Accurate answers for hydraulic cylinder displacement

The Gefran RK Series are contactless magnetostrictive linear sensors for use in hydraulic cylinders that have a linearity and accuracy of better than 0.02% full scale.

They are suitable for cylinder stroke lengths of from 50mm to 4000mm and have 10mm diameter probes. External connection to the head is via an IP67 cable connection up to 50m long. The transducers rely on the interaction between a magnet on the moving piston and the magnetostrictive rod element. The system tolerates working temperatures of up to 90ºC, 20g vibration and 100g shock, and is sealed against hydraulic pressures up to 700 bar. Direct analogue voltage output is 0 to 10Vm proportional to position, using an 18 to 30V DC power supply. An optional 12V unit provides an analogue 0 to 5V output. The timing pulses can be monitored by the Gefran EK Series remote electronics module, which offers CANopen and other digital interfaces, transmitting digital position and speed of movement information up to 10m/s. The modules are also capable of monitoring the position of two or more magnets operating on the same transducer rod element if desired.