Allen-Bradley 1444-TSCX02-02RB User Manual page 182

Chapter 4 Measurement Definition
182
In ramp 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, measure them as shown.
When measuring a ramp, any "lift" of the shaft, typically due to jacking
oil pressure, must be accounted for. Using two probes makes sure that
this lift error is minimized in the module calculations. However, where
only one ramp is available, the "lift" error must be corrected by using a
second probe operating on a portion of the shaft that is parallel to the
center line (center image
IMPORTANT For single ramp applications, the first channel of the pair (channel 0/2) must
be mounted facing the ramp while the second channel (1/3) must be
mounted facing the shaft.
Configuring Ramp Differential Expansion Measurements
Ramp Differential Expansion requires that two static channels, in pairs, be
used. These pairs are either Channels 0/1 or Channels 2/3. If one of the pair is
not facing a ramp, then that probe must be input to the second channel of the
pair.
The Ramp Differential Expansion measurement requires editing the pages in
Module Definition, and in normal Module Configuration, the HW
Configuration, and the DC page for each channel of the pair.
Rockwell Automation Publication 1444-UM001D-EN-P - June 2018
Figure 76).