Sometimes referred to as “Offset”, “Bias” “Manual Reset” or “Working Point. This is used to manually bias proportional output(s) to compensate for control deviation errors due to process load variations.
If the process variable settles below setpoint use a higher Bias value to remove the error, if the process variable settles above the setpoint use a lower Bias value.
This problem is most common with proportional only or PD control because integral action automatically performs this function when using PI or PID control.
Lower offset values will also help to reduce overshoot at process start up.