Speed of Data Acquisition using SCXI 1600 with 1102B and 1104C

[LV_ENG]

Hi,

I am using a USB SCXI-1600 with a 1102B, 1104C and 1581.

The SCXI chassis is a SCXI 1000.

I am using DAQMX 8.0 and LabView 7.1.

I have create 2 DAQMX tasks with MAX, one is reading all the channels of the 1102B and the other one is reading the channels of the 1104C (64 channels in total).

To read this 64 channels takes around 1s! Each task takes around 500ms!

The labview program is really simple, each DAQMx task goes into the DAQMx read VI set to "Analog 1D DBL NChan 1Samp" Mode.

At first, I thought I was not using a USB2 port on my PC but it was not the case.

I would be very greatful if someone knows how to make this 64 channels scan faster.

Many Thanks,

Chris

[Stuart_R]

This could be because you are making an I/O Call for every scan that you make. I would recommend configuring the code so that you read back N Samples at a time and the acquisition is hardware timed (using sample clock) instead of software timed (on demand). This will ensure that you are efficiently passing data over the USB connection. It's always better to make less calls, but transfer bigger chunks of data at a time.

Let me know how it behaves once you have configured it in this way and if you see any difference.