Rockwell Automation 1771-QB Linear Pos. - Manual (Page 127)

Initializing and Tuning the Axes
Chapter 8
8Ć9
8. Record the new axis position value from the module. This value is in the
status block words 12 and 13 at N44:12 and N44:13 for axis 1.
9. Subtract the initial axis position from the new axis position and record this
as the module distance.
10. Divide the module distance by the actual distance and record this as
transducer calibration correction factor.
11. Multiply the transducer calibration constant in the parameter block words
5 and 6 (N45:5 and N45:6) by the transducer calibration correction factor
calculated in steps 9 and 10. Enter the result as the new transducer
calibration constant and reset the axis by toggling bit 9 of the axis control
word N45:131.
12. Repeat steps 3 through 11 to verify that the transducer calibration constant
is correct.
13. Determine a valid set of parameters for the zero-position offset and the
software travel limits and enter these into the parameter block.
Example: Verifying Transducer Calibration Constants
If the values for axis 1 are:
initial position = 12.324
actual distance = 6.423
new position = 18.737
transducer calibration constant = 9.0500
Then the module distance is:
18.737 – 12.324 = 6.413
The transducer calibration correction factor is:
6.413 / 6.423 = 0.99844
and the new transducer calibration constant is:
0.99844 x 9.0500 = 9.0359