GPIB cards

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.

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 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) to change it to GIF or PNG if you want smaller file sizes. Perfect for word processor documentation.

--
Mark

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
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
http://www.geocities.com/SiliconValley/Monitor/4710/

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
http://www.geocities.com/SiliconValley/Monitor/4710/

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

, along with several commercial (non-free) utilities. 7470 will work only with NI hardware.

-- jm

------------------------------------------------------

Note: My E-mail address has been altered to avoid spam

------------------------------------------------------

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!

--

John Devereux

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...

--

John Devereux

Thanks, do you know if it works with the NI USB and ethernet products?

--

John Devereux

SNIP

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:

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:

they have free USB drivers.

These people look pretty cheap if you go to a basic GPIBSERIAL at $300 it is a giveaway.

What analog signal? Sorry, I am not following you here.

--

John Devereux

[snip]

"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.

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

------------------------------------------------------

Note: My E-mail address has been altered to avoid spam

------------------------------------------------------

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!

--

John Devereux

Guilty as charged... :-)

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

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

------------------------------------------------------

Note: My E-mail address has been altered to avoid spam

------------------------------------------------------

Hello John,

Just in case you haven't found a solution yet these folks have one for about $100 but I don't know anything about how good it works:

I believe the designer had posted here in the NG.

Regards, Joerg

Thanks Joerg, John Miles pointed this out too. Apparently he is modifying his 7470.exe GPIB plot capture utility to work with it.

--

John Devereux

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.

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...

--

John Devereux