Hollysys DCS – the steps for DCS to properly power off and power on

DCS is properly blacked out

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 the power failure and re-powering, and operate carefully and standardly.

Step 1: Carry out various checks before the power is off

1. Open the cabinet door of the control station and observe whether the card is working properly and whether there is a fault display;

2. Observe whether there is a fault from the fault diagnosis of real-time monitoring of each operation station, and record it;

3. Check whether the power box is working normally, whether the power supply fan is working, whether the 5V and 24V indicators are normal, and measure and record the voltage values;

4. Back up configuration, PID parameters, drivers and other important data required;

5. Check the power supply redundancy, which includes AC power supply redundancy and DC power supply redundancy. AC power redundancy: By disconnecting the redundant AC - 220VAC incoming line separately, half of the AC power supply loop of the system loses power, but the system should still work normally. The DC power supply redundancy test method is as follows: (1) Break the power supply of one power box first, and measure the voltage of 5V and 24V on the power terminal of each cage motherboard; (2) First turn on the power supply of the last power box, then disconnect the power supply of 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 should be between 5.10V and 5.25V, and the output voltage of the 24V power box should be between 23.00V and 25.00V. If the voltage deviation is large, it needs to be checked and processed in time, otherwise it will affect the normal operation of the card.

6. Check the network cable and layout, check the on-off of the network cable, confirm whether the connection is in good contact, and replace the faulty cable in time; 7. UPS test: test the UPS battery power supply capacity by disconnecting the UPS AC incoming line. The UPS battery should be discharged regularly, it is generally recommended to discharge once a month, discharge method: disconnect the UPS AC power supply and use battery power supply until the battery is about to be released.

The above inspection is mainly to understand the operating status of the system in advance, and if there is any abnormal phenomenon, it can be solved in time when stopping.

Step 2: Cut off the power supply in order

1. After each operation station exits the real-time monitoring and operating system in turn, turn off the power supply of the industrial computer and display of the operation station;

2. Turn off the power supply of the power box of the control station one by one;

3. Turn off the power switch of each branch;

4. Turn off the power switch of uninterruptible power supply (UPS);

5. Turn off the main power switch.

DCS outage repairs

Step 3: Carry out DCS power outage maintenance

1. The operation station and control station are purged and overhauled in a power failure. Including dust cleaning inside the industrial computer, control station cage, power box and other components;

2. Maintain the faults detected before the power failure;

3. Overhaul of system power supply lines. Including distribution boxes, terminal strips, relays, safety barriers, etc. Ensure that all components work properly and the lines are reliably connected;

4. Grounding system overhaul. Including terminal inspection, grounding inspection of each operation station (industrial computer, display), grounding inspection of each control station (power supply, cage), and ground resistance test;

5. Check the connection lines and connection points of communication lines to ensure that all components work normally and the lines are connected reliably. Mark the dual network cables.

The DCS is powered on correctly

Step 4: After the on-site and DCS maintenance work is completed, check whether the re-power-on conditions are met. The person in charge of system maintenance can only power on after confirming that the conditions are met, and the overall power-on of the system is carried out according to the following steps:

1. First of all, close the main circuit breaker of the distribution box and check whether the output voltage meets the 220V±10%;

2. Close the circuit breakers of each branch in the distribution box and check the output voltage respectively;

3. If it is equipped with UPS or stabilized power supply, please check whether the output voltage of UPS or stabilized power supply is normal, find the cause if it is abnormal, and continue the following steps of powering on the control station and operating the station after recovery.

Step 5: The control station is powered on, and the DCS power supply is powered on sequentially

Step 6: The operation station is powered on, and the display, industrial computer and other equipment of the operation station are powered on

Step 7: Conduct a DCS re-commissioning inspection

1. Open the cabinet door of the control station and observe whether the card is working properly and whether there is a fault display;

2. Observe whether there is a fault from the fault diagnosis of real-time monitoring of each operation station, mainly including card failure and communication fault prompt;

3. Whether the power box is working normally, whether the power supply fan is working, whether the 5V and 24V indicators are normal, and whether the power supply voltage is measured is normal;

4. Check the network communication, configuration operation, PID parameters, etc. of each layer.

Hollysys DCS – the steps for DCS to properly power off and power on

Hollysys DCS – the steps for DCS to properly power off and power on

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