[time-nuts] Re: hp 5061B, power-up sequence, logging

[paul swed]

Tom
I have not done this. But you're on the right track with differential
inputs.
The approach I would take is to measure each meter position without the
meter in circuit to ground.
This will give you the maximum differential voltage to watch out for with
respect to ground that might damage the diff opamp input.
Pretty sure all of the test points are easily reachable on the bottom pc
board A7 or 17??
Then figure out the meter resistance and use that value across each meter
function connected to the differential input.
This all sounds messy but really isn't. Just leave the meter in the battery
position or maybe the 100 KHz position.
Good luck sounds like a fun project.
Regards
Paul
WB8TSL

On Wed, Jan 4, 2023 at 10:20 AM Tom Van Baak via time-nuts <
time-nuts at lists.febo.com> wrote:

> I have a hp 5061B that's been in standby (Cs Off mode) for several years
> and I plan to power it up for a while and see how it's doing.
>
> This time I'd like to track its vitals during the sequence -- not by
> manually reading the meter every few minutes as I usually do -- but by
> logging meter readings automatically with a multi-channel ADC. Readings
> of interest would be: Ion Pump I, Cs Oven, Beam I, Control, 2nd
> Harmonic, and lock state.
>
> Has anyone done this? Do you have any recommendations on obtaining the
> voltages as simple as possible? It's slightly complicated by the fact
> that not all meter readings are referenced to ground. I'll probably pick
> an 8-channel USB ADC for this. Maybe using differential instead of
> single-ended inputs would work around the floating meter design.
>
> A sampling rate of 1 Hz would normally be enough, but when the CBT has
> been off for so long there are interesting pulses of CBT oven and Ion
> current and so maybe 10 Hz or even 50 Hz would be better to capture that
> detail.
>
> This is a one-off test, just to have a well documented example of Cs
> oven power-up & locking sequence. But I'd consider leaving it wired in
> so I can collect data long-term as well. Most modern rubidium and cesium
> clocks have computer connections and telemetry already, so in a sense
> this project is to explore retroactively adding similar functionality to
> 5061-era cesium standards.
>
> Anyway, if anyone has done something similar I'd be interested in
> hearing about it.
>
> Thanks,
> /tvb
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>