Position sensors are used in hydraulic systems when valves are to be effectively controlled via a closed-loop control circuit.High-end proportional solenoids have a hysteresis of 2-3 %. The hysteresis and the quality of the proportional solenoid determine the positioning accuracy with respect to the input variable of the current. For applications in which this deviation needs to be corrected, a position sensor is required to detect the exact position of the armature/slide valve and thus close the control circuit.
Depending on the applicational case, the proportional solenoid provides a reproducible output defined by a certain path or a certain force, which is proportional to the input of the exciting current. In this, the LVDT sensor delivers the travel of the plunger as a linear, analog function ranging between 4 and 20 mA. Together with the proportional solenoid, the sensor forms an assembled and calibrated unit. The valve‘s zero position can be precisely fine-tuned via the offset screw. In this manner, the proportional solenoid and the sensor form an optimally tuned unit with respect to each other.
If required, Soway customer-specifically adapts proportional solenoids to the project situation in terms of stroke length, force curve, connection dimensions or electrical connection.