Ultima Control Technical Article
Generator Controller vs PLC: What Should Control the Plant?
Generator controllers and PLCs both have a place in power-generation control. The best architecture usually gives each device a clear job rather than forcing one platform to do everything.
A generator controller is typically strong at engine and alternator control, protection, synchronising functions and generator-specific operating states. A PLC is typically strong at site coordination, custom logic, interlocks, process interfaces, SCADA integration and plant-wide control.
Where generator controllers fit
- Engine start, stop, monitoring and protection
- Alternator electrical measurement and generator alarms
- Generator-specific synchronising and load-sharing functions where supported
- Local generator operation and service information
Where PLCs fit
- Plant master logic and site operating modes
- Coordination between multiple generators, switchgear and external systems
- Custom interlocks, permissives and process interfaces
- HMI, SCADA, telemetry, reporting and operator workflows
The boundary between controller and PLC should be documented clearly. Ambiguous ownership creates problems when a fault occurs and no one knows which device is expected to make the decision.
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