Tips and Troubleshooting
P/N 400274-01 Revision A7
83
System Calibration Issues
Symptom
The measured Master Length or Follower length does not match the
values returned by the PCM-22 using the
FM12
or
FM13
serial
command
s
which return the average Master Length or Follower Length
in user units respectively.
Causes
The
User Distance Per Motor Revolution
on the PCX Drive Parameters
screen or User Distance Per Revolution on the PCX Master Axis
screen
needs to be adjusted in the direction of the measured length. If not done,
this will cause other issues as the speed is increased and the machine is
fine tuned.
For example:
A “not defined by sensor”
Product Length
measures 9.875”; FM12 and
the entered
Product Length
is 9.800”. The
User Distance Per Revolution
on the PCX Master Axis
screen needs to be multiplied by (9.875 / 9.800)
to calibrate the PCM-22 data to the mechanical data.
Synchronization Source Issues
Symptom
The Follower motion is jumpy or coarse.
Possible Causes
A) The PCM-22 is synchronized with the encoder (Master) position. Any
slippage or bounce of the encoder to the product will be reflected in
the position and motion of the Follower. Chain & sprocket coupling
to the encoder such as should not be used.
B) The number of sync steps per Master Length is much less than the
number of resolver steps per Follower length. See
Maximum Product
Velocity
and
Master Axis
.
Symptom
The
Cycle Point
appears to “walk” as the speed is increased.
Possible Causes
A)
The Master encoder should be as close as possible to the Follower
and not be allowed to vibrate or slip relative to the product. If
product slippage is occurring it, will usually appear as
Master Phase
Variation
.
Note:
Encoder selection should be based on the accuracy desired in
the operation.
For example, If your encoder delivers 12,000 counts per
revolution and the distance per revolution is 12.000 inches then
the distance per count is 0.001 inches. The PCM-22 will attempt
to track the Master to +/- 0.001 inches as this is the highest
accuracy possible.
