Accurate monitoring of hydraulic cylinder displacement
27 June 2008
The new Gefran RK Series position transducer uses a contactless magnetostrictive linear sensor for accurate and reliable displacement measurement in hydraulic applications. The RK Series is designed for OEM use within the hydraulic cylinder, typically for monitoring and control in mobile applications, such as earth moving, agricultural and mining equipment.
Suitable for cylinder stroke lengths from 50mm to 4000mm, the compact sensor has a 10mm diameter probe, with a compact, versatile head arrangement smaller than any other solution currently available on the market. External connection to the head is via an IP67 rated cable connection, up to 50m long, providing a straightforward analogue output of displacement, with an industry leading linearity and accuracy of better than 0.02% of Full Scale.
The robust and durable transducer relies on the interaction between a magnet on the moving piston and the magnetostrictive transducer rod element. This enables a non-contact, solid state position measurement, that is not subject to mechanical wear, tolerates working temperatures up to 90C, with 20g vibration and 100g shock, and is sealed against the hydraulic environment for working pressures up to 700bar.
The RK Series transducer provides a direct analogue voltage output (0-10V) proportional to position, using a standard 18-30V DC power supply: optionally available, a 12V powered unit provides an analogue 0-5Volt output. The magnetostrictive timing pulses from the transducer can also be monitored by the Gefran EK Series remote electronics module.
This module offers CANopen and other digital interfaces, transmitting digital position and speed of movement measurement information (up to 10m/sec) to the equipment control system. The EK Series modules are also capable of monitoring the position of 2 or more magnets operating on the same magnetostrictive transducer rod element, if required.
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