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VXI-11 protocol change for Infiniium software v 05.40.0000?

Question asked by happysteve on Feb 14, 2008
Latest reply on Feb 19, 2008 by dnt
Hi there,

This is regarding controlling Infiniium scopes via VXI-11 (from Linux, but I don't think that's relevant), and problems with the latest release of Agilent Infiniium software (05.40.0000). Note that the last "working" version of the software that I have access to is 05.10.0000, so this problem may have appeared at some intermediate version.

I wrote a small user library to talk to vxi11 instruments a couple of years ago, and have successfully been using it to talk to Agilent Infiniium scopes (and equipment from other manufacturers) fine... until I upgraded my Infiniium DSO8104A scope software to version 05.40.0000. At that point, my simple "send a vxi11 command and wait for the answer" program - much like the example code in Agilent's AN 1465-28 - ceased to work. I downgraded to version 05.10.0000 and everything is fine again.

Upon closer inspection, it seems that link->maxRecvSize is set, by the scope, to 0 (zero) for Agilent Infiniium software version 05.40.000, whereas previously it was set to 4294967295 (presumably the largest number you can put in an unsigned long?). Other instruments, by other manufacturers, tend to return more sane answers (e.g. 4096). My code takes account of maxRecvSize so it does not send more bytes than the instrument can cope with. As you can probably imagine, having maxRecvSize==0 throws it off somewhat!  

Does returning 0 not break the vxi-11 protocol (specifically RULE B.6.3)? Is this a bug, or a new way of doing things? If so, where is the relevant documentation or standard so that I can re-write my code?

My (open source) code for Linux is at http://optics.eee.nottingham.ac.uk/vxi11/

Cheers,

   Steve.  

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