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Single reads of ADC11 too slow in Labview

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Single reads of ADC11 too slow in Labview

Postby Chris Dancer » Thu May 01, 2003 4:58 pm

We have a labview program which collects data from 1 channel of an ADC11. It uses ADC11_single.vi in a timed loop. It should read 50 times per second (uses the wait on ms multiple for the loop delay, with an input of 20ms). This program has worked well for months, however, we just upgraded from an old Win95 PI machine (200MHz?) running LabView 6i to a Win98 500MHz PIII running LabView 6.1. The program now runs like a snail, taking only 2 or 3 samples per second, and this delay is definately coming from ADC11_single.vi taking longer to execute.
What could cause this? I have checked the usual subjects - processes running in the background, and there is nothing obvious that should cause such a slowdown.

Any ideas, anyone?
Chris Dancer

Postby Chris Dancer » Fri May 02, 2003 8:56 am

I solved the problem.

Reading on this forum about the 3 versions of the ADC11 gave me an idea: maybe the new drivers don't work so well with older ADC11s (ours is a V2). I removed the new ADC11 drivers, which I had downloaded from Pico, and replaced them with the drivers that came with the ADC11 on the CDROM. Hey presto - 50 samples / second, no problem.

I'd say you have a bug in your drivers, my friends!
Chris Dancer

Postby matthew » Fri May 02, 2003 1:12 pm

Thanks Chris,

This driver has been reviewed recently so some of the changes may have slowed it down. I'll forward this on to the relevent department.

At least the older driver works fine in the interrim.

Best Regards,
Matt Everett

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Postby Bonne » Sun Jun 15, 2003 1:30 pm

I am having the same problem with my ADC11 (V1). It only takes a few samples per second using the labview single value vi. I'm using the latest drivers, and I don't have access to older versions any more (they got lost) so is there another way I can speed up the measurements?


Postby markspencer » Mon Jun 16, 2003 7:35 am


Using the adc11_get_value is dependant on the windows clock and the processor giving time to the labview application you are running.

To avoid this you colud use adc11_get_times_and_values. This will return a block of data at a time.

Best regards,

Mark Spencer
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