[PSUBS-MAILIST] annealing acrylic

[Marc de Piolenc]

On 4/2/2014 9:57 AM, Sean T. Stevenson wrote:
> To be clear on terminology, additional thermal mass does not decrease
> stability, but rather increases the time constant of the system
> response.

Same thing, no? Adding lag to the "plant" - the thing being controlled - 
decreases the stability of the system as a whole. This is reflected in 
the need to use low gains in the feedback loop to prevent oscillation.

> Controllers simply need to be tuned in accordance with the
> system characteristics, and there are control algorithms which can
> account for the long delays typical of thermal control loops.

It's more than just a matter of tuning. It is possible to build 
controllers that contain an internal mathematical model of the plant, 
which allows them to anticipate plant response. But now we're talking 
about "observers" and other exotica which you won't find inside your 
typical thermostat.

Marc
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