pid min setting and windup

[drewcrew6]

Using an AB 5/05 if the pid is using min and max for output does the pid have to calculate from zero up and across the min setting or does it start calculations at the min setting?

I believe this is enough info but if not let me know.

Drewcrew6

 

[TConnolly]

I believe it starts from the Min setting (scaled to 16383). I used to have an SCR that wouldn't respond to anything below about 20% so I used the MIN as a quick and dirty fix and the loop still performed well. However, in the SLC family, if the rung in which the PID is located ever goes false the integral sum is reset - that I assume would produce 0 output. (Which is why SLC PIDs should be on unconditonal rungs. Note that PLC5 PID is different, the rung should be conditioned unless its in an STI.)