VXI VT1433B - Manual (Page 46)

Creating a Channel Group
The function hpe1432_createChannelGroup creates and initializes a channel group.
A channel group allows commands to be issued to several VT1433B channels at
once, simplifying system setup. Channel groups can be overlapped. The state of
an individual VT1433B channel that is in more than one channel group is
determined by the most recent operation performed on any group to which this
channel belongs.
As a side effect, this function makes all input and tach channels in the channel
group active and all source channels in the channel group inactive. This function
does not inactivate other channels within the modules that the channels are in and
does not preset the channels in the new group.
After a channel group has been created, use hpe1432_getGroupInfo to get selected
information about the group. It is possible for hpe1432_getGroupInfo to be set
up to return the number of modules, channels, inputs, sources or tachs in the
group. It can also return a list of the modules, channels, inputs, sources or tachs.
Input, Source and Tach Channels
Channel numbers must fall in particular ranges for different types of channels.
Input channel numbers range from 1 to 4095. Source channel numbers range from
4097 to 8191. Tach channel numbers range from 8193 to 12287.
A mixture of input, source and tach channels can be present in one group.
However it is also important for many functions to be sent only to the appropriate
type of channel. For example, asking for a blocksize from a tach channel can
cause an error. It may be useful to set up several channel groups at the
beginning of the program: one for input channels, one for source channels, one
for tach channels and one that combines all three channel types. The input
handle can then be used for input-only functions, the source for source-only
functions and the tach handle for tach-only functions. The “all-channels” handle
would be used for all other functions.
VT1433B User's Guide
Using the VT1433B
3-8