AnsweredAssumed Answered

vrf Dynamic i/o

Question asked by VRFuser on Jun 14, 2001
Hi Chris,

How about this as a solution/workaround:

Set up a loop 0-30, add your favourite interface select code (700 for
HP/Agilent cards, 1400 for NI and others) and float the address of a direct
I/O box (i.e. 700-730).  Inside the box, write a *IDN? and read back
instrument string.  Use an error output pin to catch any time outs.  If this
action times out, then either there is no instrument, or it doesn't
understand *IDN?.  Fire another direct IO box from the output of the error
pin and query with ID? (you may have to execute a CLEAR first - old
instruments will probably give an error status somewhere to the
misunderstood *IDN?).  Again, on this box, have another error output to
catch timeouts - again, no instrument or did not understand ID? will be the
case when this fires.  You could go on add infinitum using all the archaic
forms of figuring out what an instrument is supposed to be and then thank
the IEEE for coming up with 488.2

Note - it would be worth initially setting the timeout to something like
0.2s - this should speed the loop time, but give sufficient time for
instrument to respond if a) it is there and awake b) understands the
command.

In practice, I have used this approach over dynamic IO, as you have to pay
attention with dynamic IO to ensure you handle all non-488.2 instruments
(clearing errors etc).

Hope this helps, if you want a hard coded example, let me know.

Best Regards

Andy

-----------------------
Andy Street
Technical Consultant
Agilent Technologies
Tel: 01189-275395
Mob: 07765-897003
e-mail: andy_street@agilent.com

-----Original Message-----
From: Chris Phipps [mailto:chris.phipps@analog.com]
Sent: 14 June 2001 12:36
To: vrf@lvld.agilent.com
Subject: vrf Dynamic i/o


Hi All

Can anyone tell me how to find non 488.2/SCPI instruments on the bus using
the dynamic i/o utility provided in  the examples. Instruments such as
HP6622A & HP8562E will only respond to ID?. Is there possibly an upgrade of
firm/software that can be installed to get us over the problems?

Many thanks in advance.

Chris Phipps

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