How to Set Daq assistant for DAQPad 6016

[drikc]

Hi,

I use the DAQ assistant to receive data analog inputs of my DAQPad 6016 under Labview 8.0.

I read on 2 analog inputs and I would like to know how should I set Number of sample and Rate.

For exemple, if I want to have 1sample/second or 2,5,10,100,1000 etc...

I don't find

Thanks a lot

[Sarah_Coleman_NIUK]

Hi,

I'm not quite sure what you want but I'll explain some of the terminology you mention which will hopefully clarify things.

When you perform an analog acquisition you transfer data from the DAQ card to a buffer in computer memory before transferring the data to your application. The number of samples defines the size of the computer buffer. For finite acquisitions you define the number of samples as the number of samples you want to acquire, for continuous acquisitions it's a bit more complicated as the size of your buffer will depend on the rate at which you're acquiring data and the rate at which you read data into your application.

The sample rate is then the rate at which you want to acquire samples, so if you want to acquire 1 S/s, you set the rate at 1.

I hope this helps a bit. Let me know if you've any more questions.

[drikc]

Thanks a lot

But, indeed as you said, I use the adquisition mode in continuous, so if I want a samples of 10/s I must put 10samples and 10 for rate, right ?

but if i put 10000sample and 10k for rate the program put an error (Error -200279 occurred at DAQmx Read (Analog 1D Wfm NChan NSamp).vi:1) but not for 1sample and 1rate why ?

is the limit of the DAQPad-6016 ? if i have only one or two differential input connected (4 or 8 channel took), will it be better than 4differential?

Thanks

Message Edited by drikc on 12-13-2006 05:07 AM

Message Edited by drikc on 12-13-2006 05:07 AM

[Sarah_Coleman_NIUK]

Hi,

The 6016 has a max sample rate of 200kS/s so you should be able to read 4 channels at 10kS/s without any problem.

Error -200279 means that you've attempted to read samples that are no longer available. The suggested solutions are to increase the buffer size, read the data more frequently, or specify a fixed number of samples to read instead of reading all available samples might correct the problem.

Try gradually increasing the buffer size (ie the number of samples) until you stop seeing the error. You could also try putting a wait function in the while loop. At the moment your code is just trying to execute as quickly as possible. If you put a wait function in you can control the rate at which it executes.

Message Edited by SarahB on 12-14-2006 03:49 AM