Remote I/O, or distributed I/O, refers to I/O devices that can be installed in a remote location away from the PLC, while still maintaining a reliable connection between it and the field devices in the system. Using remote I/O allows designers the freedom to place their equipment where it is most effective without worrying about reduced signal quality or expensive wiring requirements.
Characteristics:
- Proximity: Devices can be located far from the main controller, offering increased flexibility across large or complex facilities.
- Wiring: Uses network cables or fieldbus systems to connect remote I/O modules to the main controller, significantly reducing the amount of wiring required over long distances and simplifying overall system layout.
- Latency: Comparable to local I/O when using a modern communication network. Older networks may see some increased latency.
- Reliability: remote I/O systems are highly dependable when part of a robust network infrastructure. Enables designers to build in redundancy to prevent downtime during an emergency event.
- Maintenance: Although more complex due to the distributed nature of devices and network diagnostics, the modularity of remote I/O allows for easier troubleshooting and expansion.
- Cost: Provides maximum value for large or distributed systems by reducing the need for long cable runs and simplifying future expansions.
For more information, see our article What is Remote IO?