[time-nuts] Prologix GPIB-USB vs. GPIB-LAN vs. NI was: AW: Prologix GPIB-USB vs. GPIB-LAN

[Don Latham]

I have used an interface from Softmark. I don't know if multiple
interfaces can be applied, but they are USB. There's no local storage,
everything is in the host, and I have not timed the use. OTH, they can be
bought for about $40US on ebay or straight from the Aussies at softmark.
Comes with dll's and an app...
Don

Robert Darlington
> You can *probably* replace the EEPROM with an FRAM chip (or even a free
> sample of an FRAM chip) to get around the wear issues.  I haven't opened
> my
> unit, but this is a serious issue as I'm gearing up to write software to
> make a "poor man's" network analyzer using a frequency synthesizer and a
> volt meter, switching between them pretty much as fast as possible.  Maybe
> I'll just use that NI card ;-)
>
> -Bob
>
> On Mon, Jul 6, 2009 at 11:07 AM, Samuel D. [x86/CPC]
> <sam at canardpc.com>wrote:
>
>> Damn, that's a big flaw.
>>
>> The software I'm working on send three "++addr" commands per second.
>>
>> Only 4 days @24h/day to reach the limit :-/
>>
>>
>> -----Message d'origine-----
>> De : time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] De
>> la
>> part de Mark Sims
>> Envoyé : lundi 6 juillet 2009 18:54
>> À : time-nuts at febo.com
>> Objet : [time-nuts] Prologix GPIB-USB vs. GPIB-LAN vs. NI was: AW:
>> Prologix
>> GPIB-USB vs. GPIB-LAN
>>
>>
>> The Prologix adapter has a ++addr command for changing the GPIB address.
>> You can select different instruments that way.
>>
>> Unfortunately, the version I looked seems to have a potentially fatal
>> flaw.
>> When you change the ++addr,  the device writes the internal
>> microprocessor
>> EEPROM.  The EEPROM is speced a 1 million write cycles.  If you changed
>> instruments at once a second,  in under two weeks the chip could be
>> toast.
>> My app could have worn out the chip in under a day...
>>
>> All this assumes that Prologix did not implement some sort of elaborate
>> wear
>> leveling scheme in their software,  but I suspect not.  They seem to
>> have
>> intended one to set up the device to talk to one instrument then save
>> that
>> configuration in the chip.  Dynamically hammering the thing to death
>> with
>> address changes was not the intention of the ++addr command.
>>
>> I wound up implementing  a GPIB controller (with Prologix emulator) with
>> my
>> MegaDonkey touch screen LCD controller.  It even included a HPGL/PCL
>> plotter
>> routine to draw instrument plots on the 160x80 LCD.
>>
>> ----------------------------------------
>>
>>
>>
>>
>>
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-- 
Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
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www.lightningforensics.com
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