Reusable motor block: four motors

The brief

Client

Harrowgate Plastics

Site

Extraction fans M1 to M4

Work order

HP-2611

Industry

Manufacturing

Task code

PLC-11

Difficulty

Intermediate

Type of work

Programming

Write the control for one motor once, with a seal-in, a stop, an overload and a contactor feedback check, then copy it for the other three. The test runs the same checks on all four motors, so one wrong tag in a copy shows up.

What you do

1. Read the client brief and the tag table: 25 tags, 17 inputs and 8 outputs.
2. Write the logic in ladder, Structured Text or SFC.
3. Press Simulate and watch the plant answer your program.
4. Run the factory acceptance test and fix what fails.

Skills you practise

• Reusable logic patterns
• Seal-in with permissives
• Contactor feedback monitoring
• Fault latch and reset conditions
• Independent copies

What the test checks

The factory acceptance test runs 6 numbered tests against your program. The numbers in the brief are drawn per learner. The tests are:

• Start, seal-in and Stop on every motor
• Overload, fault latch and Reset on every motor
• A contactor that does not pull in
• Feedback lost while running
• The four motors never disturb each other
• Start does nothing when the motor cannot run

In this lab

• Ladder, Structured Text and SFC in one studio
• A plant that answers: motors, tanks, conveyors
• Numbered tests mark your program