When it comes to DCS operation, many industrial control professionals are concerned about where to start learning and what issues to pay attention to in practical applications. In fact, DCS is a two-dimensional representation of on-site construction, so to truly learn it, one should start from the on-site experience and then associate it with the DCS operation interface.
First, one must have a solid theoretical foundation before one can effectively adjust or control the site by combining it with the DCS operation plan.
For example, when understanding a reaction, for different reactions, understand the effects of temperature, pressure, flow rate, component content, distribution, etc. on the reaction; for multiple control methods, distinguish between primary and secondary factors; understand the magnitude of the influence of each parameter on the reaction; and how to adjust them to the optimal level.
Experienced people say that the first step is to thoroughly read the DCS operation manual, because these are summaries of experience, and then you can gradually understand and digest them based on actual operation.
Today I'll briefly talk about how to operate a DCS system.
System software
All operations covered in this procedure are performed on the operator station. The system software consists of ADVANTROLPRO 2.50 and configuration files.
All system operations are performed using the Advantrol software.
Terms mentioned in this procedure
1) Note: This indicates that the things or operations involved may cause unpredictable and dangerous consequences.
2) Warning: Indicates that the things or operations involved may cause foreseeable system malfunctions.
3) Danger: This indicates that the things or operations involved will cause the system to shut down, or even damage the equipment and cause personal injury.
Operator's operational responsibilities
1) Monitor the operation of the DCS system to prevent potential dangers.
2) Intervene in system operation at any time to ensure safe and normal production.
3) Changes to system authorized operating parameters.
System anomaly handling
1) If the data on the DCS operation interface does not refresh (normally the data refreshes once per second), or if manual/automatic switching is not possible, contact the DCS maintenance personnel for maintenance and immediately go to the site to operate.
2) If a transmitter malfunctions, the automatic control process should be switched back to manual immediately.
3) If malfunctions occur in the valve actuator or circuit output, on-site operation should be adopted.
4) When a fault occurs in the input card of the DCS system loop, the corresponding control loop should be switched back to manual, the faulty card should be replaced, and automatic operation can only be resumed after the fault has been checked and confirmed to be eliminated.
5) If the DCS system experiences an abnormal power outage, on-site operation should be initiated. After power is restored, an engineer should check the system status, verify the circuit parameters and other system data to ensure they are normal, and confirm the opening of each regulating valve. If any abnormalities are found, the configuration should be re-downloaded, and automatic operation can only be resumed after everything is normal.
6) For other abnormal situations, please refer to the job operation procedures.
Alarm handling
When a process indicator triggers an alarm, an audible alert will be issued. The alarm information will be displayed in the alarm information bar and alarm overview screen. After understanding the alarm situation, use the mute button to turn off the current alarm sound, analyze the cause of the alarm, and take appropriate action.
Detection control points
It is necessary to closely monitor and control relevant parameters such as temperature, pressure, liquid level, current, and valve position at all times.
System Engineer (or above) Job Responsibilities
1) System software and hardware maintenance.
2) Starting and stopping the DCS system.
3) Setting and modifying operator passwords.
4) Maintenance and modification of important system operating parameters.
5) Other responsibilities related to the system.
6) Precautions:
A. When a power outage occurs, immediately switch all circuits in the system that are in automatic control to manual mode. Once power is restored, first check the system operation and data for abnormalities. If any anomalies are found, re-download the configuration and verify the system parameters. Only after everything is normal can automatic control be re-engaged. (See relevant documentation for parameter tables.)
B. Power-on sequence for system startup and operation: UPS, control station, monitor, operator station computer.
C. Shutdown sequence: Control station computer, monitor, control station, UPS.
D. Operator Password Maintenance: Operator passwords on each workstation are independent and must be created separately. Passwords are a prerequisite for ensuring the safe and normal operation of the system and must be strictly enforced.
E. Historical data is stored on the operator station's hard drive and is unaffected by factors such as system power outages. Historical data is an important means of investigating liability for accidents.
F. The operator station computer is an important component of the system and must be kept in good working order and clean.
G. When a system card malfunctions, the corresponding control loop should be immediately switched back to manual mode, and the DCS system maintenance personnel should be notified to replace the faulty card immediately. The system can only be put back into automatic mode after the fault has been checked and confirmed to be eliminated.
Operator Responsibilities
1) Monitor the operation of the DCS system to prevent potential dangers.
2) Intervene in system operation at any time to ensure safe and normal production.
3) Changes to system authorized operating parameters.
4) Automatic control commissioning method: Simply switch the manual/automatic switch of the circuit instrument on the screen to automatic.
5) Alarm handling: When a process indicator generates an alarm, there will be an audible prompt. The alarm information is indicated in the alarm information bar and alarm overview screen. After understanding the alarm situation, use the mute button to turn off the current alarm sound and confirm it in the alarm overview.
6) Handling Abnormal Situations:
► If a transmitter malfunction occurs during automatic control, switch back to manual control immediately.
► If a valve malfunction occurs, switch back to manual operation and switch to on-site operation.
► If the system experiences a power outage, immediately switch back to manual mode and ask an engineer to check the system. Only after confirming that the system is in good working order should you switch back to automatic mode.
► If the DCS operating interface data does not refresh (normally the data refreshes once per second), or if manual/automatic switching is not possible, contact instrument personnel for maintenance. Simultaneously, immediately go to the site to perform the operation.
► When a system card malfunction occurs, the corresponding control loop should be switched back to manual mode, and the faulty card should be replaced by the instrumentation personnel. Automatic mode can only be put back into operation after the fault has been checked and confirmed to be eliminated.
► If the DCS system experiences an abnormal power outage, it should be switched to manual operation. After power is restored, an engineer should check the system status, verify the circuit parameters and other system data to ensure they are normal, and confirm the opening of each regulating valve. Automatic operation can only be resumed after everything is confirmed to be normal.
► Other abnormal situations should be handled in accordance with the job operation procedures.
