Temperature Control

(pgrange@cix.compulink.co.uk)
Thu, 18 Sep 1997 15:22:16 +0200 (MET DST)

I am trying to write a temperature control routine and I just know I am
re-inventing the wheel.

So can anybody help. The problem -

I have a plate with a thin film heater fixed near to a plate cooled to
approx -160c. I need to control the heat of the first plate (with the
heater) to 0.1c of demand temperature.

I am using the PWM output of an 80C552 for the heater. The reaction time
of the heater (and the plate) is very slow ie if its cooling at approx
6c/min (heater off) at 10 - 20c it takes approx 1.5c to slow and start
heating up with the heater full on.

At present I am measuring temperatures, time intervals between 0.1c
changes and heater output.

I am using Forth for the controller so has anyone got any good bits of
code or ideas (by the way I am no mathematician. I can count that's it). I
can send directly a longer description if needed.

Thanks

Peter at ECD