Rockwell Automation GMLC Reference Manual - Manual (Page 298)

Publication GMLC-5.2 - November 1999
Auto Correction (Configure Cam) 261
• the current remaining distance to go of the auto-correction indexer is
available in the PCAM_auto_ correction_to_go variable
• the current number of good registration events is available in the
PCAM_good_registration_count variable
• the current number of consecutive out-of-tolerance registration events
is available in the PCAM_bad_registration_count variable
• and the current number of consecutive missed registration events is
available in the PCAM_missing_registration_count variable for the
slave axis
See the System Variables chapter of this manual for more information on
these variables.
Nominal Length
In the Nominal Length field, enter a value or expression equal to the
expected or desired distance between registration events on the
registering axis, in the position units of the selected master axis. This is
the value that is subtracted from the measured registration distance
whenever a good registration event occurs and then used to determine the
registration error.
Tolerance
A tolerance is a range on either side of the nominal length. Setting a
tolerance limits error correction to only those errors that fall within this
range, and prevents the motion controller from trying to correct unusually
large errors. Large errors usually mean that serious problems exist, either
with the hardware or the software running it. These large errors go well
beyond mere axis slippage, or inconsistent material errors that auto-
correction can remedy. Using auto-correction to correct these large errors
can cause harsh motion and result in damage to both equipment and
materials.