Good day to all. I'm on the hunt for a low-cost data acquisition system / data=20 logger. Although a stand-alone unit would be nice, I'd be perfectly=20 happy with something that is tethered to a PC or laptop running=20 Windows XP or Win 7. This is to replace a couple of older systems that run on Windows 98=20 and earlier only. Its just getting to be too much hassle keeping=20 those old Win98 boxes running. Ideally, the unit I get would be fairly close to the nicest old unit=20 that I have - its something called an IDVM (Intelligent Digital Volt=20 Meter). This is a parallel-port connected system that is=20 opto-isolated from the PC and has an 18 or 20-bit a/d=20 convertor. Four of its 8 input channels are selected by latching=20 relays, allowing those 4 channels to be separated from each other by=20 several hundred volts. The other 4 channels use an analog mux and=20 those channels must sit within the common-mode range of the mux. What I liked so much about this unit was the software running on the=20 PC - it allowed direct input of the polynomial coefficients needed=20 for accurate thermocouple measurement. It also has a cold-junction=20 temperature sensor right near the input connector. Finally, the unit=20 had a lab-grade internal voltage reference and extremely accurate=20 input attenuator resistors. If I recall correctly, the overall error=20 budget was something on the order of 0.02% or so. This was=20 astonishing accuracy when I purchased it back in the mid '90s. The problem is that this unit came out during the DOS / early Windows=20 era. Although the software ran just fine under DOS, and then Windows=20 98, there is absolutely NO way that it will run on a modern=20 OS. That's too bad - I really, *REALLY* like this unit. My other unit is a Quatech PCM-12H pcmcia card: 12-bit a/d, 16=20 single-ended or 8 differential inputs, with a x1 / x10 / x100 / x1000=20 Programmable Gain Amplifier in front of the 12-bit a/d=20 convertor. Its problem (aside from the incredibly lousy software=20 that it came with) is that the PGA is just too noisy. It was=20 designed to allow direct measurement of thermocouples on the x100 or=20 x1000 gain ranges but the readings are completely unusable at those=20 gain amounts - there is dozens to hundreds of LSBs worth of random=20 noise. I was unhappy when I purchased it and after coming back to it=20 several years later, I'm still unhappy with it. The final nail in the pcmcia card's coffin is that, although it was=20 sold by Superlogics as being supported by Windows XP, the card's=20 manufacturer (Quatech) has never written XP drivers for it. I just=20 now finished spending several days fighting with trying to get the=20 card recognized by XP before tracking down the new owners of Quatech=20 and getting confirmation that XP was never supported. I didn't find=20 this out when I first purchased the card because the laptop it was=20 being used in was running Windows 98se. Did I mention that I think=20 that the software that came with it is possibly the WORST ever PC=20 application that I've EVER seen? So: now I'm looking for an inexpensive but reasonable quality data=20 logging system. My great preference would be to find something akin=20 to the old IDVM system that I have: 1) isolation barrier between the input signal(s) and the computer=20 that the unit is tethered to. 2) slow a/d convertor with lots of bits that can directly read=20 thermocouple inputs *OR* a 12-to-16 bit convertor with a=20 decent-quality PGA in front. 3) 4 or more inputs. 4) programmable attenuator that can handle inputs up to 200Vdc (or more) Nice to have: 5) isolation relays on several inputs that allow multi-hundred volt=20 separation of low-level signals. The sad thing is that I could design and build the hardware myself,=20 given enough free time. What I can't do, though, is write the=20 PC-side software. My talents just don't go in that direction. For what its worth, I'm waiting for Dataq's DI-155=20 to become=20 available - I have my name on a waiting list to be notified when it=20 becomes available sometime this month. The DI-155 sells for US $149 and has 8 differential inputs feeding a=20 12-bit a/d. Its FS input ranges from plus-minus 2.5V through 50V=20 (attenuation only). I'd need to add appropriate preamp channels for=20 reading thermocouples. It also lacks isolation from the PC - I'd have to purchase a USB=20 isolator for when I need the isolation. The DI-155 mostly suits my needs but its not immediately=20 available. Thus my hunt for something that perhaps suits my needs=20 more closely. Finally, I'm not adverse to spending a little extra to purchase=20 something that can run stand-alone (not tethered to a PC). The main=20 requirement is for multiple channels, preferably with enough internal=20 gain to directly read thermocouples. However, it must also be able=20 to read standard 0-5Vdc inputs as well. Again - programmable=20 attenuation allowing inputs up to 200Vdc or greater is also appreciated. Any suggestions gratefully accepted. Many thanks! dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .