RemoteIO

RemoteIO is a concept and set of technologies used in distributed control systems to provide input and output signals at locations remote from the central processing unit. RemoteIO devices extend the reach of a controller by converting field signals from sensors and actuators into digital data that can be transmitted over a network, and by performing actuation commands sent from the controller.

Architecture and operation: A typical RemoteIO setup includes RemoteIO modules placed near the field devices, a communication link to a central controller or gateway, and a supervisory system that monitors and commands the I/O. Signals are often digitized with analog-to-digital or digital-to-analog converters, protected by galvanic isolation, and powered by local or bus power. The gateway or controller assembles I/O data, applies addressing and timing, and ensures deterministic communication when required.

Protocols and interoperability: RemoteIO commonly relies on industrial fieldbuses and industrial Ethernet protocols such as Modbus TCP/IP, Profibus, Profinet, EtherCAT, or OPC Unified Architecture. Interoperability is achieved through standardized object models or register maps that define how inputs and outputs are read or written, often with safety and cybersecurity considerations like authentication and encryption.

Applications and history: RemoteIO has been integral to process automation, manufacturing, building automation, and utility infrastructure for decades. Early implementations used discrete wires to a local controller; modern systems leverage IP networks and standardized interfaces to enable remote diagnostics, reduced wiring, and scalable I/O expansion.