[volt-nuts] 3458a RAM batteries - longer life if unit is continually powered?

[Robert Atkinson]

Always best to keep it on. No vacuum fluorescent disply to worry about so it's only the cost of power. The back up battery will last much longer. It may even be less than the shelf life as there will be a very tiny "charge" current due to the reverse leakage of the isolation diode.
 
Robert G8RPI.
 

________________________________
 From: Poul-Henning Kamp <phk at phk.freebsd.dk>
To: Discussion of precise voltage measurement <volt-nuts at febo.com>; new <pitts7 at williams-net.com> 
Sent: Wednesday, 26 March 2014, 17:58
Subject: Re: [volt-nuts] 3458a RAM batteries - longer life if unit is	continually powered?
  

In message <BC736E8BA2F94F0CB78739D7E04E9D07 at KITCHEN>, "new" writes:

>If the cal constants are in the RAMs and the RAM batteries go dead,
>the 3458 needs to go back to Loveland, right?

The CALRAM can trivially be backed up via GPIB.

The backup can either be written into new NVRAM chips using a programmer
or it can with some difficulty be written back via GPIB.

I've explained the details in previous emails to the list (see archives)
and there is software to do the backup in my "Pylt" github project.

In the meantime, keeping it power on means the battery only drain
by their self-discharge.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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