EXmatic 471 is an electro-pneumatic control unit for fully automatic control of pneumatic retractable housings of EXtract 8XX series. The combination of the control unit EXmatic 471 and a retractable probe housing of EXtract 8XX series ensures safe access to a sensor by driving it easily out of the process into the maintenance position and clean them fully-automatic with different rinsing solutions or even to take out the sensor for inspection, calibration or exchange. The cleaning intervals as well as additional functions can be programmed very easily. Output contacts can be connected to a DCS for external start and monitoring. It is an open and autonomous system and does not depend on any specific sensor transmitter.