The modular I/O section includes remote I/O systems that are designed to be built using a choice of input or output modules, but requiring only one network interface. This enables a larger number of signals to be measured or controlled than typical distributed I/O modules.
Modular I/O also provides increased flexibility through the possibility of using many different modules in one device, with only one Ethernet or serial interface. This usually means only one power supply is required, which makes installation much easier. The latest addition is the Modular Active Ethernet I/O E4200 which includes Active messaging and on-board logic control.