Reduced wiring and the resulting lower susceptibility to faults have ensured the present day success of distributed I/O in process automation. Input and output modules (remote I/O stations) are located in the vicinity of associated sensors and actuators. These are no longer individually connected to the controller, but rather through distributed process I/Os. The connection between distributed input and output modules (slaves) and central controllers (masters) is made through bus systems such as PROFIBUS.

SIMATIC PCS 7 offers numerous options for connecting I/Os as well as for sending and receiving process signals via sensors and actuators:

  • Analog and digital I/O modules of the SIMATIC S7-400 operated centrally in the automation system

  • Remote I/O ET 200 stations connected to the automation system (AS) via PROFIBUS DP with an extensive range of cost-effective signal and function modules

  • Direct AS connection of operator terminals and intelligent, distributed field/process devices (including sensors / actuators) via PROFIBUS, redundant, or in hazardous areas of zones 0, 1, 2 or 20, 21, 22