Maintenance & Reliability · SOP

Automated Storage & Retrieval System Crash Recovery

A comprehensive guide for safely recovering an Automated Storage and Retrieval System (ASRS) after a crash, Z-axis stall, or loss-of-homing event. This document covers all single-mast and dual-mast units utilizing servo-drive systems with absolute or incremental encoder feedback.

Estimated Time

45–90 min

Difficulty

Advanced

Regulation

CSA Z432 / ANSI R15.06

Version

1.0

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Purpose

To define the precise procedure for recovering an Automated Storage and Retrieval System (ASRS) from a crash state, Z-axis freefall, or encoder loss event. This SOP ensures minimal downtime, prevents secondary mechanical damage to the mast and shuttle deck, and re-establishes safe homing verification for all axes before returning the unit to full automatic production.

Scope

This procedure applies to all single-mast, dual-mast, and mini-load ASRS units installed at the facility, specifically models utilizing servo-drive systems with absolute or incremental encoder feedback. It covers recovery from: X/Y/Z axis collisions, load-handling device (LHD) jams, and emergency-stop (E-Stop) recoveries requiring manual re-homing. This SOP must be performed by a Level 3 maintenance technician or OEM-certified engineer.

Safety Precautions

LOTOComplete Zero Energy State (ZES) Lockout/Tagout per OSHA 1910.147 & CSA Z460. Verify isolation of main disconnects for S/R machine and conveyor infeed/outfeed before any mechanical intervention.
PPEWear Class 3 high-visibility vest, safety glasses, steel-toed boots, and composite hard hat with chin strap. Use a PFAS (Personal Fall Arrest System) 420lb rated when accessing top-of-mast or working above 6 ft.
CTRLMaintain continuous communication with the control room operator via two-way radio. Verify S/R machine is in manual/teach mode before entering the rack aisle. Never walk under a suspended load.

Required Tools & Materials

LOTO Kit (Padlock, Hasps, Tags, Group LOTO box)
Personal Fall Arrest System (PFAS) 420lb rated
ASRS Teach Pendant / Laptop with OEM recovery software
Multi-meter (Fluke 87V or equivalent) with current clamp
Adjustable wrench set (Metric & SAE, 8mm-24mm)
Torque wrench (5-100 Nm range)
Pry bar / recovery bar (non-sparking recommended)
Plastic shims (various thicknesses, 0.5mm-3mm)
Flashlight (Class 1 Div 2 if applicable)

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Procedure: Step-by-Step

1 Initial Assessment & Lockout. Contact control room operator to halt all upstream/downstream conveyors. Place the ASRS unit into E-Stop. Apply LOTO to the S/R machine main disconnect. Verify Zero Energy State.

2 Visual & Mechanical Inspection. Inspect the mast, shuttle deck, and load-handling device (LHD) for visible damage, twisted columns, or derailed guide rollers. Document any oil leaks or deformed racks. Do not proceed if structural damage is suspected.

3 Clearance & Manual Recovery. Remove any jammed product. If the Z-axis is coasted, attach the manual recovery winch/crank. Slowly rotate to bring the shuttle deck 12 inches off the floor level. Align the X/Y axis to the nearest safe service position.

4 Encoder & Limit Switch Verification. Manually actuate the Z-axis limit switches (S2, S3) and verify continuity. Confirm the encoder coupling is not sheared. Check the encoder disc for debris or oil contamination.

5 Power-Up & Homing Sequence. Remove LOTO (ensure all personnel are clear of the rack aisle). Switch to manual mode on the operator panel. Initiate the "Slow Speed Homing" sequence. Monitor motor current draw on the HMI. If axis exceeds 150% rated torque, E-Stop immediately.

6 Full Travel Verification. Run a single multi-floor cycle in manual mode. Verify the shuttle deck is level within 1.5mm tolerance. Check for abnormal rubbing noises at the LHD. Execute a full travel test in automatic mode at 50% speed.

7 Documentation & Return to Service. Record the recovery event in the maintenance log. Note all torque readings, cycle counts, and alignment values. Return the ASRS to production at 100% speed only after a successful 10-cycle qualification run.

Automated Storage & Retrieval System Crash Recovery

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