We have an inductive position transducer mounted to a Rexroth A4VSO 40cc hydraulic motor that we'd like to use in a mobile application (an excavator). The motor was ordered many years back with the sensor mounted to it - we'd been using this motor on a stationary test-rig. We processed the sensor coil signals using a Rexroth VT 12000 card to get -10V to +10V analog signals that could be fed back for control (we're using several analog and digital I/O cRio modules on the excavator that can process this signal). The VT 12000 card is not suitable for mobile applications.
The sensor is classified as a 'differential transducer' or 'differential transformer' - meaning that there are 2 sensor coils, between which the target is placed.
Functioning of VT 12000 signal conditioning card
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Each of these is excited by 15V AC signals from the card at 5.5 kHz frequency, and these lead to eddy currents in the metal target. An electromagnetic field is produced due to these eddy currents and in turn this opposes and reduces the intensity of the original field. The coupling effect changes with the gap between them (i.e. the position of the target) - in effect there is impedance variation with the sensor. This impedance variation is detected by the signal conditioning circuitry in the card and processed to produce a single, DC signal (-10V to +10V) corresponding to target position.
Does NI have a single product that : (a) does the same kind of signal conditioning AND, (b) can be mounted to a DIN rail (suitable to our mobile application)?
PS - The full order code for the sensor is IW9-03-01 079 EZ-532. There is no catalog available for the sensor itself, as I've confirmed from Rexroth. I'm attaching catalogs with partial info. about the sensor in the motor servovalve catalog (RA 29585, page 7), a handbook from Kaman sensors that explains inductive position sensor technology and another catalog for the VT12000 card itself (also has details on sensor).
