Virtual or V channels provide a location for storing values that do not have any I/O associated with them.  This can be results from analysis calculations, calculated expressions, or used as variables with a history.  They are called channels because they can be used pretty much anywhere a channel is used within the DAQFactory program and typically have a history.  Virtual channels are associated with a static connection name V.  This Connection is referenced just like other connections, and can be made the default connection if desired.  This means that typically you will have to put V. in front of any the name of your Virtual Channels when accessing them from the rest of DAQFactory, such as a screen component.

To manually create a V channel, right click on the V: in the Workspace, or the CHANNELS: under the V: and select Add VChannel.  Enter in the desired name of the new channel remembering the limitations on channel names.  The name must start with a letter and can only contain letters, numbers, or the underscore.  Click OK to create the V channel.  To open the V channel view for the channel and edit its parameters, expand the CHANNELS: label by clicking on the + sign to the left of it, then click on the name of your new V channel.  There is no V channel table like there is for channels.

The V channel view has some similarities to the normal channel view.  V channels have quick notes and notes just like regular channels.  The views both have a graph displaying the data, and an available table for viewing data.  

There are three types of V channels:

Variable V channels:

A new V channel starts out as a variable V channel.  Using the same methods you would use to set a real output channel, you can set the V channel to any value.  The channel maintains a history of values and thus acts very much like a regular channel.  

Application: Use this type of V channel like you would a variable when you want to track historical values.  If you do not need a history and just need to track a singular value, use a variable, as variables are faster to access.

Calculated V channels:

The next type is a calculated V channel.  You can assign an expression to the channel, and the values in the V channel will be calculated from this expression every time the V channel is referenced.  A variable V channel becomes a calculated V channel as soon as you enter an expression.  

Application: You can use calculated V channels to store complex calculations that you may use in multiple locations.  Put the expression for the calculation in a V channel and then simply reference the V channel elsewhere in DAQFactory.  This saves you from having to retype the expression multiple times.

Application: It is perfectly legal to create constant expressions.  For example, this expression will create a simple array: {3,4,7,1,3}.  Use the InsertTime function to add time to a constant expression: InsertTime({3,4,7,1,3},5h32m12,1). One example of this application is creating a lookup table of values.

Static V channels:

Static V channels are simply static arrays of data.  The data can have time associated, or simply be data values.  Captured values from graphs, and results from analysis calculations are stored in this type of V channel.  

Note: the data in both variable and static V channels is saved with your document along with the rest of the information about the V channel.  The expression in a calculated V channel is of course saved as well.