PART V | LESSON 22: DATA AND DECISIONS MATERIAL HANDLING ACADEMY

Lesson 22 Worksheet: The Latency Budget

Fill in both templates at your own belt speed. If the transmit-to-divert distance doesn't cover the budget, don't force it. Name the lever you'd pull and say why.

Project data, Riverside sort point

The confirmed WMS response time is 1 second. The scan trigger fires at the carton's leading edge. The WMS query is transmitted from a point 24 inches downstream of that trigger. The divert takes 0.25 seconds to actuate.

Deliverable A: Latency Budget Worksheet

Work the budget top to bottom. Fill each blank at the belt speed you specified, then check whether the layout covers the required distance.

Latency budget worksheet reusable template
LineValueHow you get it
Belt speed (V)  FPMYour specified speed at the sort point.
Response window1.0 sRay's confirmed number, guaranteed under peak load.
Response distance  inV x 1.0 s. How far the carton travels while the upper system answers.
Actuation time0.25 sThe divert mechanism, from the project data.
Actuation distance  inV x 0.25 s. How far the carton travels while the divert fires.
Required transmit-to-divert  inResponse + actuation distance. The minimum distance the layout has to give you.
Actual transmit-to-divert  inMeasured on your layout, from the 24 in transmit point to the divert.
Fits?Y / NActual is at least required. If it doesn't, pull one of the levers below.
Levers if it failsdistance / speed / gapMore scan-to-divert distance, a slower belt, or a bigger gap. All three are physical.

Illustrative check at 120 FPM, which is 24 inches per second: response distance 24 in, actuation distance 6 in, so you'd need about 30 in from the transmit point to the divert. That figure shows the method. It isn't Riverside's confirmed belt speed. Run yours at the speed you specified.

Deliverable B: Interface Map

Name the payloads and set your own retry rule for each link. Write down what the system does when the answer doesn't come.

Interface map reusable template
LinkPayload upPayload downTimeoutRetryFailure behavior
PLC to WCS The barcode read. The door assignment. 1 s   No answer in the window routes the carton to the hospital lane, the staffed exception spot where a person sorts what the system couldn't.
WCS to WMS The routing query, keyed to the barcode. The carrier-to-door instruction. Inside the 1 s budget.   No destination returned is treated the same as a no-read.

How each failure actually gets handled, the timeout out to the hospital lane, the degraded mode when the WMS is down entirely, is the exception routing, and that's Lesson 23.

RIVERSIDE PROJECT NOTES