With SIMATIC ET 200 a wide range of distributed I/O systems is available – for solutions in the control cabinet or without a control cabinet directly at the machine, as well as for applications in hazardous areas. The modular configuration allows the ET 200 systems to be configured or expanded in small steps. Ready-to-use, integrated add-on modules reduce the costs and offer a wide range of different application possibilities. Many different possible combinations are available: Digital and analog inputs and outputs, intelligent modules with CPU functionality, safety systems, motor starters, pneumatic devices, frequency converters as well as various different technology modules (e.g. for counting, positioning). Integral plug connections make installation quick and easy and therefore reduce the costs. The sensors and actuators can be easily connected to a bus system without the need to use a mass of single wires with cable distributors and cable racks. This makes the wiring simple and transparent, less error-prone and therefore low-cost. The ET 200 systems can be integrated into the SIMATIC PCS7 process control system with minimal engineering outlay. But it can also be used with non-Siemens process control systems.