PART V | LESSON 23: RECOVERY, DIAGNOSTICS, AND THE OPERATOR MATERIAL HANDLING ACADEMY
DRIVING QUESTION When it jams, stalls, or goes dark, how does the system recover?
Exception routing flow: a carton passes three decision diamonds, read good, destination returned in time, and lane available. Each yes continues to the divert. Each no drops to a red exception rail that converges on the gold hospital lane, which has an operator workstation and a dashed re-induction arrow back to the line. A throttle valve sits on the induction feed, and a dashed branch marks the WMS-down degraded mode.

Every no lands on one rail and ends at the hospital lane.

Give Every Failure a Destination

Jam

A photoeye that should clear stays blocked past its window. The PLC stops that zone and alerts the operator. Blunt on purpose: a jam that keeps feeding grows.

Lane-full

The photoeye at a lane's entry stays blocked, so the lane can't take more product. The carton goes elsewhere: a backup lane, recirculation, or the hospital lane.

Hospital Lane

The destination of last resort: a dedicated sort spot with an operator workstation, where a person triages each exception and re-inducts it.

Illustrative Sizing Figure

Example only. The percentages are placeholders to show the method, not measured rates for any real system.

Size the hospital lane to exception volume, not system volume: system throughput × expected exception rate. E.g. 1,200 cartons/hr × 2% = 24/hr the lane and its operator have to clear, plus margin.

DESIGN PRINCIPLE Every failure gets a destination and a recovery.