[Test-Equipment] hpib interface

[John Miles]

> I'd like to automate some tests using hpib gear, and I have a few
questions.
>
> - What kind of control system is typically used?  I have seen some old
> computers that have hpib cards and basic language programming of sorts,
but
> what is the more contemporary approach?  I'd rather write the test program
> in something like c, java, or perl, or a graphical thingy, but I'm open to
> suggestions.

I have been doing some GPIB (aka HPIB) work lately.  Take a look at the
HP7470A plotter emulator zipfile on my web site (http://www.qsl.net/ke5fx).
It's an example of how to use National Instruments GPIB adapters to talk to
various pieces of Tektronix gear, including the 490-series spectrum
analyzers and 2430 digital scope.  I am slowly adding features to it, and
releasing upgrades with (MS Visual C++) source code.  It is very easy to
talk to these cards in C, because NI has a library that lets you communicate
with the GPIB bus without worrying about the details of the physical GPIB
interface (parallel-port, ISA, PCI, USB, whatever).

I am VERY impressed with National Instruments' free web support for their
products (libraries, drivers, FAQs, newsgroups...)  If I ever need to buy a
truckload of new GPIB adapters, I know where I'll go to get them.

>
> - I'd prefer the hpib interface to be external to the pc.  Is there a
> 232-serial-port-to-hpib interface available?  Or a schematic on how to
> build one?  I don't mind programming a microcontroller to handle the
serial
> i/o and any conversions needed, but I don't know much about the hpib side
> of things (it may require a dedicated chipset).  I've seen isa and pci
hpib
> cards, but isa is dead and who knows about pci in a few years.  232 will
be
> around at least until I'm dead, and after that I won't care.

I wouldn't bet the farm on that, considering how aggressive the Wintel
cartel is about getting rid of 'legacy' hardware.  USB seems to be the wave
of the future. :)  And do Macs even include RS232 ports any more?

What will really make *my* life miserable is when they manage to make the PC
parallel port go away, but that's a different rant...

> Plus, a 232 interface could allow for a program (eg java) to run on any pc
> or o/s (win,  linux, mac).  Or, even if it's a win-specific program, at
least
> the machine can be changed or upgraded without worrying about board
> drivers and all that stuff.
>

Honestly, GPIB hardware is cheap enough, and the OEM interface libraries
ubiquitous enough, that I wouldn't obsess over exactly what type of hardware
interface you use.  Just do what I did... buy a National Instruments card of
your choice on eBay, go to http://www.ni.com for the required drivers and
linkable libraries, and party on.

-- jm