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Mission 74 · Pro PLC programming exercise

Same button, same place

Faceplates that work the same way every time, and say why not.

Give the sump's two pumps faceplates that behave the same: Stop in the same place, big buttons with words, and a Start that greys out and says why when the won't allow it. Write the PLC side: why each pump can't start, and starting and stopping from the screen.

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The 3D duty standby sump pumping station this mission runs on Pro mission
Test replay

Start and Stop from the faceplates

Test 1 of 3
Set by the testChecked by the testStep 6 of 6 · 340 ms
Level
Applied
Time
About 25 min
Reward
+300 XP
Rig
3D duty standby sump pumping station
Siemens editors
Ladder (LAD), SCL
Rockwell editors
Ladder, Structured Text
Beckhoff editors
Structured Text
Course stage
40. Operator screens 5: same button, same place
Automatic tests

What the tests check

  1. Stop sits in the same place on both faceplates.
  2. Buttons are big enough for a gloved finger and say what they do in words.
  3. When Start isn't allowed it greys out and the faceplate says why.
  4. Pump1Why and Pump2Why are 1 when tripped, 2 when FloatLow is off, else 0; Pump1Ready and Pump2Ready follow them.
  5. Start runs a ready pump; Stop stops it and wins; a pump stops when it stops being ready.
  6. A Start while not ready does nothing, and nothing restarts by itself. HighAlarm follows FloatHighHigh.
  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

A site has dozens of pumps, fans and valves, each with a faceplate that pops up on the screen. Operators move from one to the next all shift.

A Stop button that moves between faceplates gets the wrong button pressed in a hurry, and a Start that silently does nothing wastes the minutes that matter in a flood.

Where you'd find thisKeep the wet well from overflowing, and wear both pumps evenly

Underground car parks, basements and sewage networks drain into sumps like this. Two pumps are fitted so one can fail without a flood. Swapping the duty pump each cycle shares the running hours, and both run together in a storm.

  1. InflowDrains and rain
  2. Wet wellFloats measure the levelYou are here
  3. PumpsDuty, then standby
  4. Rising mainTo the sewer
On a real site: places, parts and safety
  • Basements, underpasses and car parks
  • Sewage and surface-water pumping stations
  • Factory drainage and wash-down sumps

Wet wells are confined spaces with toxic gases: lift pumps out on their rails instead of going in.

A high-high alarm must reach a person, not just a lamp, because the next step is a flood.

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

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