Temporary Value for tag used in drag
regions and pushbuttons to hold a temporary value.
Range: -99,999,999,99 to 99,999,999,999
Field Type: analog
Tag field: .TEMPVA
See also 4.8.67 .VIEWVA, 188.8.131.52 NODEVA
TEMPVA behaves like a screen tag. It allows super-fast screen response, for Drag regions, slider bars and ramp buttons, regardless of the speed of communications to the IO Tag.
Every Tag and parameter in the system including analog, digital and text points have this TEMPVA field. It is initialized to the value of the tag or parameter it is associated with when the display is called up. It responds as fast as a screen tag. The user or operator sees fast animation of his changes to drag regions rather than waiting the two or more seconds for feedback from the field device.
Example for Blocks
The Move or Bar is
Animation is connected to: Tagname:Parameter.TEMPVA
Drag Region is connected: Tagname:parameter.TEMPVA
Drag Region Button Key Up Macro:
The Button Up Keymacro is needed to pass the new value of .TEMPVA to the actual Tagname.
A second larger bar, move object, or text is connected to: Tagname:Parameter (Optional - to prevent false indication)
Example for Tag
The Move or Bar is
connected to: Tagname.TEMPVA
The Drag Region is connected to: Tagname.TEMPVA
The Button Key Up Macro is: <SETVAL>Tagname=@Tagname.TEMPVA
A second larger bar,
move object, or text is connected to: Tagname
(Optional - to prevent false indication)
There are drawbacks to this. The actual tag or parameter in the field is not guaranteed to change due to communications error, Wrong Access Level (password) or field device lockout. In these cases, TEMPVA stays at the dragged value, falsely indicating the new setpoint.
Since the change to the field variable uses the keymacro "<SETVAL>Tagname.TEMPVA", there is no “WRONG PASSWORD LEVEL” message.
One solution to these false indications is to make dual active points: one connected to the .TEMPVA and the other to the actual field point. The drag region would only be associated with the .TEMPVA. The two active points would have to be of different sizes to prevent one from writing over the other completely. Alternatively, the second active point could be a text field showing the point: the widgets knob3, knob4 and knob 5 are examples of this second text field.