05-18-2010 04:43 AM
Hi, I am currently doing a project to record heart signals which can be analysed and the data backed up to an Excel file. I have no problem with the labview program and I am acquiring the heart signal successfully.
When I use the 6008 I appear to be loosing some of the signal, it seems to be chopping the top and bottom of the wave. I am wondering is this because scope is faster than the DAQ? And maybe the DAQ is not suitable.
Thanks, any help would be appreciated.
05-18-2010 04:55 AM
05-18-2010 08:52 AM
05-20-2010 12:18 PM
Thanks for the prompt replys. I have built an amplifier circuit which also conditions my ECG. It is the output signal from this that I'm feeding into the USB DAQ. I have adjusted the gain of my circuit by changing the gain-resistor value several times but it is still out of range to capture the entire signal. I know that the 6008 can sample up to 10k samples/second so this should be plenty to capture the entire QRS complex. I have read that the 6008 has a poor onboard FIFO which overflows quickly if aquiring data at a high rate so I am wondering could this be the issue? Also I dont know what rate I am sampling at how can i check this?
05-20-2010 12:28 PM
deck wrote:Thanks for the prompt replys. I have built an amplifier circuit which also conditions my ECG. It is the output signal from this that I'm feeding into the USB DAQ. I have adjusted the gain of my circuit by changing the gain-resistor value several times but it is still out of range to capture the entire signal. I know that the 6008 can sample up to 10k samples/second so this should be plenty to capture the entire QRS complex. I have read that the 6008 has a poor onboard FIFO which overflows quickly if aquiring data at a high rate so I am wondering could this be the issue? Also I don't know what rate I am sampling at how can I check this?
I think you should post a picture of the a chart showing the error, your code not as a picture, and a schematic showing how you connect to the 6008. Without all that, we are not able to help you. I have never used the 6008, but I am quite sure then a buffer overflow occur you will not get the problems you are talking about.
05-20-2010 01:16 PM
05-21-2010 02:07 AM