Programming instructions

Chapter 3 Basic LabVIEW Data Acquisition Concepts
© National Instruments Corporation 3-9 LabVIEW Data Acquisition Basics Manual
Figure 3-5.
LabVIEW Error In Input and Error Out Output Error Clusters
For more information on error handling, refer to Part VII,
Debugging Your
Data Acquisition Application
, in this manual.
Channel, Port, and Counter Addressing
The Analog Input and Analog Output VIs have a
channel list
parameter
where you can specify the channels from which the VIs read or to which
they write. The Digital Input and Output VIs have a similar parameter,
called
digital channel list
and the equivalent value is called
counter list
for the Counter VI’s. For ease of understanding of channel addressing
concepts, the
channel list
,
digital channel list
, and
counter list
parameters
are referred to as
channel list
in this section. Any special exceptions for
these parameters will be noted.
Each channel you specify in the
channel list
becomes a member of a group.
For each group, you can acquire or generate data on the channels listed in
the group. VIs scan (during acquisition) or update (during generation) the
channels in the same order they are listed. To erase a group, pass an empty
channel list
and the group number to the VI or assign a new
channel list
to the group. Changing groups can only be done at the Advanced VI level.
Refer to the
LabVIEW Function and VI Reference Manual
or the LabVIEW
Online Reference
, by selecting
Help»Online Reference...
, for more
information.