real time programming using m series

[HarryG]

Hello everyone,

I have an m-series board (pci 6259) with which I want to perform realtime programming.
The task is to perform about 20 analog input operations in the fastest possible way every 100 to 200 usecs whereby the first scan should be externally triggered.

For a start, I wrote a program which just scans 1 channel using a single scan in a loop with a hardware trigger.

Unfortunately, it turns out to be far too slow. Any suggestions on how to improve the 'realtime' performance ?

Cheers

HarryG

[Sarah_Coleman_NIUK]

Hi Harry,

What operating system and programming language are you using?

[HarryG]

Hello,

I use w2000 and LabView 7.0

Cheers

Harry G

[Sarah_Coleman_NIUK]

Thanks Harry,

Could you post the program you've already written?

[Sarah_Coleman_NIUK]

Hi Harry,

I found your other post about increasing the channel count.

It's tough to get real time performance on a Windows OS as there can be alot going on in the background that affects the acquisition rates. However you are within the spec of the board so with efficient programming you should improve performance.

Rather then use the DAQ Assistant, you should use the lower level  DAQmx functions, these take up less memory.

Make sure you don't have unnecessary code inside loops (eg initialise functions). If you want to do analysis, try, for the most part, to do it offline.

This tutorial may help, it describes most of the functions you need in DAQ:
http://zone.ni.com/devzone/conceptd.nsf/webmain/40522A58794A358B86256E7B006B8D69

The following link has some good info also. Have a look at the multifunction synchronisation section:

http://zone.ni.com/devzone/conceptd.nsf/webmain/6DC991028566309886256F990080A720#4

Hope this helps!

Sarah