[time-nuts] HP 5335A and using the HPIB for control

[Bob kb8tq]

Hi

I’ve used the 5335 in exactly this mode for a lot of years. 

> On Mar 6, 2020, at 7:28 PM, Frank Stellmach <frank.stellmach at freenet.de> wrote:
> 
> Hello Perrier,
> 
> I'm also a bit confused, what your requirements, and what your capabilities are.
> 
> The HP5335A definitely can handle gate times up to 10^7 seconds, that means, it can resolve maximum to about 10^-16 internally.
> 
> 
> But it only outputs the first relevant 11 digits, either on its display, or over the GPIB, i.e. a gate time of >= 100sec already gives the maximum displayed resolution. There is no way of reading additional least significant digits.

Nope, it throws away the MSD’s not the LSD’s. 

> 
> (I think Bob confused the 5335A with another counter, probably the 5370A/B, which is really limited to about 32bit counter length, and will truncate leading digits when using fast register readout).
> 
> 
> The 5335A has an analogue gate timer, or the possibility to manually or by program control to open and close the gate for a pre determined time, but no fixed digital gate times like 0.1, 1, 10sec or so.
> 
> The first, analogue  way is to replace an electrolytic capacitor, 10µF, C36 on A4 board by a 33..100µF one, which will give e.g. 10.5sec max gate time via the front side potentiometer.
> 
> That's very easy, if you are capable to de-solder the old capacitor and solder the new one in the same place.
> 
> The second way is to simply press the button 'MANUAL OPEN/CLOSE' to open the gate and after 10 or 100 sec to press it again.

Third way is to run the gate via GPIB. Send it the open and close commands
that way.

> 
> That will give you 10 or even 11 digits of resolution.

It will give you the 10 LSD’s 

Bob

> 
> The program would  respectively send the command 'GO' for Gate Open and after a delay of 10 or 100sec the command 'GC' for  GATE CLOSE, and then would read the result into the PC, or display it on the counter.
> 
> Here again, it depends, if you have GPIB card / adapter , GPIB cable and any program environment, and of course some programming experience.
> 
> I have exactly this program on my W98 PC downstairs, but unfortunately it's still programmed in Turbo Pascal, as I was up to now too lazy to translate my programs into C++ or alike.. The GPIB tool kit is probably the best and easiest way to write these few lines of code.
> 
> Remark: If I remember correctly, the 5370A/B can not be programmed to open and close its gate for 10 sec (which would be about its maximum), nor can this counter, neither the 5335A be read out (its registers) during their measurement process.
> 
> Frank
> 
> 
> 
> 
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