Rockwell Automation 1440-TPS02-01RB XM-320 Position Module - Manual (Page 62)

Publication GMSI10-UM005C-EN-P - May 2010
54 Configuration Parameters
Calibration Bias Calculation
Since Probe B is gapped beyond the operating range, you must manually
calculate the calibration bias as well as the transducer DC bias.
1. To determine the Transducer DC Bias, subtract Position B Gap from
Transducer Offset, multiply by the Sensitivity and then add the
Transducer Offset voltage.
2. Use the following formula to calculate the Calibration Bias:
Radial Cancel Mode
In radial cancel mode, the movement of the shaft is detected by measuring the
gap between the probe tip and a ramp of known and consistent angle to the
center line of the shaft. If two ramps are present they should be measured as
shown below. The potential "lift" error of shaft position caused by jacking oil
pressure is eliminated in the module calculations.
Where only one ramp is available, the "lift" error must be taken into account,
and this is achieved by using a second probe operating on a portion of the
shaft which is parallel to the center line.
Transducer DC Bias 0.03 150 ( × 900 ) 3 – -25.5 = – =
Calibration Bias Transducer DC Bias Sensitivity Calibration Offset ) sin (Target Angle) Ч Ч ( – =
IMPORTANT
The formula used to calculate the Calibration Bias depends
on the Upscale setting and whether Fault High and Fault
Low are less than or equal to zero (0). Press F1 on the
Channels property page for a description of the formulas.
Calibration Bias -25.5 0.03 250 × ( ) sin(90) Ч -33 = – =