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vrf- Need Help on GPIB Limitations

Question asked by michael.asbery on Dec 10, 2000
<html><font size=3>Hi,

I could not find my IEEE488 specifications and am having a problem in ahardware testbed I am developing.  I think I might be on the edge ofthe GPIB specifications but maybe the GPIB masters out there can let meknow.

Current setup - Vee5.01/ Sicl Rev G/HP-UX 10.2/HP743 VXI Controller
<x-tab>        </x-tab><x-tab>        </x-tab>-9GPIB Devices
<x-tab>        </x-tab><x-tab>        </x-tab>-1 is a GPIB to Quad Serial device - 10 devices in the device manager
<x-tab>        </x-tab><x-tab>        </x-tab>-1 is a HP Spectrum analyzer that occasionally responds as 31 devices whenthe "Find Instruments" button is pushed
<x-tab>        </x-tab><x-tab>        </x-tab>-15meters of GPIB Cable

When I added a 10th GPIB device with a 2 meter cable, I could no longertalk to any device on the bus.  After shortening the cables to 12meters,
I could talk to the 10th instrument, but clicking on the "findinstruments" button in the device manager responds with the message"GPIB interface not found or no instruments on the bus." I amtrying to find out if I am exceeding the GPIB specification and wether Ihave to by another VXI GPIB Controller for my testbed.  I have plansto extend the testbed to 15 or 16 devices and am trying to find out if Ihave faulty equipment or  I am truly exceeding the GPIBspecifications.

Thanks in advance

</font><x-sigsep><p></x-sigsep><font face="Courier, Courier" size=3>***********************************************************
Michael N. Asbery, NRL Code 5733.20, (202)404-3014, DSN 357 fax(202)404-7661          :-)