TL;DR

A transfer arm fault is almost always a physical jam from a deformed tote or debris, or a slipped drive belt on the arm mechanism. Clear the jam and check belt tension before resetting the fault.

What you might see

tote transfer arm fault on WCS or PLC
transfer arm not extending or retracting fully
tote jammed between the shuttle and the shelf location
arm position sensor not confirming home or extended position

Likely causes

Tap to mark as ruled out

Deformed or oversized tote binding on the shelf guide rails during transfer
Drive belt or chain on the arm mechanism slipping or breaking
Position sensor (inductive or optical) not confirming the arm's retracted or extended state
Shelf level accumulation of debris causing the tote to catch mid-transfer

Required tools

WCS fault log access
Belt tension gauge (if applicable to this arm design)
Lint-free cloth for sensor cleaning
Replacement drive belt (if required)

Safety first

Confirm aisle entry interlock is engaged and all carriers are in hold before approaching a shuttle in the aisle.
Deformed totes can have sharp edges from broken plastic corners. Wear cut-resistant gloves during tote removal.

Procedure

6 steps · ~45 min

1
Identify the shuttle and level from the WCS fault log. Command all carriers to a hold state before entering the aisle.
Warning: Entering the shuttle aisle requires confirmation that all carriers are in a hold state with the aisle entry interlock engaged.
2
Locate the affected carrier and visually inspect the transfer arm position and the tote. Check whether the tote is physically caught on the shelf guide.[1]
3
Remove any jammed or deformed tote manually. Inspect the tote for damaged corners or bowed sides that caused the jam. Quarantine the damaged tote.
4
Inspect the arm drive belt or chain for slippage or breakage. Adjust belt tension per the OEM specification or replace the belt if broken.
5
Check the arm home and extended position sensors. Clean the sensor face and verify the sensor LED confirms position at both extremes of travel.
6
Reset the fault from the WCS, re-home the carrier, and run a test transfer cycle on that level to confirm the arm completes full travel without fault.

Sources

Dematic (KION) Dematic Multishuttle AS/RS (Automated Storage) general technical documentation, Dematic (KION)
AS/RS shuttle transfer arm mechanisms, belt drive maintenance, general material handling references (general)

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