Read AI and Counter in one loop reduced sample rate

[Eric_LZ]

Chasis: 9188

AI: 9219

CI: 9401

As shown in pic, without CI reading, I can adjust software controled sample rate. But with the CI reading, the max rate is around 5hz. I already changed 9219 from high resolution to high speed property. What's the matter?

[Eric_LZ]

[Carlos_O]

Hi Eric LZ,

How can you tell that the 9219 is sampling at about 5 Hz? You can use a Timing Property Node in order to get the exact Maximun Sampling Rate as shown on the picture. I also noticed that you've set the Sample Rate by using the Wait Until Next Multiple. What this does is just delay how often the data that is already acquired and stored in the PC buffer is read by LabVIEW, it really does not have to do with how often the DAQ acquires the samples (Sampling Rate). The fact that you see the data slower in your front panel does not mean that the DAQ is acquirinig slower. If you want more reference, please take a look at DAQmx Timing and Sample Rates.

Try just wiring the Wait on Next Multiple to a 100 constant, and let me know if you still get a Sampling Rate of 5 Hz. It would be great if you could show what is the content of that sub VI you are using for the 9219 and the CI so we know what effect one subVI having on the other.

I hope this helps, if there is anything else I can help or clarify let me know.

[Eric_LZ · Accepted solution]

Hi, Carlos, thanks for your reply. I acutally solved this problem by using series AI and CI connection (i.e. connect error out of AI to error in of CI) but not parallel connection as pic shows.