question about node-red-contrib-pid, heating water, solar power and, of course, nodered.
What i have:
I am using a small solar plant for my own use, about 1.5KW peak. When
the sun shines an i dont use much electric devices i feed my power to
the energy provider, for nothing.
Instead I want to use the power to heat my water.
I also have a superfast modbus power counter (SDM630) which updates
my mqtt/nodered every second with actual power values.
When i feed power to the energy provider the sdm630 reports a negative power value.
What i need is a control circuit that powers my heater in my water
tank. (Heating unit, controlled by raspi and PWM to 0-10V thyristor
switch) when the power from the meter goes below zero.
It should heat as much as it needs to get the power value to min of -10(setpoint)! (for example)
On cloudy days the power level jumps from 400W to 1500W and back in
seconds. The reaction of the node has to be superfast and should not
use power from the energy provider because it is to slow.
Superfast means, other than the examples i found for heaters - they react in minutes or houres - i need the circut to react in a second.
-500W means 490 Watt to the heating, next second -140W means 130 Watt to the heating.... at once!
Input value is only the Power from the SDM630.
Anybody knows if node-red-contrib-pid can do that?
What are the basic start values for all parameters of node-red-contrib-pid to start?
What values do you need to give me a starting point?