Issue
The LoopSingle block in LON and BACnet controllers contains an input called OutputReference. Is this input intended to be used only if Integral (iGain) is not used or can they be used simultaneously?
Environment
MNL LON Controllers
MNB BACnet controllers
Application programming created using any controller compatible version of the WorkPlace Tech Tool software.
Cause
In the Loop Single block, is the Output Reference only used if the Integral is not used or could/should they be used simultaneously?
Resolution
The "Output Reference" sets the balance point for the loop, i.e., the loop output when the input matches the setpoint. The Output Reference function operates with or without integral. If Integral is being used, its calculation can and will shift the output in the same manner as if the Output Reference were specified to be zero.
The Output Reference is usually set to an initial value that is expected to cause the loop to balance, for example, 50%. The loop is then tuned by widening the TR and using Integral and if needed Derivative. Once stability is achieved, the Output Reference is adjusted to match the output of the loop.