Basic
20 min

3-Way Sortation Diverter

conveyorsortationdiverteritem-trackingfault
3-Way Sortation Diverter scenario preview

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Briefing

An extension of the 2-way sortation diverter with a third lane. Each item passes a photoeye and carries exactly one tag (TAG_A, TAG_B, or TAG_C). After a 500 ms travel delay the correct diverter solenoid energises for 1 s to route the item into the corresponding lane. Multi-tag reads (more than one tag high) or zero-tag reads latch ERROR_LAMP. STOP_PB clears the error and halts the conveyor.

Objectives

  • CONV_RUN is on whenever the system is running (not stopped)
  • On PHOTOEYE_IN rising edge, latch tag values; validate exactly one tag set
  • After 500 ms travel delay, energise the correct diverter (A, B, or C) for 1 s
  • Multi-tag or zero-tag reads latch ERROR_LAMP and suppress diverter action
  • ERROR_LAMP latches until STOP_PB is pressed with all tags de-asserted

Hints

  • Capture tags on PHOTOEYE_IN one-shot: ITEM_A := TAG_A; ITEM_B := TAG_B; ITEM_C := TAG_C
  • Validate: VALID := (ITEM_A XOR ITEM_B XOR ITEM_C) AND NOT (ITEM_A AND ITEM_B) AND NOT (ITEM_A AND ITEM_C) AND NOT (ITEM_B AND ITEM_C)
  • Use TON_TRAVEL (500 ms) then TON_DIVERT (1 s) after valid detection
  • ERROR_BIT: S= on invalid tag, R= on STOP_PB AND NOT TAG_A AND NOT TAG_B AND NOT TAG_C

I/O Table

Inputs

PHOTOEYE_IN

Photoeye — item at entry zone

BOOL · %I0.0

TAG_A

Tag read: item is Type A

BOOL · %I0.1

TAG_B

Tag read: item is Type B

BOOL · %I0.2

TAG_C

Tag read: item is Type C

BOOL · %I0.3

DIVERTER_A_HOME

Diverter A at home position

BOOL · %I0.4

DIVERTER_B_HOME

Diverter B at home position

BOOL · %I0.5

DIVERTER_C_HOME

Diverter C at home position

BOOL · %I0.6

STOP_PB

Stop / fault-reset push-button

BOOL · %I0.7

Outputs

CONV_RUN

Conveyor drive run

BOOL · %Q0.0

DIVERTER_A

Diverter A solenoid

BOOL · %Q0.1

DIVERTER_B

Diverter B solenoid

BOOL · %Q0.2

DIVERTER_C

Diverter C solenoid

BOOL · %Q0.3

ERROR_LAMP

Error indicator lamp (latching)

BOOL · %Q0.4

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

  1. #1CONV_RUN on by default, stops on STOP_PB

    Conveyor runs immediately; STOP_PB drops it

  2. #2TAG_A item activates DIVERTER_A after 500ms

    Single TAG_A read routes item to lane A

  3. #3TAG_C item activates DIVERTER_C

    Single TAG_C read routes item to lane C

  4. #4TAG_B item activates DIVERTER_B after 500ms

    Single TAG_B read routes the item to lane B without energising either neighbouring diverter

  5. #5Multi-tag read latches ERROR_LAMP

    TAG_A and TAG_B both set causes error; STOP_PB clears

  6. #6Zero-tag read latches ERROR_LAMP

    No tag asserted when photoeye fires causes error

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Runnable simulator field guide

Three-way sortation diverter scenario: implementation, evidence and troubleshooting

Direct answer

Three-way sortation diverter scenario becomes useful when it connects product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy with accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor, then proves one product at a time reaching each of three destinations with exactly one decision, one command window and one confirmation under normal, boundary, fault and recovery conditions. The objective is a repeatable engineering or learning result, not merely activity inside a page or tool.

This guide is written for pLC programmers building deterministic routing for products that must reach one of three conveyor destinations. The intended result is specific: the learner can associate one accepted product with one route decision, actuate at the correct position and confirm the actual destination before releasing tracking state.

a guarded conveyor sortation cell with three destinations, photoelectric sensing, pneumatic diversion and package confirmation while studying three-destination routing, package tracking, actuator confirmation and jam recovery
This unbranded training scene makes the boundaries for three-destination routing, package tracking, actuator confirmation and jam recovery visible so normal, abnormal and recovery evidence can be compared without implying target-equipment validation.

System map / 02

Six concepts that control the result

Treat these as connected checkpoints. Each checkpoint has an expected state, an observable state and a boundary to the next part of the system. That structure prevents a software indication from being mistaken for physical proof.

NODE 01observable

Define the operating contract

product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy. For three-destination routing, package tracking, actuator confirmation and jam recovery, record the initial condition, actor, requested change, observable result and stopping condition before selecting a tool or implementation.

NODE 02observable

Map the evidence path

accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor. Separate request, internal state, output or service, physical or user-visible result and independent feedback so each boundary can be inspected.

NODE 03observable

Prove normal operation

one product at a time reaching each of three destinations with exactly one decision, one command window and one confirmation. Run more than one cycle from a known state and retain the values, timings or artifacts that demonstrate repeatability.

NODE 04observable

Exercise a boundary case

closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear. Choose minimum, maximum, simultaneous, delayed or restart conditions that reveal assumptions hidden by the happy path.

NODE 05observable

Diagnose a controlled fault

an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch. Preserve the first symptom, divide the system at a measurable boundary and change one condition only after predicting the result.

NODE 06observable

Transfer and hand over

the sequence replayed with recorded timing margins and then commissioned against real conveyor dynamics, guarding and device feedback. Restore normal state, remove temporary changes, repeat affected checks and document which claims remain limited to the learning environment.

Procedure / 03

A six-step practice and commissioning workflow

Run the steps in order the first time. Later, the same structure becomes a diagnostic loop: define the expected condition, observe the boundary, interpret the difference and choose one proving action.

  1. 01

    Write the acceptance case

    Convert product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy into initial conditions, one stimulus and observable pass criteria.

    Evidence: Another person can repeat the case without guessing the intended result.

    Avoid: Using page completion or an animation as the acceptance criterion.

  2. 02

    Build the map

    Document accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor and name who owns each state or decision.

    Evidence: Every request and result has a source, destination and useful inspection point.

    Avoid: Using the same value as command, status and independent feedback.

  3. 03

    Run the baseline

    Apply one product at a time reaching each of three destinations with exactly one decision, one command window and one confirmation from a clean start and record the expected evidence.

    Evidence: Repeated runs produce the same bounded result.

    Avoid: Changing several parameters before a baseline exists.

  4. 04

    Challenge assumptions

    Test closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear without changing the acceptance contract.

    Evidence: Limits, timing and restart behavior reach defined states.

    Avoid: Testing only one ideal sequence.

  5. 05

    Isolate one failure

    Introduce or analyse an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch and locate the first disagreement.

    Evidence: The proving action distinguishes the leading hypotheses.

    Avoid: Resetting, forcing or replacing before evidence is retained.

  6. 06

    Close the evidence loop

    Complete the sequence replayed with recorded timing margins and then commissioned against real conveyor dynamics, guarding and device feedback and repeat the affected regression cases.

    Evidence: A run is complete only when the requested behavior, stop behavior, fault response and recovery are observable from a fresh initial condition.

    Avoid: Treating an acknowledged message or one successful rerun as handover.

Diagnostic matrix / 04

Symptoms, proving points and next actions

The table is a reasoning aid, not a parts-replacement chart. Preserve the initial symptom, inspect the named boundary and use the interpretation to choose the next controlled test. Site safety procedures and equipment manuals remain authoritative.

Diagnostic symptoms, inspection points, interpretations and next actions for Three-way sortation diverter scenario: implementation, evidence and troubleshooting
Observed symptomInspectInterpretationNext proving action
The expected result is unclearRequirement, initial state, actor, stimulus, units and pass conditionThe operator, programmer and reviewer may be solving different versions of the task.Rewrite one observable acceptance case before continuing.
Internal state changes but the outcome does notRequest, final owner, output or service boundary and independent feedbackA software or interface indication proves intent at one layer, not the complete outcome.Trace the first boundary after the changing state.
Normal case passes but an edge case failsLimits, timing, simultaneous events, reset and restart assumptionsThe implementation contains a hidden assumption exposed by the changed condition.Add the failed boundary as a permanent regression case.
The failure disappears after resetOriginal symptom, histories, diagnostics, timestamps and active causeReset changed evidence or state without proving the initiating cause.Reproduce under a controlled condition and preserve pre/post-event data.
Simulator and target disagreeModel boundary, software version, task timing, I/O behavior, data types and configurationA learning model and the intended target do not share one of the recorded assumptions.Reduce the case and verify against current target documentation.
The result cannot be explainedPrediction, observation, proving action, alternative hypotheses and limitationsActivity occurred but the evidence is not yet transferable or reviewable.Have the learner defend the signal path and repeat a changed case.

Product evidence / 05

What the browser practice can actually demonstrate

The browser runtime joins editable control state to visible I/O and machine or process behavior, allowing the same initial conditions and stimuli to be replayed.

Where simulation stops

The model does not size conveyors, pneumatic hardware or guarding and cannot commission a production sorter or prove machine safety.

Commissioning notebook / 06

Six cases that turn the concepts into evidence

Use these as written briefs rather than click-through instructions. For every case, state the expected condition before acting, retain the first useful observation and explain why the final result proves the requirement. A different program or component choice can still be correct when it produces the same bounded behavior and evidence.

Case 01

predict → observe → prove

Prove define the operating contract

Engineering context. product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy. For three-destination routing, package tracking, actuator confirmation and jam recovery, record the initial condition, actor, requested change, observable result and stopping condition before selecting a tool or implementation. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Write the acceptance case” stage of the workflow: convert product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy into initial conditions, one stimulus and observable pass criteria. The acceptance record should show this result: another person can repeat the case without guessing the intended result. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “The expected result is unclear” as one bounded deviation. Inspect requirement, initial state, actor, stimulus, units and pass condition The working interpretation is that the operator, programmer and reviewer may be solving different versions of the task. The next proving action is to rewrite one observable acceptance case before continuing. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is using page completion or an animation as the acceptance criterion. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: How does a PLC control a three-way diverter? A defensible short answer is: It retains each product’s destination, tracks the product to the diversion point, arbitrates one route, commands the mechanism inside a valid window and confirms the actual destination.

Case 02

predict → observe → prove

Prove map the evidence path

Engineering context. accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor. Separate request, internal state, output or service, physical or user-visible result and independent feedback so each boundary can be inspected. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Build the map” stage of the workflow: document accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor and name who owns each state or decision. The acceptance record should show this result: every request and result has a source, destination and useful inspection point. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “Internal state changes but the outcome does not” as one bounded deviation. Inspect request, final owner, output or service boundary and independent feedback The working interpretation is that a software or interface indication proves intent at one layer, not the complete outcome. The next proving action is to trace the first boundary after the changing state. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is using the same value as command, status and independent feedback. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: How should a sorter recover after a jam? A defensible short answer is: Freeze or reconcile tracking against actual product positions, remove the cause under the approved procedure, establish a known state and test the affected route before automatic release.

Case 03

predict → observe → prove

Prove prove normal operation

Engineering context. one product at a time reaching each of three destinations with exactly one decision, one command window and one confirmation. Run more than one cycle from a known state and retain the values, timings or artifacts that demonstrate repeatability. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Run the baseline” stage of the workflow: apply one product at a time reaching each of three destinations with exactly one decision, one command window and one confirmation from a clean start and record the expected evidence. The acceptance record should show this result: repeated runs produce the same bounded result. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “Normal case passes but an edge case fails” as one bounded deviation. Inspect limits, timing, simultaneous events, reset and restart assumptions The working interpretation is that the implementation contains a hidden assumption exposed by the changed condition. The next proving action is to add the failed boundary as a permanent regression case. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is changing several parameters before a baseline exists. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: What should I learn first about three-destination routing, package tracking, actuator confirmation and jam recovery? A defensible short answer is: Start with the operating contract and evidence path: product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy, followed by accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor. Add advanced features only after the baseline is predictable.

Case 04

predict → observe → prove

Prove exercise a boundary case

Engineering context. closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear. Choose minimum, maximum, simultaneous, delayed or restart conditions that reveal assumptions hidden by the happy path. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Challenge assumptions” stage of the workflow: test closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear without changing the acceptance contract. The acceptance record should show this result: limits, timing and restart behavior reach defined states. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “The failure disappears after reset” as one bounded deviation. Inspect original symptom, histories, diagnostics, timestamps and active cause The working interpretation is that reset changed evidence or state without proving the initiating cause. The next proving action is to reproduce under a controlled condition and preserve pre/post-event data. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is testing only one ideal sequence. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: How do I practise three-destination routing, package tracking, actuator confirmation and jam recovery effectively? A defensible short answer is: Use short cases with known initial conditions, a written prediction, one action and an observable result. Then alter a boundary or fault and explain why the evidence changed.

Case 05

predict → observe → prove

Prove diagnose a controlled fault

Engineering context. an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch. Preserve the first symptom, divide the system at a measurable boundary and change one condition only after predicting the result. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Isolate one failure” stage of the workflow: introduce or analyse an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch and locate the first disagreement. The acceptance record should show this result: the proving action distinguishes the leading hypotheses. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “Simulator and target disagree” as one bounded deviation. Inspect model boundary, software version, task timing, I/O behavior, data types and configuration The working interpretation is that a learning model and the intended target do not share one of the recorded assumptions. The next proving action is to reduce the case and verify against current target documentation. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is resetting, forcing or replacing before evidence is retained. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: What counts as proof of competence? A defensible short answer is: A repeatable artifact or system result plus an explanation of the signal path is stronger than time spent, screenshots or a copied answer. Physical competence requires separate supervised evidence.

Case 06

predict → observe → prove

Prove transfer and hand over

Engineering context. the sequence replayed with recorded timing margins and then commissioned against real conveyor dynamics, guarding and device feedback. Restore normal state, remove temporary changes, repeat affected checks and document which claims remain limited to the learning environment. Begin with a written normal condition and identify which request, state, physical result or communication value will provide independent confirmation. Do not begin by changing the configuration; the initial state is part of the evidence and should remain reproducible.

Controlled setup. Use the “Close the evidence loop” stage of the workflow: complete the sequence replayed with recorded timing margins and then commissioned against real conveyor dynamics, guarding and device feedback and repeat the affected regression cases. The acceptance record should show this result: a run is complete only when the requested behavior, stop behavior, fault response and recovery are observable from a fresh initial condition. Record initial conditions, the exact stimulus and the observation point so another learner can repeat the case without relying on your memory.

Fault challenge. Introduce or analyse “The result cannot be explained” as one bounded deviation. Inspect prediction, observation, proving action, alternative hypotheses and limitations The working interpretation is that activity occurred but the evidence is not yet transferable or reviewable. The next proving action is to have the learner defend the signal path and repeat a changed case. Change only one condition before observing the result, and preserve timestamps or measurements where timing matters.

Review and recovery. The most common trap here is treating an acknowledged message or one successful rerun as handover. After restoring the cause, repeat the normal case and at least one stop, timeout, disconnect or restart boundary relevant to this topic. Remove temporary forces and bypasses, return the model to a known state and retain the evidence that both operation and recovery are deliberate.

Explain it aloud: Why test faults and restart behavior? A defensible short answer is: Because an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch or closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear can expose assumptions that never appear during ideal startup and steady operation.

Answer surface / 07

Questions people ask about Three-way sortation diverter scenario

These concise answers define the operating, training and product boundaries most often missed in broad summaries. The full workflow and diagnostic table above provide the evidence behind them.

How does a PLC control a three-way diverter?

It retains each product’s destination, tracks the product to the diversion point, arbitrates one route, commands the mechanism inside a valid window and confirms the actual destination.

How should a sorter recover after a jam?

Freeze or reconcile tracking against actual product positions, remove the cause under the approved procedure, establish a known state and test the affected route before automatic release.

What should I learn first about three-destination routing, package tracking, actuator confirmation and jam recovery?

Start with the operating contract and evidence path: product identity, classification, entry event, travel model, route decision, diverter position, actuation window, destination confirmation and reject policy, followed by accepted product through tracking state and position into route arbitration, actuator command, physical gate response and destination sensor. Add advanced features only after the baseline is predictable.

How do I practise three-destination routing, package tracking, actuator confirmation and jam recovery effectively?

Use short cases with known initial conditions, a written prediction, one action and an observable result. Then alter a boundary or fault and explain why the evidence changed.

What counts as proof of competence?

A repeatable artifact or system result plus an explanation of the signal path is stronger than time spent, screenshots or a copied answer. Physical competence requires separate supervised evidence.

Why test faults and restart behavior?

Because an identity, classification, tracking, position, arbitration, output, actuator, destination or recovery mismatch or closely spaced products, missing classification, conflicting route, late actuator, sensor bounce, jam, stop mid-transfer, restart and manual clear can expose assumptions that never appear during ideal startup and steady operation.

Can browser practice replace official software or hardware?

No. It can build concepts and diagnostic reasoning. Exact firmware, I/O electrical behavior, networking, safety and commissioning require current official tools, documentation and target equipment.

How should progress be documented?

Keep the requirement, initial state, program or configuration, observed values, fault hypothesis, proving action, recovery result and a concise limitations statement.