IOmodules

IO modules are modular interface units that connect sensors and actuators to a central controller, such as a programmable logic controller (PLC) or an embedded computer. They extend the input and output capabilities of a control system, enabling data acquisition from field signals and the execution of control commands to devices in automated processes. IO modules are commonly categorized by signal type, including digital input (DI), digital output (DO), analog input (AI), and analog output (AO).

Specialized variants provide additional functions such as safety interlocks, counters and timers, or signal conditioning for temperature, pressure, or current measurements. Modules may also include isolated channels, programmable scaling, and local power for sensors. In many installations, IO modules are installed in a multi-slot rack or mounted as standalone units and connect to the controller via a fieldbus or industrial Ethernet network.

Key features include galvanic isolation between channels and the controller, protection against voltage spikes, and diagnostic capabilities that report channel status, fault conditions, and supply health. Performance is specified by factors such as sampling rate, channel resolution, and the bandwidth of the communication interface.

Common applications are in factory automation, process control, robotics, energy management, and building automation. The modular approach allows systems to scale by adding modules rather than replacing the central controller, improving maintenance and flexibility. IO modules support a range of protocol families, including Profibus, Profinet, EtherCAT, EtherNet/IP, Modbus, CANopen, and OPC-UA, depending on vendor and system requirements.