electronic gearing with daqMx and 6602

[falkpl]

I am trying to perform electronic gearing and with a 6602 using daqMX and LV 7.0.  One counter out is a continuous pulse train which steps a stepper motor drive.  This motor pulls a fiber and the rate of the motor is directly proportional to the length of the fiber pulled (each step is some known number of microns of fiber).  The rate of this motor is continuously updated depending on a complex feedback loop.  I need a second counter to put out a short pulse (~10 microseconds just using the rising edge of this pulse so the duration is not all that critical) after some specified length of fiber.  How to do this in daqMx, It should be something like a pulse train which uses the other counters (the one controlling the motor) as its source instead of a clock.  I did something like this when a long time ago before daqMX.  Any help is appreciated.

Paul

[Kevin_Price]

Here's a fairly simple example I modified from an earlier posting.  I think the key to it is the DAQmx channel property CO.Pulse.Term which outputs a valid terminal name that can then be used as the source of ticks when configuring the other counter.

If you choose "continuous", then the other counter will produce a continuous pulsetrain.  You can then vary the stepper frequency on the fly to see that the other counter also speeds up accordingly.

-Kevin P.

[falkpl]

Kevin,

Thanks, thats what I ended up doing, Got it working last night, it works great.  I really am starting to like daqMX.  Do you know if there are any known issues with upgrading from daqMX 7.3 to 8.0?  I am programming in 7.0 and am waiting for a some computer upgradesto make my transition to LV 8.0.  Thanks again, glad to see that I was doing this right.

Paul

[Justin_M]

Paul,

Glad to hear you're starting to like DAQmx!  The upgrade process is pretty straightforward, and you shouldn't have any issues when moving to version 8.0.  I would recommend completely uninstalling your previous version of DAQmx first, by going to Control Panel -> Add/Remove Programs and clicking the "Change" button under National Instruments Software.  Simply installing the DAQmx 8.0 drivers should take care of the rest.

Thanks,
Justin M
Applications Engineer
National Instruments