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

[Samuel D. [x86/CPC]]

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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