How to do multiple analog output?

[gdoherty]

Hello there. 

I'm using an NI 9263 output card to control servo motors. 

My goal is to control multiple servo motors simultaneously. I'm using the 'simulate signal' function to send a PWM signal into the DAQ Assistant which outputs the needed voltage to the motors. 

I've appended a picture of the block diagram I've come up with. When I control just 1 servo motor, everything works fine. When I add the second servo into the loop, I get an error message (picture of error AND my .vi file also appended). 

I've seen on other posts that having multiple outputs controlled by the DAQ assistant can lead to problems. What would be a good path forward? Can I add multiple output channels on the DAQ assistant? If so, how would I ensure that separate duty cycles control each A_output channel? 

Cheers, 

Gabe Doherty

Bozeman, MT

[RavensFan]

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@gdoherty wrote:

I've seen on other posts that having multiple outputs controlled by the DAQ assistant can lead to problems. What would be a good path forward? Can I add multiple output channels on the DAQ assistant? If so, how would I ensure that separate duty cycles control each A_output channel? 

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You mean WILL lead to problems.  Yes you can have multiple channels in one DAQ Assistant.  Just select multiple channels.  Take your two signal wires and use the Merge Signals function to combine them.

But better yet is to ditch the DAQ Assistant and use the regular LabVIEW primitives for DAQmx.  There are examples in the example finder.  Also look at Learn 10 Functions in NI-DAQmx and Handle 80% of Your Data Acquisition Applications