Hollysys DCS - How to deal with DCS system failure?

1. View the data on the monitoring screen

When the following situations occur, it means that there is a problem with the control system, and the microcomputer maintenance personnel should be notified immediately for maintenance, and the operator should go to the site to deal with it.

(1) Frequently changing data does not change for a long time, and a few or all data do not change.

(2) In the control group screen, it cannot be switched manually and automatically, or after manually entering data, once confirmed, it will be restored to the original data and cannot be modified.

(3) In the trend chart screen, several trends are in a straight line.

(4) In the monitoring screen, multiple data fluctuates greatly at the same time.

Judge whether the fluctuation data is the relevant parameters in the process, if it is the relevant parameters, notify the instrument and microcomputer personnel to check to see whether the fluctuation of a certain adjustment system causes the change of relevant parameters, and at the same time hit the relevant adjustment system to the manual state, and if necessary, go to the site for adjustment. For example, in the full circulation device of aqueous solution, the pressure of urea synthesis tower is l9.67MPa when it is normal, if it suddenly fluctuates in a large range, it will inevitably cause pressure fluctuations in the downstream medium pressure system and low pressure system, which is due to the fluctuation of one parameter in several related parameters and the change of other parameters, not the failure of the control system itself.

If the fluctuating data process has no direct impact on each other, it may be the failure of a card of the microcomputer, and the relevant self-adjustment system will be immediately adjusted manually, and if necessary, the on-site adjustment will be carried out, and at the same time, the microcomputer and instrument personnel will be notified to check.

2. Check the working condition of the operation station

When you find that an operation station is dead, the monitoring screen data is not refreshed, and the adjustment screen does not work, check whether the system alarm indicator light in the upper right is normal, and check whether other operation stations are working normally, if it is normal, only the operation station has a problem, notify the microcomputer maintenance personnel to repair. If the data of other operating stations also remains unchanged, the system communication network is faulty, and the maintenance personnel will be notified immediately to check the operation of the network equipment and repair it.

3. Observe the power failure of the operation station

If some of the operation stations are suddenly not displayed, it means that the UPS or the mains power is cut off, and the microcomputer maintenance worker is immediately notified for maintenance. If there is electricity, the operation station can be monitored normally, and the normal adjustment of the control system will not be affected at this time.

4. Pay attention to the situation that all the control stations are powered off

Since all control station equipment is dual-powered, one UPS and one mains, the chances of this happening are very small.

When the control station is powered off, the two systems on the monitoring screen alarm red light on, the communication is interrupted, the data is not refreshed, all the self-adjusting systems are completely out of control, the regulating valve will be restored to the initial state, the gas opening valve is fully closed, and the gas closing valve is fully open. At this time, it should be immediately treated or stopped, and at the same time go to the scene for operation.

5. Pay attention to the situation that all operating stations are powered off

At this time, check whether the power indicator of the control station is normal, whether the card diagnostic indicator has a faulty red light, and the green light indicates that the card is working normally, if the above are normal, you can determine that the control station is working normally, and the self-adjusting system is working normally, but the operator can not see the monitoring screen temporarily, and can not carry out remote control operation on the site, immediately notify the microcomputer maintenance personnel for maintenance, and go to the scene for monitoring.

6. The pressure of the air source of the regulating valve instrument is low or the air of the instrument is completely cut off

When it is found that a plurality of self-adjusting systems are out of order, and the valve position of the self-adjusting valve on the monitoring screen is in the fully open or fully closed position, immediately check the air source pressure of the instrument, if the air source pressure is less than 0.4MPa, it is abnormal, and check whether the air source pipeline is blocked or leaking; If the pressure of the air source is less than 0.2MPa, the emergency stop will be carried out immediately. The self-adjusting system on the monitoring screen is all manual, the valve position of the regulating valve is adjusted to a safe position, the instrument worker is notified to check the air source, and at the same time the on-site operation is carried out, the stop valves at both ends of the regulating valve are closed, and the bypass valve is operated.

Conclusions

When DCS fails, operators should master certain identification methods, detect problems early, and deal with them appropriately, which can avoid or reduce the impact on process control.

Hollysys DCS - How to deal with DCS system failure?

Hollysys DCS - How to deal with DCS system failure?

Sections viewed

Contact

working hours