Hello, I need some help.

I want to reduce the solar power that I deliver to the grid. (cost money)

I have every 10 second the active power of my grid meter. Between -5000 and 8000 kw. ( analoog input NAI1 received from raspberry Pi)

When the power is negative I want to heat  a water tank with 0 to 2000 kw heating element. Therefor I have a analog output. (4-20mA)

Using more power will lower the input value.

There is a need to overrule when the tank is cold and there is no sun.

So the heating power will reduce with max 2kw for now.

So I need help with a PI controller and negative input from NAI1. I think a PI controller is the best solution but correct me I'm wrong.

Someone have a function block diagram for me?

Thanks for answering 

Yes, I think thats the best way to go..

After unpack I can't open the file, Error

(Logo!soft Comfort V8.8.8 (2014-06-29  16-25  (no update available))

(Logo 08A8.standaard V1.08.01)

I will read tomorrow, I have to go to work.  Thank you in advance

ixo65

 

@Tukker

(Logo!soft Comfort V8.8.8 (2014-06-29  16-25  (no update available))

LSC V8.8.8? I don't know that. I think you mean LSC V8.0.

 Indeed, to many eights instead of zeros. 

I updated the software and tried your example

Will this is going to work, I tkink it is not so easy?

The output affects the input because it goes through the same meter.

example:

sun -5000 and output will be 2000 and will lower the input to -3000 and lower the output . It will be like a yo-yo. up and down. 

that's why I'm thinking of a Pi controller

ixo65

What you're planning isn't easy.

 that seems like it, thanks for your input.