What you learn today
- All systems on one board
- Priorities
- Readability
Whoever comes into the base in the morning wants to know within two seconds: is everything fine? And if not – what first? An overview panel answers both if it is built by two rules: priorities and readability.
One status per subsystem
Every subsystem reports a single number via a Logic Memory:
| Value | Meaning | Colour |
|---|---|---|
| 0 | fine | green |
| 1 | warning, but running | yellow |
| 2 | fault | red |
A missing memory counts as a fault. Whoever does not report cannot be fine either.
Priorities
Not every fault is equally bad. The workshop orders like this: 1 life support, 2 power, 3 production, 4 logistics. The overall display shows the number of the system with the worst status – and on a tie the more important one. For that the chip reads the systems from the least important to the most important and takes over a system even with an equal status:
sge tmp s worst # equally bad counts too
select wer tmp nr wer
max worst worst sBecause life support comes last, it wins every tie. If the panel shows “1” in red, the air is in danger, no matter what else is red.
Readability
- Colour first. You see the colour from five metres, the number only from one.
- One display per system, one for everything. More numbers do not make the panel any smarter.
- Fixed place. Life support always hangs top left. Whoever knows the panel does not need to read where things are.
- Eye level. The panel hangs where you pass anyway, not above the door.
A small subroutine computes the colour for the status. Because it is called from inside another subroutine, the caller saves ra first – otherwise the first return would no longer find its way home.
Exercise
Task
Build the overview panel. Four Logic Memories “LS_Status”, “EN_Status”, “PR_Status”, “LG_Status” report 0, 1 or 2 – a missing memory counts as 2. The displays “Ueb_LS”, “Ueb_EN”, “Ueb_PR”, “Ueb_LG” show the status as number and colour (green, yellow, red). “Ueb_Basis” shows the number of the worst system (1 LS, 2 EN, 3 PR, 4 LG, on a tie the more important one) in its colour, or 0 in green if everything is fine.
Hints
Hint 1
A subroutine zeigen with name, display and number in registers, called four times – LG first, LS last.
Hint 2
In the subroutine: sge tmp s worst, select wer tmp nr wer, max worst worst s.
Hint 3
Colour: sgt colour s 1, select colour colour ROT GELB, select colour s colour GRUEN.
Quiz
4 questions. You pass from 60 % – the server does the grading.
Complete the day
- Passed the simulator exercise
- Passed the quiz with at least 60 %
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