represents the configuration of the signal input or signal output operation to be executed by the I/O
device. Creating tasks is a general feature of the MAX utility, i..e. tasks are used also for configurating
other I/O devices than the USB-6009.
In general, a task can contain one or more
global or local virtual channels
, and one such virtual channel
is based on one
physical channel
(having e.g. a screw terminal on the I/O device). A local virtual
channel exists only within it's parent task, while a global virtual channel may be used in several tasks. If
a global channel is reconfigured, all tasks which involve that global channel are updated accordingly.
All these items, i.e.
l
tasks,
l
local and global virtual channels,
l
physical channels,
can be configured in MAX. Tasks and virtual channels can be given any name (e.g. task_motor and
meas_speed, respectively), while the physical channels will have predefined names (e.g. ai0, ai1, ao0,
ao1).
Configuration of an analog input task
See
Figure 8
. Selecting
Create Task
in the menu opens a window where you can select the
measurement type, see Figure 13.
Figure 13: Window where you select the measurement type
Page 12 of 21
TechTeach: A quick guide to National Instruments USB-6009 and USB-6008 multifun...
2/14/2009
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