8 AI channel 1MS/s x 10 sec acquire and write binaryfile

[PKP]

Hi,

I need to acquire analog voltage data from 8 AI channels at 1MS/s for a period of 10 secs and write the data into a binary file. This is a large amount of data and the current VIs that I am using , modified from shipping-example VIs, cannot handle such large volumes of data.

My hardware includes:

A PXI-1042 chassis with two PXI-6133 (32MS/s) S series boards.

The DAQ is connected via fiber optic cable using PXI-8336 MXI-4 interface boards, to a PC with a Intel P4 2.8GHz, 3GB RAM.

I'd be grateful for any help. Thanks.

Philip

[devchander]

Hi Philip,

Kindly post the VI you are using.

Let's see what modifications are needed to make it work as per your sampling rate spec.

regards

Dev

[PKP]

Thanks for replying. I have attached my program. This VI works well for 100,000Hz sampling rate and writes a binary file. However, when I increase the sampling rate to 1MS/s, it gives an error saying that you are attempting to read data that is not there anymore.

The eight channels read pressure transducers and a load cell. So I will have to finally convert the voltage into pressure or force by factoring in a transducer sensitivity. I am not sure how to do that with DAQmx, as it creates tasks and does not give output lines of data. I now do the transducer voltage to pressure/force conversion when I convert the binary to a text file using another VI.

The first part of the VI is just to write a config text file for the variables of the experiment.

Thanks.

Philip

[devchander]

Hi Philip,

Form the first glance i suggest following.

• Remove 100ms wait you have put.
• Try to see if you can do away with graph display since that also takes a share of process time to update.

Also i have attached a VI that  i had used for my applications.

(Since your create header.Vi was missing in your attachment, i have put the one i was using for my appilcation. Replace with your VI.)

tell me if this works.

regards

Dev