Cart Puller Encoder Slipping: Inspection and Verification

A slipping Cart Puller encoder causes the reported position to drift away from the hook’s actual position. This can produce inconsistent hook stopping points, repeated calibration changes, or hooks that do not return to the same marked location after a complete cycle.

Before adjusting calibration

Do not repeatedly recalibrate a drifting Cart Puller until the encoder and its mechanical connection have been checked. Calibration can hide the symptom temporarily, but the position will drift again if the encoder slips.

Inspect the encoder

1. Lock out the Cart Puller and verify that it cannot move.
2. Remove the encoder’s protective cover.

Style 1: Inspect the encoder set screw. Confirm that it is tight and seated correctly on the shaft.

Style 2: Inspect the encoder collar and its fasteners. Confirm that the collar is tight and cannot rotate independently of the shaft.

• Inspect the coupling, shaft, and bracket for looseness, wear, cracking, or misalignment.
• Inspect the encoder cable and connector for damage or a loose connection.
• After correcting the cause, reinstall the protective cover before operating the Cart Puller.

Verify with a cycle test

1. Place a visible reference mark at the hook’s starting position and number the hooks if needed.
2. Run a complete Cart Puller cycle using the approved test procedure.
3. Check whether each hook returns to the same marked position.
4. Repeat the cycle. Consistent return positions indicate that the encoder is no longer slipping; continued drift requires further mechanical, wiring, or encoder diagnosis.

Recalibrate only after the drift is corrected

If the hooks return consistently but the reported position is offset, complete the Cart Puller Hook Calibration. After calibration, repeat the cycle test and verify normal hook placement with more than one board length.