Hi, there is a problem with PID loops on redundant controller system.
PID loops on IO unit will reinitialized thereself when system switch from one controller to the other, for example,
a PID loop’s initial value:
then I change these values through PID button On PAC Display Runtime as follow:
I find these values work good, so I leave it there, I want to test whether the redundancy system work well, I make the qualified backup contrller become active through the PAC Redundancy Manager, then I find all the PID loop parameters go back to initial status,
SetPoint goes back from 50 to 80
mode goes back from auto to manual
Gain goes back from -30 to -20
I goes back from 0.03 to 0.05
according to #1700 document, we know that PID loops run on the IO side, which means all PID loop’s parameter should save on the IO unit’s memory, so, why does this problem happen ?
I don’s use any PID commands in the strategy.
Thanks for all reply