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Build Guide · Motor Control

Sequence Control

Force motor 2 to start only after motor 1 is running, using a permissive contact.

Difficulty: IntermediateBuilds on: two start/stop circuitsLesson: read the theory →

What you’re building

L1L2/NSTOP1START1M1M1STOP2START2M1M2M2
Two start/stop circuits. Each motor's seal-in clearly brackets its own START button only. Motor 2's rung also carries an M1 permissive contact (in series, after the seal-in), so M2 can't start until M1 runs — and drops if M1 stops.

Parts to add

  • 1Power Source
  • 2Push Button NC (Stops)
  • 2Push Button NO (Starts)
  • 2Coil
  • 3NO Contact

Steps

  1. Build two start/stop circuits

    Build two independent seal-in circuits: Coil M1 (with its Start1, Stop1, and M1 seal-in) and Coil M2 (with Start2, Stop2, and M2 seal-in). Get both running on their own first.

  2. Add the permissive contact

    Add one more NO Contact and assign it M1. Wire it in series inside M2’s start circuit — between Start2 and coil M2. This is the permissive: M2 can only start if M1 is already running.

    Start2 (right) → M1 NO Contact (left)
    M1 NO Contact (right) → Coil M2 A1

  3. Energize and test the order

    Click Energize. Try Start2 first — nothing happens (M1 isn’t running, so the permissive is open). Start M1, then Start2 — now it works. You’ve enforced start order, exactly what a conveyor line needs.

  4. Chain it further

    Drop an M2 NO contact into a third motor’s start rung to extend the sequence: 1 → 2 → 3.

✓ Test it

  • Try Start on motor 2 first: nothing happens (M1 isn’t running, so the permissive is open).
  • Start motor 1, THEN start motor 2: now it works.
  • This enforces start order — exactly what a conveyor line needs.
Tip: Chain it: add an M2 NO contact into a third motor’s start rung to enforce 1 → 2 → 3.

Open the Sandbox and build it

Follow the steps above with the trainer open in another tab.

Open the Sandbox →PLC Sandbox
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