RTD channel automatic testing device and method for DCS

Abstract

The invention provides an RTD channel automatic testing device and method for a DCS, and relates to the technical field of electrical element testing equipment. According to the device, one end of a program control resistor module is connected with one ends of a plurality of RTD channels; the program-controlled resistance module provides a target resistance value corresponding to the resistance control instruction; one end of the channel switching module is connected with the other end of the program control resistor module; the other end of the channel switching module is connected with the other ends of the RTD channels; the control module outputs a resistance control instruction corresponding to each RTD channel according to the indexing table corresponding to each RTD channel, and generates a channel switching instruction according to the detection sequence of the plurality of RTD channels, so that the program control resistance module is connected with a target RTD channel in the plurality of RTD channels; and obtaining a test result of each RTD channel of the DCS according to a comparison result of a target temperature value corresponding to the target resistance value and a detection temperature value obtained by detecting the target RTD channel by the DCS.

Description

Technical Field

[0001] This application relates to the field of electrical component testing equipment technology, and more specifically, to an automated testing device and method for RTD channels in DCS. Background Technology

[0002] In industrial control systems, the resistance temperature detector (RTD) channel of a distributed control system (DCS) is a core component for realizing on-site temperature data acquisition and monitoring. Its measurement accuracy and stability are directly related to the safety and controllability of the production process and the precise control of process parameters. It is widely used in key industrial fields such as power, chemical, and metallurgy.

[0003] Currently, the testing of RTD channels in DCS is mostly done manually by setting up test circuits. Testers need to manually replace standard resistors and connect different RTD channels one by one. This is not only cumbersome and inefficient, but also prone to introducing test errors due to manual wiring mistakes or resistor switching deviations. It is difficult to meet the needs of multi-channel batch testing of large-scale DCS systems. Summary of the Invention

[0004] In view of this, this application provides an automated testing device and method for RTD channels in DCS.

[0005] One aspect of this application provides an automated testing device for RTD channels in a DCS, comprising: a programmable resistor module, a channel switching module, and a control module; one end of the programmable resistor module is connected to one end of multiple RTD channels of the DCS; the programmable resistor module is used to provide a target resistance value corresponding to a resistance control command; one end of the channel switching module is connected to the other end of the programmable resistor module; the other end of the channel switching module is connected to the other end of the multiple RTD channels of the DCS; the control module is connected to a first control terminal of the programmable resistor module and a second control terminal of the channel switching module; the control module is used to output the resistance control command corresponding to each RTD channel according to the index table corresponding to each RTD channel, and to generate a channel switching command according to the detection sequence of the RTD channels, so that the programmable resistor module is connected to a target RTD channel among the multiple RTD channels of the DCS, thereby obtaining the test result of each RTD channel of the DCS based on the comparison result between the target temperature value corresponding to the target resistance value and the detection temperature value obtained by the DCS from detecting the target RTD channel.

[0006] According to an embodiment of this application, one end of the channel switching module includes at least one common terminal; the other end of the channel switching module includes multiple select terminals; the common terminal is connected to one end of the programmable resistor module; and each select terminal is connected to the other end of the corresponding RTD channel.

[0007] According to an embodiment of this application, the device further includes a power supply module; the power supply module is connected in series in a circuit consisting of the programmable resistor module, the channel switching module and the control module.

[0008] According to an embodiment of this application, the device further includes an interaction module; the interaction module is connected to the control module and the DCS respectively; the interaction module is used to display the detected resistance value and the target resistance value, and is also used to input test parameters; the test parameters include at least one of multiple RTD channels to be tested, multiple target temperature values ​​for each of the RTD channels to be tested, the test duration for each of the target temperature values, and an interval time; wherein, the interval time is the time interval between the moment when switching the RTD channel to be tested and the moment when the detection of the RTD channel to be tested after the switching begins.

[0009] According to an embodiment of this application, the device further includes a communication interface module; the control module is connected to a host computer through the communication interface module; the DCS is connected to the host computer through the communication interface module; the host computer is used to receive the detected temperature value and the target temperature value, and send test parameters to the control module; the test parameters include at least one of multiple RTD channels to be tested, multiple target temperature values ​​for each of the RTD channels to be tested, the test duration for each of the target temperature values, and an interval time; wherein the interval time is the time interval between the time corresponding to switching the RTD channel to be tested and the time corresponding to the RTD channel to be tested after the detection switch begins.

[0010] Another aspect of this application provides an automated testing method for RTD channels in a DCS, comprising: outputting a resistance control command corresponding to each of the multiple RTD channels of the DCS according to the respective calibration table, such that a programmable resistor module connected to each of the multiple RTD channels provides a target resistance value corresponding to the resistance control command, thereby simulating a target temperature corresponding to the target resistance value; generating a channel switching command according to the detection sequence of the multiple RTD channels of the DCS, such that the programmable resistor module is connected to the target RTD channel, so that the DCS detects the target RTD channel to obtain a detection temperature value, thereby obtaining the test result of each RTD channel of the DCS based on the comparison result of the target temperature value and the detection temperature value.

[0011] According to an embodiment of this application, the above-mentioned outputting resistance control instructions corresponding to each of the multiple RTD channels of the DCS based on their respective calibration tables includes: obtaining a target resistance value corresponding to each of the multiple target temperature values ​​of each of the multiple RTD channels and the corresponding calibration tables; generating a resistance control instruction based on the target resistance value, so that the programmable resistor module provides a target resistance value corresponding to the resistance control instruction.

[0012] According to an embodiment of this application, the above-mentioned generation of channel switching instructions based on the detection order of multiple RTD channels of the DCS includes: determining the detection duration of each RTD channel based on the test duration and interval of each of the target temperature values; and generating channel switching instructions based on the detection order and the detection duration.

[0013] According to an embodiment of this application, the above-mentioned generation of resistance control instructions based on the target resistance values ​​includes: generating resistance control instructions corresponding to each of the target temperature values ​​based on the test sequence of the multiple target temperature values ​​of each of the RTD channels and the test duration of each of the target temperature values.

[0014] According to an embodiment of this application, after obtaining the above test results, the above method further includes: generating a calibration report that calibrates the above-detected temperature value based on the above-mentioned target temperature value.

[0015] According to embodiments of this application, the control module controls the collaborative operation of the programmable resistor module and the channel switching module. This allows the programmable resistor module to generate a target resistance value matching the target temperature, outputting precise resistance control commands based on the corresponding RTD channel calibration table. Furthermore, it enables automatic switching of multiple channels according to a preset testing sequence, achieving automated batch testing of multiple RTD channels in a DCS system. This significantly reduces the time cost and human error associated with manual wiring and resistor switching. Moreover, the comparison mechanism between the target temperature value and the DCS detection temperature value accurately determines the measurement accuracy and operating status of each RTD channel, providing reliable data support for channel fault diagnosis and effectively improving the accuracy and reliability of test results. In addition, embodiments of this application are adaptable to the testing needs of RTD channels with different calibration numbers, allowing for integration without large-scale modifications to existing DCS systems. This approach combines versatility and convenience, breaking the limitations of traditional single-channel testing solutions and meeting the needs of large-scale DCS system multi-channel synchronous testing scenarios. Meanwhile, the entire testing process was fully automated, ensuring the integrity and traceability of the test data. This not only significantly shortened the commissioning and maintenance cycle of the DCS system, but also laid a solid technical foundation for the stable operation and performance optimization of the DCS temperature acquisition system in industrial scenarios. Attached Figure Description

[0016] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which: Figure 1 This illustration schematically shows a structural diagram of an automated testing apparatus for RTD channels in a DCS according to an embodiment of this application; Figure 2 A flowchart illustrating an automated testing method for RTD channels in a DCS according to an embodiment of this application is shown. Detailed Implementation

[0017] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0019] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0020] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0021] In the embodiments of this application, the collection, updating, analysis, processing, use, transmission, provision, disclosure, and storage of data (e.g., including but not limited to user personal information) comply with relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. In particular, necessary measures have been taken to prevent unauthorized access to user personal information data and to safeguard user personal information security, network security, and national security.

[0022] In the embodiments of this application, the user's authorization or consent was obtained before obtaining or collecting the user's personal information.

[0023] Traditional testing solutions can achieve accurate testing of a single channel, but they lack the integration capability of automatic switching between multiple channels and programmable resistor output. They cannot adapt to the differentiated testing requirements of RTD channels with different index numbers, and test data needs to be recorded and compared manually, resulting in poor data traceability and long testing cycles.

[0024] As industrial production places increasing demands on the reliability of DCS systems, traditional manual testing methods are no longer sufficient to meet the needs for efficient and standardized system debugging and regular maintenance. There is an urgent need for an RTD channel testing device that can achieve automatic switching of multiple channels, precise programmable resistance control, and automatic data comparison to ensure the stable operation of the DCS temperature acquisition system.

[0025] Figure 1 The schematic diagram illustrates the structure of an automated testing apparatus for RTD channels in a DCS according to an embodiment of this application.

[0026] like Figure 1 As shown, the automated testing device for RTD channels in DCS includes: a programmable resistor module 101, a channel switching module 102, and a control module 103.

[0027] One end of the programmable resistor module 101 is connected to one end of each of the multiple RTD channels 104 of the DCS; the programmable resistor module 101 is used to provide the target resistance value corresponding to the resistance control command.

[0028] One end of the channel switching module 102 is connected to the other end of the programmable resistor module 101; the other end of the channel switching module 102 is connected to the other end of the multiple RTD channels 104 of the DCS.

[0029] The control module 103 is connected to the first control terminal of the programmable resistor module 101 and the second control terminal of the channel switching module 102 respectively. The control module 103 is used to output the resistance control command corresponding to each RTD channel according to the index table corresponding to each RTD channel, and to generate the channel switching command according to the detection order of the RTD channels, so that the programmable resistor module 101 is connected to the target RTD channel among the multiple RTD channels 104 of the DCS, thereby obtaining the test results of each RTD channel of the DCS according to the comparison result between the target temperature value corresponding to the target resistance value and the detection temperature value obtained by the DCS in detecting the target RTD channel.

[0030] In the embodiments of this application, the programmable resistor module can be a programmable resistor source. The programmable resistor source, as the core signal generation unit of the automated testing device for the RTD channel in a DCS, is used to simulate the precise resistance values ​​of the RTD sensor at different temperatures. The programmable resistor source employs a high-precision, low-temperature-drift digital-to-analog converter (DAC) and a precision resistor network, capable of generating standard resistance signals with an accuracy up to 0.01%, fully covering the entire temperature range (e.g., -200℃ to +850℃) of common RTDs such as Pt100 and Cu50. Its high output resolution and good stability are sufficient to meet the highest measurement accuracy requirements of the DCS system.

[0031] In the embodiments of this application, the control module is responsible for coordinating and controlling all hardware units, executing test logic, and processing data. The control module employs an industrial-grade microprocessor (MCU) or embedded system, running a real-time operating system (RTOS) to ensure the timeliness and reliability of control commands. Its internal memory stores the RTD indexing table, test process logic, and user-preset parameters. According to an embodiment of this application, one end of the channel switching module includes at least one common terminal; the other end of the channel switching module includes multiple select terminals; the common terminal is connected to one end of the programmable resistor module; and each select terminal is connected to the other end of the corresponding RTD channel.

[0032] In the embodiments of this application, the channel switching module can be a multi-channel high-speed switching unit; the multi-channel high-speed switching unit is responsible for automatically and accurately switching the standard signal generated by the programmable resistor source to the designated output channel. The multi-channel high-speed switching unit consists of a set of high-performance, low-thermal-electromotive force relays (or solid-state switches) forming a multi-select matrix switch. The common terminal is connected to the programmable resistor source, and its multi-channel selection terminals (such as 8 channels or 16 channels) are connected to the physical output interface of the DCS's RTD channel automated testing device. The relay selection is precisely controlled by the control module, with short switching time (millisecond level) and stable contact resistance, ensuring that no additional measurement errors are introduced.

[0033] For example, a channel switching module may include a multi-channel low thermal electromotive force (TEMF) solid-state relay, a drive control circuit, and a status feedback circuit. The drive control circuit may include an opto-isolation unit and a power amplifier unit; the control module is connected to the opto-isolation unit; the opto-isolation unit is connected to the power amplifier unit; the power amplifier unit is connected to the second control terminal of the multi-channel TEMF solid-state relay; the channel switching command from the control module is first converted into an isolated control signal by the opto-isolation unit, and then the drive capability is enhanced by the power amplifier unit to drive the selection pin (i.e., the second control terminal) of the multi-channel TEMF solid-state relay, realizing the on / off control of the corresponding channel. The status feedback circuit can be a voltage detection unit; a voltage detection unit is configured at the selection terminal of the multi-channel TEMF solid-state relay to collect the channel conduction status signal in real time and feed it back to the control module. When the specified channel is successfully turned on, the feedback circuit sends a high-level confirmation signal to the control module; if a conduction failure occurs, a low-level alarm signal is sent to ensure the accuracy and traceability of the switching action.

[0034] The automated test device for RTD channels in DCS also includes a power supply module; the power supply module is connected in series in a circuit consisting of a programmable resistor module, a channel switching module, and a control module.

[0035] In the embodiments of this application, the power module can provide a clean and stable operating power supply for the entire device. The power module adopts a wide input range, isolated switching power supply, which has good anti-interference capability and voltage stability, ensuring that the internal circuits can still operate normally in complex industrial electromagnetic environments.

[0036] According to an embodiment of this application, the automated testing device for RTD channels in a DCS further includes an interaction module; the interaction module is connected to both the control module and the DCS; the interaction module is used to display the detected resistance value and the target resistance value, and is also used to input test parameters; the test parameters include at least one of the following: multiple RTD channels to be tested, multiple target temperature values ​​for each RTD channel to be tested, the test duration for each target temperature value, and an interval time; wherein, the interval time is the time interval between the moment when switching the RTD channel to be tested and the moment when the detection of the RTD channel to be tested after the switching begins.

[0037] In the embodiments of this application, the interaction module is a human-machine interface (HMI); the HMI provides users with an intuitive operation and status monitoring window. The HMI can be a color touchscreen (HMI) that supports graphical operation. Users can easily set channel configurations, test sequences, timing parameters, start / stop control, and status displays through this color touchscreen. Channel configuration involves selecting the range of channels to be tested, such as CH1-CH8. Test sequences involve setting n temperature test points for all channels or a single channel, such as [0, 50, 100, 150], in °C. Timing parameters involve setting the output settling time (T_hold) for each resistance value and the settling interval time after channel switching (T_switch). Start / stop control is a one-click start of a fully automatic test process. Status display shows the currently tested channel, simulated temperature values, progress bars, and other information in real time.

[0038] According to an embodiment of this application, the automated testing device for the RTD channel of a DCS further includes a communication interface module; the control module is connected to a host computer through the communication interface module; the DCS is connected to the host computer through the communication interface module; the host computer is used to receive the detected temperature value and the target temperature value, and to send test parameters to the control module.

[0039] In the embodiments of this application, the communication interface module enables data interaction between the device and an external environment (such as an engineering station host computer), supporting remote control and automated data acquisition. The communication interface module supports multiple industry-standard communication protocols, such as Modbus RTU / TCP, PROFINET, Ethernet / IP, or general TCP / IP. The host computer software can remotely issue test tasks, monitor the test process in real time, and automatically collect test result data from all channels through this communication interface module, directly generating calibration reports, truly achieving automation and unmanned operation.

[0040] Figure 2 A flowchart illustrating an automated testing method for RTD channels in a DCS according to an embodiment of this application is shown.

[0041] like Figure 2 As shown, the method includes operations S201~S202.

[0042] When operating S201, according to the indexing table corresponding to each of the multiple RTD channels of the DCS, the resistor control command corresponding to each RTD channel is output, so that the programmable resistor module connected to each RTD channel provides the target resistance value corresponding to the resistor control command, thereby realizing the simulation of the target temperature corresponding to the target resistance value.

[0043] According to an embodiment of this application, based on the calibration table corresponding to each of the multiple RTD channels of the DCS, a resistance control command corresponding to each RTD channel is output, including: obtaining a target resistance value corresponding to each target temperature value based on multiple target temperature values ​​of each RTD channel and the corresponding calibration table; generating a resistance control command based on the target resistance value, so that the programmable resistor module provides a target resistance value corresponding to the resistance control command.

[0044] Furthermore, a resistance control instruction is generated based on the target resistance value, including: generating a resistance control instruction corresponding to each target temperature value based on the test sequence of multiple target temperature values ​​of each RTD channel and the test duration of each target temperature value.

[0045] In operation S202, a channel switching command is generated according to the detection sequence of multiple RTD channels of the DCS, so that the programmable resistor module is connected to the target RTD channel, so that the DCS can detect the target RTD channel and obtain the detection temperature value. Then, the test results of each RTD channel of the DCS are obtained based on the comparison between the target temperature value and the detection temperature value.

[0046] In the embodiments of this application, for an RTD channel, if the differences between multiple target temperature values ​​and their corresponding detection temperature values ​​are all within the preset deviation range corresponding to the RTD channel, the test result of the RTD channel is qualified; if the differences between multiple target temperature values ​​and their corresponding detection temperature values ​​are not within the preset deviation range, the test result of the RTD channel is unqualified.

[0047] For example, the programmable resistor module outputs target resistances of 100Ω, 119.4Ω, and 138.5Ω sequentially, corresponding to target temperature values ​​of 0℃, 50℃, and 100℃ respectively. The DCS acquires the detection temperature values ​​of this RTD channel as 0℃, 50.5℃, and 99.5℃ sequentially, with differences of 0, +0.5, and -0.5 respectively. If the preset deviation range corresponding to the RTD channel is less than or equal to ±0.5, then the test result of this RTD channel is qualified. If the DCS acquires the detection temperature values ​​of this RTD channel as 0℃, 51℃, and 99.5℃ sequentially, with differences of 0, +1, and -0.5 respectively, the presence of +1 means that the difference does not meet the requirement of all differences being less than or equal to ±0.5; therefore, the test result of this RTD channel is unqualified. However, if the preset deviation range corresponding to the RTD channel is less than or equal to ±1, then the test result of this RTD channel is qualified. For example, the RTD channel can be a PT1000 channel or a Cu50 channel. When the RTD channel is a PT1000 channel, the preset deviation range corresponding to the PT1000 channel can be less than or equal to ±0.5. When the RTD channel is a Cu50 channel, the preset deviation range corresponding to the Cu50 channel can be less than or equal to ±1.

[0048] According to an embodiment of this application, a channel switching instruction is generated based on the detection order of multiple RTD channels of the DCS, including: determining the detection duration of each RTD channel based on the test duration and interval of each target temperature value; and generating a channel switching instruction based on the detection order and detection duration.

[0049] According to an embodiment of this application, after obtaining the test results, the automated testing method for the RTD channel of DCS further includes: generating a calibration report that calibrates the detected temperature value based on the target temperature value.

[0050] The following example uses multiple RTD channels of a DCS, CH1 to CH8. Multiple target temperature values ​​are represented by an array containing n temperature values. For example, n is 4, and the array T_sequence=[0,50,100,150], unit: °C. The test duration for each target temperature value is set to T_hold, such as 10 seconds; the interval T_switch between completing one channel and switching to the next is set, such as 2 seconds.

[0051] The multiple RTD output interfaces (CH1-CHn) of the DCS RTD channel automated testing device, i.e., the multiple selection terminals of the channel switching module, are directly connected in parallel to the terminals of the DCS cabinet RTD input module or the corresponding terminals of the field junction box via dedicated test cables. The RTD input module consists of multiple RTD channels. This connection method is non-intrusive and requires no disassembly of any existing wiring in the DCS system, fundamentally ensuring safety.

[0052] After the tester starts the automated testing device for the RTD channel of the DCS, the device enters fully automatic operation mode and performs the following operations without any manual intervention: Step 1: Initialization and Self-Test. The automated test device for the RTD channel of the DCS performs a power-on self-test to check whether the status of each module is normal.

[0053] Step 2: Channel Selection. The control module controls the multi-channel high-speed switching unit to select the first channel in the detection sequence, such as CH1, according to the detection order.

[0054] Third, the control module queries the RTD index table inside CH1 according to the preset T_sequence[0] (i.e., the first target temperature value), calculates the corresponding standard resistance value R_std, and uses the standard resistance value R_std as the target resistance value. The control module sends a resistance control command to the high-precision programmable resistor source, causing the high-precision programmable resistor source to accurately output the standard resistance value R_std. This standard resistance value is connected to the corresponding RTD channel of the DCS system, i.e., the target RTD channel, through the selected CH1 channel. The control module starts a timer to maintain the output time T_hold. During this period, the DCS system reads and displays the signal of the detected temperature value collected by the target RTD channel.

[0055] The fourth step is data recording. During the T_hold time, the personnel in the DCS control room record the values ​​displayed on the DCS screen, or the software installed on the host computer automatically collects and records the detected temperature value through the communication interface module.

[0056] Step 5, Sequence Iteration. When the T_hold time is up, the control module automatically controls the programmable resistor source to output the target resistance value corresponding to the next target temperature value T_sequence[1], and repeats steps 3 to 4 until all n target temperature values ​​of channel CH1 are tested.

[0057] Step 6, Channel Switching. After all target temperature values ​​for a channel have been tested, the control module controls the multi-channel high-speed switching unit to disconnect the current CH1 channel, wait for the T_switch time, and then select the next RTD channel, such as the CH2 channel.

[0058] Step 7, Loop Testing. Repeat steps 3 through 6 for channel CH2 until all RTD channels (CH1 to CH8) that need to be tested have been tested.

[0059] Step 8: Termination and Report Generation. After all required RTD channels have been tested, the automated RTD channel testing device for DCS automatically returns to its original position, stops outputting, and displays a "Test Complete" message on the HMI. The automated RTD channel testing device for DCS can upload logs and recorded data of the entire testing process for all required RTD channels to the host computer via the communication interface module. The host computer software automatically calculates errors, generates a standard test report conforming to calibration specifications, and stores or prints it.

[0060] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. An automated testing device for RTD channels in DCS, characterized in that, The device includes: a programmable resistor module, a channel switching module, and a control module; One end of the programmable resistor module is connected to one end of each of the multiple RTD channels of the DCS; the programmable resistor module is used to provide the target resistance value corresponding to the resistance control command. One end of the channel switching module is connected to the other end of the programmable resistor module; the other end of the channel switching module is connected to the other end of multiple RTD channels of the DCS. The control module is connected to the first control terminal of the programmable resistor module and the second control terminal of the channel switching module, respectively. The control module is used to output the resistor control command corresponding to each RTD channel according to the index table corresponding to each RTD channel, and to generate the channel switching command according to the detection order of the RTD channels, so that the programmable resistor module is connected to the target RTD channel among the multiple RTD channels of the DCS, thereby obtaining the test result of each RTD channel of the DCS according to the comparison result between the target temperature value corresponding to the target resistance value and the detection temperature value obtained by the DCS from detecting the target RTD channel.

2. The automated testing device for RTD channels in DCS according to claim 1, characterized in that, One end of the channel switching module includes at least one common terminal; the other end of the channel switching module includes multiple selection terminals. The common terminal is connected to one end of the programmable resistor module; each of the selected terminals is connected to the other end of the corresponding RTD channel.

3. The automated testing device for RTD channels in DCS according to claim 1, characterized in that, The device also includes a power module; The power module is connected in series in a circuit consisting of the programmable resistor module, the channel switching module, and the control module.

4. The automated testing device for RTD channels in DCS according to claim 1, characterized in that, The device also includes an interaction module; The interaction module is connected to both the control module and the DCS. The interaction module is used to display the detected resistance value and the target resistance value, and also to input test parameters. The test parameters include at least one of the following: multiple RTD channels to be tested, multiple target temperature values ​​for each RTD channel to be tested, the test duration for each target temperature value, and an interval time. The interval time is the time interval between the moment when the RTD channel to be tested is switched and the moment when the detection of the switched RTD channel begins.

5. The automated testing device for RTD channels in DCS according to claim 1, characterized in that, The device also includes a communication interface module; The control module is connected to the host computer through the communication interface module; The DCS is connected to the host computer through the communication interface module; The host computer is used to receive the detected temperature value and the target temperature value, and send test parameters to the control module; the test parameters include at least one of the following: multiple RTD channels to be tested, multiple target temperature values ​​for each RTD channel to be tested, test duration for each target temperature value, and interval time; wherein, the interval time is the time interval between the time corresponding to the switching of the RTD channel to be tested and the time corresponding to the RTD channel to be tested after the start of detection switching.

6. An automated testing method for RTD channels in DCS, characterized in that, The method includes: According to the indexing table corresponding to each of the multiple RTD channels of the DCS, the resistance control command corresponding to each RTD channel is output, so that the programmable resistor module connected to each RTD channel provides the target resistance value corresponding to the resistance control command, thereby realizing the simulation of the target temperature corresponding to the target resistance value. Based on the detection sequence of multiple RTD channels of the DCS, a channel switching command is generated to connect the programmable resistor module to the target RTD channel, so that the DCS detects the target RTD channel to obtain the detection temperature value, and then obtains the test results of each RTD channel of the DCS based on the comparison result between the target temperature value and the detection temperature value.

7. The automated testing method for RTD channels in DCS according to claim 6, characterized in that, The step of outputting resistance control commands corresponding to each of the multiple RTD channels according to the indexing table of each RTD channel in the DCS includes: Based on the multiple target temperature values ​​of each RTD channel and the corresponding calibration table, the target resistance value corresponding to each target temperature value is obtained; A resistance control command is generated based on the target resistance value, so that the programmable resistor module provides a target resistance value corresponding to the resistance control command.

8. The automated testing method for RTD channels in DCS according to claim 6, characterized in that, The step of generating channel switching instructions based on the detection order of multiple RTD channels of the DCS includes: The detection duration of each RTD channel is determined based on the test duration and interval of each target temperature value. A channel switching instruction is generated based on the detection sequence and the detection duration.

9. The automated testing method for RTD channels in DCS according to claim 7, characterized in that, The step of generating resistance control commands based on the target resistance value includes: Based on the test sequence of multiple target temperature values ​​of each RTD channel and the test duration of each target temperature value, a resistance control command corresponding to each target temperature value is generated.

10. The automated testing method for RTD channels in DCS according to claim 6, characterized in that, After obtaining the test results, the method further includes: Generate a calibration report that calibrates the detected temperature value based on the target temperature value.

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