Emerson Process Management ControlWave XFC - Manual (Page 116)

F-14 / Appendix F CI-ControlWave XFC
Users may set the valves Output Control into either Manual or Automatic (Auto). When
Manual Mode has been selected, the current value of the Analog Output will be frozen.
Users may change the Manual Analog Output value, by right clicking on the field and
entering a new value. When the mode is changed back to Automatic, the valve control
starts from the last Manual value entered for Bumpless transfer.
If the user selects Raise Lower Mode, the DO associated with raising the valve must be
selected and a separate DO must be selected for lowering the valve. When the Raise Lower
Mode is being used, the Current Data section will display if the Raise DO is Off’ or Raising
and it will display the Lower DO state, i.e., Off or Lowering.
In the Manual Control mode, users may select whether to Raise or Lower the valve by using
the Manual Raise or Manual Lower Output buttons. If the valve is raising and the operator
pushes the Manual Lower Output button, the Raise Output will be automatically set to Off.
If the valve is lowering and the Manual Raise Output button, is pressed, the Lower DO
will automatically be set Off.
When switching back and forth between the Automatic and Manual Modes, both Raise and
Lower DOs will be set to Off.
F.5.6 Run Switching
Sections F.5.6.1 and F.5.6.2 provide information on run switching properties (see Figure F-
10). Enable/Disable Run Switching via a button to the right of Run Switching.
Figure F-10 – Run Switching Web Page
F.5.6.1 Common Properties
Current Rank shows how many runs are required to be open. Maximum Rank is selected by
the user (from 1 to 2). Process Variable (PV) Selection can be Differential Pressure,
Frequency or Flow Rate. The Transition Time is the amount of time required to allow run
switching to access (opening or closing a run). Valve Settle Time is the amount of time
allowed after the Transition Time for the process variable (PV) to settle, before allowing
another run switching action to occur.