Wind Up Inhibit WUH

Issue

Wind Up Inhibit WUH

Product Line

Satchwell Sigma

Environment

BAS

BAS2000

BAS2800

BAS2800+

Sigma

Cause

In Sigma a control object is displaying WUH as reason for state (RFS).

However, it cannot be found on the objects attributes in Object Editor

Resolution

The site was likely to have been upgraded from BAS.

In BAS, the Wind Up Inhibit (WUH) was used to prevent Control objects from continuing to operate (the integral action would continue to act and increase or decrease the control output) when the plant was in an 'off' state.

In Sigma, WUH is no longer used, therefore there is no reference to it within the object when edited.

However, during a BAS to Sigma upgrade, the reference is retained and then becomes inaccessible. The controller will display WUH as a reason for state when the control object is displayed in Sigma or EBO.

To correct, record the parameters and delete the control object, re-create and restore the same parameters.