The USB-6008 allows only software-timed updates to its
digital to analog converter (DAC), up to 150 samples per second, so a
continuous analog output is “possible,” but it will be limited to slow update
rates and the timing will not be as accurate as a card capable of hardware
timed analog outputs.
For a LabVIEW example of software-timed analog output,
please see the "Gen Mult Volt Updates-SW Timed.vi" example, available
in the LabVIEW example finder (Help»Find Examples»Hardware Input and
Output»DAQmx»Analog Generation»Voltage).
Another example can be found at the
following link:
Continuous Software Timed Analog Output
for the USB-6008 and USB-6009
You could modify these examples to
output a square wave instead of sine wave and place a control on the front
panel to change the amplitude on the fly.
The amplitude control should be placed inside of the while loop.
Jared T.
