Slow USB DAQ-6008

[DrDamo]

I am hooking up a USB DAQ-6008 to a new computer running windows 7, with labview 8.6.1. I am trying to read in a 5V TTL pulse which occurs at various frequencies depending on a laser step rate. I have wired it as an RSE using GND(channel 1) and ai0+(channel 2). I need the DAQ to continously look for triggers. When I have the test panel open, selecting continous mode, the maximum data points and sampling rate I can get to work is 1pt and 1Hz. Any ideas on what I am doing horribly wrong?

Thanks,

Damian

[Dennis_Knutson]

You are talking about the test panel in MAX? What do you have for the rate and samples to read?

[DrDamo]

Through measurement and automation. I start at what looks to be the default at 1000Hz and 1000samples in the test panel. That does not work and suggests I reduce the sampling and number of datapoints to be read. I do this until I am left with 1Hz and 1sample.

[Dennis_Knutson]

What error do you get? Can you reduce the number of samples or change to Finite mode and get a higher rate/number of samples?

The version of LabVIEW is irrelevant. What is the version of DAQmx that you are using? I don't think windows 7 was supported until 9.0.2.

Message Edited by Dennis Knutson on 02-10-2010 09:57 AM

[DrDamo]

I have just tried to run it in SignalExpresss 3. And I get the same error -200361 when running at 1000Hz and 1000samples to be read.

[DrDamo]

I have just tried finite. It gives the same error as continous. Even when I try smaller values.

[ColeTrain]

Hello DrDamo,

With a number of our DAQ devices, a good rule of thumb is to request 1/10 of the sample rate you are requesting.  So instead of 1000 samples and 1000 Hz, you should do 100 samples and 1000 Hz. 

The onboard memory of the 6008 is only 512 B.  At 12 bits of resolution, this means each sample takes 2 bytes.  So we will fill the memory after 256 samples.  If we return 100 samples at a time, we would not leave so many on the 6008.  Adjusting these should help fix your problem.