Start-up after a restart

You pull the workshop chip, change one line and plug it back in. At that very moment light, pump and heater switch on together, the grid collapses and the life support in the neighbouring module goes off. The start-up is the place where an otherwise good script slips up most often.

What holds after inserting#

So the chip starts with an empty head in a world that keeps running. Whatever it remembered in registers – hysteresis state, counters, sequence step – is gone. You had also better not rely on old contents of the stack. Anything that should survive a restart belongs in a Logic Memory.

Once before the loop#

Everything that should only happen at start sits before the label of the main loop:

1. Defined beginning: set the outputs deliberately instead of inheriting the old state of the devices.
2. Check memory: read stored values and check them. A Logic Memory can contain anything, including nonsense from an earlier script.

lbn soll SPEICHER HASH("Sollwert") Setting Average
sge ok soll SOLL_MIN          # NaN gives 0 here
sle tmp soll SOLL_MAX
and ok ok tmp
select soll ok soll SOLL_STD
sbn SPEICHER HASH("Sollwert") Setting soll   # write the repaired value back

The repaired value is written back. That way the memory holds something valid again, also for other chips that read it.

Gentle start#

In the power grid every tick counts: if demand exceeds supply, all normal loads on the grid go off. Switching many loads on in the same tick is therefore the riskiest thing a chip can do. A staggered start is better: one more stage every few ticks. Light first, then the pump, finally the heater.