Christian Kleiber "if you don't work with a closed loop you won't be able to control anything

Dear Christian:
I think there is a misunderstanding here, of course I want to work with close loop without a close loop control is meaningless.

because in a PID the output is a function of the older outputs and error(sp-pv)"
and so in mine.

if you use only PROPORTIONAL in PID you will have a steady state error I don't want to use only proportional, that's why I'm interested to know dError/dOut Effect. and steady state errors can be compensated by adding a constant.

thank you