A compact PLC used in Distributed Profibus / Profinet systems where small group of I/Os are located in groups in a plant distributed over a large area. The modules as small as 4 digital inputs and 4 digital outputs or 2 analog inputs are available as individual modules at an economical pricing and the ET 200S modules can be supported with an interface module and connects by Profibus cable or Profinet cable. This enables localized PLC systems near to field equipments enables easy monitoring and a boon to maintenance engineer. It reduces cabling between each input/output to field equipments and a simple Profibus/Profinet cable connects the system to Main PLC.