Re: Is a USB to GPIB dongle/convertor a difficult project ?


"Joerg" <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> a écrit dans le message de
news: nbmSj.13931$2g1.11917@xxxxxxxxxxxxxxxxxxxxxxx

Hi Joerg,

Just for your information we have just developped and commercialized a
new low cost USB/GPIB interface, nicknamed smart488 (well, more
information at http://www.alciom.com/en/smart488.htm, but my goal here is
not to promote it but to answer to the OP...). On the hardware side such
a project is not that difficult. We haven't used a FTDI chip plus a
microcontroller as Prologix did, but a single USB-enabled microcontroller
(a Microchip 18F4550), which allows us to build a more compact device and
to simplify advanced firmware features like firmware download through USB
and no driver required on the PC side. However the firmware side for such
a project is far more complex. GPIB basics are quite easy to understand
as long as you buy the IEEE488 specs, but making such an interface
compatible with a significant number of GPIB equipments is not that easy.
If you develop such a product yourself take care of the EOI subtilities
in particular...


No pun intended, Robert, but the Prologix over here seems to be cheaper
than the the price your French distributor charges:

http://www.sparkfun.com/commerce/product_info.php?products_id=549
versus
http://www.lextronic.fr/P3171-cordon-dinterface-usb--gpib.html

But I guess that's because the USD/Euro exchange rate has pretty much
flipped around within a couple years.

Yes, we hope that the US$ will be higher soon... and I think we are not
alone to have the same hope over the world ;+). A 60% increase of the $US to
Eur exchange rate in a couple of years is not really understandable, at
least by an engineer !

Is there a chance your adapter will be marketed in the US anytime soon?

As soon as a distributor will ring us ;;+).

For future versions you might want to consider a separate USB cable like
on the Prologix. The main reason is that large analyzers must often be
pushed close to the wall because of their depth. That requires a USB
connector so you can insert one of those right angle adapters and then the
USB cable. Otherwise there is a chance the USB cable will be bent at too
sharp a radius or even hit the wall.

We hesitated twice between the option of a fixed USB cable and the use of a
standard type-B USB connector. We finally decided that the fixed cable
option was better just because it is more reliable. You're right, cable may
be deteriorated, but we didn't want to have the risk of disconnected type-B
connectors behind a pile of a dozen heavy equipments... Moreover the built
in cable allowed us to have drastically better EMC results...

Cheers,
Robert



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