Need advise how to do

[jcp]

Hi experts;
I use 90-30 series PLC and CPU352. I want following please advise how i can implement this?
I have a Setpoint which store in a %R1 when user change the setpoint a new value ADD or subtract from the setpoint %R1 and again update %R1. but i want to get old value and move to the PV variable of PID.
For example if user increase the set point from 62 to 70 then 70 move to setpoint and 62 move to PV. when PV=SP then both have the same value untill again use increase or decrease the setpoint.
Please give me idea how i achive this?
Regards

 

[Steve Bailey]

The PV is the feedback from the system under PID control. If you want the PID to function properly you don't artificially manipulate the PV value. For example, if the PID function is controlling temperature, the PV is a measurement of the actual temperature.

 

[jcp]

Sir;
if i send u detail explanation what the pid control can u give me idea how i implement this?
i hope u favour me.
regards