[time-nuts] Prologix GPIB-USB vs. GPIB-LAN vs. NI was: AW: Prologix GPIB-USB vs. GPIB-LAN
holrum at hotmail.com
Mon Jul 6 16:54:04 UTC 2009
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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