DCS system controller switching stability test method and device

Abstract

The invention discloses a DCS system controller switching stability test method and device. Continuous pulse signals are provided for DI by opening / closing contacts of a switching signal generator, DI signals are directly transmitted to DO in a control system, controller switching is simulated in the receiving and transmitting process of the control system, and after switching is completed, DO output waveforms are checked; if the DO waveform can keep a complete continuous pulse waveform, the switching process of the controller is not disturbed, namely, the switching stability of the controller is higher; if the DO waveform is delayed for a plurality of cycles, the larger the number of the delayed cycles is, the larger the disturbance in the switching process of the controller is, namely the worse the switching stability of the controller is. The stability of the system when the controller is switched is judged from the perspective of data, the judgment is accurate and reasonable, and the test method is simple, convenient and feasible.

Description

Technical Field

[0001] The invention belongs to the technical field of DCS system controllers, in particular to a DCS system controller switching stability testing method and device. Background Art

[0002] The DCS system is the main control system widely used in power generation, petrochemical and other enterprises. The quality of its performance directly affects the stability of the control system operation and the accuracy of control. Therefore, it is necessary to test the control performance of newly built or DCS systems that have been in operation for a period of time to ensure that all performances meet the standards for commissioning. The stability test of controller switching is an important part of this.

[0003] The DCS system is generally composed of multiple pairs of controllers and their I / O cards. The I / O card obtains the data on site and sends the data processed by the controller to the on-site equipment; the controller performs operation and processing according to the pre-configured logical sequence, generally including three parts: data input (including switch quantity DI and analog quantity AI), data processing and data output (including switch quantity DO and analog quantity AO).

[0004] The DCS system has very high requirements for the stability of system operation. Its controllers are usually redundantly configured. When the main operating controller fails, it can automatically switch to the hot standby controller to ensure the stable operation of the DCS system. During the switching process of the redundantly configured controllers of the DCS system, it is possible to cause certain disturbances to the system, which will have a certain impact on the stable operation of the system.

[0005] When conducting a switching stability test on a controller, it is generally conducted by simulating a main operating controller failure, and the following methods are available: turning off the power of the main controller, pressing the switch button of the main controller, or unplugging the communication network cable of the main controller. When conducting a simulated switching test on a controller, the conventional method is to observe the controller operation status indicator on site to determine whether the controller switching is successful, or to select several signals and observe the trend graphs of these signals to determine whether the controller switching process has an impact on these signals. In short, conventional test methods are based on naked eye observation.

[0006] The switching of the controller is completed in an instant, and the switching time is generally between a few milliseconds and tens of milliseconds. In such a short time, even if the switching causes the signal to change, it is generally difficult to detect with the naked eye. Therefore, conventional testing methods have great limitations.

[0007] In addition, the controller switching time can also be used as a reference for switching stability. The shorter the switching time, the smaller the impact of the switching on the system. In this regard, the Technical Guidelines for Reliability Assessment of Thermal Automation Systems in Thermal Power Plants (DL / T 261-2012) also clearly stipulates the controller switching time, but in practice, due to the lack of a suitable test method, the controller switching time test has not been implemented so far.

[0008] At present, the publicly available controller switching stability test method usually uses a periodic signal with a fixed number of pulses as the signal source, sets a counting module in the controller, and determines the stability of the controller switching by calculating the difference between the count value and the number of pulses of the signal source. This method has two limitations: First, since the number of pulses of the signal source cannot be set too large (setting it too large will cause other interference items to take effect, such as when the processing cycle is consistent with the DI pulse width, it will occasionally cause data collection disorder under critical conditions), when the pulse width is very small, the time left for simulating controller failure is very short, which will inevitably cause a rush and affect the test accuracy. Second, the test logic requires counting and clearing modules, which increases the complexity of the processing, which in turn affects the accuracy of the test. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a DCS system controller switching stability testing method and device, which determines the stability of the DCS system when the controller switches by detecting the degree of disturbance to the DCS system when the controller switches.

[0010] To this end, the present invention adopts the following technical solution: a DCS system controller switching stability testing method, which includes:

[0011] Step 1), select the controller, DI / DO card and its channel used for the test, connect the output end of the switch signal generator to the configured DI card channel; use a recorder or oscilloscope to view the DO output, configure a test logic in the controller, and transmit the DI signal directly to the output channel of the DO card;

[0012] Step 2), configure the switch signal generator and adopt the continuous transmission mode;

[0013] Step 3), start the switch signal generator and start sending signals according to the configuration requirements;

[0014] Step 4), simulate controller failure and complete controller switching;

[0015] Step 5), after the controller switching is completed, check the DO output waveform, check the 0 / 1 jump delay, and convert the delay time t into the controller processing cycle number n, n=t / T, T is the controller processing cycle.

[0016] The present invention utilizes the open / closed contacts of the switch signal generator to provide a continuously output pulse periodic signal, configures a test logic in the controller, assigns DI directly to DO, simulates controller switching during the signal sending process, checks the 0 / 1 jump delay of the DO output waveform after the switching is completed, and converts the delay time t into the number of processing cycles n of the controller. The smaller n is, the smaller the disturbance caused by the controller switching is, that is, the higher the switching stability of the controller is.

[0017] Furthermore, in step 1), the switch signal generator provides an open / closed contact signal, which becomes a 0 / 1 pulse signal after being read by the DI card.

[0018] Furthermore, in step 2), the duty cycle of the pulse output by the switch signal generator is 50%, and the pulse width is the same as the processing period T of the controller.

[0019] Furthermore, in step 4), the controller failure is simulated by turning off the power of the main controller, pressing a switch button of the main controller, or unplugging the communication network cable of the main controller.

[0020] Furthermore, the DCS system controller switching stability test method further includes step 6): repeating steps 3)-5) multiple times in sequence, taking the average value of all n as N, where N is the disturbance caused by the controller switching, reflecting the magnitude of the disturbance. By taking the average value of multiple tests, the accuracy of the stability judgment is further improved.

[0021] The present invention adopts another technical solution as follows: a DCS system controller switching stability testing device, which includes:

[0022] Test preparation unit: Select the controller, DI / DO card and its channels used for the test, connect the output of the switch signal generator to the configured DI card channel; use a recorder or oscilloscope to view the DO output, configure a test logic in the controller, and transmit the DI signal directly to the output channel of the DO card;

[0023] Test configuration unit: configure the switch signal generator and adopt the continuous sending mode;

[0024] Signal sending unit: Start the switch signal generator and start sending signals according to the configuration requirements;

[0025] Controller switching unit: simulates controller failure and completes controller switching;

[0026] Data reading and calculation unit: After the controller is switched, check the DO output waveform, check the 0 / 1 transition delay, and convert the delay time t into the controller processing cycle number n, n = t / T, T is the controller processing cycle.

[0027] The beneficial effects of the present invention are as follows: the present invention judges the stability of the system when the controller switches from the perspective of data, and the judgment is reasonable; the constructed test logic is simple, and only the DI signal needs to be directly assigned to the DO channel, and there is no need to process complex counting and clearing modules, nor is there any need to build trend screens (observing signal fluctuations with the naked eye often requires building some signal trend screens), and the test method is simple and easy with high accuracy; the present invention obtains the test result by comparing the DO waveform with the signal source waveform and converting it into the number of processing cycles, so it has quantitative characteristics and is highly persuasive. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A flow chart of a DCS system controller switching stability testing method according to the present invention;

[0030] Figure 2 This is a schematic diagram of a DCS system controller switching stability test device according to the present invention;

[0031] Figure 3 This is a comparison diagram between the undisturbed DO waveform and the actual DO waveform in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment is a DCS system controller switching stability test method. Figure 1 As shown, the steps are as follows:

[0035] Step 1), select the controller, DI / DO card and its channel used for the test, connect the output of the switch signal generator to the DI channel; use a recorder or oscilloscope to view the DO output, configure a test logic in the controller, and directly transmit the DI signal to the output channel of the DO card;

[0036] Step 2), assuming that the controller processing cycle is 100ms, configure the switch signal generator to output a pulse with a pulse width of 100ms and a duty cycle of 50%, and adopt a continuous transmission mode;

[0037] Step 3), start the switch signal generator and send the signal according to the configuration requirements;

[0038] Step 4), simulate controller failure and complete controller switching;

[0039] Step 5), after the controller switches, check the DO output waveform, check the 0 / 1 jump delay, and convert the delay time t into the number of controller processing cycles n (n = t / T). Figure 3 The waveform shown, t = 300ms, n = 300 / 100 = 3;

[0040] Step 6), repeat the test from step 3) to step 4) for 3 times, and obtain n=3, n=1, n=2 respectively. The average value of n in the 4 tests is 2, that is, N is 2. In this embodiment, it can be considered that the disturbance caused by the controller switching is 2.

[0041] The present invention uses the switch signal generator to open / close the contact to provide a continuous pulse signal to DI, and the control system transmits the DI signal directly to DO. The controller switching is simulated during the control system's transceiver process. After the switching is completed, the DO output waveform 0 / 1 jump delay is checked, and the delay time t is converted into the number of controller processing cycles n. The smaller the N value, the smaller the disturbance of the controller switching process, that is, the higher the controller switching stability.

[0042] Specifically, in step 1), the switch signal generator provides an open / closed contact signal, which becomes a 0 / 1 pulse signal after being read by the DI card.

[0043] Specifically, in step 4), the simulation method is any one of turning off the power of the main controller, pressing the switch button of the main controller, or unplugging the communication network cable of the main controller.

[0044] Example 2

[0045] This embodiment is a DCS system controller switching stability test device. Figure 2 As shown, it consists of a test preparation unit, a test configuration unit, a signal sending unit, a controller switching unit, a data reading and calculation unit and an average value calculation unit.

[0046] The test preparation unit: selects the controller, DI / DO card and its channels used for the test, connects the output of the switch signal generator to the DI channel; uses a recorder or oscilloscope to view the DO output, configures a test logic in the controller, and directly transmits the DI signal to the output channel of the DO card;

[0047] The test configuration unit: sets the switch signal generator so that the output pulse duty cycle is 50%, the pulse width is the same as the controller processing cycle T, and the output mode is continuous output;

[0048] The signal sending unit starts the switch signal generator and sends the signal according to the configuration requirements;

[0049] The controller switching unit: simulates a main operating controller failure and completes controller switching (the simulation method is to turn off the power of the main controller, press the switch button of the main controller, or unplug the communication network cable of the main controller);

[0050] The data reading and calculation unit: after the controller switching is completed, check the DO output waveform, check the 0 / 1 jump delay, and convert the delay time t into the number of processing cycles n of the controller (n=t / T);

[0051] The average value calculation unit repeats the test for multiple times and takes the average value of all n, namely N, which is the disturbance caused by the controller switching and reflects the magnitude of the disturbance.

[0052] Specifically, in the test preparation unit, the switch signal generator provides an open / closed contact signal, which becomes a 0 / 1 pulse signal after being read by the DI card.

[0053] Specifically, in the controller switching unit, the simulation method is any one of turning off the power of the main controller, pressing the switching button of the main controller, or unplugging the communication network cable of the main controller.

[0054] It is obvious that those skilled in the art can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art to the present invention based on the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A DCS system controller switching stability test method, characterized in that: include: Step 1), select the controller, DI / DO card and its channel used for the test, connect the output end of the switch signal generator to the configured DI card channel; use a recorder or oscilloscope to view the DO output, configure a test logic in the controller, and transmit the DI signal directly to the output channel of the DO card; Step 2), configure the switch signal generator and adopt the continuous transmission mode; Step 3), start the switch signal generator and start sending signals according to the configuration requirements; Step 4), simulate controller failure and complete controller switching; Step 5), after the controller switching is completed, check the DO output waveform, check the 0 / 1 jump delay, and convert the delay time t into the controller processing cycle number n, n=t / T, T is the controller processing cycle.

2. The DCS system controller switching stability testing method according to claim 1 is characterized in that: In step 1), the switch signal generator provides an open / closed contact signal, which becomes a 0 / 1 pulse signal after being read by the DI card.

3. The DCS system controller switching stability testing method according to claim 1 is characterized in that: In step 2), the duty cycle of the pulse output by the switch signal generator is 50%, and the pulse width is the same as the controller processing period T.

4. The DCS system controller switching stability testing method according to claim 1 is characterized in that: In step 4), the simulation method of the controller failure is any one of turning off the power of the main controller, pressing the switch button of the main controller, or unplugging the communication network cable of the main controller.

5. The DCS system controller switching stability testing method according to claim 1, characterized in that: The method also includes step 6): repeating steps 3) to 5) for multiple times, taking the average value of all n as N, where N is the disturbance caused by the controller switching, reflecting the magnitude of the disturbance.

6. A DCS system controller switching stability test device, characterized in that: include: Test preparation unit: Select the controller, DI / DO card and its channels used for the test, and connect the output of the switch signal generator to the configured DI card channel; Use a recorder or oscilloscope to check the DO output, configure a test logic in the controller, and transmit the DI signal directly to the output channel of the DO card; Test configuration unit: configure the switch signal generator and adopt the continuous sending mode; Signal sending unit: Start the switch signal generator and start sending signals according to the configuration requirements; Controller switching unit: simulates controller failure and completes controller switching; Data reading and calculation unit: After the controller is switched, check the DO output waveform, check the 0 / 1 transition delay, and convert the delay time t into the controller processing cycle number n, n = t / T, T is the controller processing cycle.

7. The DCS system controller switching stability testing device according to claim 6, characterized in that: In the test preparation unit, the switch signal generator provides an open / closed contact signal, which becomes a 0 / 1 pulse signal after being read by the DI card.

8. The DCS system controller switching stability testing device according to claim 6, characterized in that: In the test configuration unit, the pulse width T is the processing cycle of the controller, and the duty cycle is 50%.

9. The DCS system controller switching stability testing device according to claim 6, characterized in that: In the controller switching unit, the simulation method is any one of turning off the power of the main controller, pressing the switching button of the main controller, or unplugging the communication network cable of the main controller.

10. The DCS system controller switching stability testing device according to claim 6, characterized in that: It also includes an average value calculation unit: repeat the steps in the signal sending unit, the controller switching unit and the data reading and calculation unit for multiple times, and take the average value of all n as N, where N is the disturbance caused by the controller switching, reflecting the degree of the disturbance.

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