Distributed Control System Operations
- dcs operations, distributed control system
The philosophy of the Distributed Control System (DCS) operations in correlation with the Safety Instrumented System (SIS) has one boundary that should not be crossed over. This boundary is refer to the separation of DCS operations from the Safety Instrumented System (SIS). DCS should operate on its operations window while SIS should autonomously operate without any control from DCS, and there should be no operator interface that can bypass the SIS system when it runs logically. The operator can only interfere the plant shutdown scheme by using the emergency shutdown window that has provided.
Distributed Control System Separations Philosophy
The main reason of the operations separation from DCS and SIS in the production operations window are as per the following:
1. The defense-in-depth concept for safety assurance in plant operations, where the DCS as the normal operations window and SIS as the secondary layer to ensure the safe operations
2. Failure on DCS will not impact on SIS performance
3. SIS has stricter technical requirement for its safety operations, such as SIL and SIF requirement, while DCS has no such specific strict requirement
4. DCS has human interface for the monitoring and control while SIS has no such thing, it means SIS is dedicated to run autonomously and separate with DCS, to put by itself the un-normal operations condition to the safe state
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