Mission 86 · PRO

One screen for the whole plant: PLC SCADA training exercise

Four stations report one state each, and the overview says which one needs you.

Give the control room one screen over the whole factory. Write one state for each of the four stations, the reason the line is waiting, one state for the plant and a count of line stops. Then choose what earns a place on the overview.

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Every Coaching lesson, from zero
Every mission and lesson, as you level up
A practical test for every title, with a certificate
Rewind any test, one scan at a time
Worked solutions when you're stuck
The code converter, as much as you like

The 3D model factory this mission runs on

Level: Advanced
Time: About 40 min
Reward: +650 XP
Rig: 3D model factory
Siemens editors: Ladder (LAD), SCL
Rockwell editors: Ladder, Structured Text
Beckhoff editors: Structured Text
Stage: 43. SCADA 1: one screen for the whole plant

Required behaviour

One screen for the whole plant: what your code must do

The plant control is written and working. A SCADA overview reads a few tags from each station, so every station reports the same way: 0 Off, 1 Running, 2 Waiting, 3 Fault. UtilStatus: 3 while CompressorFault is on; otherwise 0 unless Utilities is on; 2 while AirPressure or SteamPressure is below 6.0 bar; else 1. BatchStatus: 0 unless Run is on; 2 while Step is 0, when the buffer tank has enough; else 1. LineStatus: 0 unless Run is on; 1 while LineRun is on; else 2. LineReason says why the line waits: 1 air low (AirPressure below 5.5 bar), else 2 packs backed up (AccumFull is on). Write 0 whenever the line is not waiting. PackStatus: 3 while CellTrip is on; otherwise 1 while Run is on; else 0. PlantStatus is the worst news first: 4 emergency stop (State 30); else 3 if any station is in Fault; else 2 starting (State 10); else 1 running (State 20); else 0 stopped. LineStops counts how often the line has had to wait: add 1 each time LineStatus becomes 2. On the Operator screen tab, choose what the overview shows, how it says a state, whether it says why, and the order of the stations.

States: 0 Off, 1 Running, 2 Waiting, 3 Fault, the same for all four.
Line reason: 1 air low, 2 packs backed up, 0 not waiting.
Plant: 4 emergency stop, 3 fault, 2 starting, 1 running, 0 stopped.
Line stops: Add 1 each time LineStatus becomes 2.

Tag table

One screen for the whole plant: inputs and outputs

Your program reads 18 inputs and sets 23 outputs. One more input drives the simulation or shows a reading, for you to test with. The names are the same in every maker’s editor.

Tag	Data type	Your code	What it means on the machine
`Start`	`BOOL`	ReadsAn input your code needs	Start the factory
`Stop`	`BOOL`	ReadsAn input your code needs	Stop the factory where it is
`Reset`	`BOOL`	ReadsAn input your code needs	Reset after an emergency stop or a light-curtain trip
`EStop`	`BOOL`	ReadsAn input your code needs	Emergency stop pressed
`CompressorFault`	`BOOL`	ReadsAn input your code needs	Try it: the compressor trips
`AirPressure`	`REAL`	ReadsAn input your code needs	Air receiver pressure, bar
`SteamPressure`	`REAL`	ReadsAn input your code needs	Boiler steam pressure, bar
`VesselLevel`	`REAL`	ReadsAn input your code needs	Mixing vessel level, %
`VesselTemp`	`REAL`	ReadsAn input your code needs	Batch temperature, °C
`SugarAdded`	`REAL`	ReadsAn input your code needs	Sugar the weigh feeder has added to this batch, kg
`BufferLevel`	`REAL`	ReadsAn input your code needs	Filler buffer tank level, %
`BadBottle`	`BOOL`	ReadsAn input your code needs	Camera: a bottle with no label is passing
`GateEye`	`BOOL`	ReadsAn input your code needs	A bottle is in front of the reject gate
`AccumFull`	`BOOL`	ReadsAn input your code needs	Three packs are waiting for the robot
`CurtainClear`	`BOOL`	ReadsAn input your code needs	Light curtain beams unbroken
`PalletFull`	`BOOL`	ReadsAn input your code needs	A full pallet is waiting or on its way to the wrapper
`PalletOnWrapper`	`BOOL`	ReadsAn input your code needs	A pallet is on the wrapper turntable
`WrapDone`	`BOOL`	ReadsAn input your code needs	The pallet on the wrapper is wrapped
`PersonInCell`	`BOOL`	Not neededFor testing or watching; your code can leave it out	Try it: someone walks into the robot cell
`Compressor`	`BOOL`	WritesAn output your code sets	Run the air compressor
`BoilerOn`	`BOOL`	WritesAn output your code sets	Switch the boiler on
`WaterValve`	`BOOL`	WritesAn output your code sets	Water into the mixing vessel
`Feeder`	`BOOL`	WritesAn output your code sets	Run the sugar weigh feeder
`Agitator`	`BOOL`	WritesAn output your code sets	Run the agitator
`SteamValve`	`BOOL`	WritesAn output your code sets	Steam to the vessel jacket
`TransferPump`	`BOOL`	WritesAn output your code sets	Pump the batch to the buffer tank
`LineRun`	`BOOL`	WritesAn output your code sets	Run the bottling line
`RejectGate`	`BOOL`	WritesAn output your code sets	Fire the reject gate
`RobotEnable`	`BOOL`	WritesAn output your code sets	Let the robot palletise
`PalletOut`	`BOOL`	WritesAn output your code sets	Move the full pallet to the wrapper
`Wrap`	`BOOL`	WritesAn output your code sets	Run the stretch wrapper
`AGVCall`	`BOOL`	WritesAn output your code sets	Call the AGV to collect the wrapped pallet
`GreenLamp`	`BOOL`	WritesAn output your code sets	Stack light: producing
`AmberLamp`	`BOOL`	WritesAn output your code sets	Stack light: starting or waiting
`RedLamp`	`BOOL`	WritesAn output your code sets	Stack light: emergency stop or light-curtain trip
`UtilStatus`	`INT`	WritesAn output your code sets	Overview: utilities, 0 Off, 1 Running, 2 Waiting, 3 Fault
`BatchStatus`	`INT`	WritesAn output your code sets	Overview: batching, 0 Off, 1 Running, 2 Waiting, 3 Fault
`LineStatus`	`INT`	WritesAn output your code sets	Overview: bottling line, 0 Off, 1 Running, 2 Waiting, 3 Fault
`LineReason`	`INT`	WritesAn output your code sets	Overview: why the line waits, 1 air low, 2 packs backed up
`PackStatus`	`INT`	WritesAn output your code sets	Overview: packing, 0 Off, 1 Running, 2 Waiting, 3 Fault
`PlantStatus`	`INT`	WritesAn output your code sets	Overview: 0 stopped, 1 running, 2 starting, 3 fault, 4 emergency stop
`LineStops`	`INT`	WritesAn output your code sets	Overview: times the line has had to wait

In Siemens SCL, write a block’s own tags with # in front, as TIA Portal does: #Start. Rockwell and TwinCAT use the name on its own: Start.

Automatic tests

One screen for the whole plant: what the tests check

Every station reports 0 Off, 1 Running, 2 Waiting or 3 Fault, by the same rules as the brief.
A waiting line gives its reason: 1 air low, 2 packs backed up, and 0 when it isn't waiting.
PlantStatus puts the worst news first: emergency stop, then a fault, then starting, running, stopped.
LineStops goes up by one each time the line starts to wait, however long the wait lasts.
The overview shows one state and one number for each station, in words, in process order, and says why a station waits.

Try it Use the buttons below the model and watch the rig respond.
Test solution Every check runs on your code in one press.
Rewind PRO (needs Pro) If one fails, step back through it one scan at a time to see why.

Stuck on this mission? Ask the members in the Locker Room.

Why it matters

Where you’d see this on site

A bottling hall's control room has one overview on the wall. Utilities, batching, the line and packing each show as a block, grey when all is well.

When the line stops, the costly minutes are the ones spent finding out why. An overview that says 'waiting: air low' sends the fitter to the compressor, not to the line.

Where you'd find thisOne controller for a whole factory: when each machine may run, and what keeps it safe

A small drinks factory makes an orange drink. Sugar and water are batched and pasteurised, then pumped to a filler. Bottles are filled, capped, labelled and inspected, packed in sixes, stacked on pallets by a robot, wrapped and carried to the dock by a driverless forklift. Every machine has its own controls; the plant controller decides when each may run, hands work from one to the next, and stops everything safely.

BatchMix and pasteurise
FillFill, cap, label
InspectReject bad bottles
PackRobot stacks packsYou are here
ShipWrap, AGV to dock

On a real site: places, parts and safety

Soft drinks and juice bottling halls
Sauces, dairy and liquid food plants
Household and personal-care liquids

An emergency stop is wired through a safety relay that cuts the power on its own. The program must then hold everything off and wait for a deliberate Reset and Start, so nothing moves by surprise.

Robot cells are fenced. Light curtains and interlocked doors stop the robot when someone goes in, and a restart needs a reset from outside the cell, in the spirit of ISO 10218 and ISO 13849.

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

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