[time-nuts] GPIB interfaces these days

[Alexander Huemer]

Hi!

On Fri, Nov 02, 2018 at 01:04:02AM -0700, Rex wrote:
> So I've got some test equipment devices (mostly HP) with GPIB (or actually
> HPIB) connectors. Also a few others as non-HP stuff.
> 
> Mostly I have talked to them with a NI GPIB card in a PCMCIA slot in a
> laptop. Works great but the small notebook PC I have with a PCMIA slot is
> from the early 2000's and I'm worrying what if it dies. It is running XP but
> usually not on the internet.
> 
> I also have a couple very early aluminum case Prologix USB interfaces that I
> haven't tried to use in 10 years. I think I remember hearing these early
> ones had some issues, and I'd have to dig to re-learn how to talk to them.
> 
> So I haven't looked at GPIB interface devices in a long time but I'm getting
> a bit paranoid about the good NI PCMCIA card in a very old PC.
> 
> I don't remember seeing much discussion about this lately.
> 
> Is there anything new I should look at. I would have thought there might be
> something with Arduino or maybe Ras Pi by now, possibly needing some
> interfacing hardware, but I'm not aware of anything.
> 
> So, any advice from the group?  Old or new. Are my very old Prologix
> interfaces still worth looking at?

There are quite a number of reasonably-priced Agilent 82357B on eBay, 
see [1]. They work reasonably well. Since they are interfaced via USB, 
talked to them from recent laptops is not an issue.
There are also several open-hardware projects that implement GPIB, e.g.  
[2,3].
All these solutions have the drawback that they cannot react quickly 
enough to ATN messages on the bus, implying that they can only function 
as controller on the bus, not as instrument. Whether that is an issue 
for you or not is something you'll have to assess yourself. The details 
around the ATN issue are outlined in [2]. German article though that 
might need translation.
I believe it should be feasible to implement a GPIB<-->USB interface 
with instrument impersonation capability with reasonably effort in at 
least those two ways:
- By using a CPLD/FPGA instead of a microcontroller. The Lattice devices 
  with the open source yosys/icestorm/arachne toolchain come to mind.
- By using a microcontroller + additional, discrete logic to take care 
  of ATN handling.

I am not going to implement either due to lack of time and extrinsic 
motivation, but would much appreciate if somebody picks up one of the 
ideas.

-Alex OE2AHL

[1] https://www.ebay.com/itm/183267275589
[2] https://www.mikrocontroller.net/articles/GPIB-RS232-Schnittstelle
[3] http://scasagrande.blogspot.com/2012/04/gpibusb-for-sale.html