refresh 6008

[cees10]

i have a application for 6008

i use 8 analog  channels  and write all data to log file in labview  8.5

i have a problem  saving at high  frequentie   max is 10 hz  that i can write to a file

if  really need to save all channels to   1000 hz   for more the 8 hours

but for some reason the log file cannot  write  this frequentie  

have any body  idea how to solve this?

i use IBM laptop T42p    xp pro  2 gib mem  lots of room harddisk

[Hillman]

Hi cees10,

Thanks for the post!

Can I firstly ask why you need to save so much data?

Secondly, this is a large amount of data to be writing in a burst to a file, can we see your code?

Thirdly, what sort of file are you saving too?

However, you wont be able to write a 2.4Gb file in one go into memory. You will need to split the data into several files. And to clear the other point up, you won't write one peice of data to a file every 1/1000, you would write bursts of data to a file. Your processor couldn't physically provide the power to do it per sample!

Kind Regards,

Message Edited by Hillman on 10-21-2008 05:07 PM

[cees10]

thanks mister hillman

I need so much data becuase i want to see a relation between acceleration and force needed  (also aerodynamic parameter like temp humidity air pressure)

so can see the code but its on this comp

I save to a txt file

I ask  in  very begin when i started with labview   how big a file size could be they told me unlimited!!

I am new to labview   so how sould a do writing to file?  in   1/1000 of a second?

or does labview handle this it selve?

[Dennis_Knutson]

There are a lot of different ways to save data to a file. Some are faster and more efficient than others. If you are using something like the Write to Measurement File, you are using one of the slowest methods. Have you looked at the shipping examples for binary or tdms file writes? Even if you want to stick with text, you will be much better off using low level functions. For example, with the low level functions, you would open the file once before your acquisition loop and then close it outside when the loop finishes. It would be helpful to see what you are doing now.

[Hillman]

Hi cees10,

This is an example of writing to a measurement file.

This is a normal AI continous setup. I have used the express write to measurement file because it has the option to create a new file when the max size has been reached (among other functions), as well as writing columns of data per number of channels. 

Obviously, at high frequencies you would probably need to introduce the producer/consumer method - because the write to measurement file may slow down the DAQ loop. 

Let me know what you think,

(example in LabVIEW 8.6)

Kind Regards, 

[cees10]

i tried to upload a file but get error after error

so i cannot show anything

sorry

[Dennis_Knutson]

What kind of file and what is the error message?

[cees10]

another problem ,with   my gps

i really have no idea why i get this error message

[Hillman]

Hi cees10,

This is a different issue and I would recommend opening a new post!

Kind Regards