[time-nuts] PTS D310 and GPIB

[GandalfG8 at aol.com]

In a message dated 03/08/2009 13:29:23 GMT Daylight Time, rexa at sonic.net  
writes:

>From my  digging around in the last few days, it seems that the design 
of the two  sections in the D310 are not too much like the 310. It looks 
more like the  500 or 3200 without the final stages. For instance the 
reference  frequencies in the regular 310 come from one SGC module, 
whereas the D310  uses SGA and SGB. I was surprised when I found that the 
D310 used  different strategies than the 310.

So it is a bit different and if you  look at the datasheet for the D310, 
the 0.1 Hz resolution is standard. I  certainly expected the 310 and D310 
to be based on the same design, but  they aren't.

Now, back to the GPIB commands. Looking at the GPIB  section in the PTS 
500 manual, it appears that it uses the command format  that I expected. 
For the extra .1 digit, just add one more digit in the  'F' command. So 
where did I go wrong?

Seems the manual is not quite  right in its examples. I was stringing 
commands together like  'f1234567a0[LF]', the a0 being command for max 
output level. That's what  the manuals show in an example or two, but 
seems the hardware gets  confused if there is more that 1 command with 
just 1 LF at the end. I  think 'f1234567[LF]a0[LF]' is ok.

If I send it just 'f1234567[LF]' I  get 123456.7 Hz, which is what I 
expected. With 'f1234567a0[LF]' I get  1.234567 MHz. So it seems the 
controller wants a LF after each command to  not get confused.

There may be some finesse points I haven't worked out  yet, but I'm on 
the right track now.



-----------
Hi Rex
 
I'm glad to hear you're getting it sorted and that sounds like a really  
interesting unit, I'm quite jealous:-)
 
I hadn't expected the D310 to be anything more than two standard 310s  in 
the same box so that's another variant to add to the list.
 
Between PTS, Wavetek, and Rockland, there's a variety of units that throw  
up some interesting similarities, although sometimes with subtle or not so  
subtle differences , and then there are some quite different,  such as the 
PTS310 and the DDS version of the PTS160.
 
I bought one of the latter a while ago, without realising up front what it  
was, only to have a small and so far unidentified daughter board, not  
obviously part of the DDS board itself, detach itself in transit. I  put that to 
one side and never did investigate further, probably time I did, but  the 
PTS160 manual doesn't even acknowledge the existence of that version.
 
regards
 
Nigel
GM8PZR