AO device compatible with voltage and current signal output

Abstract

The utility model relates to the field of signal output in a DCS (Distributed Control System), in particular to an AO device compatible with voltage and current signal output, which improves the system compatibility. According to the scheme, the circuit comprises an AO output module, a DAC module, an isolation module and a control module, the isolation module is connected with the control module and the DAC module, the DAC module is connected with the AO output module, a fourth pin and a third pin of a voltage reference chip (U4) are connected with a first voltage output end, the fourth pin and the third pin are further grounded through a sixteenth capacitor (C16), and the control module is connected with the control module. A first pin is grounded through a seventeenth capacitor (C17), a second pin is grounded, a fifth pin and a sixth pin are connected with a third pin of a digital-to-analog converter (U2), the sixth pin and the second pin are connected with a fifteenth capacitor (C15) through a fourteenth capacitor (C14), and a fourth pin, the fifth pin and the sixth pin of the digital-to-analog converter (U2) are respectively connected with a control module. An eighth pin of the digital-to-analog converter (U2) is connected with a first voltage output end, and a first pin of the digital-to-analog converter (U2) is connected with an in-phase input end of the third operational amplifier (U3).

Description

Technical Field

[0001] The utility model relates to the field of signal output in a DCS (Distributed Control System), and in particular to an AO device capable of outputting compatible voltage and current signals. Background Art

[0002] DCS is widely used to control main and auxiliary equipment in various power generation modes, including thermal power, hydropower, nuclear power, gas-steam combined cycle, wind power, and solar power. To improve system versatility, it is necessary to support universal analog input.

[0003] Existing DCS analog output technology, such as a DCS analog output AO card structure disclosed in CN212846459U, includes an analog output 4-20mA module, a main processor module, a communication transmission module and a power supply module; the communication transmission module is connected to the DCS analog output AO card structure.

[0004] The analog control value industrial Ethernet signal transmitted by the upper-level DCS central control unit is decoded and sent to the main processing module through the serial protocol. The main processor, in cooperation with the auxiliary system, analyzes the signal transmitted by the serial protocol according to the set program, and accordingly changes the current output value of each channel of the analog output 4-20mA module to realize the signal output of the analog card.

[0005] However, the signal of the above solution is not isolated by photoelectricity, and cannot be electrically isolated from the field. In addition, it is also impossible to select voltage or current output by switching the circuit. Therefore, the versatility and compatibility are poor. Utility Model Content

[0006] The purpose of the utility model is to overcome the shortcomings of the prior art and provide an AO device compatible with voltage and current signal output, thereby achieving electrical isolation from the field and improving compatibility.

[0007] The present invention adopts the following technical solutions to achieve the above-mentioned purpose. The present invention provides an AO device compatible with voltage and current signal output, including an AO output module, a DAC module, an isolation module and a control module. The isolation module is connected to the control module and the DAC module respectively, and the DAC module is connected to the AO output module. The DAC module includes a voltage reference chip U4, a digital-to-analog converter U2, a third operational amplifier U3, a ninth capacitor C9, a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, and a seventeenth capacitor C17. The fourth and third pins of the voltage reference chip U4 are connected to the first voltage output end, and the fourth and third pins of the voltage reference chip U4 are also grounded through the sixteenth capacitor C16. The voltage reference chip U4 The first pin of the digital-to-analog converter U2 is connected to the ground through the seventeenth capacitor C17, the second pin of the voltage reference chip U4 is grounded, the fifth pin and the sixth pin of the voltage reference chip U4 are connected to the third pin of the digital-to-analog converter U2, the sixth pin and the second pin of the voltage reference chip U4 are connected to the fifteenth capacitor C15 through the fourteenth capacitor C14, the fourth pin, the fifth pin and the sixth pin of the digital-to-analog converter U2 are respectively connected to the isolation module, the seventh pin and the second pin of the digital-to-analog converter U2 are grounded, the eighth pin of the digital-to-analog converter U2 is connected to the first voltage output end, and is grounded through the ninth capacitor C9, the first pin of the digital-to-analog converter U2 is connected to the non-inverting input end of the third operational amplifier U3, the inverting input end of the third operational amplifier U3 is connected to the output end, and the output end outputs the analog voltage signal to the AO output module.

[0008] Furthermore, the isolation module includes a digital isolator chip U1, a tenth capacitor C10 and an eleventh capacitor C11. The third to sixth pins of the digital isolator chip U1 are respectively connected to the control module, the seventh pin and the first pin of the digital isolator chip U1 are respectively connected to the second voltage output end, the second pin and the eighth pin of the digital isolator chip U1 are grounded, the tenth pin and the sixteenth pin of the digital isolator chip U1 are respectively connected to the first voltage output end, the ninth pin and the fifteenth pin of the digital isolator chip U1 are grounded, and the twelfth to fourteenth pins of the digital isolator chip U1 are respectively connected to the fourth pin, the fifth pin and the sixth pin of the digital-to-analog converter U2.

[0009] Furthermore, the AO output module includes a fifth operational amplifier U5A, a fifth operational amplifier U5B, an instrumentation amplifier U6, a window comparator U7, a sixteenth resistor R16, and a thirteenth resistor R13. The non-inverting input terminal of the fifth operational amplifier U5B is connected to the non-inverting input terminal of the fifth operational amplifier U5A through the sixteenth resistor R16, and the inverting input terminal of the fifth operational amplifier U5B is connected to the output terminal of the fifth operational amplifier U5B; the inverting input terminal of the fifth operational amplifier U5A is connected to the sixth pin of the instrumentation amplifier U6, and the output terminal of the fifth operational amplifier U5A is also connected to the third pin of the instrumentation amplifier U6. The second pin of the instrumentation amplifier U6 is connected to the first pin of the window comparator U7 through the thirteenth resistor R13, and the third pin of the window comparator U7 is output.

[0010] Furthermore, the AO output module further includes a first transient suppression diode TVS1 and a twenty-first capacitor C21 , and the output end of the fifth operational amplifier U5A is grounded through the first transient suppression diode TVS1 and the twenty-first capacitor C21 , respectively.

[0011] The AO output module further includes a first overvoltage protection resistor RT1 , which is connected between the output terminal of the fifth operational amplifier U5A and the twenty-first capacitor C21 .

[0012] Furthermore, the AO output module further includes a rectifier diode D1 , which is connected between the output terminal of the fifth operational amplifier U5A and the first overvoltage protection resistor RT1 .

[0013] The AO output module further includes a second transient suppression diode TVS2 and a twenty-fourth capacitor C24. The output end of the fifth operational amplifier U5B is grounded through the second transient suppression diode TVS2 and the twenty-fourth capacitor C24, respectively.

[0014] Furthermore, the AO output module further includes a second overvoltage protection resistor RT2 , and the second overvoltage protection resistor RT2 is connected between the output end of the fifth operational amplifier U5B and the twenty-fourth capacitor C24 .

[0015] Furthermore, the AO output module also includes a first transistor Q1 and a ninth resistor R9. The output end of the fifth operational amplifier U5A is connected to the base of the first transistor Q1 through the ninth resistor R9. The collector of the first transistor Q1 is connected to the third voltage output end. The emitter of the first transistor Q1 is connected to the output end of the fifth operational amplifier U5A.

[0016] Furthermore, the AO output module also includes a switching diode D2, which is two parallel diodes, wherein the anode of one diode is grounded and the cathode is connected to the inverting input terminal of the fifth operational amplifier U5A, and the cathode of the other diode is connected to the first voltage output terminal and the anode is connected to the inverting input terminal of the fifth operational amplifier U5A.

[0017] Beneficial effects of the utility model:

[0018] The utility model realizes electrical isolation between the system and the site through the isolation module, thereby improving the reliability and stability of the system.

[0019] The isolated signal is sent to the DAC module, which converts the digital signal into an analog signal. If the DAC module outputs a voltage signal and the voltage output range and drive capability do not meet the module's output requirements, the AO output module converts the voltage into the required voltage and current signals. The current output includes a disconnection detection function. When a disconnection occurs, the current loop is lost. This condition is detected and fed back to the controller module through the isolation module, enabling simultaneous voltage and current output selection, improving compatibility and versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural block diagram of an AO device compatible with voltage and current signal output provided by an embodiment of the present utility model;

[0021] Figure 2 This is a schematic diagram of the circuit structure of a digital isolator chip provided by an embodiment of the present utility model;

[0022] Figure 3 This is a schematic diagram of the circuit structure of the DAC module provided by an embodiment of the present utility model;

[0023] Figure 4 and Figure 5 This is a schematic diagram of the circuit structure of the AO output module provided by an embodiment of the present utility model;

[0024] Figure 6 This is a schematic diagram of the circuit structure of a DC-DC power supply module provided by an embodiment of the present utility model;

[0025] Figure 7 This is a schematic diagram of a voltage stabilizer circuit structure provided by an embodiment of the present utility model;

[0026] Figure 8 This is a schematic diagram of the circuit structure of the filter module provided by the embodiment of the utility model;

[0027] In the accompanying drawings, U4 is a voltage reference chip, U2 is a digital-to-analog converter, U3 is a third operational amplifier, U1 is a digital isolator chip, U5A and U5B are fifth operational amplifiers, U6 is an instrumentation amplifier, and U7 is a window comparator. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0029] The utility model provides an AO device compatible with voltage and current signal output, such as Figure 1 As shown, it includes an AO output module, a DAC module, an isolation module and a control module. The isolation module is connected to the control module and the DAC module respectively, and the DAC module is connected to the AO output module.

[0030] The DAC module is as follows Figure 3 As shown, it includes a voltage reference chip U4, a digital-to-analog converter U2, a third operational amplifier U3, a ninth capacitor C9, a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, and a seventeenth capacitor C17. The fourth and third pins of the voltage reference chip U4 are connected to the first voltage output terminal AO1_5V, the fourth and third pins of the voltage reference chip U4 are also grounded through the sixteenth capacitor C16, the first pin of the voltage reference chip U4 is grounded through the seventeenth capacitor C17, the second pin of the voltage reference chip U4 is grounded, the fifth and sixth pins of the voltage reference chip U4 are connected to the third pin of the digital-to-analog converter U2, and the voltage The sixth pin and the second pin of the voltage reference chip U4 are connected through the fourteenth capacitor C14 and the fifteenth capacitor C15, the fourth pin, the fifth pin and the sixth pin of the digital-to-analog converter U2 are respectively connected to the isolation module, the seventh pin and the second pin of the digital-to-analog converter U2 are grounded, the eighth pin of the digital-to-analog converter U2 is connected to the first voltage output terminal AO1_5V, and is grounded through the ninth capacitor C9, the first pin of the digital-to-analog converter U2 is connected to the non-inverting input terminal of the third operational amplifier U3, the inverting input terminal of the third operational amplifier U3 is connected to the output terminal, and the output terminal of the third operational amplifier U3 outputs the analog voltage signal V_OUT1 to the AD output module.

[0031] Isolation modules such as Figure 2As shown, the isolation module includes a digital isolator chip U1, a tenth capacitor C10 and an eleventh capacitor C11. The third to sixth pins of the digital isolator chip U1 are respectively connected to the control module, the seventh pin and the first pin of the digital isolator chip U1 are respectively connected to the second voltage output terminal VCC_3V3, the second pin and the eighth pin of the digital isolator chip U1 are grounded, the tenth pin and the sixteenth pin of the digital isolator chip U1 are respectively connected to the first voltage output terminal AO1_5V, the ninth pin and the fifteenth pin of the digital isolator chip U1 are grounded, and the twelfth to fourteenth pins of the digital isolator chip U1 are respectively connected to the fourth, fifth and sixth pins of the digital-to-analog converter U2.

[0032] AO output module such as Figure 4 and Figure 5 As shown, it includes a fifth operational amplifier U5A, a fifth operational amplifier U5B, an instrumentation amplifier U6, a window comparator U7, a sixteenth resistor R16, and a thirteenth resistor R13. The non-inverting input terminal of the fifth operational amplifier U5B is connected to the non-inverting input terminal of the fifth operational amplifier U5A through the sixteenth resistor R16. The non-inverting input terminal of the fifth operational amplifier U5A receives the analog voltage signal V_OUT1 sent by the DAC module. The inverting input terminal of the fifth operational amplifier U5B is connected to the output terminal of the fifth operational amplifier U5B; the output terminal of the fifth operational amplifier U5B outputs the voltage signal AV_OUT1;

[0033] The inverting input terminal of the fifth operational amplifier U5A is connected to the sixth pin of the instrumentation amplifier U6. The output terminal of the fifth operational amplifier U5A is also connected to the third pin of the instrumentation amplifier U6. The output terminal of the fifth operational amplifier U5A outputs a current signal AI_OUT1. The second pin of the instrumentation amplifier U6 is connected to the first pin of the window comparator U7 via a thirteenth resistor R13. The third pin of the window comparator U7 outputs a current output disconnection detection signal I_OUT1_JC.

[0034] In one embodiment of the present invention, the AO output module further includes a first transient suppression diode TVS1 and a twenty-first capacitor C21, and the output end of the fifth operational amplifier U5A is grounded through the first transient suppression diode TVS1 and the twenty-first capacitor C21 respectively.

[0035] In one embodiment of the present invention, the AO output module further includes a first overvoltage protection resistor RT1 , which is connected between the output terminal of the fifth operational amplifier U5A and the twenty-first capacitor C21 .

[0036] In one embodiment of the present invention, the AO output module further includes a rectifier diode D1 , which is connected between the output end of the fifth operational amplifier U5A and the first overvoltage protection resistor RT1 .

[0037] In one embodiment of the present invention, the AO output module further includes a second transient suppression diode TVS2 and a twenty-fourth capacitor C24, and the output end of the fifth operational amplifier U5B is grounded through the second transient suppression diode TVS2 and the twenty-fourth capacitor C24 respectively.

[0038] In one embodiment of the present invention, the AO output module further includes a second overvoltage protection resistor RT2 , and the second overvoltage protection resistor RT2 is connected between the output end of the fifth operational amplifier U5B and the twenty-fourth capacitor C24 .

[0039] In one embodiment of the present utility model, the AO output module also includes a first transistor Q1 and a ninth resistor R9. The output end of the fifth operational amplifier U5A is connected to the base of the first transistor Q1 through the ninth resistor R9. The collector of the first transistor Q1 is connected to the third voltage output end AO1_24V. The emitter of the first transistor Q1 is connected to the output end of the fifth operational amplifier U5A.

[0040] In one embodiment of the present utility model, the AO output module also includes a switching diode D2, which is two diodes connected in parallel, wherein the anode of one diode is grounded and the cathode is connected to the inverting input terminal of the fifth operational amplifier U5A, and the cathode of the other diode is connected to the first voltage output terminal and the anode is connected to the inverting input terminal of the fifth operational amplifier U5A.

[0041] The DC-DC power supply module used in this utility model is as follows Figure 6 As shown, the model is BO524S-1WR3. The first pin of the DC chip is grounded, the second pin is connected to the voltage end of VCC_5V, a capacitor C25 is connected between the first and second pins, the fourth pin of the DC chip is connected to the voltage end of AO1_24V, the third pin is grounded, a capacitor C26 is connected between the fourth and third pins, and a rectifier diode D3 is also connected between the capacitor C26 and the third pin of the DC chip.

[0042] The utility model adopts a high-voltage, low-noise, low-leakage current linear regulator, such as Figure 7 As shown, the input pin 3 of the voltage regulator U8 is connected to the AO1_24V voltage terminal, the output pin 1 of the voltage regulator U8 outputs a 5V voltage, the input pin 3 of the voltage regulator U8 is grounded through the capacitor C27, the output pin 1 of the voltage regulator U8 is grounded through the capacitor C28, and the ground pin GND of the voltage regulator U8 is grounded.

[0043] The filter module used in this utility model is as follows Figure 8 As shown, the AO1_24V voltage terminal is grounded through capacitors C29, C30, and C31, respectively. The 24V output voltage is filtered by capacitors C29, C30, and C31.

[0044] The working principle of this utility model:

[0045] The control module isolates the system and field sides through an isolation module. The isolated signal is sent to the DAC module, which converts the digital signal into an analog signal. The DAC module outputs a voltage signal. However, if the voltage output range and drive capability do not meet the module's output requirements, the AO output module converts the voltage into the required voltage and current signals. The current output has a disconnection detection function. If a disconnection occurs, the current loop is lost, and this disconnection is detected and fed back to the controller module through the isolation module.

[0046] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant fields. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the claims appended hereto.

Claims

1. An AO device compatible with voltage and current signal output, characterized in that: The invention comprises an AO output module, a DAC module, an isolation module and a control module, wherein the isolation module is respectively connected to the control module and the DAC module, the DAC module is connected to the AO output module, the DAC module comprises a voltage reference chip (U4), a digital-to-analog converter (U2), a third operational amplifier (U3), a ninth capacitor (C9), a fourteenth capacitor (C14), a fifteenth capacitor (C15), a sixteenth capacitor (C16), and a seventeenth capacitor (C17), the fourth pin and the third pin of the voltage reference chip (U4) are connected to the first voltage output end, the fourth pin and the third pin of the voltage reference chip (U4) are also grounded via the sixteenth capacitor (C16), the first pin of the voltage reference chip (U4) is grounded via the seventeenth capacitor (C17), and the voltage reference chip ( The second pin of the digital-to-analog converter (U4) is grounded, the fifth pin and the sixth pin of the voltage reference chip (U4) are connected to the third pin of the digital-to-analog converter (U2), the sixth pin and the second pin of the voltage reference chip (U4) are connected to the fifteenth capacitor (C15) respectively through a fourteenth capacitor (C14), the fourth pin, the fifth pin and the sixth pin of the digital-to-analog converter (U2) are connected to the isolation module respectively, the seventh pin and the second pin of the digital-to-analog converter (U2) are grounded, the eighth pin of the digital-to-analog converter (U2) is connected to the first voltage output end and is grounded through a ninth capacitor (C9), the first pin of the digital-to-analog converter (U2) is connected to the non-inverting input end of the third operational amplifier (U3), the inverting input end of the third operational amplifier (U3) is connected to the output end, and the output end outputs an analog voltage signal to the AO output module.

2. The AO device compatible with voltage and current signal output according to claim 1, characterized in that: The isolation module comprises a digital isolator chip (U1), a tenth capacitor (C10) and an eleventh capacitor (C11); the third to sixth pins of the digital isolator chip (U1) are respectively connected to the control module; the seventh and first pins of the digital isolator chip (U1) are respectively connected to the second voltage output end; the second and eighth pins of the digital isolator chip (U1) are grounded; the tenth and sixteenth pins of the digital isolator chip (U1) are respectively connected to the first voltage output end; the ninth and fifteenth pins of the digital isolator chip (U1) are grounded; and the twelfth to fourteenth pins of the digital isolator chip (U1) are respectively connected to the fourth, fifth and sixth pins of the digital-to-analog converter (U2).

3. The AO device compatible with voltage and current signal output according to claim 1, characterized in that: The AO output module comprises a fifth operational amplifier (U5A), a fifth operational amplifier (U5B), an instrumentation amplifier (U6), a window comparator (U7), a sixteenth resistor (R16), and a thirteenth resistor (R13); the non-inverting input of the fifth operational amplifier (U5B) is connected to the non-inverting input of the fifth operational amplifier (U5A) via the sixteenth resistor (R16); the inverting input of the fifth operational amplifier (U5B) is connected to the output of the fifth operational amplifier (U5B); the inverting input of the fifth operational amplifier (U5A) is connected to the sixth pin of the instrumentation amplifier (U6); the output of the fifth operational amplifier (U5A) is also connected to the third pin of the instrumentation amplifier (U6); the second pin of the instrumentation amplifier (U6) is connected to the first pin of the window comparator (U7) via the thirteenth resistor (R13); and the third pin of the window comparator (U7) is output.

4. The AO device compatible with voltage and current signal output according to claim 3, characterized in that: The AO output module further includes a first transient suppression diode (TVS1) and a twenty-first capacitor (C21), and the output end of the fifth operational amplifier (U5A) is grounded through the first transient suppression diode (TVS1) and the twenty-first capacitor (C21), respectively.

5. The AO device compatible with voltage and current signal output according to claim 4, characterized in that: The AO output module further includes a first overvoltage protection resistor (RT1), which is connected between the output end of the fifth operational amplifier (U5A) and the twenty-first capacitor (C21).

6. The AO device compatible with voltage and current signal output according to claim 5, characterized in that: The AO output module further includes a rectifier diode (D1), which is connected between the output end of the fifth operational amplifier (U5A) and the first overvoltage protection resistor (RT1).

7. The AO device compatible with voltage and current signal output according to claim 3, characterized in that: The AO output module further includes a second transient suppression diode (TVS2) and a twenty-fourth capacitor (C24), and the output end of the fifth operational amplifier (U5B) is grounded through the second transient suppression diode (TVS2) and the twenty-fourth capacitor (C24), respectively.

8. The AO device compatible with voltage and current signal output according to claim 6, characterized in that: The AO output module further includes a second overvoltage protection resistor (RT2), which is connected between the output end of the fifth operational amplifier (U5B) and the twenty-fourth capacitor (C24).

9. The AO device compatible with voltage and current signal output according to claim 3, characterized in that: The AO output module further includes a first transistor (Q1) and a ninth resistor (R9); the output end of the fifth operational amplifier (U5A) is connected to the base of the first transistor (Q1) via the ninth resistor (R9); the collector of the first transistor (Q1) is connected to the third voltage output end; and the emitter of the first transistor (Q1) is connected to the output end of the fifth operational amplifier (U5A).

10. The AO device compatible with voltage and current signal output according to claim 3, characterized in that: The AO output module further includes a switching diode (D2), wherein the switching diode (D2) is two diodes connected in parallel, wherein the anode of one diode is grounded and the cathode is connected to the inverting input terminal of the fifth operational amplifier (U5A), and the cathode of the other diode is connected to the first voltage output terminal and the anode is connected to the inverting input terminal of the fifth operational amplifier (U5A).

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