DCS, SIS and Emergency Shutdown Systems
Understand the different roles of the distributed control system, safety instrumented system and emergency shutdown functions in an LNG facility.
System context
Automation and safeguarding
Technical topic pages show the knowledge scope behind LNG University learning. Course, assessment and credential availability depends on the applicable program.
Relevant roles
Control-room personnel · Instrument technicians · Process engineers · Process-safety professionals
Prerequisites
Instrumentation fundamentals · P&ID fundamentals
Knowledge level
Intermediate technical coverage with system and operational context.
Learning outcomes
What this topic is intended to help you understand
- Distinguish regulatory control from independent protective functions.
- Explain alarms, interlocks, trips, permissives and shutdown levels.
- Interpret the relationship among DCS graphics, SIS logic and cause-and-effect documentation.
Technical scope
Equipment, concepts and terminology
- DCS architecture
- SIS architecture
- ESD hierarchy
- Alarms
- Permissives
- Interlocks
- Trips
- Voting logic
- Bypasses and inhibits
- Operator interfaces
Operating context
How the topic connects to plant operation
- Alarm response
- Sequence monitoring
- Trip recognition
- Reset conditions
- Managing bypass visibility
Safeguards and controls
Protection and risk-control context
- Independence of protection layers
- Access control
- Proof testing
- Management of overrides
- Cybersecurity boundaries
Technical learning does not replace site procedures, OEM documentation, engineering calculations, permits, supervision or facility-specific authorization.
Engineering documents
Documents commonly connected to this subject
- Cause & effect chart
- Control narrative
- Logic diagram
- Alarm philosophy
- SRS where applicable