[time-nuts] Off the wall: anyone with experience programming HP3456A?

Tom Van Baak tvb at leapsecond.com
Sat Sep 10 11:18:47 EDT 2005


> > Does it work, in a loop, to send 3456A commands
> > to read voltage, get the response, and then 5370A
> > commands to read frequency, and get a response?
> > 
> > /tvb
> 
> Yes, but I've been getting occasional squirrely values from the 3456A in
> that mode, possibly because of a timeout and without using the bus
> signals there's no way to check whether the instrument has actually
> completed.  There are code workarounds to that, but I was hoping to use
> the "data ready" bit to validate the reading.
> 
> But I think I may have found the problem -- I just ran through the
> internal test set, and I'm getting a failure on the RAM test.  That
> probably explains the SRQ failure, and may even explain why every so
> often a reading isn't in the right format.  Now I just need to find a
> couple of ancient 4118 RAM chips.
> 
> John

I've got an old 3456A and can pull its RAM chips
for you if needed.

I dug up an old QBASIC program from 1999 where
I talked to a 3456A to log mains voltages. See:
http://www.leapsecond.com/tools/3456.bas

It looks like the controller simply waited for the
CR/NL terminated single-line response from the
T3 trigger command. T1 or T2 would be trouble,
in this case, I think.

/tvb






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