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Differences Between Relay Control and Sequence Control

Relay Control

- Only on/off control can be performed.

- The frequency of failure or breakdown is high and maintenance is not easy.

- Circuits are modified by changing wiring.

- For large-scale systems, large space and long design period are required.

- Identifying the cause of a failure or an error and replacing the failed device are not easy.



Sequence Control

- On/off control and complex control can be performed.

- Reliability is high and maintenance is easy.

- Circuits are flexibly modified by using programs.

- Even for large-scale systems, large space and long design period are not required, offering flexibility and extendibility.

- All failures and errors can be monitored. The failed device can be replaced easily.



Reference : Mitsubishi's FA E-Learning
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