Project: base control panel

The base is growing, and several chips control the pressure in different areas. Instead of setting each one individually, the base gets a central desk. It takes the players' input, checks it and passes it on. Everything from this week in one chip.

The setup#

The two logic memories are the interface. The desk writes into them, the area chips read from them. That way every value has exactly one writer.

Milestones#

1. Setpoint via dial: the dial position is the target pressure in kPa. It is limited to 50 to 110 kPa and ends up in “Solldruck”.
2. Operating mode via lever: 0 = off, 1 = automatic. The value ends up in “Betriebsart”, the light “Bereit” shows it.
3. Feedback: the display “Pult” shows the target pressure that is really passed on.
4. Failure: if the dial is missing, the last valid setpoint stays. If the lever is missing, the operating mode is 0.

Keeping the last value#

So far you took a fixed fallback value on a failure. Here it is better to keep the last good value: the pressure in the base should not jump just because someone rebuilds the desk.

lbn new DIAL HASH("Druck") Setting Average
snan missing new
select target missing target new  # no dial: old value stays

For that to work, target needs a start value before the start label. In the game a register keeps its value after an upload, but on the very first build there is just something in it.