Fault diagnosis method and device for switching value input module

Abstract

The invention discloses a fault diagnosis method and device for a switching value input module, and relates to the technical field of equipment fault detection.The method comprises the steps that a fuse is arranged on a DI channel where each DI terminal module is located, and a fusing detection resistor is additionally arranged on the side, close to field equipment, of each fuse; the fusing detection resistor is connected in parallel between the positive electrode and the negative electrode of the DI channel; the on-off input module fault diagnosis method comprises the following steps: collecting channel current of each DI channel in real time; when the channel current acquired in real time is greater than or equal to the loop query current, determining that the field equipment contact is closed; when the channel current collected in real time is within the fuse query current range, it is judged that the field equipment contact is disconnected; and when the channel current acquired in real time is 0, judging that the fuse is in fault. The accuracy and the maintenance efficiency of fault diagnosis of the switching value input module are improved, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of equipment fault detection, and in particular to a method and device for diagnosing faults of a switch input module. Background Art

[0002] Digital instrumentation and control systems are used to centrally monitor and manage the entire production process. Their typical architecture employs a two-tier network structure. The first tier is the process control layer, comprised of several control stations. Each station can operate independently and perform functions such as signal acquisition and output, and control processing. The second tier is the operation and information management layer, consisting of operator stations, engineer stations, and servers. It provides operations, monitoring, and data analysis and storage. It receives data collected from the first tier in real time and transmits operator commands to the first tier.

[0003] The control station of the digital instrumentation and control system is mainly composed of controller modules, I / O modules, I / O terminal modules and other auxiliary equipment.

[0004] (1) Controller module: It is mainly composed of CPU, ROM and RAM. It is the brain of the control station and is responsible for executing control algorithms and logical operations.

[0005] (2) I / O module: responsible for the input and output of field signals, converting various physical quantities on site into electrical signals, and then converting them into digital signals that can be recognized by the digital instrumentation and control system, or converting the control signals of the digital instrumentation and control system into signals that can be executed by field equipment.

[0006] (3) I / O terminal module: This module isolates and protects the I / O module from field signals and provides power to the field signal circuit. Signal cables from the field are connected to the digital instrumentation and control system through the I / O terminal module.

[0007] Digital instrumentation and control systems use digital input (DI) modules to collect the digital status or alarm signals of field equipment. DI modules are used to participate in automatic equipment control, store historical data, display human-machine interfaces, and perform alarm functions. Each DI module supports the acquisition of 16 or more DI signals. After completing data processing via a microprocessor, the DI module communicates with the controller module via a high-speed fieldbus. The DI module supports online diagnostics and hot-swappable operation. To facilitate maintenance and replacement of the DI module, a DI terminal module is configured between the DI module and the field equipment to connect the signal cables from the field equipment. When a DI module fails and needs to be replaced, only the faulty DI module needs to be unplugged and the spare DI module inserted, without disconnecting the signal cables, thus shortening the repair time.

[0008] The DI module connects to the chassis backplane via a connector and acquires DI signals from each channel via a matching DI terminal module. In actual use, especially during on-site installation and commissioning, overcurrent can easily occur in the DI signal loop due to incorrect termination or strong electrical induction. To address this, a separate fuse is configured for each channel on the terminal module to prevent overcurrent from damaging the DI module. The fuse is hot-swappable and can be replaced online without affecting the normal operation of other channels. However, since the terminal module lacks self-diagnosis, when a fuse blows, the digital I&C system cannot determine whether the local device corresponding to that channel has a "contact open" or a "fuse blown." Since the digital I&C system cannot indicate a fuse fault, operation and maintenance personnel cannot quickly locate and correct the fault, hindering their ability to assess equipment status. For critical digital status signals, such as monitored variable out-of-limit conditions or actuator failures, this fault can even lead to serious accidents, disrupting normal plant operations.

[0009] The prior art method for implementing DI channel fuse fault diagnosis is as follows.

[0010] (1) Fuse local indicator light. Add power and indicator lights to both ends of the fuse. When the fuse blows, the local indicator light on the terminal module indicates the fault. This method relies on regular manual inspections of the control station and cannot send fault information to the digital instrumentation and control system in real time, affecting the accuracy of the DI signal real-time indication and control and maintenance efficiency.

[0011] (2) Collecting fuse status through an additional channel. This method collects fuse status through an additional DI channel. When the fuse is normal, the DI channel collects the contact closure signal; when the fuse is faulty, the DI channel collects the contact opening signal. Combined with the original DI channel for collecting local signals, they jointly participate in the real-time indication and control of the local signals. This method occupies an additional DI channel, which reduces the number of I / O points deployed in the same space in the control station, reducing economic efficiency.

[0012] (3) The status of the entire DI channel is diagnosed by connecting a large resistor in parallel to the local device. This method connects a large resistor in parallel at both ends of the local device switch contacts and determines the status of the entire DI channel circuit (including the signal cable) by detecting the current value of the channel. If the DI module detects a small current, it is determined that the local device "contact is disconnected"; if the DI module detects that the current is 0, it is determined that the DI channel circuit between the local device and the DI module is disconnected (including situations such as the terminal module fuse being blown, the local signal cable being disconnected, etc.). This method requires the installation of additional equipment on the local device side, which cannot be implemented in most cases due to the limitations of factory and equipment installation conditions. Summary of the Invention

[0013] The purpose of this application is to provide a method and device for diagnosing faults of a switching input module, thereby improving the accuracy of fault diagnosis and maintenance efficiency of the switching input module and reducing maintenance costs.

[0014] To achieve the above objectives, this application provides the following solutions: In a first aspect, the present application provides a method for diagnosing a fault in a switching input module, wherein a fuse is configured on a DI channel where each DI terminal module is located, and a fuse detection resistor is added on the side of the fuse close to the field device, wherein the fuse detection resistor is connected in parallel between the positive and negative poles of the DI channel; the method for diagnosing a fault in a switching input module comprises: Real-time acquisition of channel current of each DI channel; When the channel current collected in real time is greater than or equal to the loop query current, determining that the field device contacts are closed; When the channel current collected in real time is within the fuse query current range, determining that the field device contact is disconnected; When the channel current collected in real time is 0, it is determined that the fuse is faulty.

[0015] Optionally, the calculation formula for the loop query current is: ; in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

[0016] Optionally, the fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current; The first fuse query current is expressed as: ; The second fuse query current is expressed as: ; in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

[0017] Optionally, the switch input module fault diagnosis method further includes: When it is determined that the field device contact is closed or the field device contact is open, setting the signal quality safety bit to good; When it is determined that the fuse is faulty, the signal quality safety bit is set to bad, and a fault signal is sent to the operator station.

[0018] Optionally, when it is determined that the fuse is faulty, the DI signal value at the current moment is set to a preset fail-safe value or the DI signal value at the moment when the previous signal quality safety bit was good.

[0019] In a second aspect, the present application provides a device for diagnosing faults in a switching input module, the device comprising: a fuse, a fuse detection resistor, and a status determination module configured on a DI channel where each DI terminal module is located; the fuse detection resistor is located on a side of the fuse close to a field device and is connected in parallel between the positive and negative poles of the DI channel; The state determination module is used for: Real-time acquisition of channel current of each DI channel; When the channel current collected in real time is greater than or equal to the loop query current, determining that the field device contacts are closed; When the channel current collected in real time is within the fuse query current range, determining that the field device contact is disconnected; When the channel current collected in real time is 0, it is determined that the fuse is faulty.

[0020] Optionally, the calculation formula for the loop query current is: ; in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

[0021] Optionally, the fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current; The first fuse query current is expressed as: ; The second fuse query current is expressed as: ; in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

[0022] Optionally, the switch input module fault diagnosis device includes: a controller module; The controller module is configured to set a signal quality safety bit to good when determining that the field device contact is closed or the field device contact is open; The controller module is used to set the signal quality safety bit to bad and send a fault signal to the operator station when it is determined that the fuse is faulty.

[0023] Optionally, the controller module is further configured to set the DI signal value at the current moment to a preset fail-safe value or the DI signal value at the moment when the previous signal quality safety bit was good when it is determined that the fuse is faulty.

[0024] According to the specific embodiments provided by the present application, the present application discloses the following technical effects: The present application provides a method and device for diagnosing faults of a switching input module, wherein a fuse is configured on the DI channel where each DI terminal module is located, and a fuse detection resistor is added on the side of the fuse close to the field equipment. The fuse detection resistor is connected in parallel between the positive and negative poles of the DI channel, and then the state of the switching input module is determined by judging the magnitude of the channel current, so that each DI channel is configured with an independent fuse as a protection measure. At the same time, each fuse has fault diagnosis capabilities, which can not only prevent the channel from overcurrent and burn the DI module, but also quickly locate the fault position, thereby improving the accuracy of switching input module fault diagnosis and maintenance efficiency. Since the present application reduces the workload of manual inspections, it can reduce maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A flowchart of a method for diagnosing faults in a switching input module provided in one embodiment of the present application.

[0027] Figure 2 This is a schematic diagram of the double-sided network structure of the digital instrumentation and control system.

[0028] Figure 3 This is a schematic diagram of the DI terminal module interface circuit provided in one embodiment of the present application.

[0029] Figure 4 This is a schematic diagram of the DI channel signal processing flow provided in one embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] In an exemplary embodiment, after the fuse configured for each DI channel of the DI terminal module is blown, the digital instrumentation and control system cannot determine whether the local device corresponding to the DI channel is "contact open" or "fuse open". This application provides a method for diagnosing faults of a switching input module, which configures a fuse on the DI channel where each DI terminal module is located. , and add a fuse detection resistor on the side of the fuse close to the field device , the fuse detection resistor Connect in parallel between the positive and negative electrodes of the DI channel, such as Figure 3 As shown. Fuse detection resistor Much larger than the channel resistance , Figure 3 INn+ indicates the positive pole of the nth channel DI signal, which is a contact. If it is closed, there is current in the channel loop. CNn indicates the nth channel. Each DI module has 16 channels. Figure 3 Only one channel is taken as an example.

[0033] This application processes the circuit through the DI module ( Figure 3 The processing circuit in the middle determines whether the fuse is blown according to the channel current value and sends the fault diagnosis information to the controller module.

[0034] The DI module processing circuit can handle 3 states.

[0035] State (1): When the channel current To query the current (high current) in the loop and determine whether the field device contacts are closed.

[0036] State (2): When the channel current Query the current (small current) of the fuse and determine whether the contacts of the field device are open.

[0037] State (3): When the channel current If it is 0, it is determined that the fuse of the DI terminal module is faulty.

[0038] like Figure 1 and Figure 4 As shown, the switch input module fault diagnosis method includes steps 101 to 102.

[0039] Step 101: Collect the channel current of each DI channel in real time.

[0040] Step 102: When the channel current collected in real time is greater than or equal to the loop query current, it is determined that the field device contacts are closed; when the channel current collected in real time is within the fuse query current range, it is determined that the field device contacts are open; when the channel current collected in real time is 0, it is determined that the fuse is faulty.

[0041] On-site equipment is Figure 2 Sensors in local equipment.

[0042] The present application configures a fuse on the DI channel where each DI terminal module is located, and adds a fuse detection resistor on the side of the fuse close to the field equipment. The fuse detection resistor is connected in parallel between the positive and negative poles of the DI channel, and then the state of the switch input module is determined by judging the magnitude of the channel current, so that each DI channel is configured with an independent fuse as a protection measure. At the same time, each fuse has fault diagnosis capabilities, which can not only prevent the channel from overcurrent and burn the DI module, but also quickly locate the fault position, thereby improving the accuracy of switch input module fault diagnosis and maintenance efficiency. Since the present application reduces the workload of manual inspections, it can reduce maintenance costs.

[0043] The controller module integrates other fault diagnostic information into its software algorithm, assigns a signal quality bit to the corresponding DI signal in the DI channel, and records the cause of the fault in the channel status flag. If the signal quality bit indicates "bad," the controller module sets the DI signal to a preset fail-safe value or maintains the DI value from the last good signal quality bit. This participates in subsequent automatic control logic, stabilizing the production process to a safe operating condition. The signal quality bit also provides displays and alarms on human-machine interface devices, alerting operation and maintenance personnel to promptly detect faults, allowing them to quickly locate and eliminate them.

[0044] When the fuse blows, the digital instrumentation and control system can provide real-time fault diagnosis information, which is convenient for operation and maintenance personnel to find faults in time, locate and eliminate faults quickly. The structure of the digital instrumentation and control system is as follows: Figure 2 This application enables the digital instrumentation and control platform to have independent fuses for each DI channel as a protection measure, and also provides fault diagnosis capabilities for each fuse.

[0045] In an exemplary embodiment, (1) when the channel current , determine whether the field device contacts are closed. This is the loop query current, which is calculated based on the query voltage Vc and the channel resistance Rn.

[0046] The calculation formula of the loop query current is: (1).

[0047] in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

[0048] (2) When the channel current In the interval, that is, satisfied , determine that the field device contacts are disconnected. and Query the current of the first fuse and the second fuse respectively, according to the query voltage With fuse detection resistor Calculated.

[0049] The fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current.

[0050] The first fuse query current is expressed as: (2).

[0051] The second fuse query current is expressed as: (3).

[0052] in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

[0053] (3) When the channel current =0, it is determined that the fuse of the DI terminal module is faulty.

[0054] When the channel current , not satisfied 、 and =0, it is an unknown state.

[0055] In formula (1), because the fuse detection resistor Much larger than the channel resistance , and The parallel resistance is much smaller than ,therefore The calculation does not take into account . Query the current threshold dead zone for the loop to offset and The fluctuation, offset and cable resistance of the current threshold are affected to prevent the frequent jitter of the current threshold judgment result. SD1 is much smaller than / .

[0056] In formulas (2) and (3), because the fuse detection resistor Much larger than the channel resistance , and The series resistance is much larger than ,therefore and The calculation does not take into account . Query the current threshold dead zone for the fuse to offset and To prevent the current threshold judgment result from frequent jitter, Much smaller than / The loop current and fuse current must meet .

[0057] In an exemplary embodiment, the method for diagnosing a fault in a switching input module further includes: setting a signal quality safety bit to good when determining that the field device contact is closed or open; and setting a signal quality safety bit to bad when determining that the fuse is faulty, and sending a fault signal to an operator station.

[0058] When it is determined that the fuse is faulty, the DI signal value at the current moment is set to a preset fail-safe value or the DI signal value at the moment when the previous signal quality safety bit was good.

[0059] The present application method can ultimately realize a digital instrumentation and control platform with an independent fuse for each DI channel as a protection measure, and at the same time, it can have fault diagnosis capabilities for each fuse. It can not only prevent the channel overcurrent from burning the DI module, but also prevent the digital instrumentation and control system from having no corresponding fault diagnosis capabilities after the fuse blows, and being unable to quickly locate and eliminate the fault, which affects the judgment of the equipment status. The present application method not only improves the accuracy and maintenance efficiency of the real-time indication and control of the DI signal, but also greatly reduces the operating and maintenance costs and reduces the workload of manual inspections. Taking a nuclear power plant as an example, there are about 100 DCS system control cabinets for a single unit in the plant, which are distributed in different rooms in different plant buildings and floors. It takes about 0.5 man-days to complete a manual inspection. The total labor cost can be reduced by about 182.5 man-days throughout the year.

[0060] Based on the same inventive concept, embodiments of the present application further provide a device for diagnosing a fault in a switching input module for implementing the aforementioned method for diagnosing a fault in a switching input module. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the device for diagnosing a fault in a switching input module provided below can be found in the aforementioned limitations of the method for diagnosing a fault in a switching input module, and will not be further elaborated here.

[0061] In an exemplary embodiment, a switch input module fault diagnosis device is provided, comprising: a fuse, a fuse detection resistor, and a status determination module configured on a DI channel where each DI terminal module is located; the fuse detection resistor is located on a side of the fuse close to a field device and is connected in parallel between the positive and negative poles of the DI channel.

[0062] The status determination module is used to: determine that the contacts of the field device are closed when the channel current collected in real time is greater than or equal to the loop query current; determine that the contacts of the field device are open when the channel current collected in real time is within the fuse query current range; and determine that the fuse is faulty when the channel current collected in real time is 0.

[0063] The calculation formula of the loop query current is: .

[0064] in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

[0065] The fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current.

[0066] The first fuse query current is expressed as: .

[0067] The second fuse query current is expressed as: .

[0068] in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

[0069] The switch input module fault diagnosis device includes: a controller module.

[0070] The controller module is configured to set a signal quality safety bit to good when determining that the field device contacts are closed or the field device contacts are open.

[0071] The controller module is used to set the signal quality safety bit to bad and send a fault signal to the operator station when it is determined that the fuse is faulty.

[0072] The controller module is further configured to set the current DI signal value to a preset fail-safe value or the DI signal value at the moment when the last signal quality safety bit was good when determining that the fuse is faulty.

[0073] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for diagnosing faults in a switch input module, characterized in that: A fuse is configured on the DI channel where each DI terminal module is located, and a fuse detection resistor is added on the side of the fuse close to the field device, and the fuse detection resistor is connected in parallel between the positive and negative poles of the DI channel; The switch input module fault diagnosis method comprises: Real-time acquisition of channel current of each DI channel; When the channel current collected in real time is greater than or equal to the loop query current, determining that the field device contacts are closed; When the channel current collected in real time is within the fuse query current range, determining that the field device contact is disconnected; When the channel current collected in real time is 0, it is determined that the fuse is faulty.

2. The method for diagnosing faults of a switching input module according to claim 1, wherein: The calculation formula of the loop query current is: ; in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

3. The method for diagnosing faults of a switching input module according to claim 1, wherein: The fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current; The first fuse query current is expressed as: ; The second fuse query current is expressed as: ; in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

4. The method for diagnosing a fault in a switching input module according to claim 1, wherein: The switch input module fault diagnosis method further includes: When it is determined that the field device contact is closed or the field device contact is open, setting the signal quality safety bit to good; When it is determined that the fuse is faulty, the signal quality safety bit is set to bad, and a fault signal is sent to the operator station.

5. The method for diagnosing a fault in a switching input module according to claim 4, wherein: When it is determined that the fuse is faulty, the DI signal value at the current moment is set to a preset fail-safe value or the DI signal value at the moment when the previous signal quality safety bit was good.

6. A fault diagnosis device for a switch input module, characterized in that: The switch input module fault diagnosis device includes: a fuse, a fuse detection resistor, and a status determination module configured on the DI channel where each DI terminal module is located; the fuse detection resistor is located on the side of the fuse close to the field device and is connected in parallel between the positive and negative poles of the DI channel; The state determination module is used for: Real-time acquisition of channel current of each DI channel; When the channel current collected in real time is greater than or equal to the loop query current, determining that the field device contacts are closed; When the channel current collected in real time is within the fuse query current range, determining that the field device contact is disconnected; When the channel current collected in real time is 0, it is determined that the fuse is faulty.

7. The switch input module fault diagnosis device according to claim 6, characterized in that: The calculation formula of the loop query current is: ; in, To query the current for the loop, The query voltage of the DI module, is the channel resistance of the DI module, Query the current threshold deadband for the loop.

8. The switch input module fault diagnosis device according to claim 6, characterized in that: The fuse query current range is greater than or equal to the first fuse query current and less than or equal to the second fuse query current; The first fuse query current is expressed as: ; The second fuse query current is expressed as: ; in, Query the current for the first fuse, Query the current for the second fuse, The query voltage of the DI module, is the fuse detection resistor, Query the current threshold deadband for the fuse.

9. The switch input module fault diagnosis device according to claim 6, characterized in that: The switch input module fault diagnosis device includes: a controller module; The controller module is configured to set a signal quality safety bit to good when determining that the field device contact is closed or the field device contact is open; The controller module is used to set the signal quality safety bit to bad and send a fault signal to the operator station when it is determined that the fuse is faulty.

10. The switch input module fault diagnosis device according to claim 9, characterized in that: The controller module is further configured to set the current DI signal value to a preset fail-safe value or the DI signal value at the moment when the last signal quality safety bit was good when determining that the fuse is faulty.

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