- From: Calin A. Culianu <calin_at_ajvar.org>
- Date: Wed, 2 Oct 2002 11:09:08 -0400 (EDT)
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
Received on 2002-10-02Z14:09:08