make waveform graph signals look steady

[riot]

Hi everybody!

 I need some help, i am continuously acquiring 4 diferent analog  signals using a usb 6009.At the same time i´m using the pfio terminal for doing some  triggerring.

Since i must use the cursors for calculating frequency, amplitude and period. It is necessary that all these 4 signals appear steady (not moving) so i can use the cursors.

By now i´ve been trying to accomplish this using the Trigger express Vi, but just one of the signals appear steady and i need the four signals appear steady . Besides, i would like to have the ability to show the signals moving( as they are now  presented) and when i decide to make the measurements with the cursors the signals just appear steady( not moving). Any ideas about how to do this?

[Norbert_B]

Riot,

first of all the bad news: i have serious doubts that you can solve your request at all using the 6009.

Here is why:

- If your 4 signals don't have the exact same frequency, it will never work since you can trigger only on a single signal.

- There are three ways to stabilize the signal during display:

a) The acquisitionrate is a multiple of the signal's frequency which is of type integer (so e.g. 20). If the multilple is floating point, the signal will move.

b) You acquire a finite amount of samples and trigger on the same position of the signal (e.g. zero-crossing).

c) you acquire a finit amount of samples and no more. Then you display this data for analysis. If analysis is finished, you'd acquire the next set of data.

- a) is very unlikely to happen (i'd asume that you will get the jackpot in the lottery easier than this).

- b) is impossible with the 6009, you'd need a scope device for this.

So if any solution works, c) would be the one.

If you want to have a "moving signal", you could switch between continuous acquisition (moving) and finite (static).

hope this helps,

Norbert