CORRECTION Re: Analog Input Board Recommendations

Oops.. I meant to say 1000 Hz per channel, not 1000 kHz!! :)

On Wed, 2 Oct 2002, Calin A. Culianu wrote:

>
> Greetings,
>
> I am humbly requesting some advice from you data acquisition and control
> experts out there...
>
> I wanted to ask you guys what would be the best DAQ board for our
> application? (More on the specifics of out application below).  I have
> been perusing the products offered by both Measurement Computing and NI
> and can't decide what to get.  It seems the Measurement Computing boards
> are somewhat cheaper than the NI boards, even though they seem to have
> better specs overall. (higher sampling rates, etc).
>
> However, I know that the multiplexer on a board is often an issue --
> especially if you are sampling from more than one channel at a time.  We
> plan on doing mapping of cardiac tissue, using voltage 'sensors'.  We plan
> on having 64 electrodes map out an 8x8 grid of cardiac tissue in order to
> record cardiac wave propagation on the tissue.  Since 8 * 8 == 64, we
> basically need the ability to sample all 64 channels at once, at a rate of
> 1000 kHz per channel (for an overall rate of 64 kS/s).
>
> Here are the two boards I am looking at:
>
> Measurement Computing --
> PCI-DAS6402/16 High-Speed PCI-bus Compatible, 16-bit, 64-Channel AI.  This
> one publishes a 200kS/s sampling rate, and only costs $1,199.00.
>
> National Instruments --
> NI PCI-6033E 100 kS/s, 16-Bit, 64 Analog Input Multifunction DAQ - This
> one seems to have a lower sampling rate than the above board, but costs
> $1,695, which is about $500 more!
>
>
> Like I mentioned above, sometimes the multiplexer speed is one of the
> unpleasant surprises you get with a cheaper board.  They may say they can
> do 200kS/s, but that might only be for 1 channel.. as soon as you ask the
> multiplexer to switch channels, it's possible that you need to wait a bit
> until the multiplexer settles (in order to avoid ghosting or interference
> from the previous channel), which can drive the overall effective sampling
> rate for 64-channels to something well under 100kS/s -- or even.. *gasp*
> under 64kS/s!! (We had such surprises from the PCI-DAS 1602 board from
> measurement computing).
>
> Has anyone on this list used either boards to do massive 64-channel data
> acquisition?  How happy were you with the overall performance of these
> boards?  Any other boards you can recommend?
>
> Thanks so much for taking the time to read this email and to help,
>
> -Calin
>
>
>
>
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Received on 2002-10-02Z14:13:20