hj91 / node-red-contrib-easy-pid-controller Goto Github PK

While the flow is running, add the ability to stop the PID, stop the accumulation of error coefficients, or reset the accumulated error coefficients.

Hello hj91 and thank you for the great controller. It was missing in Node Red something like this.
Perfect really.
I also want to start to program one, but now you make the first big step :) Thank you.

My ideas / improvements:
-Integral part need some limit (Maybe parameter like -100% or +100%). Otherwise the I-part run to a big value, and if suddenly the act reach the set, the I-part need to go down again a long time.

• value for selected sensor is just in total Volts. Maybe we can do 2 decimal places to be more exactly.
• in my opinion the PID result should be some value like -100% to +100%. Because of the I-part issue (first point) the value increases endless. I think same limit you did with the Sensor output. Best case will be for controller like -100% to +100% with two decimal points. Maybe we can also select "Sensor" type like "-100% to +100%"
• if we switch off the controller, should be the integral part 0 again? I think yes. So after start we start with 0 for the I-part, correct? It isn't like this.

These should just be suggestions. I would be happy if we could develop this together.
Thank you in advance for reading my ideas!

Best regards
Kevin

It may be my lack of understanding with this node, and I'm happy to be corrected. But my assumption was the value control signal (0-10v or 4-20mA), on the output of the node, would be used to drive the actuator.

1. I have observed that value follows the PV only, and has no PID control applied.

• Expected behaviour: This would be the output of the PID node and have PID calculation applied to the signal.
• Observed behaviour: This is a scaled valve of the input PV and has no PID applied.
  Is this just a scale representation of the input PV?

2. output appears to have the PID applied to it as the response changes with proportional and integral settings. However the integral drives this signal past the outputs limits.

• Expected behaviour: The output is limited to a range (say 0-100%). I thought this would be value signal and used to control the process.
• Observed behaviour: The output signal looks like the output from the PID algorithm, and not particularly the output of a PID block used in process control. This signal will suffer from "integral windup" where the output saturates and may not return to a controllable range of 0-100%.
  Is output the signal to use for controlling the process? If so, why is the output wider than 0-100% and how is integral windup prevented?

This picture shows value follows PV and that PID is not applied to Value.

Happy to provide any more information, or accept any guidance from mis-understandings.

Hi hj91!
The first to thank you for your excellent job!

I am designing a system at home where I need all photovoltaic production to be used to heat water.

What I need is, if the solar panels are generating 1kw (this measurement is extracted by mqtt from the inverter and it would be the setpoint remote) I need to divert all that power to a resistor controlled by a dimmer with 0-10v signal input through a Shelly Dimmer 0-10v

Regulator 25A
https://es.aliexpress.com/item/20000003997748.html?spm=a2g0o.cart.0.0.eec37a9dSt4vWf&mp=1&gatewayAdapt=glo2esp

https://shelly-api-docs.shelly.cloud/gen2/Devices/ShellyPlus10V

SP is the instantaneous solar power extracted by MQTT from the solar inverter, logically the SP will be continuously oscillating according to the solar generation.

PV will be a ShellyEM with a clamp measuring the consumption of the dimmer. (This value can be obtained by Json HTTP)

OUT will be the Shelly Dimmer 0-10 connected to the SSVR. (

The ultimate goal is that the PV = SP

Do you think could do it with your node?

There was also the option to do it in a ESP32, but seeing your contribution I see it easier to do it in Nodered. I leave you the scheme I had, sorry for my disastrous English!

Thanks for your attention!