Analog output fault detection and pass-through circuit

Abstract

The application discloses a kind of analog output fault detection and transmission circuit.The analog output fault detection and transmission circuit includes: sampling circuit is used to sample the source end voltage of analog output module, the positive end voltage and negative end voltage of analog output module output end;The output end of analog output module is connected to load.Short-circuit detection module is used to determine whether the output of analog output module exists short-circuit fault according to source end voltage, positive end voltage and negative end voltage.Open circuit detection module is used to determine whether the output of analog output module exists open circuit fault according to source end voltage, positive end voltage and negative end voltage.Fault transmission module is used to control analog output module to stop output when the output of analog output module exists short-circuit fault or open circuit fault.The technical scheme of the application realizes timely detecting that the output loop of analog output module exists open circuit fault or short-circuit fault, and timely and reliably carries out fault transmission.

Description

Technical Field

[0001] This invention relates to the field of fault detection and circuit protection technology, and in particular to an analog output fault detection and transparent transmission circuit. Background Technology

[0002] In distributed control systems (DCS) of industries such as petroleum, chemical, and thermal power, the 4-20mA analog output loop is the mainstream drive link for field control valves and electric actuators. It typically employs a standard current transmission mechanism where 4mA corresponds to 0% valve closure and 20mA corresponds to 100% valve opening. The continuously adjustable output current precisely regulates the opening of the field actuators, achieving closed-loop control of process parameters. To eliminate ground loop interference, prevent high-voltage intrusion from damaging the analog output (AO) card, or meet safety regulations for explosion-proof areas, signal isolators or isolation safety barriers are commonly used between the DCS AO card and the field valve positioner. Because the AO card output only has unidirectional control sending capability and lacks an independent feedback channel, when open circuits or short circuits occur in field cables or valve positioners, the control system cannot actively identify the loop anomaly, easily leading to potential risks such as inconsistencies between given commands and actual field actions, and process control failure.

[0003] Currently, fault detection solutions for the output circuit of analog output modules mainly involve using an optocoupler connected in series in the output circuit to collect the circuit current and identifying open circuit faults based on the optocoupler's on / off state. Alternatively, the voltage at the analog output module port can be sampled to determine the open circuit or short circuit status of the line by collecting the voltage on the load side of the output circuit.

[0004] However, the above technical solutions cannot reliably transmit signals based on short-circuit or open-circuit faults in the output circuit of the analog output module. Summary of the Invention

[0005] This invention provides an analog output fault detection and transmission circuit to promptly detect open-circuit or short-circuit faults in the output circuit of the analog output module and promptly control the analog output module to stop outputting, thereby achieving the purpose of fault transmission.

[0006] According to one aspect of the present invention, an analog output fault detection and transmission circuit is provided. The analog output fault detection and transmission circuit of the present invention includes a sampling module, a short circuit detection module, an open circuit detection module, and a fault transmission module. The sampling circuit is used to sample the source voltage, positive voltage, and negative voltage of the analog output module; the output of the analog output module is connected to the load. Both the first input terminal of the short-circuit detection module and the first input terminal of the open-circuit detection module are connected to positive voltages, both the second input terminal of the short-circuit detection module and the second input terminal of the open-circuit detection module are connected to source voltages, and both the third input terminal of the short-circuit detection module and the third input terminal of the open-circuit detection module are connected to negative voltages. The short-circuit detection module is used to determine whether there is a short-circuit fault in the output of the analog output module based on the source voltage, positive voltage, and negative voltage; the open-circuit detection module is used to determine whether there is an open-circuit fault in the output of the analog output module based on the source voltage, positive voltage, and negative voltage. The fault transmission module connects the output terminals of the short-circuit detection module and the open-circuit detection module, and is used to control the analog output module to stop outputting when there is a short-circuit fault or open-circuit fault in the output of the analog output module.

[0007] Optionally, the analog output fault detection and transparent transmission circuit of this embodiment of the invention further includes a logic operation module and an inversion operation module; The output of the short-circuit detection module is connected to the fault transmission module through the logic operation module; the output of the open-circuit detection module is connected to the fault transmission module through the inversion operation module and the logic operation module in sequence. The first input terminal of the logic operation module is connected to the output terminal of the short circuit detection module, the second input terminal of the logic operation module is connected to the output terminal of the open circuit detection module, and the output terminal of the logic operation module is connected to the fault pass-through module. The input terminal of the inverting operation module is connected to the output terminal of the open circuit detection module, and the output terminal of the inverting operation module is connected to the second input terminal of the logic operation module; the inverting operation module is used to perform logical inversion processing on the output result of the open circuit detection module and output it to the logic operation module; The logic operation module is used to output a fault signal to the fault pass-through module when there is a short circuit or open circuit fault in the output of the analog output module; the fault pass-through module is used to control whether the analog output module outputs based on the fault signal.

[0008] Optionally, the short-circuit detection module includes: a first voltage conversion unit and a first comparison unit; The first input terminal of the first voltage conversion unit serves as the first input terminal of the short-circuit detection module, the second input terminal of the first voltage conversion unit serves as the second input terminal of the short-circuit detection module, and the third input terminal of the first voltage conversion unit serves as the third input terminal of the short-circuit detection module; the first output terminal of the first voltage conversion unit is connected to the non-inverting input terminal of the first comparator unit, and the second output terminal of the first voltage conversion unit is connected to the inverting input terminal of the first comparator unit. The first voltage conversion unit is used to convert the first voltage difference based on the source voltage, positive voltage, and negative voltage. The converted first voltage difference is only related to the load size. The first voltage difference is the voltage difference between the non-inverting input terminal and the inverting input terminal of the first comparator unit. The first comparison unit is used to output a first comparison signal based on the first voltage difference. The first comparison signal is used to characterize whether there is a short circuit fault in the output of the analog output module.

[0009] Optionally, the open-circuit detection module includes: a second voltage conversion unit and a second comparison unit; The first input terminal of the second voltage conversion unit serves as the first input terminal of the open circuit detection module, the second input terminal of the second voltage conversion unit serves as the second input terminal of the open circuit detection module, and the third input terminal of the second voltage conversion unit serves as the third input terminal of the open circuit detection module; the first output terminal of the second voltage conversion unit is connected to the non-inverting input terminal of the second comparator unit, and the second output terminal of the second voltage conversion unit is connected to the inverting input terminal of the second comparator unit. The second voltage conversion unit is used to convert the second voltage difference based on the source voltage, positive voltage, and negative voltage. The converted second voltage difference is only related to the load size. The second voltage difference is the voltage difference between the non-inverting input and the inverting input of the second comparator unit. The second comparison unit is used to output a second comparison signal based on the second voltage difference. The second comparison signal is used to characterize whether there is an open circuit fault in the output of the analog output module.

[0010] Optionally, the analog output module includes a constant current source, a first conjugate inductor, a first resistor, and a second conjugate inductor; the first input terminal of the first conjugate inductor is connected to the power supply voltage, and the second input terminal of the first conjugate inductor is connected to the output terminal of the constant current source; the first output terminal of the first conjugate inductor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is connected to the first input terminal of the second conjugate inductor; the first output terminal of the first conjugate inductor is connected to the second input terminal of the second conjugate inductor; the first output terminal of the second conjugate inductor is connected to the positive terminal of the load, and the second output terminal of the second conjugate inductor is connected to the negative terminal of the load; The sampling circuit includes: a second resistor and a voltage follower circuit; The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first input terminal of the short circuit detection module and the first input terminal of the open circuit detection module. The input terminal of the voltage follower circuit is connected to the second output terminal of the first conjugate inductor, and the output terminal of the voltage follower circuit is connected to the third input terminal of the short-circuit detection module and the third input terminal of the open-circuit detection module. The second input terminal of the short-circuit detection module and the second through input terminal of the open-circuit detection module are connected to the first input terminal of the first conjugate inductor.

[0011] Optionally, the short-circuit detection module includes: a first comparator, a first capacitor, a third resistor, a fourth resistor, and a fifth resistor; The first capacitor is connected between the non-inverting input and the inverting input of the first comparator. The first end of the third resistor is connected to the first end of the first capacitor. The second end of the third resistor serves as the first input of the short-circuit detection module. The first ends of the fourth resistor and the fifth resistor are both connected to the second end of the first capacitor. The second end of the fourth resistor serves as the second input terminal of the short circuit detection module, and the second end of the fifth resistor serves as the third input terminal of the short circuit detection module. The open-circuit detection module includes: a second comparator, a sixth resistor, a seventh resistor, and an eighth resistor; The first end of the sixth resistor is connected to the non-inverting input of the second comparator, and the second end of the sixth resistor serves as the first input of the open-circuit detection module. The first terminals of the seventh and eighth resistors are both connected to the inverting input terminal of the second comparator. The second terminal of the seventh resistor serves as the second input terminal of the open-circuit detection module, and the second terminal of the eighth resistor serves as the third input terminal of the open-circuit detection module.

[0012] Optionally, the inverting operational module includes a first operational amplifier, a ninth resistor, a tenth resistor, and an eleventh resistor; The first terminals of the ninth and tenth resistors are both connected to the inverting input of the first operational amplifier. The second terminal of the ninth resistor serves as the input of the inverting operational module. The second terminal of the tenth resistor is grounded. The first terminal of the eleventh resistor is connected to the non-inverting input of the first operational amplifier. The second terminal of the eleventh resistor is grounded. The output of the first operational amplifier serves as the output of the inverting operational module.

[0013] Optionally, the logic operation module includes a first diode, a second diode, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a sixteenth resistor; The first terminal of the twelfth resistor is connected to the power supply voltage. The first terminals of the thirteenth and fourteenth resistors are both connected to the second terminal of the twelfth resistor, and the second terminal of the thirteenth resistor is grounded. The first terminals of the fifteenth and sixteenth resistors are both connected to the second terminal of the fourteenth resistor. The anode of the first diode is connected to the second terminal of the fifteenth resistor, and the anode of the second diode is connected to the second terminal of the sixteenth resistor. The cathode of the first diode serves as the first input terminal of the logic operation module, the cathode of the second diode serves as the second input terminal of the logic operation module, and the second terminal of the fourteenth resistor serves as the output terminal of the logic operation module.

[0014] Optionally, the fault pass-through module includes: a first operational amplifier unit, a signal modulation unit, a second operational amplifier unit, and a switching unit; The input terminal of the first operational amplifier unit is connected to the fault signal, and the output terminal of the first operational amplifier unit is connected to the input terminal of the signal modulation unit to amplify the fault signal. The control terminal of the signal modulation unit is connected to the modulation signal, and the output terminal of the signal modulation unit is connected to the input terminal of the second operational amplifier unit. Under the control of the modulation signal, the fault signal is transmitted to the second operational amplifier unit. The control terminal of the switching unit is connected to the output terminal of the second operational amplifier unit, the first terminal of the switching unit is connected to the positive input terminal of the analog output module, and the second terminal of the switching unit is connected to the negative input terminal of the analog output module. The switching unit is used to turn on or off according to the fault signal to control the on or off state of the input terminal of the analog output module.

[0015] Optionally, the signal modulation unit includes a transformer, a first transistor, a second transistor, a third transistor, and a fourth transistor; The first terminal of the primary winding of the transformer is connected to the first terminal of the first transistor, and the second terminal of the primary winding of the transformer is connected to the first terminal of the second transistor; the first terminal of the secondary winding of the transformer is connected to the first terminal of the third transistor, and the second terminal of the secondary winding of the transformer is connected to the first terminal of the fourth transistor. The control terminals of the first transistor, the second transistor, the third transistor, and the fourth transistor are respectively connected to the modulation signal; the second terminals of the first transistor, the second transistor, the third transistor, and the fourth transistor are all grounded. The center tap of the primary winding of the transformer serves as the input terminal of the signal modulation unit, and the center tap of the secondary winding of the transformer serves as the output terminal of the signal modulation unit.

[0016] The technical solution of this invention samples the source voltage, positive voltage, and negative voltage of the analog output module using a sampling circuit. A short-circuit detection module determines whether the load is below a short-circuit threshold based on these voltages, thus determining if a short-circuit fault exists in the analog output module's output. Similarly, an open-circuit detection module determines whether the load is above an open-circuit threshold based on these voltages, thus determining if an open-circuit fault exists in the analog output module's output. When an open-circuit or short-circuit fault is detected in the analog output module's output, a fault transmission module promptly controls the analog output module to stop outputting, achieving fault transmission and preventing potential safety hazards.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an analog output fault detection and transparent transmission circuit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another analog output fault detection and transparent transmission circuit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a short-circuit detection module provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of an open-circuit detection module provided in an embodiment of the present invention; Figure 5 The circuit structure diagram of an analog output fault detection and transparent transmission circuit provided in an embodiment of the present invention is shown. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Figure 1This is a schematic diagram of an analog output fault detection and pass-through circuit provided by an embodiment of the present invention. This embodiment is applicable to safety barriers or isolators suitable for 4-20mA analog output applications. Figure 1 As shown, the analog output fault detection and transmission circuit of this embodiment includes a sampling module 1, a short-circuit detection module 2, an open-circuit detection module 3, and a fault transmission module 4. The sampling circuit 1 samples the source voltage VOUT+, the positive voltage VOUT1, and the negative voltage VOUT2 of the output terminal of the analog output module 5. The output terminal of the analog output module 5 is connected to a load 6. The first input terminal of the short-circuit detection module 2 and the first input terminal of the open-circuit detection module 3 are both connected to the positive voltage VOUT1. The second input terminal of the short-circuit detection module 2 and the second input terminal of the open-circuit detection module 3 are both connected to the source voltage VOUT+. The third input terminal of the short-circuit detection module 2 and the third input terminal of the open-circuit detection module 3 are both connected to the negative voltage VOUT2. The short-circuit detection module 2 is used to determine whether a short-circuit fault exists in the output of the analog output module 5 based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2. The open-circuit detection module 3 is used to determine whether an open-circuit fault exists in the output of the analog output module 5 based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2. The fault pass-through module 4 is connected to the output terminals of the short-circuit detection module 2 and the open-circuit detection module 3, and is used to control the analog output module 5 to stop outputting when a short-circuit or open-circuit fault exists in its output.

[0023] In this embodiment of the invention, the analog output module 5 can output an analog signal based on the control signal. For example, the analog output module 5 can be integrated into a DCS system, converting the control signal inside the DCS into an analog signal for output. The analog signal can be a 4-20mA current signal. The analog signal output by the analog output module 5 can be used to control actuators such as valves and frequency converters, and the magnitude of the analog signal can adjust the valve opening. The load 6 can be the load of the output circuit of the analog output module 5.

[0024] The source voltage VOUT+ can be the voltage at the power supply terminal of the analog output module 5. The sampling circuit 1 is connected to the power supply terminal, the positive output terminal, and the negative output terminal of the analog output module 5 respectively to obtain the source voltage VOUT+, the positive terminal voltage VOUT1, and the negative terminal voltage VOUT2.

[0025] The short-circuit detection module 2 can determine whether the load 6 is below the short-circuit threshold based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2. If the load 6 is below the short-circuit threshold, it can be determined that there is a short-circuit fault in the output of the analog output module 5. The short-circuit threshold can be determined based on the actual application scenario of the analog output module 5. For example, it can be determined by referring to the load size of the output circuit of the analog output module 5 during normal operation. For example, when the load 6 is below the short-circuit threshold, the short-circuit detection module 2 outputs a low-level signal, indicating that there is a short-circuit fault in the output of the analog output module 5.

[0026] The open-circuit detection module 3 can determine whether the load 6 exceeds the open-circuit threshold based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2. If the load 6 exceeds the short-circuit threshold, it can be determined that there is an open-circuit fault in the output of the analog output module 5. The open-circuit threshold can be determined based on the actual application scenario of the analog output module 5. For example, it can be determined by referring to the load size of the output circuit of the analog output module 5 during normal operation. For example, when the load 6 exceeds the open-circuit threshold, the open-circuit detection module 3 outputs a high-level signal, indicating that there is an open-circuit fault in the output of the analog output module 5.

[0027] The fault pass-through module 4 can control the on / off state of the input terminal of the analog output module 5 based on the output signal of the short-circuit detection module 2; or, based on the output signal of the open-circuit detection module 3. For example, when the output signal of the short-circuit detection module 2 indicates a short-circuit fault in the output of the analog output module 5, the fault pass-through module 4 controls the input terminal of the analog output module 5 to be turned off; or, when the output signal of the open-circuit detection module 3 indicates an open-circuit fault in the output of the analog output module 5, the fault pass-through module 4 controls the input terminal of the analog output module 5 to be turned off. Turning off the input terminal of the analog output module 5 prevents it from outputting analog signals.

[0028] Specifically, sampling module 1 samples the voltages at the power supply terminal, positive output terminal, and negative output terminal of analog output module 5 in real time, and outputs the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2 to short-circuit detection module 2 and open-circuit detection module 3, respectively. Short-circuit detection module 2 determines whether a short-circuit fault has occurred in the output of analog output module 5 based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2. Open-circuit detection module 3 determines whether an open-circuit fault has occurred in the output of analog output module 5 based on the source voltage VOUT+, positive voltage VOUT1, and negative voltage VOUT2, thus timely detecting the operating status of the valve positioner. The fault transmission module 4 is connected to the output terminals of the short-circuit detection module 2 and the open-circuit detection module 3 respectively. When there is a short-circuit fault in the output of the analog output module 5, the input terminal of the analog output module 5 is turned off, so that the analog output module 5 no longer outputs analog signals; or when there is an open-circuit fault in the output of the analog output module 5, the input terminal of the analog output module 5 is turned off, so that the analog output module 5 no longer outputs analog signals.

[0029] According to the technical solution of this invention, a sampling circuit samples the source voltage, positive voltage, and negative voltage of the analog output module. A short-circuit detection module determines whether the load is below a short-circuit threshold based on the source, positive, and negative voltages, thereby determining whether a short-circuit fault exists in the analog output module's output. Similarly, an open-circuit detection module determines whether the load is above an open-circuit threshold based on the same voltages, thus determining whether an open-circuit fault exists in the analog output module's output. When an open-circuit or short-circuit fault exists in the analog output module's output, a fault transmission module promptly controls the analog output module to stop outputting, achieving fault transmission and preventing safety accidents.

[0030] Figure 2 This is a schematic diagram of another analog output fault detection and pass-through circuit provided in an embodiment of the present invention. Figure 2As shown, in some embodiments, the analog output fault detection and transmission circuit further includes an inverting operation module 7 and a logic operation module 8. The output of the short-circuit detection module 2 is connected to the fault transmission module 4 via the logic operation module 8, and the output of the open-circuit detection module 3 is connected to the fault transmission module 4 via the inverting operation module 7 and the logic operation module 8 in sequence. The first input of the logic operation module 8 is connected to the output of the short-circuit detection module 2, the second input of the logic operation module 8 is connected to the output of the open-circuit detection module 3, and the output of the logic operation module 8 is connected to the fault transmission module 4. The input of the inverting operation module 7 is connected to the output of the open-circuit detection module 3, and the output of the inverting operation module 7 is connected to the second input of the logic operation module 8; the inverting operation module 7 is used to perform logical inversion processing on the output of the open-circuit detection module 3 and output it to the logic operation module 8. The logic operation module 8 is used to output a fault signal to the fault transmission module 4 when there is a short-circuit fault or open-circuit fault in the output of the analog output module 5; the fault transmission module 4 is used to control whether the analog output module 5 outputs based on the fault signal.

[0031] In this system, the condition for determining a short-circuit fault in the output of analog output module 5 is that the load 6 is below the short-circuit threshold, while the condition for determining an open-circuit fault is that the load 6 is above the open-circuit threshold; the two judgment logics are opposite. When either a short-circuit or open-circuit fault exists in the output of analog output module 5, the output signals of short-circuit detection module 2 and open-circuit detection module 3 are inverted. Inverting module 7 can invert the output signal of open-circuit detection module 3, ultimately ensuring that the output signals of short-circuit detection module 2 and inverting module 7 are consistent when either a short-circuit or open-circuit fault exists in the output of analog output module 5. For example, when the load 6 is above the open-circuit threshold, open-circuit detection module 3 outputs a high-level signal. After passing through inverting module 7, it outputs a low-level signal, indicating that an open-circuit fault exists in the output of analog output module 5.

[0032] The logic operation module 8 can output a fault signal L based on the output signal of the short-circuit detection module 2 or the output signal of the inverting operation module 3. For example, the logic operation module 8 can be an AND gate circuit. When the short-circuit detection module 2 outputs a low-level signal or the inverting operation module 3 outputs a low-level signal, the logic operation module 8 outputs the fault signal L to the fault pass-through module 4.

[0033] The following explanation uses the example of a low-level signal output from short-circuit detection module 2 indicating a short-circuit fault in the output of analog output module 5, and a low-level signal output from inverting module 7 indicating an open-circuit fault in the output of analog output module 5. Specifically, logic operation module 8 is connected to the output of short-circuit detection module 2 and the output of inverting module 7. When at least one of the output signals from short-circuit detection module 2 and inverting module 7 is low, logic operation module 8 outputs a fault signal L. The fault pass-through module 4 controls the input of analog output module 5 to shut off based on the fault signal L, thus preventing analog output module 5 from outputting analog signals.

[0034] Figure 3 This is a schematic diagram of a short-circuit detection module provided in an embodiment of the present invention. Figure 3 As shown, in some embodiments, the short-circuit detection module 2 includes a first voltage conversion unit 21 and a first comparison unit 22. The first input terminal of the first voltage conversion unit 21 serves as the first input terminal of the short-circuit detection module 2, the second input terminal of the first voltage conversion unit 21 serves as the second input terminal of the short-circuit detection module 2, and the third input terminal of the first voltage conversion unit 21 serves as the third input terminal of the short-circuit detection module 2. The first output terminal of the first voltage conversion unit 21 is connected to the non-inverting input terminal of the first comparison unit 22, and the second output terminal of the first voltage conversion unit 21 is connected to the inverting input terminal of the first comparison unit 22. The first voltage conversion unit 21 is used to adjust the first voltage difference based on the source voltage VOUT+, the positive terminal voltage VOUT1, and the negative terminal voltage VOUT2. The conversion is performed, and the first voltage difference after the conversion is... It is only related to the load size; where the first voltage difference The voltage difference is the voltage difference between the non-inverting and inverting input terminals of the first comparator unit. The first comparator unit is used to determine the voltage difference based on the voltage difference. Output the first comparison signal A1, which is used to characterize whether there is a short circuit fault in the output of the analog output module.

[0035] Specifically, the first voltage conversion unit 21 has a positive input voltage VOUT1 connected to its first input terminal, a source voltage VOUT+ connected to its second input terminal, and a negative input voltage VOUT2 connected to its third input terminal. The first voltage conversion unit 21 can convert the voltage data output from the sampling module into a first voltage difference that is only related to the load size. First voltage difference This can reflect whether the load size is below the short-circuit threshold. For example, the first voltage difference... for: The load size is lower than the short-circuit threshold, and the first voltage difference... Less than zero; load size exceeds short-circuit threshold, first voltage difference Greater than zero.

[0036] The first comparison unit 22 can be based on the voltage at the non-inverting input terminal. and inverting input voltage The magnitude relationship is used to output a first comparison signal A1. The first comparison signal A1 can be a high-level signal or a low-level signal. For example, the first voltage difference... If the first voltage difference is greater than zero, the first comparison unit 22 outputs a high-level signal; If the voltage difference is less than zero, the first comparison unit 22 outputs a low-level signal. Therefore, the first comparison unit 22 can determine the voltage difference based on the first voltage difference. It can be determined whether the load is below the short-circuit threshold, and then the first comparison signal A1 can be used to determine whether there is a short-circuit fault in the output of the analog output module.

[0037] Figure 4 This is a schematic diagram of an open-circuit detection module provided in an embodiment of the present invention. Figure 4 As shown, in some embodiments, the open-circuit detection module 3 includes: a second voltage conversion unit 31 and a second comparison unit 32. The first input terminal of the second voltage conversion unit 31 serves as the first input terminal of the open-circuit detection module 3, the second input terminal of the second voltage conversion unit 31 serves as the second input terminal of the open-circuit detection module 3, and the third input terminal of the second voltage conversion unit 31 serves as the third input terminal of the open-circuit detection module 3. The first output terminal of the second voltage conversion unit 31 is connected to the non-inverting input terminal of the second comparison unit 32, and the second output terminal of the second voltage conversion unit 31 is connected to the inverting input terminal of the second comparison unit 32. The second voltage conversion unit 31 is used to adjust the second voltage difference based on the source voltage VOUT+, the positive terminal voltage VOUT1, and the negative terminal voltage VOUT2. The conversion is performed, and the resulting second voltage difference... It is only related to the load size. Specifically, the second voltage difference... The voltage difference is the voltage difference between the non-inverting and inverting input terminals of the second comparator unit 32. The second comparator unit 32 is used to determine the voltage difference based on the voltage difference. Output a second comparison signal A2, which is used to characterize whether there is an open circuit fault in the output of the analog output module.

[0038] Specifically, the second voltage conversion unit 31 connects to the positive terminal voltage VOUT1 at its first input terminal, to the source terminal voltage VOUT+ at its second input terminal, and to the negative terminal voltage VOUT2 at its third input terminal. The second voltage conversion unit 31 can convert the voltage data output by the sampling module into a second voltage difference that is only related to the load size. Second voltage difference This can reflect whether the load size exceeds the open-circuit threshold. For example, the second voltage difference... for: The load size is lower than the open circuit threshold, and the second voltage difference... Less than zero; load size exceeds open circuit threshold, second voltage difference Greater than zero.

[0039] The second comparison unit 32 can be based on the voltage at the non-inverting input terminal. and inverting input voltage The magnitude relationship is used to output a second comparison signal A2. The second comparison signal A2 can be a high-level signal or a low-level signal. For example, the second voltage difference... If the voltage difference is greater than zero, the second comparison unit 32 outputs a high-level signal; the second voltage difference... If the voltage difference is less than zero, the second comparison unit 32 outputs a low-level signal. Therefore, the second comparison unit 32 can determine the voltage difference based on the second voltage difference. The system determines whether the load exceeds the open circuit threshold, and then uses the second comparison signal A2 to determine whether there is an open circuit fault in the output of the analog output module.

[0040] Figure 5 This is a circuit structure diagram of an analog output fault detection and pass-through circuit provided in an embodiment of the present invention. Figure 5 As shown, in some embodiments, the analog output module 5 includes a constant current source 51, a first conjugate inductor L1, a first resistor R1, and a second conjugate inductor L2. The first input terminal of the first conjugate inductor L1 is connected to the power supply voltage, and the second input terminal of the first conjugate inductor L1 is connected to the output terminal of the constant current source 51. The first output terminal of the first conjugate inductor L1 is connected to the first terminal of the first resistor R1, and the second terminal of the first resistor R1 is connected to the first input terminal of the second conjugate inductor L2. The first output terminal of the first conjugate inductor L1 is connected to the second input terminal of the second conjugate inductor L2. The first output terminal of the second conjugate inductor L2 is connected to the positive terminal OUTM+ of the load, and the second output terminal of the second conjugate inductor L2 is connected to the negative terminal OUTM- of the load.

[0041] The analog output module 5 may further include an AO card (not shown in the figure), the input terminal of which is the input terminal of the analog output module 5, and the output terminal of which is connected to the input terminal of the constant current source 51. The AO card is used to output analog signals, and the constant current source 51 is used to generate stable analog signals corresponding to the output of the AO card. In some embodiments, an isolation circuit may also be included between the AO card and the constant current source 51.

[0042] The analog output module 5 also includes a diode D and a capacitor C. The first input terminal of the first conjugate inductor L1 is connected to the power supply voltage via diode D and capacitor C. For example, the power supply voltage can be 13V. The anode of diode D is connected to the positive terminal of the power supply voltage, the cathode of diode D1 and the first terminal of capacitor C are both connected to the first input terminal of the first conjugate capacitor L1, and the second terminal of capacitor C is connected to the negative terminal of the power supply voltage.

[0043] The constant current source 51 may include an operational amplifier circuit U, a transistor Q, and a resistor R. The operational amplifier circuit U can perform voltage-to-current conversion. The output terminal of the operational amplifier circuit U is connected to the control terminal of the transistor Q. The first terminal of the transistor Q is connected to the second input terminal of the first conjugate capacitor L1, and the second terminal of the transistor Q is connected to the first terminal of the resistor R. The second terminal of the resistor R is grounded. The transistor Q may be an N-type MOSFET.

[0044] The sampling circuit includes a second resistor R2 and a voltage follower circuit 11. The first end of the second resistor R2 is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is connected to the first input terminal of the short-circuit detection module 2 and the first input terminal of the open-circuit detection module 3. The input terminal of the voltage follower circuit 11 is connected to the second output terminal of the first conjugate inductor L1, and the output terminal of the voltage follower circuit 11 is connected to the third input terminal of the short-circuit detection module 2 and the third input terminal of the open-circuit detection module 3. The second input terminals of the short-circuit detection module 2 and the second input terminals of the open-circuit detection module 3 are connected to the first input terminal of the first conjugate inductor L1.

[0045] The positive terminal voltage VOUT1 can be the voltage at the second terminal node of the first resistor R1. After passing through the second resistor R2, the positive terminal voltage VOUT1 is connected to the first terminal of the short-circuit detection module 2 and the first terminal of the open-circuit detection module 3. The source terminal voltage VOUT+ can be the voltage at the first input terminal of the first conjugate inductor L1. The second terminal of the short-circuit detection module 2 and the second terminal of the open-circuit detection module 3 can be connected to the cathode of the diode D and the first terminal of the capacitor C to connect to the source terminal voltage VOUT+. The negative terminal voltage VOUT2 can be the voltage at the second output terminal of the first conjugate inductor L1. The negative terminal voltage VOUT2 is connected to the third terminal of the short-circuit detection module 2 and the third terminal of the open-circuit detection module 3 via the voltage follower circuit 11.

[0046] The voltage follower circuit 11 may include an operational amplifier U1, a second capacitor C2, and a seventeenth resistor R17. The second capacitor C2 is connected between the non-inverting and inverting inputs of the operational amplifier U1. The first terminal of the seventeenth resistor R17 serves as the input of the voltage follower circuit 11, connected to the negative terminal voltage VOUT2. The second terminal of the seventeenth resistor R17 is connected to the first terminal of the second capacitor C2. The inverting input of the operational amplifier U1 is connected to its output. The first terminal of the second capacitor C2 is connected to the non-inverting output of the operational amplifier U1, and the second terminal of the second capacitor C2 is connected to the inverting output of the operational amplifier U1.

[0047] Continue to refer to Figure 5 The short-circuit detection module 2 includes: a first comparator U2, a first capacitor C1, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The first capacitor C1 is connected between the non-inverting and inverting inputs of the first comparator U2. The first end of the third resistor R3 is connected to the first end of the first capacitor C1, and the second end of the third resistor R3 serves as the first input of the short-circuit detection module 2. The first ends of both the fourth resistor R4 and the fifth resistor R5 are connected to the second ends of the first capacitor C1. The second end of the fourth resistor R4 serves as the second input of the short-circuit detection module 2, and the second end of the fifth resistor R5 serves as the third input of the short-circuit detection module 2.

[0048] In this system, the first comparator U2 and the first capacitor C1 can form a first comparison unit, and the third resistor R3, the fourth resistor R4, and the fifth resistor R5 can form a first voltage conversion unit. The first terminal of the first capacitor C1 is connected to the non-inverting input terminal of the first comparator U2, and the second terminal of the first capacitor C1 is connected to the inverting input terminal of the first comparator U2.

[0049] The derivation of the formula for the first voltage conversion unit to convert the first voltage difference may include: ; ; ; ; ; ; make ,but ; ; Again , ,but .in, The voltage across the first resistor R1, R1 is the voltage of the load, R4 is the resistance of the first resistor R1, R5 is the resistance of the fifth resistor R5, RL is the equivalent resistance of the load, and I is the current of the output circuit of the analog output module.

[0050] Through the above conversion, after conversion by the first voltage conversion unit, the voltage at the non-inverting input terminal of the first comparator U2 is... and inverting input voltage The first voltage difference between The sign of the voltage depends solely on the resistance of the load RL. First voltage difference The value can be greater than zero or less than zero. That is, when the load resistance RL is below the short-circuit threshold, the first comparator U2 outputs a low-level signal; when the load resistance RL is above the short-circuit threshold, the first comparator U2 outputs a high-level signal. (Short-circuit threshold) It can be .

[0051] For example, the resistance of the first resistor R1 is 300Ω. Then the short-circuit threshold Approximately 44Ω. When the load resistance RL is greater than the short-circuit threshold. hour, When the first comparator U2 outputs a high-level signal, the analog output module is in normal operating condition. This occurs when the load resistance RL is less than the short-circuit threshold. hour, The first comparator U2 outputs a low-level signal, indicating a short-circuit fault in the analog output module 5. Therefore, the first voltage difference can be converted into data that is only related to the resistance value of the load by the first voltage conversion unit. When the parameters in the first conversion unit are determined, a fixed short-circuit threshold can be determined. Short circuit threshold The current I in the output circuit of analog output module 5 does not change, thus allowing users to refer to the short-circuit threshold. Design short-circuit fault detection points.

[0052] It is understandable that by selecting an appropriate resistor value, the high-level signal output by the short-circuit detection module 2 can be 13V and the low-level signal can be -13V.

[0053] The open-circuit detection module 3 includes: a second comparator U3, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The first terminal of the sixth resistor R6 is connected to the non-inverting input of the second comparator U3, and the second terminal of the sixth resistor R6 serves as the first input terminal of the open-circuit detection module 3. The first terminals of both the seventh resistor R7 and the eighth resistor R8 are connected to the inverting input of the second comparator U3. The second terminal of the seventh resistor R7 serves as the second input terminal of the open-circuit detection module 3, and the second terminal of the eighth resistor R8 serves as the third input terminal of the open-circuit detection module 3.

[0054] Among them, the second comparator U3 can form the second comparison unit, and the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 can form the second voltage conversion unit.

[0055] The derivation of the formula for converting the second voltage difference by the second voltage conversion unit may include: ; ; ; ; ; ; make ,but ; ; Again , ,but Where R7 is the resistance value of the seventh resistor R7, and R8 is the resistance value of the eighth resistor R8.

[0056] After the above conversion, the voltage at the non-inverting input of the second comparator U3 is converted by the second voltage conversion unit. and inverting input voltage The second voltage difference between The sign of the voltage depends solely on the resistance of the load RL. Second voltage difference The value can be greater than zero or less than zero. That is, when the load resistance RL is lower than the open-circuit threshold, the second comparator U3 outputs a low-level signal; when the load resistance RL is higher than the open-circuit threshold, the second comparator U3 outputs a high-level signal. Open-circuit threshold It can be .

[0057] For example, the resistance of the first resistor R1 is 300Ω. Then the open-circuit threshold Approximately 2200Ω. When the load resistance RL is greater than the open-circuit threshold. hour, The second comparator U3 outputs a high-level signal, indicating an open-circuit fault in the analog output module. This occurs when the load resistance RL is less than the short-circuit threshold. hour, The second comparison signal output by the second comparator U3 is a low-level signal, and the output of the analog output module 5 is in normal working condition. Therefore, the second voltage difference can be converted into a signal by the second voltage conversion unit. This data is converted to be solely dependent on the resistance value of the load. When the parameters in the second conversion unit are determined, a fixed open-circuit threshold can be established. Open circuit threshold It does not change with the current in the output circuit of analog output module 5, thus allowing users to refer to the open-circuit threshold. Design open-circuit fault detection points.

[0058] It is understandable that by selecting an appropriate resistor value, the high-level signal output by the open-circuit detection module 3 can be 13V and the low-level signal can be -13V.

[0059] Continue to refer to Figure 5 In some embodiments, the inverting operational module 7 includes a first operational amplifier U4, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11. The first terminals of both the ninth and tenth resistors R9 and R10 are connected to the inverting input of the first operational amplifier U4. The second terminal of the ninth resistor R9 serves as the input of the inverting operational module 7, and the second terminal of the tenth resistor R10 is grounded. The first terminal of the eleventh resistor R11 is connected to the non-inverting input of the first operational amplifier U4, and the second terminal of the eleventh resistor R11 is grounded. The output of the first operational amplifier U4 serves as the output of the inverting operational module 7.

[0060] In this circuit, the inverting operational module 7 connects a second comparison signal to the second terminal of the ninth resistor R9 and outputs a third comparison signal at the output terminal of the first operational amplifier U4. The third comparison signal is the inverse of the second comparison signal. For example, if the second comparison signal is high, it indicates that there is an open circuit fault in the output of the analog output module. Similarly, if the third comparison signal is low, it indicates that there is an open circuit fault in the output of the analog output module.

[0061] Continue to refer to Figure 5In some embodiments, the logic operation module 8 includes a first diode D1, a second diode D2, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a sixteenth resistor R16. The first terminal of the twelfth resistor R12 is connected to a power supply voltage. The first terminals of the thirteenth resistor R13 and the fourteenth resistor R14 are both connected to the second terminal of the twelfth resistor R12, and the second terminal of the thirteenth resistor R13 is grounded. The first terminals of the fifteenth resistor R15 and the sixteenth resistor R16 are both connected to the second terminal of the fourteenth resistor R14. The anode of the first diode D1 is connected to the second terminal of the fifteenth resistor R15, and the anode of the second diode D2 is connected to the second terminal of the sixteenth resistor R16. The cathode of the first diode D1 serves as the first input terminal of the logic operation module 8, the cathode of the second diode D2 serves as the second input terminal of the logic operation module 8, and the second terminal of the fourteenth resistor R14 serves as the output terminal of the logic operation module 8.

[0062] In this circuit, the cathode of the first diode D1 is connected to the output terminal of the short-circuit detection module 2. When the first comparison signal output by the short-circuit detection module 2 is low, the first diode D1 conducts. The cathode of the second diode D2 is connected to the output terminal of the inverting operation module 7. When the third comparison signal output by the inverting operation module 7 is low, the second diode D2 conducts. When at least one of the first diode D1 and the second diode D2 is conducting, the logic operation module 8 outputs a fault signal L at the second terminal of the fourteenth resistor R14.

[0063] Continue to refer to Figure 5 In some embodiments, the fault transmission module 4 includes: a first operational amplifier unit 41, a signal modulation unit 42, a second operational amplifier unit 43, and a switching unit 44. The input terminal of the first operational amplifier unit 41 is connected to a fault signal L, and the output terminal of the first operational amplifier unit 41 is connected to the input terminal of the signal modulation unit 42, for amplifying the fault signal L. The control terminal of the signal modulation unit 42 is connected to a modulation signal, and the output terminal of the signal modulation unit 42 is connected to the input terminal of the second operational amplifier unit 43, for transmitting the fault signal L to the second operational amplifier unit 43 under the control of the modulation signal. The control terminal of the switching unit 44 is connected to the output terminal of the second operational amplifier unit 43. The first terminal of the switching unit 44 is connected to the positive input terminal mA+ of the analog output module 5, and the second terminal of the switching unit 44 is connected to the negative input terminal mA- of the analog output module 5. The switching unit 44 is used to control the on or off state of the input terminal of the analog output module according to the on or off state of the fault signal L.

[0064] Through the fault transmission module 4, the field fault information of the output circuit of the analog output module 5 can be promptly transmitted back to the input terminal of the analog output module 5, such as to the AO card. The central control room can determine whether there is a fault based on the on or off state of the input terminal of the analog output module 5, and determine the fault type based on the output signals of the short circuit detection module 2 and the open circuit detection module 3, which facilitates accurate location and timely and efficient maintenance.

[0065] The first operational amplifier unit 41 may include a second operational amplifier U5, a third capacitor C3, an eighteenth resistor R18, a nineteenth resistor R19, and a twentieth resistor R20. The first terminals of the third capacitor C3 and the eighteenth resistor R18 are both connected to the non-inverting input of the second operational amplifier U5. The second terminal of the eighteenth resistor R18 serves as the input terminal of the first operational amplifier unit 41, and the fault signal L is input through the second terminal of the eighteenth resistor R18. The second terminal of the third capacitor C3 and the first terminal of the twentieth resistor R20 are both connected to the inverting input of the second operational amplifier U5. The first terminal of the nineteenth resistor R19 is connected to the output terminal of the second operational amplifier U5, and the second terminal of the nineteenth resistor R19 is connected to the second terminal of the twentieth resistor R20. The second terminal of the nineteenth resistor R19 serves as the output terminal of the first operational amplifier unit 41, and the fault signal L, after being amplified by the first operational amplifier unit 41, is output through the second terminal of the nineteenth resistor R19.

[0066] Optionally, the signal modulation unit 42 includes a transformer T, a first transistor Q1, a second transistor Q2, a third transistor Q3, and a fourth transistor Q4. The first terminal of the primary winding of transformer T is connected to the first terminal of the first transistor Q1, and the second terminal of the primary winding of transformer T is connected to the first terminal of the second transistor Q2. The first terminal of the secondary winding of transformer T is connected to the first terminal of the third transistor Q3, and the second terminal of the secondary winding of transformer T is connected to the first terminal of the fourth transistor Q4. The control terminals of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are respectively connected to the modulation signal. The second terminals of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 are all grounded. The center tap of the primary winding of transformer T serves as the input terminal of the signal modulation unit 42, and the center tap of the secondary winding of transformer T serves as the output terminal of the signal modulation unit 42.

[0067] In this transistor configuration, the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 can all be N-type MOSFETs. The control terminal of the first transistor Q1 can be the gate of the N-type MOSFET, its first terminal can be the drain, and its second terminal can be the source. Similarly, the control terminal of the second transistor Q2 can be the gate of the N-type MOSFET, its first terminal can be the drain, and its second terminal can be the source. Likewise, the control terminal of the third transistor Q3 can be the gate of the N-type MOSFET, its first terminal can be the drain, and its second terminal can be the source. Finally, the control terminal of the fourth transistor Q4 can be the gate of the N-type MOSFET, its first terminal can be the drain, and its second terminal can be the source.

[0068] The signal modulation unit 42 may further include a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, and a twenty-fifth resistor R25. The first terminal of the fourth capacitor C4 is connected to the modulation signal, and the second terminal of the fourth capacitor C4 is connected to the control terminal of the first transistor Q1. The twenty-first resistor R21 is connected between the control terminal and the second terminal of the first transistor Q1. The first terminal of the fifth capacitor C5 is connected to the modulation signal, and the second terminal of the fifth capacitor C5 is connected to the control terminal of the second transistor Q2. The twenty-second resistor R22 is connected between the control terminal and the second terminal of the second transistor Q2. The first terminal of the sixth capacitor C6 is connected to the modulation signal, and the second terminal of the sixth capacitor C6 is connected to the control terminal of the third transistor Q3. The twenty-third resistor R23 is connected between the control terminal and the second terminal of the third transistor Q3. The first terminal of the seventh capacitor C7 is connected to the modulation signal, and the second terminal of the seventh capacitor C7 is connected to the control terminal of the fourth transistor Q4. The twenty-fourth resistor R24 ​​is connected between the control terminal and the second terminal of the fourth transistor Q4. The first terminal of the 25th resistor R25 is connected to the center tap of the secondary winding of transformer T. The first terminal of the 8th capacitor C8 is connected to the second terminal of the 25th resistor R25, and the second terminal of the 8th capacitor C8 is grounded. The control terminals of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4 can be connected to a high-level signal or a low-level signal, which can be set according to the actual situation.

[0069] The signal modulation unit 42 transmits the fault signal L from the primary winding of transformer T to the secondary winding, and outputs it to the second operational amplifier unit 43 at the second terminal of the twenty-fifth resistor R25. The second operational amplifier unit 43 may include an operational amplifier circuit.

[0070] Switching unit 44 may include a fifth transistor Q5. The control terminal of the fifth transistor Q5 may be the control terminal of switching unit 44, the first terminal of the fifth transistor Q5 may be the first terminal of switching unit 44, and the second terminal of the fifth transistor Q5 may be the second terminal of switching unit 44. The fifth transistor Q5 may be an N-type MOSFET. The control terminal of the fifth transistor Q5 may be the gate of the N-type MOSFET, the first terminal of the fifth transistor Q5 may be the source of the N-type MOSFET, and the second terminal of the fifth transistor Q5 may be the drain of the N-type MOSFET.

[0071] Taking the high-level modulation signal connected to the first transistor Q1, second transistor Q2, third transistor Q3, and fourth transistor Q4 as an example, when the center tap of the primary winding of transformer T is connected to the fault signal L, the first transistor Q1, second transistor Q2, third transistor Q3, and fourth transistor Q4 are turned on. The signal modulation unit 42 transmits the fault signal L from the primary winding of transformer T to the secondary winding and outputs it to the second operational amplifier unit 43. When the second operational amplifier unit 43 outputs a low-level signal, the fifth transistor Q5 is turned off, the switching unit 44 is turned off, controlling the turn-off of the input terminal of the analog output module 5. The analog output module 5 no longer outputs analog signals, thus achieving the purpose of fault transmission. When the output of the analog output module 5 is in normal operation, when the second operational amplifier unit 43 outputs a high-level signal, the fifth transistor Q5 is turned on, the switching unit 44 is turned on, controlling the turn-on of the input terminal of the analog output module 5, and the analog output module 5 can output analog signals.

[0072] For example, an analog output fault detection and pass-through circuit may include the following fault pass-through value table. As shown in Table 1, when the load resistance value is higher than the open circuit threshold... When the load resistance is below the open-circuit threshold, the inverting module outputs a low-level signal. When either the short-circuit detection module or the inverting module outputs a low-level signal, the logic calculation module will also output a low-level signal, the switching unit will turn off, and thus control the input terminal of the analog output module 5 to turn off.

[0073] Table 1 Fault Transmission Value Table In summary, the technical solution of this invention is built through hardware without the need for embedded systems, ensuring reliable performance. Furthermore, the components of the detection circuit are general-purpose materials, resulting in controllable costs and a superior cost-performance ratio.

[0074] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0075] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An analog output fault detection and transparent transmission circuit, characterized in that, Includes a sampling module, a short-circuit detection module, an open-circuit detection module, and a fault pass-through module; The sampling circuit is used to sample the source voltage, positive voltage, and negative voltage of the analog output module; the output of the analog output module is connected to the load. The first input terminal of the short-circuit detection module and the first input terminal of the open-circuit detection module are both connected to the positive terminal voltage, the second input terminal of the short-circuit detection module and the second input terminal of the open-circuit detection module are both connected to the source terminal voltage, and the third input terminal of the short-circuit detection module and the third input terminal of the open-circuit detection module are both connected to the negative terminal voltage. The short-circuit detection module is used to determine whether there is a short-circuit fault in the output of the analog output module based on the source terminal voltage, the positive terminal voltage, and the negative terminal voltage; the open-circuit detection module is used to determine whether there is an open-circuit fault in the output of the analog output module based on the source terminal voltage, the positive terminal voltage, and the negative terminal voltage. The fault transmission module is connected to the output terminal of the short circuit detection module and the output terminal of the open circuit detection module, and is used to control the analog output module to stop outputting when there is a short circuit fault or open circuit fault in the output of the analog output module.

2. The analog output fault detection and pass-through circuit according to claim 1, characterized in that, It also includes a logic operation module and an inversion operation module; The output of the short-circuit detection module is connected to the fault transmission module through the logic operation module; the output of the open-circuit detection module is connected to the fault transmission module through the inversion operation module and the logic operation module in sequence. The first input terminal of the logic operation module is connected to the output terminal of the short circuit detection module, the second input terminal of the logic operation module is connected to the output terminal of the open circuit detection module, and the output terminal of the logic operation module is connected to the fault pass-through module. The input terminal of the inverting operation module is connected to the output terminal of the open-circuit detection module, and the output terminal of the inverting operation module is connected to the second input terminal of the logic operation module; the inverting operation module is used to perform logical inversion processing on the output result of the open-circuit detection module and output it to the logic operation module; The logic operation module is used to output a fault signal to the fault pass-through module when there is a short circuit fault or open circuit fault in the output of the analog output module. The fault transmission module is used to control whether the analog output module outputs based on the fault signal.

3. The analog output fault detection and pass-through circuit according to claim 1, characterized in that, The short-circuit detection module includes: a first voltage conversion unit and a first comparison unit; The first input terminal of the first voltage conversion unit serves as the first input terminal of the short-circuit detection module, the second input terminal of the first voltage conversion unit serves as the second input terminal of the short-circuit detection module, and the third input terminal of the first voltage conversion unit serves as the third input terminal of the short-circuit detection module; the first output terminal of the first voltage conversion unit is connected to the non-inverting input terminal of the first comparator unit, and the second output terminal of the first voltage conversion unit is connected to the inverting input terminal of the first comparator unit. The first voltage conversion unit is used to convert the first voltage difference according to the source voltage, the positive terminal voltage, and the negative terminal voltage. The converted first voltage difference is only related to the load size. The first voltage difference is the voltage difference between the non-inverting input terminal and the inverting input terminal of the first comparator unit. The first comparison unit is used to output a first comparison signal based on the first voltage difference. The first comparison signal is used to characterize whether there is a short circuit fault in the output of the analog output module.

4. The analog output fault detection and pass-through circuit according to claim 1, characterized in that, The open-circuit detection module includes: a second voltage conversion unit and a second comparison unit; The first input terminal of the second voltage conversion unit serves as the first input terminal of the open circuit detection module, the second input terminal of the second voltage conversion unit serves as the second input terminal of the open circuit detection module, and the third input terminal of the second voltage conversion unit serves as the third input terminal of the open circuit detection module; the first output terminal of the second voltage conversion unit is connected to the non-inverting input terminal of the second comparator unit, and the second output terminal of the second voltage conversion unit is connected to the inverting input terminal of the second comparator unit. The second voltage conversion unit is used to convert the second voltage difference according to the source voltage, the positive terminal voltage, and the negative terminal voltage. The converted second voltage difference is only related to the load size. The second voltage difference is the voltage difference between the non-inverting input terminal and the inverting input terminal of the second comparator unit. The second comparison unit is used to output a second comparison signal based on the second voltage difference. The second comparison signal is used to characterize whether there is an open circuit fault in the output of the analog output module.

5. The analog output fault detection and pass-through circuit according to claim 1, characterized in that, The analog output module includes a constant current source, a first conjugate inductor, a first resistor, and a second conjugate inductor; the first input terminal of the first conjugate inductor is connected to the power supply voltage, and the second input terminal of the first conjugate inductor is connected to the output terminal of the constant current source. The first output terminal of the first conjugate inductor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is connected to the first input terminal of the second conjugate inductor; the first output terminal of the first conjugate inductor is connected to the second input terminal of the second conjugate inductor; the first output terminal of the second conjugate inductor is connected to the positive terminal of the load, and the second output terminal of the second conjugate inductor is connected to the negative terminal of the load; The sampling circuit includes: a second resistor and a voltage follower circuit; The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first input terminal of the short-circuit detection module and the first input terminal of the open-circuit detection module. The input terminal of the voltage follower circuit is connected to the second output terminal of the first conjugate inductor, and the output terminal of the voltage follower circuit is connected to the third input terminal of the short-circuit detection module and the third input terminal of the open-circuit detection module. The second input terminal of the short-circuit detection module and the second through input terminal of the open-circuit detection module are connected to the first input terminal of the first conjugate inductor.

6. The analog output fault detection and pass-through circuit according to claim 1, characterized in that, The short-circuit detection module includes: a first comparator, a first capacitor, a third resistor, a fourth resistor, and a fifth resistor; The first capacitor is connected between the non-inverting input and the inverting input of the first comparator, the first end of the third resistor is connected to the first end of the first capacitor, and the second end of the third resistor serves as the first input of the short-circuit detection module. The first ends of the fourth resistor and the fifth resistor are both connected to the second end of the first capacitor. The second end of the fourth resistor serves as the second input end of the short circuit detection module, and the second end of the fifth resistor serves as the third input end of the short circuit detection module. The open-circuit detection module includes: a second comparator, a sixth resistor, a seventh resistor, and an eighth resistor; The first end of the sixth resistor is connected to the non-inverting input of the second comparator, and the second end of the sixth resistor serves as the first input of the open-circuit detection module. The first ends of the seventh resistor and the eighth resistor are both connected to the inverting input of the second comparator. The second end of the seventh resistor serves as the second input of the open circuit detection module, and the second end of the eighth resistor serves as the third input of the open circuit detection module.

7. The analog output fault detection and pass-through circuit according to claim 2, characterized in that, The inverting operational module includes a first operational amplifier, a ninth resistor, a tenth resistor, and an eleventh resistor; The first end of the ninth resistor and the first end of the tenth resistor are both connected to the inverting input of the first operational amplifier. The second end of the ninth resistor serves as the input of the inverting operational module. The second end of the tenth resistor is grounded. The first end of the eleventh resistor is connected to the non-inverting input of the first operational amplifier. The second end of the eleventh resistor is grounded. The output of the first operational amplifier serves as the output of the inverting operational module.

8. The analog output fault detection and pass-through circuit according to claim 2, characterized in that, The logic operation module includes a first diode, a second diode, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a sixteenth resistor; The first terminal of the twelfth resistor is connected to the power supply voltage. The first terminals of the thirteenth and fourteenth resistors are both connected to the second terminal of the twelfth resistor, and the second terminal of the thirteenth resistor is grounded. The first terminals of the fifteenth and sixteenth resistors are both connected to the second terminal of the fourteenth resistor. The anode of the first diode is connected to the second terminal of the fifteenth resistor, and the anode of the second diode is connected to the second terminal of the sixteenth resistor. The cathode of the first diode serves as the first input terminal of the logic operation module, and the cathode of the second diode serves as the second input terminal of the logic operation module; the second terminal of the fourteenth resistor serves as the output terminal of the logic operation module.

9. The analog output fault detection and pass-through circuit according to claim 2, characterized in that, The fault transmission module includes: a first operational amplifier unit, a signal modulation unit, a second operational amplifier unit, and a switching unit; The fault signal is connected to the input terminal of the first operational amplifier unit, and the output terminal of the first operational amplifier unit is connected to the input terminal of the signal modulation unit for amplifying the fault signal. The control terminal of the signal modulation unit is connected to the modulation signal, and the output terminal of the signal modulation unit is connected to the input terminal of the second operational amplifier unit, so as to transmit the fault signal to the second operational amplifier unit under the control of the modulation signal. The control terminal of the switching unit is connected to the output terminal of the second operational amplifier unit, the first terminal of the switching unit is connected to the positive input terminal of the analog output module, and the second terminal of the switching unit is connected to the negative input terminal of the analog output module. The switching unit is used to control the on or off state of the input terminal of the analog output module according to the fault signal.

10. The analog output fault detection and pass-through circuit according to claim 9, characterized in that, The signal modulation unit includes a transformer, a first transistor, a second transistor, a third transistor, and a fourth transistor; The first end of the primary winding of the transformer is connected to the first end of the first transistor, and the second end of the primary winding of the transformer is connected to the first end of the second transistor; the first end of the secondary winding of the transformer is connected to the first end of the third transistor, and the second end of the secondary winding of the transformer is connected to the first end of the fourth transistor. The control terminals of the first transistor, the second transistor, the third transistor, and the fourth transistor are respectively connected to the modulation signal; the second terminals of the first transistor, the second transistor, the third transistor, and the fourth transistor are all grounded. The center tap of the primary winding of the transformer serves as the input terminal of the signal modulation unit, and the center tap of the secondary winding of the transformer serves as the output terminal of the signal modulation unit.

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