Modbus RS485 I/O Expansion System

Local I/O Expansion Solution that Requires No Software.

  • Local I/O expansion solution
  • No software configuration required
  • Works with any Modbus Master (RS485)
  • Scalable and customizable I/O solution
  • I/O Modules (isolated): 0-10 V I/O Module, 4-20 mA I/O Module, Digital I/O Module
  • Installs in minutes onto 35 mm DIN rail
  • Class I, Division 2 (Zone 2)
  • -40 ˚C to 80 ˚C


OleumTech® provides a fast and economical solution for expanding local input/output (I/O) counts to any Modbus Master device with the RS485 I/O Expansion System. The RS485 I/O Expansion System does not require any software or programming, making it one the of the easiest local I/O expansion solutions available.

The RS485 I/O Expansion System accepts 9-30 VDC and RS485 Interface Module controls data traffic and distributes the power to connected I/O Modules over the DataRail®, which minimizes wiring. Modbus slave IDs are assigned using the rotary ID switch dial available on each I/O Module.


To build a RS485 I/O Expansion System, a RS485 Expansion Kit is required. It includes a RS485 Interface Module and all the mounting hardware for installing onto 35 mm DIN rails. Users simply add desired I/O Modules to the system. The supplied DataRails supports up to five pairs of I/O Modules to a system in any I/O combination. One system can support up to sixteen pairs of I/O Modules using optional longer length DataRails.