Rockwell Automation 1440-SDM02-01RA XM-124 Standard Dynamic Measurement Module - Manuel (Page 76)

76 Rockwell Automation Publication 1440-UM001C-EN-P - May 2014
Chapter 2 Configure the XM-124 Standard Dynamic Measurement Module
Position measurements, including thrust, can be measured in one of three ways:
• Normal -The two sensors are used independently tot perform two separate
position measurements. See below for a description for a description of
Normal mode measurements.
• Head-to-head
(1)
- The two sensors are used together, facing each other on
either side of the target, to perform a single position measurement. This
mode can be used to extend the measurable range beyond that of a single
sensor.
• Radial Cancel
(1)
- The two sensors are used together to perform a single
position measurement. The second sensor is set up to measure the radial
movement of the target. The radial movement is then subtracted from the
position measurement performed by the first sensor.
In Normal mode the module behaves as a two channel differential unit with the
probes mounted on the casing and measuring the shaft position relative to the
Calibration Bias Sets the zero or green position. The zero position is the normal
operating position. Setting the zero position compensates for the
static gap. This enables the module to display only the displacement
around the zero position.
Use one of the formulas below to calculate the Calibration Bias. The
formula that you use depends on the Upscale setting and whether
DC High Limit and DC Low Limit are both less than or equal to zero
(0).
If DC High Limit is greater than zero, use one of these formulas:
Upscale set to ‘Towards’ Formula
Calibration bias = Transducer DC Bias + (Sensitivity x Calibration
Offset) x sin (Target Angle)
Upscale set to ‘Away’ Formula
Calibration Bias = Transducer DC Bias - (Sensitivity x Calibration
Offset) x sin (Target Angle)
If DC High Limit and DC Low Limit are both less than or equal to 0,
use one of these formulas:
Upscale set to ‘Towards’ Formula
Calibration bias = Transducer DC Bias - (Sensitivity x Calibration
Offset) x sin (Target Angle)
Upscale set to ‘Away’ Formula
Calibration Bias = Transducer DC Bias + (Sensitivity x Calibration
Offset) x sin (Target Angle)
Volts
Important: Check with the manufacturer about
operating thrust position and acceptable
tolerances before making any adjustments.
Calculate Bias (XM Serial Configuration Utility
only) Automatically calculates the Calibration Bias value.
Parameter Name Values are Comments
IMPORTANT The XM-124 module supports only Normal mode position measurements. If
Head-to-Head or Radial Cancel measurements are required, then the XM-320
module (catalog number 1440-TPS02-01RB) must be used.
(1) Head-to-Head and Radial Cancel modes are not available in the XM-124. See IMPORTANT note, above.