how to set the sampling rate of multimeter

[fragrance2008]

I try to acquire data from agilent multimeter 3458a. To achieve so, I modify an example slightly, then I can get some data from the multimeter.

Now the problem is that I don't know how to set up the sampling rate of the multimeter.

The VI I used is attached:

[Dennis_Knutson]

What does the manual say? Do not make the mistake of starting with some half understood code. You have to understand how the instrument works before you do anything.

[fragrance2008]

yes, you are right, I do not quite understand the example. I read through the instrument manual and try to figure out how to build a small block for setting sampling rate. But until now, i have no idea. Do you know how to get some small example on setting up sampling rate? Could you give me some hints? That could be a big favor for me.

Thanks  in advance.

[Dennis_Knutson]

Any example is going to be dependent on the instrument command. In general, you would use something like the Format into String with the sample rate as the variable in the scan string. The formatted string gets passed to a VISA Write. Post back with the syntax for setting sample rate if in fact there is a command to set this.

[Pattos]

Hi fragrance2008,

I am sorry but I cannot open your VI as I do not have LV2009.

But I guess that you are having the same issue I had with an 3457a.

The problem was that somewhere inside the code where all the specifications like Range etc. are made a RESET or PRESET was done which swallowed up all the time. I just modified the VI slightly, so the Preset is done only once in the beginning.

Hope I could help you with your problem.

Regards, 

[fragrance2008]

Hi Pattos,

I found out the subvi which determines the sampling rate. I modified it and set the sampling rate with 'NRDGS 200, Timer;Timer 0.01;' then I got error message: trigger too fast. When I change the timer to 0.02, then no error message. I use a 10 Hz Sine signal, and Direct Sampling DC method. 

How can I know the limitation of the sampling rate for certain signal? Any idea?

[Pattos]

So you get an error when you use a timer interval of 0.01s and no error when you use 0.02s.

Have you checked if the 3458a can measure that fast with your specific settings (range etc.)?

have you checked the manual for other commands that could help you?

Ohh, and btw you can look up the sampling rate for certain signals within the specifications of the 3458a.

Message Edited by Pattos on 10-15-2009 04:54 AM

[fragrance2008]

I check the sampling range for DSDC, 0.01 s should be in the range. I don't know why my vi doesn't work for the sampling rate.

[Pattos]

Have you checked NPLC ??

I am kind of out of Ideas right now.

[fragrance2008]

I have already set the NPLC to 0 in oder to have the fastest speed.

But the 'trigger too fast' error is still there.  I really have no idea now. 😞