DCS data changes
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The day before yesterday, there were abnormalities in the custom control loops of Zhejiang Zhongkong ECS100-DCS, but the cause was unknown: 1. The four addresses where abnormalities occurred were all located in the first four channels of the AI cards; 2. Based on the trend, it was the MV values that changed first, with the PV values changing subsequently; 3. The AO outputs of the relevant loops were distributed across different AO cards in various chassis; 4. The MV values changed over a period of about 5 seconds, with some cases showing an inverted triangle pattern and others a regular triangle pattern. 5. It appeared for the first time, and the duration was short. Can anyone help analyze it?
You need to analyze and investigate this phenomenon based on the actual conditions. I encountered a similar situation once in my air separation plant: a temporary cable was used to test the oxygen pump motor, and since this temporary cable was located quite close to the cable tray, starting the motor caused fluctuations in the measurement values from the AI sensor connected to the expansion machine, which almost led to an emergency shutdown. Now we are all requiring the electrical department to take the motor back to the maintenance workshop for repair, in order to prevent similar situations from occurring again.