34980a scan rate

[labview_MH]

Hi,

I am trying to use 34980a Switch with 34922a mux modules to collect DC voltages. 

Here is how I am trying to achieve the intended data collection:

Step 1: Initialize the switch, reset it, configure it to measure DC Voltages and then configure scan with sweep count of 1.

Step 2: Inside the for loop, format the reading, initialize the scan, then fetch the readings. I loop 4 times, each time getting 480 DC voltages.

Issue: first loop the scan runs at a much slower rate. 480 readings take about 2 minutes. The 2nd, 3rd and 4th loop, the scan runs much faster. Less than 30 seconds per scan. 

Why do I have this scan rate issue? Eventually I need to collect close to 5K voltage readings so I cannot live with 2 mintues per 480 readings. 

If I skip step #1 VI (init/rst/config) and then run step 2 VI only, then all 4 scan loops run fast. I am quite confused.

Mahesh

[Reyquaza]

Hi labview_MH,

I'm not familiar with Agilent VIs, but it looks like you have three configure VIs inside your loop; would you be able to configure outside the loop? If so, this may speed up your first iteration.

Also, could you upload your images in the form of VI snippets? This would help us understand the code.

[Dennis_Knutson]

What loops? None are in your images.