DCS power off correctly

When the DCS needs to be powered off for maintenance due to overhaul or other reasons, we often directly power off the DCS, but sometimes this non-standard operation will bring serious consequences, such as configuration loss, PID parameter loss, etc. Therefore, it is necessary to strictly check the important parameters before and after power failure and power on again, and operate carefully and normatively.

Step 1: Carry out various inspections before power-off. 1. Open the cabinet door of the control station and observe whether the card works normally and whether there is any fault display; 2. Observe whether there is a fault from the fault diagnosis monitored in real time by each operation station and record it; 3. Check whether the power box works normally, whether the power fan works, whether the 5V and 24V indicators are normal, and measure and record the voltage values; 4. Backup configuration, PID parameters, drive and other important data required; 5. Check the power supply redundancy, which includes AC power supply redundancy and DC power supply redundancy. AC power supply redundancy: by disconnecting one circuit of redundant AC~220VAC incoming line respectively, half of the AC power supply circuits of the system lose power, but the system should still work normally. The DC power supply redundancy test method is as follows: (1) First cut off the power supply of one power box, and measure the voltage of 5V and 24V on the power terminal of each cage and cage motherboard; (2) First connect one power box, then disconnect the other power box, and then measure the voltage of 5V and 24V on the power terminal of each cage motherboard. The 5V output voltage of the power box shall be 5.10V ～ 5.25V, and the 24V output voltage of the power box shall be 23.00V ～ 25.00V. If the voltage deviation is large, it needs to be checked and handled in time, otherwise it will affect the normal operation of the card. 6. Check the network cable and layout, check the connection and disconnection of the network cable, confirm whether the connection is in good contact, and replace the faulty cable in time; 7. UPS test: test the power supply capacity of UPS battery by disconnecting the AC incoming line of UPS. The UPS battery should be discharged regularly, generally once a month. Discharge method: disconnect the UPS AC power supply and use battery power until the battery is about to be released.

The above inspections are mainly to know the operation status of the system in advance, and if there is any abnormal phenomenon, it can be solved in time when parking.

Step 2: cut off the power supply in sequence 1. After each operation station exits the real-time monitoring and operating system in turn, turn off the power supply of the industrial personal computer and display of the operation station; 2. Turn off the power supply of control station power box one by one; 3. Turn off all branch power switches; 4. Turn off the UPS power switch; 5. Turn off the main power switch.

DCS power failure maintenance

Step 3: DCS power failure maintenance 1. Operation station and control station power failure purging maintenance. Including dust removal of components inside the IPC, control station cage, power box, etc; 2. Maintain the faults detected before power failure; 3. Maintenance of system power supply line. Including distribution box, terminal strip, relay, safety barrier, etc. Ensure that all components work normally and lines are connected reliably; 4. Maintenance of grounding system. Including terminal inspection, grounding inspection of each operation station (IPC, display), grounding inspection of each control station (power supply, cage), and grounding resistance test; 5. Check the connecting lines and connection points of communication lines to ensure that all components work normally and the lines are connected reliably. Mark the double network cable.

DCS is powered on correctly

Step 4: After all maintenance work on site and DCS is completed, check and confirm whether the conditions for power on are met. The person in charge of system maintenance can only power on after confirming that the conditions are met. The overall power on of the system shall be carried out according to the following steps: 1. First close the main circuit breaker of the distribution box and check whether the output voltage is 220V ± 10%; 2. Close all branch circuit breakers in the distribution box and check the output voltage respectively; 3. If the UPS or regulated power supply is equipped, please check whether the output voltage of the UPS or regulated power supply is normal. If it is abnormal, find out the reason. After recovery, continue the following steps of power on and operation of the control station. Step 5: the control station is powered on, and the DCS power supply is powered on in turn Step 6: the operation station is powered on, and the display, industrial personal computer and other equipment of the operation station are powered on Step 7: DCS is put into operation again to check 1. Open the cabinet door of the control station, and observe whether the card works normally and whether there is any fault display; 2. Observe whether there is any fault from the fault diagnosis monitored in real time by each operation station, mainly including card fault and communication fault prompt; 3. Whether the power box works normally, whether the power fan works, whether the 5V and 24V indicators are normal, and whether the measured power supply voltage is normal; 4. Check the network communication, configuration operation and PID parameters of each layer.