Conveyor Solutions Engineering — Professional Training Program
The Layered Flow Diagram
Module 5 Reference Guide  ·  Riverside Fulfillment Center

What This Document Is

A working reference showing how a real system design builds from an operational flow sketch through all four engineering layers. Use it while working through Module 5 and again when building your Capstone flow diagrams.

How to Read It

Each stage builds on the one before it. Start at the Operational Flow and work down. Notice what gets added at each layer and more importantly why it gets added at that stage and not earlier.

The Rule

Each layer has a job. Do not mix them. Rate numbers do not belong on Layer 1. Equipment names do not belong on the Operational Flow. Build in sequence and the design tells you what it needs.

Operational Flow Layer 1 — Process Flow Layer 2 — Volume & Rate Layer 3 — Decision Points Layer 4 — People & Constraints
BEFORE ENGINEERING BEGINS

The Operational Flow

This is what the discovery meeting produced. It shows how Riverside moves product today — before any automation is assumed. No conveyor language. No equipment names. Just the operation as it exists. Every system design starts here. If you skip this step you are designing a solution before you understand the problem.

LOADING DOCKS ZONE A Apparel / Housewares ZONE B Packaged Food CENTRAL STAGING Manual sort by carrier MANUAL SORT DOCK DOOR 1 Carrier A — 55% DOCK DOOR 2 Carrier B — 35% DOCK DOOR 3 Overflow — 10% ⚠ 3% misdirect rate — associates sorting without confirmed scan data
What this layer shows

The operation as-is. No automation assumed. This is the output of the discovery meeting, nothing more.

The test

Can you narrate this flow out loud without stopping? If not, you do not understand the operation yet. Do not proceed to Layer 1.

What is not here yet

Conveyors. Equipment names. Rates. Speeds. People locations. None of it. This is the problem, not the solution.

LAYER 1

Process Flow — The System Architecture

Now automation is the answer. The operational flow becomes the engineering blueprint. Cart pushes become throw-on lines. Manual staging becomes a merge point. Manual sort becomes a sorter. Still no rates, no equipment models, no people. You are drawing what the system does, not how fast or what brand.

LOADING DOCKS ZONE A Pick induction ZONE B Pick induction THROW-ON LINE A THROW-ON LINE B MERGE POINT SCAN POINT SORTER 3 destinations DOOR 1 Takeaway spur DOOR 2 Takeaway spur DOOR 3 Takeaway spur HOSPITAL LANE no-read / exception
What changed from operational flow

Cart pushes are now throw-on lines. Central staging is now a merge point. Manual sort is now a sorter. The operation drove every decision.

The test

Can you narrate this as a complete story without gaps? Every path a carton takes from induction to destination must be on the diagram.

What is not here yet

No CPM values. No belt speeds. No equipment models. No people. No controls logic. That all comes next.

Hospital lane

Exceptions need a defined path. If you do not draw it now you will forget to design it. Every system needs one.

LAYER 2

Volume & Rate — The System Gets Numbers

The flow from Layer 1 now gets CPM values at every section. Work backward from the required output. 20 CPM combined at the sorter. Distribute by volume split. Calculate belt speeds from those rates. Every segment of the system must have a number before Layer 3 begins.

LOADING DOCKS ZONE A Pick induction ~10 CPM est. ZONE B Pick induction ~10 CPM est. 80 FPM 80 FPM MERGE POINT 20 CPM 20 CPM 120 FPM SORTER 20 CPM in 150 FPM DOOR 1 11 CPM — 55% Spur: 195 FPM DOOR 2 7 CPM — 35% Spur: 195 FPM DOOR 3 2 CPM — 10% Spur: 195 FPM ⚠ Open Item: Zone A / Zone B split unconfirmed. Assumed 50/50. Confirm with customer. If peaks do not coincide, throw-on lines can be sized differently.
Work backward

Start at the dock doors. Work back through the sorter to each throw-on line. Rate at every segment before any speed is calculated.

Open items belong here

Zone A / Zone B split is unconfirmed. Flag it now. An assumption you did not document is a gap that surfaces later as a dispute.

Spur speed calculation

Takeaway spur speed is not the sorter speed. Use the Speed of Takeaway Spur calculator. Divert angle drives the difference.

The test

Every segment has a CPM value. Every belt has a speed. If any section is blank this layer is not complete.

LAYER 3

Decision Points & Smart Handoffs

Every point where a decision is made gets labeled. Where does the WMS query fire? How long does it have to respond? The scan-to-divert distance is a physical calculation driven by belt speed and WMS latency. It must be confirmed in writing before the layout is finalized. Anti-gridlock logic and exception paths are defined here.

LOADING DOCKS ZONE A 10 CPM ZONE B 10 CPM MERGE 20 CPM INDUCTION THROTTLE anti-gridlock SCAN POINT → WMS query fires here WMS HANDSHAKE Latency: confirmed in writing from customer IT team ⚠ Do not estimate SCAN-TO-DIVERT DISTANCE = belt speed × WMS latency SORTER encoder tracking lane full monitor gridlock prevention DOOR 1 11 CPM DOOR 2 7 CPM DOOR 3 2 CPM HOSPITAL no-read / timeout No-read → hospital lane WMS timeout → hospital lane
WMS latency is not estimated

Scan-to-divert distance is a physical dimension. It is calculated from confirmed latency. If IT cannot give you a number, the layout cannot be finalized.

Anti-gridlock lives here

The induction throttle point is a Layer 3 decision. If destination lanes fill and recirculation backs up, induction stops. Define the condition before the controls contractor writes a line of code.

Exception paths must be explicit

No-read, WMS timeout, and lane-full conditions all need a defined path. If the diagram does not show it, it will not be designed or priced.

The test

Every decision point is labeled. Every exception has a path. WMS latency is confirmed in writing. If any of those are missing, Layer 3 is not done.

LAYER 4

People & Constraints — The Physical Reality

Operator locations, forklift crossings, pull cord runs, accumulation zones, maintenance access. By the time Layer 4 is complete, a knowledgeable person can read the diagram and understand the full system — the rates, the control logic, and the physical constraints — without asking a single question.

LOADING DOCKS ZONE A 10 CPM / 80 FPM ZONE B 10 CPM / 80 FPM PULL CORD PULL CORD FORKLIFT CROSSING ⚠ guarded MERGE 20 CPM ACCUM ZONE A slug release ACCUM ZONE B slug release SCAN POINT → WMS OPERATOR SORTER 150 FPM 20 CPM LOTO accessible maint access ✓ DOOR 1 11 CPM accum zone — singulated OP DOOR 2 7 CPM accum zone — singulated DOOR 3 2 CPM gravity spur — low volume HOSPITAL staffed station OP Operator location Pull cord E-stop Accumulation zone Forklift crossing
People are in the design

Every operator location is shown. Operators at the scan station, Door 1, Door 2, and the hospital lane. If a person works near the system they are on the diagram.

Forklift crossing

Two near misses were reported. The crossing is marked, guarded, and on the diagram. If it is not on the diagram it will not be priced or installed.

Pull cord path

Every conveyor run with operator access has pull cord. It is shown on the diagram. It goes in the electrical RFQ with dimensions. Not as a footnote.

The final test

A knowledgeable person can read this diagram and understand the system intent, the rates, the control logic, and the physical constraints without asking the engineer a single question.