I am a homebrewing, the process I am trying to control requires the control of an electric pot
with 28 liters of water in which some kg of malts are immersed, at different temperature steps.
To try to keep the temperature I use node node-red-contrib-pid
Each recipe can vary in the quantity of liters of water and kg of immersed malts
An example a receipe step ...
For this the 'first time' that I make a new recipe,
I must be able to change the parameters dynamically ( es. Prop_Band ),
to make the T oscillate, as little as possible,
around the value of the setpoint of each step.
My idea is for each recipe to find the right parameters and store them in a 'profile',
which I will use when replicing a recipe.
I tried to dynamically change the Prop_Band value, during the heating process
but I get an abnormal result
Initially I set the PB = 5 and the SetPoint = 28 in the PID and everything works fine.
When I try to modify the PB from 5 to 3,
I verify that also the PID set point has been modified,
the PID starts to intervene at 24 and ends at 27
The anomaly that returned is that,
the change in the value of the PB took place correctly,
but the SetPoint has also decreased by going from 28 to 27
I did other tests ...
if I change PB = 2 the SetPoint goes down to 26.5
if I change PB = 1 the SetPoint goes down to 26
DESCRIPTION OF THE ENVIRONMENT SYSTEM
The pot has a 2.8Kw electric heater on the base to heat the water.
A pump is applied to the pan tap which allows the recirculation
of the liquid during operation.
The temperature is read with a probe,
at the exit from the tap, before the pump enters.
Inside the pot, there is a basket with a perforated bottom,
equipped with feet to raise the basket from the bottom,
avoiding direct contact of the malts with the heating elements