[time-nuts] Off the wall: anyone with experience programmingHP3456A?

Brooke Clarke brooke at pacific.net
Sat Sep 10 14:13:56 EDT 2005


Hi John:

The problem is caused by modern computers being much faster than the 
ones available in the late 1970s.  With the older computers, after 
sending a command the instrument had plenty of time to make a 
measurement and format the response.

With today's fast computers if you send a command then immediately ask 
for a response, the instrument has just started to make the measurement 
and this can cause problems.

The newer instruments that support SCPI commands have nice ways to 
handle this, but the R2D2 instruments need a little wait time prior to 
any data request.

Have Fun,

Brooke Clarke, N6GCE
-- 
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com



John Miles wrote:

>>. . . 
> 
>>One other thing we've found, particularly with the older HP instruments,
>>is that you often need to insert a sleep of anything from 500uS to 5ms
>>after issuing a command before sending another command.
> 
> 
> Interesting; I hadn't run across that.  The examples in the manuals commonly
> show multiple commands in a single string; maybe the old-school BASIC
> controllers were smart enough to pause briefly after transmitting semicolons
> or string terminators...?
> 
> -- john, KE5FX
> 
> 
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