R
I've been working on a number of PID loops but have been caught up on the bumpless transfer feature of AB PLC-5. When I try to use a proportional-only controller, it offsets the output by changing the bias when changing from manual to automatic.
Firstly, is there a problem with the way the PID loop was programmed? I have seen on the list before some discussion regarding making the Set
Point follow the Process Variable when in manual.
Second, can anyone explain just what bumpless transfer is used for and why the bias isn't removed over time (ie it will never reach set point because it is permanantly offset).
Thanks in advance for your help. I'm sure I'll have more questions in the future
Rob Schmidt
Firstly, is there a problem with the way the PID loop was programmed? I have seen on the list before some discussion regarding making the Set
Point follow the Process Variable when in manual.
Second, can anyone explain just what bumpless transfer is used for and why the bias isn't removed over time (ie it will never reach set point because it is permanantly offset).
Thanks in advance for your help. I'm sure I'll have more questions in the future
Rob Schmidt