Positioner CMSXThe positioner CMSX from Festo is a digital, electropneumatic positioner that can be attached to pneumatic quarter turn and linear actuators for a wide range of applications in the process industry. It enables simple and efficient control of the position of process valves actuated by pneumatic actuators.The CMSX is suitable for single-acting and double-acting quarter turn actuators with a swivel angle of approx. 0-100° and a mechanical interface in accordance with VDI/VDE 3845. It is also suitable for double-acting linear actuators.The position of the CMSX is specified by an analogue setpoint value signal (0–10 V or 0/4–20 mA). The actual position of quarter turn actuators is detected using a potentiometric angle sensor integrated in the positioner and for linear actuators by an external potentiometric position sensor and transmitted to the control electronics of the positioner. The closed-loop controller compares the analogue setpoint value with the measured value and controls the solenoid valves of the positioner accordingly. The solenoid valves control the actuator by pressurising and exhausting the cylinder chambers until the deviation is reduced to zero.The control parameters are adjusted and determined fully automatically so that the maximum amount of time can be saved and optimal control behaviour can be achieved.Several freely configurable functions as well as input and output signals give the CMSX the flexibility to tackle any task. The various actuator types, flow rates and safety functionsare available in different versions.