[volt-nuts] HP3458A _really_ long term stability

[Poul-Henning Kamp]

In message <2783.1315238745 at critter.freebsd.dk>, Poul-Henning Kamp writes:

>I finally had a chance to drop my HP3458A into a friendly Cal-lab and since
>the last sticker on it says it is due for calibration in "2-1996" we are
>talking seriously overdue calibration.
>
>The result:
>	Internal 40K resistor:   -11.66ppm
>	Internal 7V Voltage ref: -28.96ppm
>
>That's not too shabby over 15 years...

Update:

Greg Burnett and I have been chatting offline, and it transpires,
based on the serial number of 2823A00556, that it is more like 22
years.

Appearantly this instrument was never calibrated after it left
the factory in late 1988 or early 1989.

The stickers say "Next test" (in german), they give no hint that
a calibration has happened, and the CALNUM? was 5 when I received
the meter, consistent with the factory calibration.

Further more, we probably didn't let the meter acclimatize long
enough yesterday, so in particular the 7V cal may be a couple of
PPM off (didn't want to overstay my welcome).

-- 
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.