Agilent ENA E5071C "Query UNTERMINATED" advice

[Tuomas Haitto]

I have noticed, that if running VNA-Tools II and Agilent ENA E5071C (2-port analyzer, firmware A 11.23) with Windows XP analyzer might lost GPIB connection and give "Query UNTERMINATED" error.

This strange issue can happen when doing SwitchTerm measurement and after that normal Thru measurement (measuring all four S-parameters). Only option (which i know)

on this case is power on/off the analyzer and continue thru measurement. This problem i have not faced with Windows 7 (64-bit), so user whose has had

such an issues, might try to run VNA-Tools II on WIndows 7   

[Michael Wollensack METAS]

I've seen this behavior with the Agilent ENA drivers as well on our E5061B using Windows XP and Windows 7 (64 Bit). The "Query UNTERMINATED" error message occurs randomly. Sometime it work for weeks and suddenly the error came up four times a day and then it worked again. I had the error only when I'm using the GPIB interface, when I'm using the USB or LAN interface of the VNA it never happened anymore.

I recorded a lot of GPIB traffic to understand why it happens, but it is still unclear to me.