1608fs

[sivakumard]

Hi All..

I have a while loop and i am collecting some data from the hardware through DAQ-1608FS. I am using finite sample mode for sample clock in while loop. I wrote a code to continue the while loop iteration with finite timing delays and writing the data to a LVM file. When observing the data in LVM file we noticed that the iteration timings are increasing(adding some delay while sampling). Can anyone help me in finding the sollution. adding an excel file which is showing the values of set timings and sampling start timings. Please verify it.Thanks in advance.

[Dennis_Knutson]

First, this board is for NI products and the 1608 is from Measurement Computing so you've posted to the wrong board.

Second, any finite sampling mode with a wait inside a while loop and normal file I/O is going to be subject to os jitter and other delays so uneven timestamps is to be expected. You have not attached any code but my guess is that is what is happening. You probably need to switch to a continuous sampling mode and a better way of writing to file. Look at a producer/consumer architecture and using tdms.

[sivakumard]

Hi 

for your reference i am adding the vi file image and the written sampling data in lvm file. Please verify it and give me suitable sollution to avoid the time delay and give me some suggestions to eliminate or reduce the jitter.

thank you

[Dennis_Knutson]

Don't configure and close inside the loop. Use continuous sampling mode. Don't write the file inside the loop. Use a producer/consumer architecture.

[sivakumard]

i didnt get you. will you please elaborate it. Thank you.

[sivakumard]

my application is to sample the data for spesified time so that it will wait for 1 sec and then start sampling.
for that i wrote code like as shown in the snippets. you said that configure the sampling outside the loop.can it reduce my delay time?

[Dennis_Knutson]

Of course it will reduce the time. You have to do all of my suggestions to have x number of seconds of data without gaps.