USB 6008 sampling an analog input

[LeeBowers1]

I have a USB6008 daq device and am having problems sampling just a single analog input at a rate of 1khz

Even using MAX,I get error messages 200361, 200474. it tells me to reduce the smaple rate or stop any concurrent programs

can anyone help please

[Ben.h]

Hi

Could you please upload the VI and let me know which version of LabVIEW you are currently using?

Regards

Ben

NIUK Applications Engineer

[LeeBowers1]

Hello

I am using version 8.6.1 and I do not have a VI as such, I am just using standard library DAq functions with no joy whatsoever. I have never experienced this problem with plug in pci multi func cards, just with this usb one

[Ben.h]

Upload your code then I can look at it, possibly modify it and get it working for you

Regards

Ben

[LeeBowers1]

I can see where you're coming from, by uploading code. BUT even if I use MAX and creat a new DAQmx task I get error -200361 N samples, 1k rate and 1k to read. BUT if I use test panels it seems to work ok ??? So, its like it has nothing to do with any LabVIEW code at all but is lower down at the acquisition.

[Ben.h]

Test panels are used to verify data acquisition and hardware functionality. The error you are experiencing is a result of a combination of factors.

1. The USB-6008/6009 has a relatively small onboard FIFO.
2. Communication with the device is message based over USB which is inherently slower than equivalent communication over PCI.

So the code needs to be modified to take this into account, you won't be able to use N samples unless the data is being processed with a good program architecture, like using a producer/consumer loop architecture. Limit the number of sample you wish to acquire and process.

Unless I can see the rest of your code I won;t be able to help you any further with your issue.

Ben Hartrick BEng (hons) MIET

Applications Engineer

National Instruments