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Mission 58 · Pro PLC programming exercise

Hold it at 80

Run an ISA-88 style batch with an exothermic reaction and safe Hold and Abort.

Make a batch: charge 200 L of A and 100 L of B by totalised flow, heat, hold the reaction between 78 and 82 °C for 30 s, cool to 40 °C and discharge. Support Hold, Restart, Abort and Reset, and abort automatically above 95 °C.

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The 3D batch reactor control this mission runs on Pro mission
Test replay

A whole batch

Test 1 of 4
Set by the testChecked by the testStep 19 of 19 · 110.1 s
Level
Expert
Time
About 120 min
Reward
+1500 XP
Rig
3D batch reactor control
Siemens editors
SCL, LAD
Rockwell editors
Structured Text, Ladder
Course stage
30. Machine lab 5: expert systems
Automatic tests

What the tests check

  1. Charges stop on totalised volume: 200 L of A, 100 L of B.
  2. B only flows with the agitator proven.
  3. Reaction held 78–82 °C with steam below 79 and cooling above 81, for 30 s in band.
  4. Hold keeps the phase and its totals; Restart carries on.
  5. Abort and over-temperature make everything safe: cooling on, nothing else.
  1. Try it Use the buttons below the model and watch the rig respond.
  2. Test solution Every check runs on your code in one press.
  3. Replay If one fails, step through it one scan at a time to see why.
Why it matters

Where you’d see this on site

Chemical and pharma batch plants are built on ISA-88: every operator knows Hold and Abort, and every recipe is phases.

An exothermic reaction makes its own heat, faster as it gets hotter. Lose the cooling, or let the temperature drift high, and it runs away. Hold and Abort have to be safe in every phase, not just the one you tested.

Where you'd find thisMake the batch, keep the reaction in hand, and stop safely at any moment

Chemical, pharma and food batch plants follow recipes in phases. Operators can hold a batch and restart it, or abort it; the controller must know exactly what is safe in every state. Some reactions release heat, and if cooling falls behind they run away.

  1. ChargeA, then B
  2. React80 °C for 30 sYou are here
  3. CoolTo 40 °C
  4. DischargeTo receiver
On a real site: places, parts and safety
  • Speciality chemicals and resins
  • Pharmaceutical and biotech batch suites
  • Food ingredients and flavours

Runaway reactions caused disasters such as Seveso (1976) and T2 Laboratories (2007). Real reactors have independent high-temperature trips and relief systems.

ISA-88 defines the state model used here, so operators everywhere know what Hold and Abort mean.

The sizes, timings and cutaways are teaching choices, not a drawing of any one real installation.

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