Digital Multimeters (DMMs) and Precision DC Sources

cancel
Showing results for 
Search instead for 
Did you mean: 

4070 sampling rate too low, only 18 Samples per seconds?? Why?

Hi guys,

 

From datasheet, 4070 can read up to 3kS/s using 5 1/2 bits. However, I can only read up to about 18 samples per second under NI Signal Express by choosing "run as fast as possible".  Why is my device reading so slowly? How could I rise the sampling speed? If I use labview function, it is still quite low.

Any suggestion?

 

Cheers,

Danny

0 Kudos
Message 1 of 4
(6,299 Views)

The 3kS/s is when in digitizing mode.  You are currently just telling it to measure single samples whenever the software gets around to asking it for data.  18S/s is pretty good when software timed.

 

In LabVIEW, look at the VIs in the NI-DMM->configuration palette.  There is a VI in there for configuring the "multipoint" acquisition and more in the Acquisition palette for you to play with.


GCentral
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines
"Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5
0 Kudos
Message 2 of 4
(6,296 Views)

This might be useful.

Of course, another option is to lower the resolution in digits (not bits).

-John Sullivan
Problem Solver
0 Kudos
Message 3 of 4
(6,287 Views)

The 3kS/s is using multipoint mode with no switch involved, not digitizer mode.  In digitizer mode you can get up to 1.8MS/s.  There is an example called Maximizing DC Reading Rate that you can use to try different timing scenarios and see what your reading rate and noise free resulution are for your specific setup.  Be aware that the effective noise free resolution reading is not only determined by the speed of the DMM but noise in the source signal as well as any noise caused or picked up by cabling.

 

-Mark

0 Kudos
Message 4 of 4
(6,237 Views)