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GPIB cards

Discussion in 'Electronic Equipment' started by John Devereux, Oct 31, 2005.

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  1. Hi,

    I have several "older" instruments, acquired through ebay. They all
    can plot via their GPIB bus. I gather it is possible to run software
    on a PC that emulates a HP plotter, and so capture the result.

    What are the current recommended GPIB cards to do this? The "standard"
    seems to be NI cards (ISA and PCI). These are quite expensive,
    although seem to turn up on ebay. Any others? A low cost USB type
    would be nice (if they exist), but unsure about compatibility with
    available software.

    Has anyone programmed one of the USB microcontrollers to bit-bang
    GPIB, and fit it into a GPIB plug?
     
  2. Andrew Holme

    Andrew Holme Guest

    I lashed-up a minimal GPIB to RS232 converter using a PIC 16F84, to capture
    plotter output from my spectrum analyzer. My SA doesn't use the ATN
    Talk/Listen stuff; so I only needed to support the basic handshake lines
    (NRFD, NDAC, DAV).

    It's serial-port-powered, with the GPIB signals connected directly to the
    PIC. I just needed a pull-up resistor on DAV, and I toggle the DDR bits to
    simulate open-collector outputs on NRFD and NDAC.
     
  3. qrk

    qrk Guest

    You may want to look into NI's GPIB to Ethernet boxes. You can find
    these on EBay periodically. NI also has some drivers/programs that
    allow you to issue GPIB commands from the command line. You can do
    almost all of your GPIB commands from a batch file and go out/in thru
    the Ethernet port.

    On the plotting side, if you can't find a suitable HPGL to printer
    program, you can do a data dump and use Gnuplot
    <http://www.gnuplot.info/> to plot the results. This can be part of
    your batch file. Some HP instruments (late 80s and newer) allow you to
    do a PCL printer dump via GPIB. I have a program that will take the
    PCL data dump and convert it into a PCX image format (ask if you want
    it). You can use Nconvert (get the "XnView Complete version (Plugins &
    NConvert)" zip version and extract nconvert)
    <http://perso.wanadoo.fr/pierre.g/xnview/en_ncdownload.html> to change
    it to GIF or PNG if you want smaller file sizes. Perfect for word
    processor documentation.
     
  4. mike

    mike Guest

    There are a bunch of issues surrounding the older GPIB cards.
    You'd think you could get 488-1 functionality from 488.1 cards.
    But you'd be optimistic.
    It's as though NI purposely obsoleted them thru hardware and sw changes...
    Unless you get one of the 488-2 cards, you'll be stuck in dos mode.

    I've had success bit banging a card with a 9914 chip. Never tried the
    ones with the NEC chip.

    The cheapest solution for plots is a GPIB thinkjet printer.
    mike

    --
    Wanted, Serial cable for Dell Axim X5 PDA.
    Return address is VALID but some sites block emails
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    FS 500MHz Tek DSOscilloscope TDS540 Make Offer
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  5. mike

    mike Guest

    I have a similar configuration built around a 16F877A. I had trouble
    powering it. With 5V on the PIC, the GPIB levels didn't go high enough
    to reliably drive the PIC.
    Pullups dragged the serial port power down. I was trying to drive it
    with a HP 200LX...not exactly a serial port powerhouse ;-)
    Found out by accident that the thing
    runs off the gpib port powered parasitically thru the PIC output pins.
    I unplugged the power and it just kept running...
    But I wouldn't trust it for anything critical. Ended up adding a wall wart.
    How did you power yours?


    mike

    --
    Wanted, Serial cable for Dell Axim X5 PDA.
    Return address is VALID but some sites block emails
    with links. Delete this sig when replying.
    FS 500MHz Tek DSOscilloscope TDS540 Make Offer
    Bunch of stuff For Sale and Wanted at the link below.
    MAKE THE OBVIOUS CHANGES TO THE LINK
    ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/
     
  6. John Miles

    John Miles Guest

    NI's PCI-GPIB is what I'd recommend. Their USB solution is also good,
    if the budget is there.

    Software-wise, you can acquire plots with 7470.exe from
    http://www.speakeasy.org/~jmiles1/ke5fx/7470.htm , along with several
    commercial (non-free) utilities. 7470 will work only with NI hardware.

    -- jm
     
  7. I have indeed been looking at these - a bit pricy but like the idea of
    independence from a particular computer / driver.
    I have just been playing with gnuplot too - a nice utility especially
    for batch use as you suggest.
    OK, thanks for the offer. I expect there is a linux utility somewhere
    to do this, but if not I know where to come!
     
  8. No! Surely not! :)
    I wanted to be able to capture the plot to a file - I can already take
    a "screen shot" with a digital camera...
     
  9. Thanks, do you know if it works with the NI USB and ethernet products?
     
  10. Johnson

    Johnson Guest

    I used an National Instruments card purchased from EBay -- but have found it
    much easier to pull the analog signal directly from the machine -- here's a
    link to some of the HP G/L language which I scanned from a HP publication:
    http://www.tech-diy.com/HP Graphics Language.htm

    For USB consider this -- the Measurement Computing ADC/DAC cards are set up
    for USB -- you could use Softwire to program the digital out to interface
    the GPIB with a shift register -- it would be somewhat slow (and you will
    have to figure out how to solder a 50 pin SCSI jack.)

    For USB, consider the FTDI cihps: http://www.ftdichip.com/FTProducts.htm
    they have free USB drivers.
     
  11. Fred Bloggs

    Fred Bloggs Guest

    These people look pretty cheap if you go to a basic GPIB<->SERIAL at
    $300 it is a giveaway. http://www.team-solutions.com/TeamProductsFamily.htm
     
  12. What analog signal? Sorry, I am not following you here.
     
  13. Andrew Holme

    Andrew Holme Guest


    "DTR"->|----.
    |
    | ____
    | | | +5V
    "RTS"->|----o-----| L05|-----o----------------------.
    | |____| | |
    | + | | |
    ### | --- ----||-+ PMOS
    100uF --- | --- 100n ||->
    | | | ||-+
    | | | | 100
    === === === | ___ "Rx"
    GND GND GND o---|___|--->Data
    | Out
    |
    | ___
    '---|___|----"Tx"
    (-10V)
    15k


    View in a fixed-pitch font.
     
  14. John Miles

    John Miles Guest

    USB: definitely. Ethernet: yes, it should be fine too, since they both
    support the NI488.2 driver standard.

    However, I don't believe their Ethernet adapter drivers are a free
    download. If you buy an Ethernet adapter, be sure the seller includes
    the drivers for it.

    -- jm
     
  15. Thanks for the info. I have just twigged that you are the author of
    7470.EXE, I think it was seeing this program that started me down this
    road!
     
  16. John Miles

    John Miles Guest

    Guilty as charged... :)

    I'm actually about to start work on a version of 7470 that will support
    this new, economy-priced GPIB adapter:

    http://www.sparkfun.com/shop/index.php?shop=1&itemid=500

    The guy who designed it came over a few days ago to try his latest
    version out on the HP 8566B and a few other "challenging" instruments
    here in the basement. If you can wait a few weeks, this board could be
    one option for you. It is not a full-fledged GPIB bus controller
    (meaning it can't be used to address specific instruments under host
    control), but it should be able to handle device-initiated plots for
    most of the equipment supported by 7470 and PrintCapture.

    -- jm
     
  17. Joerg

    Joerg Guest

  18. Dave

    Dave Guest

    Unless you are particlarly short of cash, save youself a lot of hassle
    and buy a NI card on eBay. As you say, NI are the standard now.

    ISA ones are very cheap indeed, but you will not get drivers for the
    latest versions of Windoze.
    Others have, but I personally would rather take some intersting
    mesurements than mess about saving a few pounds whilst giving myself a
    headache.

    If you make one youself, it is extreamly unlikely to be 100% NI
    compatable. So you might as well buy a used one from Computer Boards
    (good choice) or similar, which will cost even less than a NI one, and
    probably more compatable than anything you could make in a reasonable
    period of time.
     
  19. Done. The card just arrived today!

    Working very nicely so far - can download plots from spectrum analyser
    and dynamic signal analyser. I am using a demo version of PrintCapture
    on Windows to get everything working. Next step is to do the same on
    Linux. I need to figure out how to put the interface into "listen"
    mode and capture the HPGL data into a file. Something for the weekend!
    Agreed, I was not really thinking of making one myself. I thought
    someone else might have something on sale that was compatible and
    cheap...
     
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