Batch mixer with recipes

The brief

Client

Brightwell Cleaning Products

Site

Blending tank BT-3

Work order

BC-2617

Industry

Chemicals and cleaning products

Task code

PLC-17

Difficulty

Intermediate

Type of work

Programming

Pick one of three recipes with two selector bits, run a fill, mix and discharge batch to that recipe, lock the recipe while the batch runs, and abort to a safe state when the hardwired high-high switch opens.

What you do

1. Read the client brief and the tag table: 13 tags, 7 inputs and 5 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

• Recipe selection with ADD
• MOVE into a timer preset
• Locking a value at the start of a batch
• Step sequencing
• Hardwired high-high abort

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:

• Recipe 1 batch: fill, mix, discharge, done
• Recipes 2 and 3 use their own level and time
• Start is refused without a recipe
• The recipe is locked while a batch runs
• High-high aborts to a safe state
• Stop and Reset return to idle

In this lab

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