Hardware diagnostic circuits for intelligent functional safety barriers, safety barriers

Abstract

The present application provides a hardware diagnostic circuit and a safety isolation fence for an intelligent functional safety isolation fence. The hardware diagnostic circuit includes: an AC / DC unit, which is used to convert the AC voltage of the power supply into a DC voltage and provide it to each unit; a signal output unit, the signal output unit includes a decoupling module, the decoupling module is used to decouple the input converted voltage coupling signal and output it as a current signal; a monitoring unit, which is used to monitor whether a non-functional safety state occurs in the hardware diagnostic circuit; a cut-off unit, which is respectively connected to the signal output unit and the monitoring unit, and is used to cut off the power supply to achieve an output safety state when a non-functional safety state occurs. The present application can simultaneously transmit multiple signals to a PLC or DCS, while reducing the hardware cost of the output channel.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a hardware diagnostic circuit and a safety isolation barrier for an intelligent functional safety isolation barrier. Background Art

[0002] Safety isolation fence products transmit analog signals or temperature signals from field transmitters, flow meters, temperature sensors and other equipment to PLC, DCS and related SIS systems. If any weak link in the entire control system or signal transmission loop fails, it may cause malfunction or equipment shutdown, and even more seriously, it may cause catastrophic consequences. Therefore, the functional safety of the isolation fence as a signal transmission unit is particularly important.

[0003] In the process of isolating and transmitting current or voltage analog signals and temperature signals, more and more intelligent methods are used. In smart products, the concept of safety is becoming more and more important, so functional safety certification is becoming more and more popular. Traditional smart products use MCU to diagnose related safety functions on each isolation side, which brings great pressure on hardware costs. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present application is to provide a hardware diagnostic circuit and a safety isolation barrier for an intelligent functional safety isolation barrier, which are used to solve the problem that the hardware cost of the intelligent isolators and safety barriers in the prior art is high due to the use of dual or multiple MCUs and the large number of signal points that need to be collected by the on-site PLC or DCS.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a hardware diagnostic circuit for an intelligent functional safety isolation fence, wherein the hardware diagnostic circuit includes: an AC / DC unit, which is used to convert the AC voltage of the power supply into a DC voltage and provide it to each unit; a signal output unit, wherein the signal output unit includes a decoupling module, wherein the decoupling module is used to decouple the input converted voltage coupling signal and output it as a current signal; a monitoring unit, which is used to monitor whether a non-functional safety state occurs in the hardware diagnostic circuit; and a cut-off unit, which is respectively connected to the signal output unit and the monitoring unit, and is used to cut off the power supply when a non-functional safety state occurs to achieve an output safety state.

[0006] In one embodiment of the present application, the signal output unit includes: a decoupling module, a first field effect transistor, and an operational amplifier; wherein the current signal decoupled by the decoupling module flows through an EMC protection circuit for absorbing EMC interference, and the first field effect transistor.

[0007] In one embodiment of the present application, the EMC protection circuit includes: a transient suppression diode, a fuse, a first inductor, a second inductor, a first capacitor, and a second capacitor; wherein the two ends of the transient suppression diode serve as the positive and negative electrodes of the current signal output end, respectively.

[0008] In an embodiment of the present application, the types of EMC interference include: any one or more of electrical fast pulse group impact, surge, and static electricity.

[0009] In one embodiment of the present application, the monitoring unit includes: a first monitoring circuit for monitoring the power supply, and a second monitoring circuit for monitoring the accuracy of the transmission signal; when the first monitoring circuit monitors that the power supply is undervoltage, and / or the second monitoring circuit monitors that the transmission signal accuracy exceeds the standard, the first monitoring circuit and / or the second monitoring circuit instructs the cut-off unit to cut off the power supply to achieve an output safety state.

[0010] In one embodiment of the present application, the first monitoring circuit includes: a first comparator and a voltage divider circuit; when the supply voltage of the power supply passes through the voltage divider circuit, it is compared with a reference voltage by the first comparator. When the supply voltage is lower than the reference voltage and undervoltage occurs, the first comparator outputs a level signal to the cut-off unit indicating that the non-functional safety state has occurred.

[0011] In one embodiment of the present application, the second monitoring circuit includes: a second comparator, a third comparator, and a first AND gate logic circuit; wherein the second comparator and the third comparator respectively compare the converted coupling voltage with the feedback voltage to determine whether it exceeds the standard; if the accuracy exceeds the standard, the first AND gate logic circuit outputs a level signal to the cut-off unit indicating that the non-functional safety state has occurred.

[0012] In one embodiment of the present application, the cut-off unit includes: a second field effect transistor, a third field effect transistor, and a second AND gate logic circuit; when the second AND gate logic circuit receives the level signal output by the monitoring unit indicating the occurrence of the non-functional safety state, it outputs a cut-off level signal to cut off the second field effect transistor and the third field effect transistor, so that the power supply cannot be output to achieve an output safety state; otherwise, it outputs a conduction level signal to conduct the second field effect transistor and the third field effect transistor.

[0013] In one embodiment of the present application, the second field effect transistor is an N-channel enhancement type, and the third field effect transistor is a P-channel enhancement type.

[0014] To achieve the above-mentioned purpose and other related purposes, the present application provides a safety isolation barrier, including the hardware diagnostic circuit for the intelligent functional safety isolation barrier as described above.

[0015] As described above, the present application provides a hardware diagnostic circuit and a safety isolation fence for an intelligent functional safety isolation fence. The hardware diagnostic circuit includes: an AC / DC unit, which is used to convert the AC voltage of the power supply into a DC voltage and provide it to each unit; a signal output unit, the signal output unit includes a decoupling module, the decoupling module is used to decouple the input converted voltage coupling signal and output it as a current signal; a monitoring unit, which is used to monitor whether a non-functional safety state occurs in the hardware diagnostic circuit; a cut-off unit, which is respectively connected to the signal output unit and the monitoring unit, and is used to cut off the power supply when a non-functional safety state occurs to achieve an output safety state. It has the following beneficial effects:

[0016] It can transmit multiple signals to PLC or DCS at the same time, while reducing the hardware cost of the output channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a module schematic diagram of a hardware diagnostic circuit for an intelligent functional safety isolation barrier in an embodiment of the present application.

[0018] Figure 2 Schematic diagram of a circuit of a hardware diagnostic circuit for an intelligent functional safety isolation barrier in an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] It should be noted that in the following description, reference is made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may also be used, and that mechanical composition, structure, electrical and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims of the published patents. The terms used here are only for describing specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0021] Furthermore, as used in this document, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms "comprises", "includes", "includes" indicate the presence of stated features, operations, elements, components, items, kinds, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition occur only when a combination of elements, functions or operations are inherently mutually exclusive in some way.

[0022] The safety barrier limits the energy entering the scene, that is, it limits the voltage and current, so that no sparks will be generated in the on-site lines under any conditions, thereby preventing explosions. This explosion-proof method is called intrinsic safety.

[0023] The isolated safety barrier adds isolation function to the safety barrier, which can prevent the ground loop current from interfering with the signal and protect the system from the influence of dangerous energy on the scene. For example, if a large current flows into the on-site line, it will damage the isolation barrier but will not affect the IO.

[0024] Functional Safety, also known as functional safety, refers to the safety components of a system or device. Safety is achieved by ensuring that the system or components can function normally after receiving input signals. For example, if a temperature sensor is installed in a motor, the motor stops running if the temperature exceeds a certain value. This function belongs to functional safety.

[0025] Generally, intelligent functional safety isolation barriers realize the transmission of analog signals and temperature signals, and output them to PLC, DCS or SIS systems through software calculation and conversion.

[0026] This application proposes a hardware diagnostic circuit and a safety isolation barrier for an intelligent functional safety isolation barrier, aiming to realize an intelligent functional safety product of a single MCU through hardware diagnosis, thereby greatly reducing hardware costs and improving product competitiveness.

[0027] like Figure 1 As shown, a module schematic diagram of a hardware diagnostic circuit for an intelligent functional safety isolation barrier in an embodiment of the present application is shown. As shown in the figure, the hardware diagnostic circuit includes:

[0028] The AC / DC unit 110 is used to convert the AC voltage of the power supply into a DC voltage and provide it to each unit;

[0029] In this embodiment, the AC / DC unit 110 generates an AC voltage through a transformer and generates a DC voltage therethrough, so as to provide a DC power supply voltage to each output unit.

[0030] The signal output unit 120 includes a decoupling module 121, and the decoupling module 121 is used to decouple the converted voltage coupling signal and output it as a current signal.

[0031] In this embodiment, the decoupling module 121, that is, the signal output unit 120, includes an EMC protection circuit, whose main function is to absorb EMC interference, including EMC interference such as electrical fast pulse group impact, surge, static electricity, etc., to improve the anti-interference ability of signal transmission.

[0032] Electromagnetic compatibility (EMC) refers to the ability of a device or system to operate in accordance with requirements in its electromagnetic environment and not to generate intolerable electromagnetic interference to any device in the environment. Therefore, EMC includes two requirements: on the one hand, the electromagnetic interference generated by the device to the environment during normal operation cannot exceed a certain limit; on the other hand, it means that the device has a certain degree of immunity to the electromagnetic interference in the environment, that is, electromagnetic sensitivity.

[0033] The monitoring unit 130 is used to monitor whether a non-functional safety state occurs in the hardware diagnosis circuit.

[0034] Specifically, the monitoring unit 130 includes: a first monitoring circuit 131 for monitoring the power supply, and a second monitoring circuit 132 for monitoring the accuracy of the transmission signal.

[0035] When the first monitoring circuit detects that the power supply is undervoltage, and / or the second monitoring circuit detects that the transmission signal accuracy exceeds the standard, the first monitoring circuit and / or the second monitoring circuit instructs the cut-off unit 140 to cut off the power supply to achieve an output safety state.

[0036] The cut-off unit 140 is connected to the signal output unit 120 and the monitoring unit 130 respectively, and is used to cut off the power supply to achieve an output safety state when a non-functional safety state occurs.

[0037] like Figure 2 As shown in FIG. 1 , a schematic diagram of a hardware diagnostic circuit for an intelligent functional safety isolation barrier in an embodiment of the present application is shown. As shown in the figure, VCC2 and VCC3 are AC voltages generated by transformers. Figure 1The DC voltage generated by the AC / DC unit 110 is used to provide power supply voltage to each output unit and to supply power to the reference chip to generate VCC2.5.

[0038] In one embodiment of the present application, Figure 1 The first monitoring circuit 131 includes a first comparator U16A and a voltage divider circuit, wherein the voltage divider circuit is composed of a resistor R2 and a resistor R49.

[0039] When the power supply voltage of the power supply passes through the voltage divider circuit, it is compared with the reference voltage VCC2.5 by the first comparator U16A. When the power supply voltage is lower than the reference voltage VCC2.5 and undervoltage occurs, the first comparator U16A sends a signal to Figure 1 The cut-off unit 140 outputs a level signal indicating the occurrence of the non-functional safety state, for example, a level signal indicating the occurrence of the non-functional safety state at a low level.

[0040] In one embodiment of the present application, Figure 1 The second monitoring circuit 132 includes: a second comparator U16B, a third comparator U16C, and a first AND gate logic circuit U11;

[0041] Among them, the second comparator U16B and the third comparator U16C respectively compare the converted coupling voltage VOUT2 with the feedback voltage (the voltage value fed back by each node in this circuit for the artificial input voltage) to determine whether it exceeds the standard. If the difference between the coupling voltage VOUT2 and the feedback voltage is large, it means that the accuracy exceeds the standard.

[0042] If the accuracy exceeds the standard, the first AND gate logic circuit U11 outputs a level signal indicating the occurrence of the non-functional safety state to the cut-off unit. For example, the fourth pin of the first AND gate logic circuit U11 outputs a low level.

[0043] In this embodiment, the first comparator U16A, the second comparator U16B, and the third comparator U16C share the same comparator device, and the comparator includes 14 pins, and 3 pins are selected and allocated to each comparator. Figure 2 U16A, U16B, and U16C will do.

[0044] In one embodiment of the present application, Figure 1 The cut-off unit 140 includes a second field effect transistor T11 , a third field effect transistor T12 , and a second AND gate logic circuit U10 .

[0045] The second AND gate logic circuit U10 receives Figure 1The monitoring unit 130 includes a first monitoring circuit 131 and / or a second monitoring circuit 132. When the level signal outputted indicates the occurrence of the non-functional safety state, such as a low level signal, it outputs a cut-off level signal to cut off the second field effect transistor T11 and the third field effect transistor T12. For example, the fourth pin of the second AND gate logic circuit U10 outputs a low level so that the power supply cannot be output to achieve an output safety state.

[0046] On the contrary, the fourth pin of the second AND gate logic circuit U10 outputs a high level to turn on the second field effect transistor T11 and the third field effect transistor T12.

[0047] In one embodiment of the present application, the second field effect transistor T11 is of NPN type, and the third field effect transistor T12 is of PNP type.

[0048] In one embodiment of the present application, Figure 1 The signal output unit 120 includes: a decoupling module, a first field effect transistor T10, and an operational amplifier U12;

[0049] The current signal decoupled by the decoupling module flows through the EMC protection circuit for absorbing EMC interference and the first field effect transistor T10. Preferably, the first field effect transistor T11 is of NPN type.

[0050] In one embodiment of the present application, the EMC protection circuit includes: a transient suppression diode TVS10, a fuse F6, a first inductor L10, a second inductor L11, a first capacitor C32, and a second capacitor C33.

[0051] In this embodiment, specifically, the entire current loop can be expressed as: Figure 1 The DC voltage VCC2 generated by the AC / DC unit 110 passes through the third field effect transistor T12 in the cut-off unit 140, flows through the first inductor L10, and then to the fuse F6 as the output positive terminal 4+, flows into 5- through the positive load, and then to the second inductor L11, passes through the first field effect transistor T10 to the resistor R34 and returns to GND2.

[0052] A VOUT1 coupling voltage is given after input measurement, calculation and conversion, and the loop current I=VOUT1 / R34 is made through the decoupling circuit; wherein, the two ends of the transient suppression diode TVS10 serve as the positive and negative electrodes of the current signal output end respectively.

[0053] The hardware diagnostic circuit for the intelligent functional safety isolation barrier described in this application can meet the requirements of output functional safety through hardware diagnostic technology.

[0054] In an embodiment of the present application, the present application provides a safety isolation fence, comprising Figure 1 The hardware diagnostic circuit for the intelligent functional safety isolation barrier.

[0055] In summary, a hardware diagnostic circuit and a safety isolation fence for an intelligent functional safety isolation fence are provided. The hardware diagnostic circuit includes: an AC / DC unit, which is used to convert the AC voltage of the power supply into a DC voltage and provide it to each unit; a signal output unit, which includes a decoupling module, which is used to decouple the input converted voltage coupling signal and output it as a current signal; a monitoring unit, which is used to monitor whether a non-functional safety state occurs in the hardware diagnostic circuit; and a cut-off unit, which is respectively connected to the signal output unit and the monitoring unit, and is used to cut off the power supply when a non-functional safety state occurs to achieve an output safety state.

[0056] The present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0057] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A hardware diagnostic circuit for an intelligent functional safety isolation barrier, characterized in that: The hardware diagnostic circuit comprises: An AC / DC unit, used for converting the AC voltage of the power supply into a DC voltage and providing it to each unit; A signal output unit, the signal output unit comprising a decoupling module, the decoupling module is used to decouple the converted voltage coupling signal and output it as a current signal; A monitoring unit, used for monitoring whether a non-functional safety state occurs in the hardware diagnostic circuit; a cut-off unit, which is connected to the signal output unit and the monitoring unit respectively, and is used to cut off the power supply to achieve an output safety state when a non-functional safety state occurs; Wherein, the monitoring unit comprises: a first monitoring circuit for monitoring the power supply, and a second monitoring circuit for monitoring the accuracy of the transmission signal; When the first monitoring circuit detects that the power supply is undervoltage, and / or when the second monitoring circuit detects that the transmission signal accuracy exceeds the standard, the first monitoring circuit and / or the second monitoring circuit instructs the cut-off unit to cut off the power supply to achieve an output safety state; Wherein, the first monitoring circuit includes: a first comparator, and a voltage divider circuit; When the power supply voltage of the power supply passes through the voltage divider circuit and is compared with the reference voltage by the first comparator, when the power supply voltage is lower than the reference voltage and undervoltage occurs, the first comparator outputs a level signal indicating the occurrence of the non-functional safety state to the cut-off unit; Wherein, the second monitoring circuit includes: a second comparator, a third comparator, and a first AND gate logic circuit; Among them, the second comparator and the third comparator respectively compare the converted coupling voltage with the feedback voltage to determine whether it exceeds the standard; if the accuracy exceeds the standard, the first AND gate logic circuit outputs a level signal indicating the occurrence of the non-functional safety state to the cut-off unit.

2. The hardware diagnostic circuit for the intelligent functional safety isolation barrier according to claim 1, characterized in that: The signal output unit includes: a decoupling module, a first field effect transistor, and an operational amplifier; The current signal decoupled by the decoupling module flows through the EMC protection circuit for absorbing EMC interference and the first field effect transistor.

3. The hardware diagnostic circuit for the intelligent functional safety isolation barrier according to claim 2, characterized in that: The EMC protection circuit includes: a transient suppression diode, a fuse, a first inductor, a second inductor, a first capacitor, and a second capacitor; Wherein, the two ends of the transient voltage suppression diode serve as the positive and negative electrodes of the current signal output end respectively.

4. The hardware diagnostic circuit for the intelligent functional safety isolation barrier according to claim 2, characterized in that: EMC interference types include: electrical fast pulse group impact, surge, and static electricity, any one or more.

5. The hardware diagnostic circuit for the intelligent functional safety isolation barrier according to claim 1, characterized in that: The cut-off unit includes: a second field effect transistor, a third field effect transistor, and a second AND gate logic circuit; When the second AND gate logic circuit receives the level signal output by the monitoring unit indicating the occurrence of the non-functional safety state, it outputs a cut-off level signal to cut off the second field effect transistor and the third field effect transistor, so that the power supply cannot be output to achieve the output safety state; otherwise, it outputs a conduction level signal to turn on the second field effect transistor and the third field effect transistor.

6. The hardware diagnostic circuit for the intelligent functional safety isolation barrier according to claim 5, characterized in that: The second field effect transistor is an N-channel enhancement type, and the third field effect transistor is a P-channel enhancement type.

7. A safety isolation fence, characterized in that: A hardware diagnostic circuit for an intelligent functional safety isolation barrier comprising any one of claims 1 to 6.

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