Project: multi-room controller

Lab, kitchen, store: three rooms, three times the same hysteresis. Copied, that makes three times eight lines and three chances to copy a limit wrongly. With a subroutine the rule exists once, and the rooms call it one after another.

The setup#

Sensor and heater of a room carry the same name, the type tells them apart. In addition there is a flashing light “Heizstoerung” as a collective alarm.

Passing names via registers#

lbn and sbn also take the name hash from a register. So the subroutine gets the room in name:

move name LAB
move nr 0
jal room

Inside the subroutine it then says lbn temp SENSOR name Temperature Average and sbn HEATER name On heat. Which room is meant is decided solely by the content of name.

Remembering the state per room#

A hysteresis needs a memory. One register for all three rooms is not enough, so every room gets a slot in the stack, its number is in nr:

room:
get heat db nr          # fetch this room's state
# ... hysteresis ...
put db nr heat          # and write it back
sbn HEATER name On heat
j ra

Milestones#

1. Lab heats with hysteresis: on below 19 °C, off from 21 °C, keep the state in between.
2. Three rooms independent: every room controls by its own sensor without disturbing the others.
3. One sensor fails: only its heater goes off, the collective alarm lights up.
4. Everything fine: if all sensors are there, the collective alarm is off.