The digiVIT self tuning digital eddy current sensor

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Kaman’s newest addition to their line of high precision, high resolution non-contact position/displacement sensors is the digiVIT. 

The digiVIT’s digital circuit design provides what other sensors with digital circuits do, pushbutton calibration and active temperature compensation.

What makes it unique in the industry is the self tuning bridge. The digiVIT will perform with nearly any inductive coil sensor on the market today.

With analog eddy current position/displacement sensors, a matching of the sensor parameters is required to balance the bridge circuit. These parameters are influenced by sensor size, target material, and sensor cable length.

Changes to any of these required retuning the bridge parameters to rebalance the bridge, a long and costly effort.  Current digital circuit sensors offer the ability to store and recall bridge balancing parameters, offering some flexibility with the hardware, but the bridge values still had to be determined the old fashioned way. 

The digiVIT’s self-tuning bridge is truly unique.  As the initial step of the linearization calibration routines, the parameters of the bridge are varied and analysed by the software resulting in the optimum tuning of the bridge for the given sensor, target, cable configuration.

No longer do you need to replace a physical SIP card, or load a ‘configuration’ file to change the sensor size, cable length or target material. 

Another ease-of-use aspect of the digiVIT is that there is no need to connect to a computer to calibrate, configure or otherwise set up the digiVIT. 

All features and functions are self contained and accessible through 4 push buttons on the front face of the enclosure.

The digiVIT has very flexible analog output options.  The user can select from one of 6 outputs, 0-5VDC, +/-5VDC, 0-10VDC, +/-10VDC, 4-20mA & 0-20mA.  For digital communication a UDP/IP Ethernet connection is built in.

The flexibility is enhanced by the variety of calibrations available. A 2 point calibration is suitable when all that is needed is a repeatable output.

For a more linear output a 6 point calibration can be performed achieving a typical nonlinearity of <0.3%FS.  For best performance a 21 point calibration can be performed resulting in typical nonlinearity of <0.1%FS.

Active temperature compensation calibrations can be performed by simply pressing a button at two positions along the output curve at two temperatures in the normal operating temperature band.

With temperature compensation calibration the thermal sensitivity can be improved from the standard of <0.1%FS/°C to <0.02%FS/°C.

The built in digital display can be configured to display a percent of the calibrated range or any of the optional analog outputs.  Other features include ‘no sensor’ and ‘shorted sensor’ notification, re-zeroing the output, and two point output adjust.