mxDAQ AO fails, Legacy DAQ AO ok on DAQCard 6715. Why?

[bashev]

Outputting a mxDAQ sine wave through Measurement&Automation fails, with error -50400: The transfer did not complete within the timeout period or within the specified number of retries (see attached screenshot).

However, the Legacy DAQ sine wave through Measurement&Automation is ok on DAQCard 6715.

Why? Same setting are applied on both Lagacy DAQ and mxDAQ.

[Aaron_W.]

Bashev,

Thank you for posting on the NI Forums. I have a couple of questions that should help me get to the root of the problem. First off, what versions of the drivers, DAQmx and Traditional DAQ, are you using with the DAQCard 6715?  Have you been able to get the device to work with DAQmx for Analog Output at all, maybe with different Rates or different modes? If not, have you been able to use the card at all with the DAQmx driver? Thanks!

[bashev]

I have the following drivers: 

Measurement & Automation Explorer 4.5.0f0

NI Traditional DAQ 744

DAQmx 890f4

[bashev]

I tried numerous setting with DAQmx and Measurement&Automation Explorer AO panel. None work. However, the card passes Self-Test under DAQmx and seems that the DO panels work.

[bashev]

Reinstalling DAQmx didn't help.

[Aaron_W.]

bashev,

I was able to find this in the DAQmx 8.9 Readme found here. 

NI DAQCard-6715 Analog Output

Hardware-timed single-point mode and hardware-timed nonbuffered mode are nonfunctional. Your application is using hardware-timed nonbuffered mode if you have set up a sample clock and a buffer size of 0, or set up a sample clock, but do not begin writing until after you start the task. All other waveform and static analog output modes work as expected.

The 6715 is an older card and I am guessing this is why the hardware-timed output is not working for your test panels. I looked back all the way to DAQmx 8.0 and hardware-timed analog output is still non-functional in that version as well. It appears as that functionality did not make the transistion into DAQmx. 

Message Edited by Aaron W. on 07-01-2009 11:50 AM

[bashev]

So, how do I get my sine wave with DAQmx with 6715? Do I need an external clock. I am using an SCB-68 block. It seems weird that this card works with Legacy DAQ, but not DAQmx. If I am able to use Legacy DAQ from Labview, I will be happy as well.

[Aaron_W.]

You will be able to use Legacy DAQ from LabVIEW to do Analog output from the device. Like I said earlier, the card is older and was designed before we started making the DAQmx driver. We have gone through many series of boards since then and due to hardware changes we can't offer complete functionality of older boards as we consistently develop newer drivers. My recommendation would be to see if you can successfully use the card with Legacy DAQ as I feel that is the best option at this point. Thanks.