How to use 2 digital outputs at the same time NI USB 6210 / Matlab

[GabrielPGSilva]

Can someone help me please? I have a National Instruments NI USB-6210 board and I need to use it connected to a stepper motor drive to control it in open loop. For this I need a pulse train that controls the stepper motor to be output from one of the NI USB-6210's digital outputs and, at the same time, a pulse train to control the direction of the stepper motor that is output from another of the NI USB-6210's digital outputs. How can I do this using Matlab's data acquisition toolbox?

[RIObotics]

Hi Gabriel,

Not hard.  You're essentially looking for 2 functions from the USB-6210.  You'll need:

1. Counter output, to generate a pulse train for your stepper motor: https://www.mathworks.com/help/daq/generate-pulse-data-on-a-counter-channel.html

2. Digital output, to control direction of your motor: https://www.mathworks.com/help/daq/generate-non-clocked-digital-data.html

-John

[GabrielPGSilva]

Hi, John! Thank you for your help. The problem is that when I add the digital output for the direction control I get the following warning:

Warning: Added channel does not support clocked sampling: clocked operations are disabled. Only on-demand operations are
allowed.

And then the counter ouput is disabled. Any ideas on how can I solve this? Thanks.

[Kevin_Price · Accepted solution]

The digital task for direction control can be software-timed (a.k.a. "on demand", meaning: make no config calls to DAQmx Timing).  Set the direction DO state via a software call and then after DAQmx Write returns, generate your pulse train.  This was what I meant over here.

-Kevin P

[RIObotics]

Thanks Kevin, you're absolutely right.  Didn't realize this was a double post.