor electrically connected to the first end of the ninth capacitor and the third end of the isolation transformer module, a second end of the ninth capacitor electrically connected to the second end of the fourth inductor and the anode of the fourth diode, and the anode of the third diode and the cathode of the fourth diode are both electrically connected to the fourth end of the isolation transformer module.

[0008] Preferably, the DC-AC conversion unit further includes a first resistor, a second resistor, a tenth capacitor and an eleventh capacitor, wherein the first resistor is arranged in series between a control end of the first triode and a first end of the first triode, the second resistor is arranged in series between a control end of the second triode and a first end of the second triode, the tenth capacitor has a first end electrically connected to the first end of the first resistor and a second end electrically connected to the cathode of the first diode and the anode of the second diode, respectively, and the eleventh capacitor is arranged in series between the first end of the second inductor and the control end of the second triode.

[0009] Preferably, the bidirectional transmission circuit further includes a signal identification module arranged in parallel with the first signal coupling module, the signal identification module includes at least two comparison units, the negative phase input terminals of the at least two comparison units are all electrically connected to the output terminal of the intrinsically safe energy limiting module, and the reference signals input by the positive phase input terminals of any two comparison units are different.

[0010] Preferably, the general-purpose signal includes an intrinsically safe analog input signal AI, an intrinsically safe analog output signal AO, an intrinsically safe digital input signal DI and an intrinsically safe digital output signal DO, and the at least two comparison units include a first comparison unit, a second comparison unit, a third comparison unit and a signal decode unit, the first comparison unit includes a first negative phase input end and a first positive phase input end, and is configured to obtain a first comparison signal after comparing the general-purpose signal with a first reference signal, and transmit the first comparison signal to the signal decode unit, the second comparison unit includes a second negative phase input end and a second positive phase input end, and ... AO, an intrinsically safe digital input signal DI and an intrinsically safe digital output signal DO, and the at least two comparison units include a first comparison unit, a second comparison unit, a third comparison unit and a signal decode unit, the third comparison unit has a third negative phase input end and a third positive phase input end, and is configured to obtain a third comparison signal after comparing the general-purpose signal with the third reference signal, and transmit the third comparison signal to the signal decoding unit; the third comparison unit has a third negative phase input end and a third positive phase input end, and is configured to obtain a third comparison signal after comparing the general-purpose signal with the third reference signal, and transmit the third comparison signal to the signal decoding unit; the signal decoding unit is configured to determine a type of the general-purpose signal according to the first comparison signal, the second comparison signal, and the third comparison signal, wherein the first reference signal, the second reference signal, and the third reference signal become gradually smaller.

[0011] Preferably, the first comparison unit comprises a first comparator, a first comparison register and a second comparison register, a first end of the first comparison register is electrically connected to a first voltage signal input end, a first end of the second comparison register is grounded, a second end of the first comparison register, a second end of the second comparison register and a positive phase input end of the first comparator are electrically connected, a negative phase input end of the first comparator is electrically connected to an output end of the intrinsically safe energy limiting module, and an output end of the first comparator is electrically connected to the signal decode unit; the second comparison unit comprises a second comparator, a third comparison register and a fourth comparison register, a first end of the third comparison register is electrically connected to a first voltage signal input end, a first end of the fourth comparison register is grounded, a second end of the third comparison register, a second end of the fourth comparison register and a positive phase input end of the first comparator are electrically connected The positive phase input terminal of the second comparator is electrically connected, the negative phase input terminal of the second comparator is electrically connected to the output terminal of the intrinsically safe energy limiting module, the output terminal of the second comparator is electrically connected to the signal decode unit, the third comparison unit comprises a third comparator, a fifth comparison register and a sixth comparison register, a first end of the fifth comparison register is electrically connected to a first voltage signal input terminal, a first end of the sixth comparison register is grounded, the second end of the fifth comparison register, the second end of the sixth comparison register and the positive phase input terminal of the third comparator are electrically connected, the negative phase input terminal of the third comparator is electrically connected to the output terminal of the intrinsically safe energy limiting module, the output terminal of the third comparator is electrically connected to the signal decode unit, and the first voltage signal input terminal is electrically connected to the power supply module.

[0012] Preferably, the first comparison unit further comprises a first pull-up resistor, a third resistor, a fourth resistor and a twelfth capacitor, a first end of the first pull-up resistor is electrically connected to the first voltage signal input terminal, a second end of the first pull-up resistor and a first end of the third resistor are electrically connected to the output terminal of the first comparator, a second end of the third resistor is electrically connected to the second end of the second comparison resistor, a first end of the fourth resistor is electrically connected to the negative phase input terminal of the first comparator, and a second end of the fourth resistor is electrically connected to the output terminal of the intrinsically safe energy limiting module, a first end of the twelfth capacitor is electrically connected to the first bias voltage input terminal of the first comparator, a second end of the twelfth capacitor is grounded, and a second bias voltage input terminal of the first comparator is grounded; the second comparison unit further comprises a second pull-up resistor, a fifth resistor and a sixth resistor, a first end of the second pull-up resistor is electrically connected to the first voltage signal input terminal, a second end of the second pull-up resistor and a sixth resistor are electrically connected to the output terminal of the intrinsically safe energy limiting module, 1 the first terminal of the fifth register is electrically connected to the output terminal of the second comparator, 2 the first end of the third pull-up resistor is electrically connected to the first voltage signal input terminal, the second end of the third pull-up resistor and the first end of the seventh resistor are electrically connected to the output terminal of the third comparator, the second end of the seventh resistor is electrically connected to the second end of the sixth comparison resistor, the first end of the eighth resistor is electrically connected to the negative input terminal of the third comparator, and the second end of the eighth resistor is electrically connected to the output terminal of the intrinsically safe energy limiting module; the third comparison unit further comprises a third pull-up resistor, a seventh resistor and an eighth resistor, the first end of the third pull-up resistor is electrically connected to the first voltage signal input terminal, the second end of the third pull-up resistor and the first end of the seventh resistor are electrically connected to the output terminal of the third comparator, the second end of the seventh resistor is electrically connected to the second end of the sixth comparison resistor, the first end of the eighth resistor is electrically connected to the negative input terminal of the third comparator, and the second end of the eighth resistor is electrically connected to the output terminal of the intrinsically safe energy limiting module.

[0013] Preferably, the power supply module includes a power supply, a voltage regulator module, a voltage conversion module, a first rectification module and a second rectification module, the power supply is configured to provide a DC power supply signal, the voltage regulator module is configured to stably output the DC power supply signal, the voltage conversion module is configured to convert the DC power supply signal into an AC power supply signal, the first rectification module and the second rectification module are both configured to rectify the AC power supply signal into a DC current signal, the first rectification module has a first voltage and is configured to power the intrinsically safe energy limiting module and the first signal coupling module, and the second rectification module has a second voltage and is configured to power the second signal coupling module and the control module.

[0014] Preferably, the bidirectional transmission circuit further comprises a signal protection module disposed in series between the second signal coupling module and the control module and configured to provide electrostatic protection and surge protection for the bidirectional transmission circuit. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a module of a bidirectional transmission circuit for general-purpose signals according to an embodiment of the present application; [Diagram 2] 1 is a schematic diagram of a circuit structure of a bidirectional transmission module according to an embodiment of the present application; [Diagram 3] FIG. 13 is a schematic diagram of a module of another general-purpose signal bidirectional transmission circuit according to an embodiment of the present application. [Figure 4] FIG. 2 is a schematic diagram of a circuit structure of a signal identification module according to an embodiment of the present application; [Diagram 5] FIG. 2 is a schematic diagram of a circuit structure of a power supply module according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the technical solution of the present application will be fully described through specific embodiments with reference to the drawings in the embodiments of the present application.

[0017] The embodiment of the present application provides a bidirectional transmission circuit for bidirectional transmission of multiple types of general-purpose signals between a field device and a PLC / DCS in an industrial control system. Fig. 1 is a schematic diagram of a module of a bidirectional transmission circuit for general-purpose signals according to the embodiment of the present application. As shown in Fig. 1, the bidirectional transmission circuit for general-purpose signals includes a power supply module 10 and a bidirectional transmission module 20, the bidirectional transmission module 20 includes an intrinsically safe energy-limiting module 21, a first signal coupling module 22, an isolation transformer module 23, a second signal coupling module 24 and a control module 25, the first signal coupling module 22 is electrically connected to the intrinsically safe energy-limiting module 21 and the isolation transformer module 23, the second signal coupling module 24 is electrically connected to the isolation transformer module 23 and the control module 25, and the power supply module 10 is electrically connected to the intrinsically safe energy-limiting module 21, the first signal coupling module 22, the second signal coupling module 24 and the control module 25.

[0018] The intrinsically safe energy limiting module 21 includes a control signal receiving end 215 and at least one general-purpose signal input end (input ends 211, 212, 213, 214 as shown in FIG. 1), where the control signal receiving end 215 is configured to receive a control signal, and each general-purpose signal input end is configured to input a general-purpose signal; the control module 25 includes a control signal output end 251 and a general-purpose signal receiving end 252, where the control signal output end 251 is configured to output a control signal, and the general-purpose signal receiving end 252 is configured to receive a general-purpose signal; the first signal coupling module 22 couples a first DC signal DC 1 The first AC signal AC 1 The isolation transformer module 23 is configured to adjust the first AC signal AC 1 to the second signal coupling module 24, which is configured to transmit the first AC signal AC 1 to the second DC signal DC 2Adjust the second DC signal DC 2 to the general signal receiving end, and the second signal coupling module 24 further comprises a third DC signal DC 3 to the second AC signal AC 2 and the isolation transformer module 23 is further configured to adjust the second AC signal AC 2 to the first signal coupling module 22, which is further configured to transmit a second alternating current signal AC 2 The fourth DC signal DC 4 Adjust the fourth DC signal to DC 4 to the control signal receiving end.

[0019] For example, as shown in FIG. 1, the bidirectional transmission circuit of a general-purpose signal includes a power supply module 10 and a bidirectional transmission module 20, in which the power supply module 10 is configured to provide AC or DC power to the intrinsically safe energy limiting module 21, the first signal coupling module 22, the second signal coupling module 24 and the control module 25 in the bidirectional transmission module 20.

[0020] The intrinsically safe energy limiting module 21 includes a control signal receiving end 215 and at least one general-purpose signal input end (as shown by input ends 211, 212, 213, 214 in FIG. 1 ), and one general-purpose signal input end can receive one general-purpose signal. In an industrial control system, the general-purpose signal includes signals such as a pressure signal of a pressure sensor, a temperature signal of a temperature sensor, a position signal of a positioning valve, a position signal of a solenoid valve, or an on and off signal of a proximity switch. When the general-purpose signal input end of the intrinsically safe energy limiting module 21 in the bidirectional transmission circuit receives a general-purpose signal having high voltage or high current from the signal detection end, the intrinsically safe energy limiting module 21 first performs a voltage limiting process on the received general-purpose signal having high voltage, or performs a current limiting process on the received general-purpose signal having high current, so that the general-purpose signal having high voltage or high current meets the intrinsic safety certification, and transmits the general-purpose signal after intrinsic safety certification to the first signal coupling module 22, and the first signal coupling module 22 converts the first DC signal DC 1 The first AC signal AC 1 Adjust the first AC signal to AC 1 is coupled to an isolation transformer module 23, which converts a first AC signal AC 1 is isolated and transmitted to the second signal combining module 24, and the second signal combining module 24 converts the first AC signal AC 1 to the second DC signal DC 2 Adjust the second DC signal DC 2 to the general-purpose signal receiving end of the control module 25, thereby realizing the signal transmission from the intrinsically safe energy limiting module 21 on the dangerous side of the general-purpose signal to the control module 25 on the safe side. The isolation transformer module 23 is equipped with an isolation transformer, which functions to mutually isolate the input and output in the bidirectional transmission of the general-purpose signal, improves the anti-interference ability of the signal transmission, and at the same time, avoids excessive voltage or current, and protects the board of the DCS or PLC. The control module 25 includes a host machine, a PLC / DCS, etc., and is configured to receive the general-purpose signal and issue a corresponding control signal according to the general-purpose signal. The control signal includes those that turn on or off the solenoid valve, those that turn on or off the proximity switch, etc.

[0021] For example, when a pressure sensor configured to monitor the pressure of a device to be detected, such as the gas pressure in a gas tank, is connected to the danger side of the bidirectional transmission circuit, the control module 25 continuously receives the pressure signal transmitted from the intrinsically safe energy limiting module 21 when the pressure signal of the pressure sensor received by the control module 25 is smaller than the preset danger threshold value, and when the pressure signal of the pressure sensor received is higher than the preset danger threshold value or lower than the minimum danger value, the control module 25 outputs a control signal to control the opening or closing of the solenoid valve at the gas outlet of the gas tank. When the control module 25 outputs the control signal through the control signal output terminal 251, the second signal coupling module 24 converts the third DC signal DC 3 to the second AC signal AC 2 Adjust the second AC signal to AC 2 is coupled to the isolation transformer module 23, which converts the second AC signal AC 2 is isolated and transmitted to the first signal combining module 22, and the first signal combining module 22 transmits the second AC signal AC 2 The fourth DC signal DC 4 Adjust the fourth DC signal to DC 4 to the control signal receiving end 215 of the intrinsically safe energy limiting module 21, so as to realize the signal transmission from the control module 25 on the safe side to the intrinsically safe energy limiting module 21 on the dangerous side. The signal output end of the intrinsically safe energy limiting module 21 outputs the fourth DC signal DC 4 A control signal having the above-mentioned value is transmitted to a rotary motor of a solenoid valve at a gas outlet of the gas tank, so that the solenoid valve can be operated to open / close or close by the rotary motor, thereby preventing gas leakage or excessive pressure in the gas tank.

[0022] From the above, the bidirectional transmission circuit of a general-purpose signal in an embodiment of the present application comprises a power supply module and a bidirectional transmission module, and the bidirectional transmission module comprises an intrinsically safe energy limiting module, a first signal coupling module, an isolation transformation module, a second signal coupling module and a control module. The intrinsically safe energy limiting module includes a control signal receiving end and at least one universal signal input end. After receiving one or more universal signals transmitted by the signal detection end, the intrinsically safe energy limiting module transmits the universal signals to a first signal coupling module after passing through intrinsic safety authentication. The first signal coupling module adjusts a first DC signal in the universal signals to a first AC signal. The isolation transformer module is configured to isolate and transmit the first AC signal to a second signal coupling module. The second signal coupling module is configured to adjust the first AC signal to a second DC signal and transmit the second DC signal to the universal signal receiving end of the control module. The transmission of the universal signal to the control end at the detection end is realized. When the control signal issued by the control end is transmitted to the second signal coupling module, the second signal coupling module adjusts a third DC signal in the control signal to a second AC signal. The first signal coupling module is further configured to adjust the second AC signal to a fourth DC signal and transmit the fourth DC signal to the control signal receiving end of the intrinsically safe energy limiting module. Transmission of the control signal to the detection end By adopting the bidirectional transmission circuit according to the present embodiment, it is possible to enhance the interference resistance of general-purpose signals, improve the interference resistance capability of signal transmission, realize the bidirectional transmission of general-purpose signals in one type of circuit, effectively reduce production costs, and improve the applicability of the control system.

[0023] Based on the above embodiment, Fig. 2 is a schematic diagram of a circuit structure of a bidirectional transmission module according to an embodiment of the present application. As shown in Fig. 2, preferably, the first signal combining module 22 includes a first filtering unit 221, a first AC-DC conversion unit 222 and a DC-AC conversion unit 223, and the second signal combining module 24 includes a second filtering unit 241, a second AC-DC conversion unit 242 and a DC-AC conversion unit 223, where the first filtering unit 221 and the second filtering unit 241 are both configured to filter general signals and control signals, and the first AC-DC conversion unit 222 filters the second AC signal AC 2 The fourth DC signal DC 4 Adjust the fourth DC signal to DC 4 to the control signal receiving end, and the second AC-DC conversion unit 242 converts the first AC signal AC 1 to the second DC signal DC 2 Adjust the second DC signal DC 2 to the general-purpose signal receiving end, and the DC-AC conversion module 223 converts the first DC signal DC 1 The first AC signal AC 1 The third DC signal DC in the control signal is adjusted to 3 to the second AC signal AC 2 The control circuit is configured to adjust the

[0024] Continuing to refer to Figures 1 and 2, preferably, the first filtering unit 221 includes a first capacitor (C41) and a second capacitor (C42), a first end of the first capacitor (C41) is electrically connected to each general-purpose signal input terminal (as shown in pin 1 of I / O-1 in Figure 2), a second end of the first capacitor (C41) is electrically connected to a control signal receiving terminal (as shown in pin 2 of I / O-1 in Figure 2), a first end of the second capacitor (C42) is electrically connected to each general-purpose signal input terminal, and a second end of the second capacitor (C42) is electrically connected to the control signal receiving terminal.

[0025] The first AC-DC conversion unit 222 includes a third capacitor (C44) and a fourth capacitor (C43), and the DC-AC conversion unit 223 includes a first inductor (L21-2), a second inductor (L21), a fifth capacitor (C47), a first diode (D13), a second diode (D14), a first triode (T22) and a second triode (T21). A first end of the third capacitor (C44) is electrically connected to each general signal input terminal, a first end 3 of the first triode (T22), a control end 1 of the first triode (T22) and an anode 1 of the first diode (D13). A second end of the third capacitor (C44) is electrically connected to a first end of the fourth capacitor (C43) and a first end 4 of the isolation transformer module 23. The second end of the fourth capacitor C43 is electrically connected to the control signal receiving end, the first end 3 of the second triode T21, the control end 1 of the second triode T21, the cathode 2 of the second diode D14, the first end 1 of the second inductor L21 and the first end of the fifth capacitor C47; the first end of the first inductor L21-2 is electrically connected to the second end 6 of the isolation transformer module 23; the second end of the first inductor L21-2 is electrically connected to the second end of the second inductor L21, the second end of the fifth capacitor C47, the second end 2 of the first triode T22 and the second end 2 of the second triode T21; and the cathode 3 of the first diode D13 is electrically connected to the anode 3 of the second diode D14.

[0026] The second filtering unit 241 includes a third inductor (L7), a fourth inductor (L8), a sixth capacitor (C33) and a seventh capacitor (C32), a first end of the third inductor (L7) is electrically connected to each general-purpose signal receiving terminal (as shown in pin 1 of I / O-2 in FIG. 2) and a first end of the sixth capacitor (C33), a second end of the third inductor (L7) is electrically connected to a first end of the seventh capacitor (C32), a first end of the fourth inductor (L8) is electrically connected to a control signal output terminal (as shown in pin 2 of I / O-2 in FIG. 2) and a second end of the sixth capacitor (C33), and a second end of the fourth inductor (L8) is electrically connected to the second end of the seventh capacitor (C32).

[0027] The second AC-DC conversion unit 242 includes an eighth capacitor (C30), a ninth capacitor (C31), a third diode (D7) and a fourth diode (D8). A first end of the eighth capacitor (C30) is electrically connected to the second end of the third inductor (L7) and the cathode 2 of the third diode (D7). A second end of the eighth capacitor (C30) is electrically connected to the first end of the ninth capacitor (C31) and the third end 1 of the isolation transformer module 23. A second end of the ninth capacitor (C31) is electrically connected to the second end of the fourth inductor (L8) and the anode 1 of the fourth diode (D8). The anode 3 of the third diode (D7) and the cathode 3 of the fourth diode (D8) are all electrically connected to the fourth end 3 of the isolation transformer module 23.

[0028] For example, still referring to FIG. 1 and FIG. 2, a general-purpose signal can be transmitted bidirectionally in a circuit, and the bidirectional transmission circuit can realize an analog input (AnalogInput, AI), i.e., a function of connecting an intrinsically safe transmitter, or an analog output (AnalogOuput, AO), i.e., a function of connecting an intrinsically safe positioning valve, and can further realize a function of connecting a digital input (DigitInput, DI), i.e., an intrinsically safe proximity switch input, a relay output, and can also realize a function of connecting a digital output (DigitOuput, DO), i.e., a switch input, a current source output for driving an intrinsically safe solenoid valve on site.

[0029] 1, the universal signal input terminals 211 and 214 of the intrinsically safe energy limiting module 21 are connected to the universal signal output terminal of the intrinsically safe transmitter, the universal signal generated by the intrinsically safe transmitter can be transmitted from the intrinsically safe energy limiting module 21 in the dangerous side to the control module 25 in the safe side, and the control signal for the intrinsically safe transmitter of the control module 25 can be transmitted from the safe side to the control signal receiving terminal of the intrinsically safe energy limiting module 21 in the dangerous side. As shown in FIG. 2, the DC-AC conversion unit 223 is a shared unit of the first signal combining module 22 and the second signal combining module 24, and in the circuit of the bidirectional transmission module, the DC-AC conversion unit 223 works together with the isolation transformer module 23 to realize the bidirectional transmission of the universal signal.

[0030] The DC-AC conversion unit 223 includes a first inductor (L21-2), a second inductor (L21), a fifth capacitor (C47), a first diode (D13), a second diode (D14), a first triode (T22) and a second triode (T21). As shown in Fig. 2, the first inductor (L21-2), the second inductor (L21) and the fifth capacitor (C47) constitute an LLC oscillation network circuit, and high and low power supply voltages are provided by the power supply module 10 to both ends of the first end 1 and the second end 2 of the second inductor (L21). When the LLC oscillation network circuit is operated to oscillate, the first triode (T22) or the second triode (T21) is alternately turned on, and the first triode (T22) or the second triode (T21) is alternately turned off. When the general-purpose signal inputs 211 and 214 of the circuit receive a general-purpose signal, the LLC oscillator network circuit converts the general-purpose signal into a first DC signal DC 1 The first AC signal AC 1 Adjust the first AC signal to AC 1 is coupled to the first terminal 4 and the second terminal 6 of the isolation transformer module 23 and outputted through the third terminal 1 and the fourth terminal 3 of the isolation transformer module 23, and the first AC signal AC 1 to the second DC signal DC 1The control signal output terminal of the circuit is adjusted to the third DC signal DC 3 When the LLC oscillator network circuit outputs the third DC signal DC 3 to the second AC signal AC 2 Adjust the second AC signal to AC 2 is coupled to the third end 1 and the fourth end 3 of the isolation transformer module 23 and outputted through the first end 4 and the second end 6 of the isolation transformer module 23, 222 The second AC signal AC 2 The fourth DC signal DC 4 and output it.

[0031] The isolation transformer module 23 can adopt an isolation transformer, and the transformation ratio of the isolation voltage is 1:1. According to the isolation transformer transmission characteristics, the third terminal 1 and the fourth terminal 3 of the isolation transformer module 23 meet the characteristics of high and low level alternate output. When the third terminal 1 of the isolation transformer module 23 is at high level and the fourth terminal 3 is at low level, the first AC signal AC 1 flows from the high level of the third terminal 1 of the isolation transformer module 23 through the second terminal of the eighth capacitor (C30), the third inductor (L7), the sixth capacitor (C33), the seventh capacitor (C32), the fourth inductor (L8), the anode 1 of the fourth diode (D8), and returns to the low level of the fourth terminal 3 of the isolation transformer module 23, completing the first period of AC-DC conversion filtering. When the third terminal 1 of the isolation transformer module 23 is at a low level and the fourth terminal 3 is at a high level, the first AC signal AC 1 flows from the high level of the fourth terminal 3 of the isolation transformer module 23 through the anode 3 of the third diode (D7), the third inductor (L7), the sixth capacitor (C33), the seventh capacitor (C32), the fourth inductor (L8), the second terminal of the ninth capacitor (C31), and returns to the low level of the third terminal 1 of the isolation transformer module 23, completing the second period of AC to DC conversion filtering, and forming the first AC signal AC 1 is the first and second period AC to DC conversion After passing through the filtering function, the stable output of the second DC signal DC 2is formed and enters the general-purpose signal receiving end of the control module 25 (as shown as pin 1 of I / O-2 in FIG. 2), completing the transmission of the general-purpose signal generated by the intrinsically safe transmitter from the intrinsically safe energy limiting module 21 on the hazardous side to the control module 25 on the safe side.

[0032] The eighth capacitor (C30) and the ninth capacitor (C31) have a filtering function of converting an AC signal into a DC signal, a π-type filter circuit consisting of the third inductor (L7), the sixth capacitor (C33), the seventh capacitor (C32), and the fourth inductor (L8) has an energy storage and filtering function, and the third diode (D7) and the fourth diode (D8) One-way conduction Diode, and the circuit One-way conduction Meet the requirements of.

[0033] 1 and 2, when the universal signal received by the control module 25 meets the standard of the safety signal, the intrinsically safe energy limiting module 21 continuously transmits the universal signal to the control module 25, and when the control module 25 monitors that the universal signal emitted by the equipment in the dangerous side exceeds the alarm value, the control module 25 issues a control signal through the control signal output terminal (as shown in FIG. 2, pin 2 of I / O-2). Through the cooperation of the LLC oscillator network circuit and the isolation transformer module 23, the third DC signal DC 3 to the second AC signal AC 2 and the second AC signal AC 2 is output via a first terminal 4 and a second terminal 6 of the isolation transformer module 23.

[0034] When the first terminal 4 of the isolation transformer module 23 is at a high level and the second terminal 6 is at a low level, the first triode (T22) is cut off and the second triode (T21) is closed, and the second AC signal AC 2passes through the second end of the third capacitor (C44) of the first AC-DC conversion unit 222, the first capacitor (C41), the second capacitor (C42), the first end 3 of the second triode (T21), the second end 2 of the second triode (T21), and the first inductor (L21-2) of the first filtering unit 221, and returns to the low level of the second end 6 of the isolation transformer module 23, completing the first period of AC-DC conversion filtering. When the first end 4 of the isolation transformer module 23 is at a low level and the second end 6 of the isolation transformer module 23 is at a high level, the first triode (T22) at this time is closed and the second triode (T21) is cut off, and the second AC signal AC output by the high level second end 6 of the isolation transformer module 23 is 2 passes through the first end of the first inductor (L21-2), the second end 2 of the first triode (T22), the first end 3 of the first triode (T22), the first capacitor (C41), the second capacitor (C42), and the fourth capacitor (C43) of the first filtering unit 221, and returns to the low level of the first end 4 of the isolation transformer module 23, thereby completing the second cycle of AC-DC conversion filtering, and generating the second AC signal AC 2 is the first and second period AC to DC conversion After passing through the filtering function, the stable output of the fourth DC signal DC 4 is formed and enters the control signal receiving end of the intrinsically safe energy limiting module 21 (as shown in pin 2 of I / O-1 in FIG. 2), completing the transmission of the control signal for the intrinsically safe transmitter output by the control module 25 from the safe side to the control signal receiving end of the intrinsically safe energy limiting module 21 on the dangerous side.

[0035] The third capacitor (C44) and the fourth capacitor (C43) have a filtering function of converting an AC signal into a DC signal, and the π-type filter circuit consisting of the first capacitor (C41) and the second capacitor (C42) has energy storage and filtering functions.

[0036] Based on the above embodiment, still referring to FIG. 2, the DC-AC conversion unit 223 further includes a first resistor (R49), a second resistor (R48), a tenth capacitor (C46) and an eleventh capacitor (C45). The first resistor (R49) is arranged in series between the control end 1 of the first triode (T22) and the first end 3 of the first triode (T22). The second resistor (R48) is arranged in series between the control end 1 of the second triode (T21) and the first end 3 of the second triode (T21). a first end of the tenth capacitor (C46) electrically connected to the first end of the first resistor (R49) and a second end of the tenth capacitor (C46) electrically connected to the cathode 3 of the first diode (D13) and the anode 3 of the second diode (D14); and an eleventh capacitor (C45) arranged in series between the first end 1 of the second inductor (L21) and the control end 1 of the second triode (T21).

[0037] For example, the bidirectional transmission circuit of the general-purpose signal is provided with a specific resistor and capacitor to realize the normal transmission of the signal without interference. For example, the first resistor (R49), the second resistor (R48), the tenth capacitor (C46) and the eleventh capacitor (C45) are set to balance the stability of the circuit of the DC-AC conversion unit 223, among which the first resistor (R49) can be a bleeder resistor with a large resistance value, to prevent the first triode (T22) from being frequently turned on and off at high voltage, which causes damage to the device, and the tenth capacitor (C46) and the eleventh capacitor (C45) serve as a blocking capacitor to alternately turn on the second triode (T21) and the first triode (T22), convert the DC signal into an AC signal, and oscillate in the LLC oscillation network circuit.

[0038] As one possible embodiment, Fig. 3 is a schematic diagram of another general-purpose signal bidirectional transmission circuit module according to an embodiment of the present application, and Fig. 4 is a schematic diagram of the circuit structure of a signal identification module according to an embodiment of the present application. As shown in Fig. 3, the bidirectional transmission circuit 20 further includes a signal identification module 26, which is arranged in parallel with the first signal combining module 22, and the signal identification module 26 includes at least two comparison units, and the negative phase input terminals of the at least two comparison units are both electrically connected to the output terminal of the intrinsically safe energy limiting module 21, and the reference signals input by the positive phase input terminals of any two comparison units are different.

[0039] Exemplarily, the bidirectional transmission circuit 20 further includes a signal identification module 26, which is configured to determine the type of the general-purpose signal. The signal identification module 26 is paralleled with the first signal coupling module 22, and is configured to include at least two comparison units, each of which includes a comparator, and the first DC signal DC of the general-purpose signal output by the intrinsically safe energy limiting module 21 is determined. 1 The type of the general-purpose signal is determined by comparing the general-purpose signal with a plurality of reference signals. A display device and an information presentation device can be connected to the signal identification module 26, and the type of the general-purpose signal can be presented by display or sound, making it easier for the operator to operate the signal.

[0040] Preferably, referring to FIG. 3 and FIG. 4, the general-purpose signal includes an intrinsically safe analog input signal AI, an intrinsically safe analog output signal AO, an intrinsically safe digital input signal DI and an intrinsically safe digital output signal DO, and the at least two comparison units include a first comparison unit 261, a second comparison unit 262, a third comparison unit 263 and a signal decode unit 264, the first comparison unit 261 includes a first negative phase input terminal (-) and a first positive phase input terminal (+), and the first comparison unit 261 is connected to the general-purpose signal and the first reference signal U 1and obtain a first comparison signal (a) after comparing the general-purpose signal with the second reference signal U, and transmit the first comparison signal (a) to the signal decoding unit 264. The second comparison unit 262 has a second negative phase input terminal (-) and a second positive phase input terminal (+). The second comparison unit 262 compares the general-purpose signal with the second reference signal U 2 and obtain a second comparison signal (b) after comparing the general-purpose signal with the third reference signal U, and transmit the second comparison signal (b) to the signal decoding unit 264. The third comparison unit 263 has a third negative phase input terminal (-) and a third positive phase input terminal (+). The third comparison unit 263 compares the general-purpose signal with the third reference signal U 3 and obtain a third comparison signal (c) after comparing the first comparison signal (a), the second comparison signal (b) and the third comparison signal (c), and transmit the third comparison signal (c) to the signal decoding unit 264, the signal decoding unit 264 being configured to determine a type of the general-purpose signal according to the first comparison signal (a), the second comparison signal (b) and the third comparison signal (c), among which: 1 , second reference signal U 2 and the third reference signal U 3 gradually becomes smaller.

[0041] Exemplarily, the general-purpose signals include an intrinsically safe analog input signal AI, an intrinsically safe analog output signal AO, an intrinsically safe digital input signal DI, and an intrinsically safe digital output signal DO. The signal identification module 26 is connected in parallel with the first signal combination module 22. Among the general-purpose signals, any one of the AI, AO, DI, and DO signals is compared by the comparison unit of the signal identification module 26, and the type of the signal is determined. Exemplarily, the first reference signal U 1 , second reference signal U 2 and the third reference signal U 3 is set so that it gradually decreases, and the first DC signal DC 1 The voltage value of the first reference signal U 1 , second reference signal U 2 and the third reference signal U 3 Compared to the first DC signal DC for the AI, AO, DI, and DO general-purpose signals, 1 Determine the type of signal.

[0042] The first comparison unit 261 includes an AI comparator and outputs a first DC signal DC 1 is inputted from the first negative phase input terminal (-) of the first comparison unit 261, and the first reference signal U 1 is input from the first positive phase input terminal (+), and the first DC signal DC 1 and the first reference signal U 1 and obtain a first comparison signal (a) after comparing with the first DC signal DC 1 The voltage value of the first reference signal U 1 If the voltage value is higher than the voltage value of the first comparison signal (a), the first comparison signal (a) is 1, and the first DC signal DC 1 The voltage value of the first reference signal U 1 If the voltage value of the first comparison signal (a) is not higher than the voltage value of the first comparison signal (a), the second comparison unit 262 includes a DI comparator and converts the first DC signal DC 1 is inputted from the second negative phase input terminal (-) of the second comparison unit 262, and the second reference signal U 2 is input from the second positive phase input terminal (+), and the first DC signal DC 1 and the second reference signal U 2 After comparing with the first DC signal DC 1 The voltage value of the second reference signal U 2 If the voltage value of the second comparison signal (b) is higher than the voltage value of the first DC signal DC 1 The voltage value of the second reference signal U 2 If the voltage value of the second comparison signal (b) is not higher than the voltage value of the first DC signal DC 1 is input from the third negative phase input terminal (-) of the third comparison unit 263, and the third reference signal U 3 is input from the third positive phase input terminal (+), and the first DC signal DC 1 and the third reference signal U 3 and obtain a third comparison signal (c) after comparing it with the first DC signal DC 1 The voltage value of the third reference signal U 3 If the voltage value of the third comparison signal (c) is higher than the voltage value of the first DC signal DC 1 The voltage value of the third reference signal U 3 If the voltage value of the first reference signal U is not higher than the voltage value of the third comparison signal (c), the third comparison signal (c) is 0.1 and the second reference signal U 2 and the third reference signal U 3 The ratio value may be set to 3:2:1.

[0043] signal The first comparison received by the decode unit 264 signal If (a) is 1, directly determine that the general-purpose signal is an AI signal; signal The first comparison received by the decode unit 264 Signal (a) If is 0, continue to read the second comparison signal (b); signal If the second comparison signal (b) received by the decode unit 264 is 1, directly determine that the general-purpose signal is a DI signal; signal The second comparison received by the decode unit 264 Signal (b) If it is 0, continue to read the third comparison signal (c); signal If the third comparison signal (c) received by the decoding unit 264 is 1, directly determine that the general-purpose signal is the AO signal; signal If the third comparison signal (c) received by the decoding unit 264 is 0, it directly verifies that the general-purpose signal is a DO signal, which does not affect the signal transmission, and at the same time, by performing step-by-step comparison, it verifies the type of the general-purpose signal in the bidirectional transmission process, and enhances the anti-interference characteristics of the bidirectional transmission circuit.

[0044] Preferably, still referring to FIG. 1 and FIG. 4, the first comparison unit 261 includes a first comparator AI, a first comparison register (R80) and a second comparison register (R70), a first end of the first comparison register (R80) is electrically connected to a first voltage signal VCC2 input terminal, a first end of the second comparison register (R70) is grounded to GND2, a second end of the first comparison register (R80), a second end of the second comparison register (R70) and a positive phase input terminal (+) of the first comparator AI are electrically connected, and a negative phase input terminal (+) of the first comparator AI is grounded to GND2. The input terminal (-) is electrically connected to the output terminal of the intrinsically safe energy limiting module 21, the output terminal of the first comparator AI is electrically connected to the signal decoding unit 264, the second comparison unit 262 includes a second comparator DI, a third comparison register (R81) and a fourth comparison register (R71), a first terminal of the third comparison register (R81) is electrically connected to the first voltage signal VCC2 input terminal, a first terminal of the fourth comparison register (R71) is grounded to GND2, and a second terminal of the third comparison register (R81) and a fourth comparison register (R71) are electrically connected to the first voltage signal VCC2 input terminal. The second end of the comparison register (R71) and the positive phase input end (+) of the second comparator DI are electrically connected, the negative phase input end (-) of the second comparator DI is electrically connected to the output end of the intrinsically safe energy limiting module 21, the output end of the second comparator DI is electrically connected to the signal decoding unit 264, the third comparison unit 263 includes a third comparator AO, a fifth comparison register (R82) and a sixth comparison register (R72), and a first end of the fifth comparison register (R82) is electrically connected to the first voltage signal VCC2 input end. the first end of the sixth comparing register (R72) is grounded to GND2; the second end of the fifth comparing register (R82), the second end of the sixth comparing register (R72) and the positive phase input terminal (+) of the third comparator AO are electrically connected; the negative phase input terminal (-) of the third comparator AO is electrically connected to the output terminal of the intrinsically safe energy limiting module 21; the output terminal of the third comparator AO is electrically connected to the signal decoding unit 264; and the first voltage signal VCC2 input terminal is electrically connected to the power supply module 10.

[0045] For example, the first voltage signal VCC2 input terminal is electrically connected to the power supply module 10, and is configured to provide a reference voltage for stably operating the comparator. In the comparison circuit of the first comparison unit 261, the first terminal of the first comparison resistor (R80) is electrically connected to the first voltage signal VCC2 input terminal, and the second terminal of the first comparison resistor (R80), the second terminal of the second comparison resistor (R70) and the positive phase input terminal (+) of the first comparator AI are electrically connected, and the relationship of the resistance ratio between the first comparison resistor (R80) and the second comparison resistor (R70) is reasonably set to generate the first reference signal U of the comparator. 1 For example, if the ratio of the resistance values ​​of the first comparison resistor R80 and the second comparison resistor R70 is set to 3:1, the first reference signal U 1 The value of U 1 = 3 / 4VCC2, which is used to determine the AI ​​signal by comparing it with the general-purpose signal. In the comparison circuit of the second comparison unit 262, if the ratio of the resistance values ​​of the third comparison resistor (R81) and the fourth comparison resistor (R71) is set to satisfy 1:1, the second reference signal U 2 The value of U 2 = 1 / 2 VCC2, which is used to determine the DI signal by comparing it with a general-purpose signal. In the comparison circuit of the third comparison unit 263, if the ratio of the resistance values ​​of the fifth comparison register (R82) and the sixth comparison register (R72) is set to satisfy 3:1, 3 Reference signal U 3 The value of U 3 = 1 / 4VCC2, which is used to compare with the general-purpose signal to determine the AO signal. As shown in Figure 4, it can be understood that the signal identification module 26 may further include a fourth comparison unit 265, which is not introduced here, but by adopting a method in which the comparison circuits are paralleled, more signals can be introduced and verified, and the applicability of the circuit can be expanded.

[0046] Preferably, still referring to FIG. 4, the first comparison unit 261 further includes a first pull-up resistor (R50), a third resistor (R60), a fourth resistor (R90) and a twelfth capacitor (C54), in which a first end of the first pull-up resistor (R50) is electrically connected to the first voltage signal VCC2 input end, a second end of the first pull-up resistor (R50) and a first end of the third resistor (R60) are electrically connected to the output end of the first comparator AI, a second end of the third resistor (R60) is electrically connected to the second end of the second comparison resistor (R70), and a twelfth capacitor (C54) are electrically connected to the output end of the first comparator AI. The first end of the fourth resistor (R90) is electrically connected to the negative phase input end of the first comparator AI, the second end of the fourth resistor (R90) is electrically connected to the output end of the intrinsically safe energy limiting module 21, the first end of the twelfth capacitor (C54) is electrically connected to the first bias voltage input end of the first comparator AI, the second end of the twelfth capacitor (C54) is grounded, and the second bias voltage input end of the first comparator AI is grounded. The second comparison unit 262 further includes a second pull-up resistor (R51), a fifth resistor (R61) and a sixth resistor (R91), and the second pull-up The first end of the resistor (R51) is electrically connected to the first voltage signal VCC2 input end, the second end of the second pull-up resistor (R51) and the first end of the fifth resistor (R61) are electrically connected to the output end of the second comparator DI, the second end of the fifth resistor (R61) is electrically connected to the second end of the fourth comparison resistor (R71), the first end of the sixth resistor (R91) is electrically connected to the negative phase input end of the second comparator DI, and the second end of the sixth resistor (R91) is electrically connected to the output end of the intrinsically safe energy limiting module 21, and the third comparison unit 263 is The third pull-up resistor (R52), a seventh resistor (R62), and an eighth resistor (R92), a first end of which is electrically connected to the first voltage signal VCC2 input end, a second end of which is electrically connected to the output end of the third comparator AO, a second end of which is electrically connected to the second end of the sixth comparator resistor (R72), a first end of which is electrically connected to the negative phase input end of the third comparator AO, and a second end of which is electrically connected to the negative phase input end of the third comparator AO.Electrically connected to the output terminal of the intrinsically safe energy limiting module 21.

[0047] Exemplarily, the comparison circuit further includes a plurality of kinds of resistors and capacitors that cooperate to complete the comparison of signals of the comparison units, such as the first pull-up resistor (R50), the third resistor (R60), the fourth resistor (R90) and the twelfth capacitor (C54) of the first comparison unit 261 for balancing the voltage of the first voltage signal VCC2 and ensuring that the first comparator AI operates normally. The second comparison unit 262 further includes a second pull-up resistor (R51), a fifth resistor (R61) and a sixth resistor (R91), and the third comparison unit 263 further includes a third pull-up resistor (R52), a seventh resistor (R62) and an eighth resistor (R92). By rationally setting a plurality of resistor values, the stability and comparison accuracy of the comparators can be effectively improved.

[0048] 5 is a schematic diagram of a circuit structure of a power supply module according to an embodiment of the present application. Referring to FIG. 1, FIG. 3 and FIG. 5, the power supply module 10 preferably includes a power supply 11, a voltage regulator module 12, a voltage conversion module 13, a first rectifier module 14 and a second rectifier module 15.

[0049] The power supply 11 (P1) is configured to provide a DC power supply signal, the voltage regulator module 12 is configured to stably output a DC power supply signal VCC1, the voltage conversion module 13 is configured to convert the DC power supply signal into an AC power supply signal, the first rectification module 14 and the second rectification module 15 are both configured to rectify the AC power supply signal into a DC current signal, the first rectification module 14 has a first voltage VCC3 and is configured to power the intrinsically safe energy limiting module 21 and the first signal coupling module 22, and the second rectification module 15 has a second voltage VCC4 and is configured to power the second signal coupling module 24 and the control module 25.

[0050] For example, the bidirectional transmission circuit is a key unit between the field device and the PLC / DCS, and the signal conversion and isolation technology is a key technology of the bidirectional transmission circuit, and the power supply module 10 provides a stable power supply for the signal conversion and isolation technology. Referring to FIG. 1 and FIG. 5, the power supply 11 (P1) provides a DC power signal, and the DC power signal is protected by a transient diode TVS1 (Transient Voltage Suppressor, TVS), and then One-way conduction The diode D1 supplies power to the voltage regulator module 12, which generates a stable output DC power signal VCC1; the voltage conversion module 13 converts the DC power signal VCC1 into an AC power signal, which is sent to the power isolation transformer, and the power isolation transformer transmits the AC power signal to the first rectifier module 14 and the second rectifier module 15 in an isolated manner; the first rectifier module 14 and the second rectifier module 15 are AC-DC conversion transformers, and the voltage division ratios of the two are the same or different; the first rectifier module 14 and the second rectifier module 15 rectify the AC power signal to generate two-way DC power signals, which are provided to the safe side and the dangerous side of the bidirectional transmission circuit for signal judgment. For example, the first rectifier module 14 outputs a first voltage VCC3 to power the intrinsically safe energy limiting module 21 and the first signal coupling module 22, and the second rectifier module 15 outputs a second voltage VCC4 to power the second signal coupling module 24 and the control module 25. Because general-purpose signals are subject to frequent changes, the first rectifier module 14 and the second rectifier module 15 can be adjusted to make the voltage values ​​of the first voltage VCC3 and the second voltage VCC4 the same or different, and at the same time, the power supply 11 (P1) can be a positive power supply or a negative power supply.

[0051] Based on the above embodiment, the power supply module 10 further includes a third rectification module and a fourth rectification module (not shown in the drawings), and the third rectification module or the fourth rectification module is configured to output a first voltage signal VCC2 to the signal identification module 26 to provide a comparison reference voltage for identifying the type of the general-purpose signal, and the circuit diagram is not described in this embodiment.

[0052] Preferably, the bidirectional transmission circuit 20 further includes a signal protection module 27. 7 is provided in series between the second signal coupling module 24 and the control module 25 and is configured to provide electrostatic protection and surge protection for the bidirectional transmission circuit.

[0053] For example, still referring to FIG. 3, a signal protection module 27 is connected in series between the circuits of the second signal coupling module 24 and the control module 25, and components such as an electrostatic isolator, a surge protector, etc. are provided to avoid signal transmission distortion and signal interference caused by electrostatic and surge effects in the bidirectional transmission of general-purpose signals, and improve the accuracy of the transmission of general-purpose signals.

[0054] As described above, the bidirectional transmission circuit of the general-purpose signal according to the embodiment of the present application realizes the transmission of the general-purpose signal from the detection end to the control end through the unified cooperation and combination of multiple modules, and realizes the transmission of the control signal from the control end to the detection end and the confirmation of the type of the general-purpose signal. By adopting the bidirectional transmission circuit according to the embodiment, the interference resistance of the general-purpose signal is enhanced, the interference resistance ability of the signal transmission is improved, and 1 seed Therefore, it is possible to realize two-way transmission of multiple types of general-purpose signals in a circuit of the same type, thereby effectively reducing production costs and improving the applicability of the control system.

Claims

1. A power supply module; the system includes an intrinsically safe energy limiting module, a first signal coupling module, an isolation transformer module, a second signal coupling module, and a control module; the first signal coupling module is electrically connected to the intrinsically safe energy limiting module and the isolation transformer module, the second signal coupling module is electrically connected to the isolation transformer module and the control module, and the power supply module is electrically connected to the intrinsically safe energy limiting module, the first signal coupling module, the second signal coupling module and the control module; The intrinsically safe energy limiting module includes a control signal receiving end configured to receive a control signal, and at least one general-purpose signal input end, each of which is configured to receive a general-purpose signal; The control module includes a control signal output end configured to output the control signal, and a general-purpose signal receiving end configured to receive the general-purpose signal; The first signal combining module is configured to adjust a first DC signal in the general signal to a first AC signal, the isolation transformer module is configured to isolate and transmit the first AC signal to the second signal combining module, and the second signal combining module is configured to adjust the first AC signal to a second DC signal and transmit the second DC signal to the general signal receiving end; the second signal combining module is further configured to adjust a third DC signal in the control signal to a second AC signal, the isolation transformation module is further configured to transmit the second AC signal to the first signal combining module in an isolated manner, and the first signal combining module is further configured to adjust the second AC signal to a fourth DC signal and transmit the fourth DC signal to the control signal receiving end; and The first signal combining module includes a first filtering unit, a first AC-DC conversion unit and a DC-AC conversion unit; the second signal combining module comprises a second filtering unit, a second AC-DC conversion unit and the DC-AC conversion unit; the first filtering unit and the second filtering unit are both configured to filter the general-purpose signal and the control signal; the first AC-DC conversion unit is configured to convert the second AC signal into a fourth DC signal and transmit the fourth DC signal to the control signal receiving end; the second AC-DC conversion unit is configured to convert the first AC signal into a second DC signal and transmit the second DC signal to the general-purpose signal receiving end; the DC-AC conversion unit is configured to condition a first DC signal in the general signal to a first AC signal, and condition a third DC signal in the control signal to a second AC signal; Bidirectional transmission circuit for general-purpose signals.

2. The first filtering unit includes a first capacitor and a second capacitor, a first end of the first capacitor is electrically connected to each of the general-purpose signal input terminals, a second end of the first capacitor is electrically connected to the control signal receiving terminal, a first end of the second capacitor is electrically connected to each of the general-purpose signal input terminals, and a second end of the second capacitor is electrically connected to the control signal receiving terminal; The first AC-DC conversion unit includes a third capacitor and a fourth capacitor, and the DC-AC conversion unit includes a first inductor, a second inductor, a fifth capacitor, a first diode, a second diode, a first triode and a second triode, a first end of the third capacitor is electrically connected to each general signal input terminal, a first end of the first triode, a control end of the first triode and an anode of the first diode, a second end of the third capacitor is electrically connected to a first end of the fourth capacitor and a first end of the isolation transformer module, and a second end of the first inductor electrically connected to the control signal receiving end, the first end of the second triode, the control end of the second triode, the cathode of the second diode, the first end of the second inductor, and the first end of the fifth capacitor; a first end of the first inductor electrically connected to the second end of the isolation transformer module; a second end of the first inductor electrically connected to the second end of the second inductor, the second end of the fifth capacitor, the second end of the first triode, and the second end of the second triode; and a cathode of the first diode electrically connected to the anode of the second diode. the second filtering unit includes a third inductor, a fourth inductor, a sixth capacitor, and a seventh capacitor, a first end of the third inductor is electrically connected to the general-purpose signal receiving port and the first end of the sixth capacitor, a second end of the third inductor is electrically connected to the first end of the seventh capacitor, a first end of the fourth inductor is electrically connected to the control signal output port and the second end of the sixth capacitor, and a second end of the fourth inductor is electrically connected to the second end of the seventh capacitor; the second AC-DC conversion unit comprises an eighth capacitor, a ninth capacitor, a third diode and a fourth diode, a first end of the eighth capacitor is electrically connected to the second end of the third inductor and the cathode of the third diode, a second end of the eighth capacitor is electrically connected to the first end of the ninth capacitor and the third end of the isolation transformer module, a second end of the ninth capacitor is electrically connected to the second end of the fourth inductor and the anode of the fourth diode, and the anode of the third diode and the cathode of the fourth diode are both electrically connected to the fourth end of the isolation transformer module; 2. The bidirectional transmission circuit according to claim 1.

3. the DC-AC conversion unit further comprises a first resistor, a second resistor, a tenth capacitor and an eleventh capacitor; the first resistor is provided in series between a control end of the first triode and a first end of the first triode; the second resistor is provided in series between a control end of the second triode and a first end of the second triode; the tenth capacitor has a first end electrically connected to the first end of the first resistor and a second end electrically connected to the cathode of the first diode and the anode of the second diode, the eleventh capacitor is provided in series between the first end of the second inductor and the control end of the second triode; 3. The bidirectional transmission circuit according to claim 2.

4. A signal identification module is provided in parallel with the first signal combination module, The signal identification module comprises at least two comparison units; The negative input terminals of the at least two comparison units are electrically connected to the output terminal of the intrinsically safe energy limiting module, and the reference signals input by the positive input terminals of any two comparison units are different; 2. The bidirectional transmission circuit according to claim 1.

5. The general-purpose signals include an intrinsically safe analog input signal AI, an intrinsically safe analog output signal AO, an intrinsically safe digital input signal DI, and an intrinsically safe digital output signal DO; The at least two comparison units include a first comparison unit, a second comparison unit, a third comparison unit and a signal decode unit; the first comparison unit has a first negative phase input terminal and a first positive phase input terminal, and is configured to obtain a first comparison signal after comparing the general-purpose signal with a first reference signal, and transmit the first comparison signal to the signal decoding unit; the second comparison unit has a second negative phase input terminal and a second positive phase input terminal, and is configured to obtain a second comparison signal after comparing the general-purpose signal with a second reference signal, and transmit the second comparison signal to the signal decoding unit; the third comparison unit has a third negative phase input terminal and a third positive phase input terminal, and is configured to obtain a third comparison signal after comparing the general-purpose signal with a third reference signal, and transmit the third comparison signal to the signal decoding unit; the signal decode unit is configured to determine a type of the generic signal based on the first comparison signal, the second comparison signal, and the third comparison signal; The first reference signal, the second reference signal, and the third reference signal gradually become smaller.

5. The bidirectional transmission circuit according to claim 4.

6. the first comparison unit comprises a first comparator, a first comparison register and a second comparison register, a first end of the first comparison register is electrically connected to a first voltage signal input end, a first end of the second comparison register is grounded, a second end of the first comparison register, a second end of the second comparison register and a positive phase input end of the first comparator are electrically connected, a negative phase input end of the first comparator is electrically connected to an output end of the intrinsically safe energy limiting module, and an output end of the first comparator is electrically connected to the signal decoding unit; the second comparison unit comprises a second comparator, a third comparison register and a fourth comparison register, a first end of the third comparison register is electrically connected to a first voltage signal input end, a first end of the fourth comparison register is grounded, a second end of the third comparison register, a second end of the fourth comparison register and a positive phase input end of the second comparator are electrically connected, a negative phase input end of the second comparator is electrically connected to an output end of the intrinsically safe energy limiting module, and an output end of the second comparator is electrically connected to the signal decoding unit; the third comparison unit comprises a third comparator, a fifth comparison register and a sixth comparison register, a first end of the fifth comparison register is electrically connected to a first voltage signal input end, a first end of the sixth comparison register is grounded, a second end of the fifth comparison register, a second end of the sixth comparison register and a positive phase input end of the third comparator are electrically connected, a negative phase input end of the third comparator is electrically connected to an output end of the intrinsically safe energy limiting module, and an output end of the third comparator is electrically connected to the signal decoding unit; The first voltage signal input terminal is electrically connected to the power supply module; 6. The bidirectional transmission circuit according to claim 5.

7. the first comparison unit further comprises a first pull-up resistor, a third resistor, a fourth resistor and a twelfth capacitor, a first end of the first pull-up resistor is electrically connected to the first voltage signal input terminal, a second end of the first pull-up resistor and a first end of the third resistor are electrically connected to the output terminal of the first comparator, a second end of the third resistor is electrically connected to the second end of the second comparison resistor, a first end of the fourth resistor is electrically connected to the negative phase input terminal of the first comparator, and a second end of the fourth resistor is electrically connected to the output terminal of the intrinsically safe energy limiting module, a first end of the twelfth capacitor is electrically connected to the first bias voltage input terminal of the first comparator, a second end of the twelfth capacitor is grounded, and a second bias voltage input terminal of the first comparator is grounded; the second comparison unit further comprises a second pull-up resistor, a fifth resistor and a sixth resistor, a first end of the second pull-up resistor is electrically connected to the first voltage signal input end, a second end of the second pull-up resistor and a first end of the fifth resistor are electrically connected to the output end of the second comparator, a second end of the fifth resistor is electrically connected to the second end of the fourth comparison resistor, a first end of the sixth resistor is electrically connected to the negative phase input end of the second comparator, and a second end of the sixth resistor is electrically connected to the output end of the intrinsically safe energy limiting module; the third comparison unit further comprises a third pull-up resistor, a seventh resistor and an eighth resistor, a first end of the third pull-up resistor is electrically connected to the first voltage signal input end, a second end of the third pull-up resistor and a first end of the seventh resistor are electrically connected to the output end of the third comparator, a second end of the seventh resistor is electrically connected to the second end of the sixth comparison resistor, a first end of the eighth resistor is electrically connected to the negative phase input end of the third comparator, and a second end of the eighth resistor is electrically connected to the output end of the intrinsically safe energy limiting module; 7. The bidirectional transmission circuit according to claim 6.

8. The power supply module includes a power supply configured to provide a DC power signal, a voltage regulator module configured to stably output the DC power signal, a voltage conversion module configured to convert the DC power signal into an AC power signal, and a first rectification module and a second rectification module each configured to rectify the AC power signal into a DC signal; the first rectification module has a first voltage and is configured to power the intrinsically safe energy limiting module and the first signal coupling module, and the second rectification module has a second voltage and is configured to power the second signal coupling module and the control module.

2. The bidirectional transmission circuit according to claim 1.

9. a signal protection module disposed in series between the second signal coupling module and the control module and configured to provide electrostatic protection and surge protection for the bidirectional transmission circuit; 2. The bidirectional transmission circuit according to claim 1.

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