Traveling Standard

I have several voltmeters in my lab, and like the man with two clocks who never knows what time it is, I have meters that give different answers.

In order to resolve this problem I want to build a Traveling Standard (TS) that I can send out to be measured by other volt nuts with better meters than I own.

Here is the first message I posted about a TS to the volt-nuts mail list.

I was very pleased with the responses I got back, which included this one. What a great reply - it gave me lots to think about.

Here are my design notes.

A proposed TS protocol.

I have posted some pictures as the unit is developed, along with some plots of the voltage versus time and temperature

The detailed schematic is attached to this page.

Results Table:

Date Ambient
Temperature
Volunteer Instrument Samples LM199AH
Average
LM199AH
Std. Dev.
Samples MAX6350E
Average
MAX6350E
Std. Dev.
2012-01-04 - 2012-01-08 69.955 1 3458A 20 6.9973253500 0.0000032489 20 5.0005381000 0.0000085156
2012-04-19 - 2012-04-21 2 3457a
(7.5 digit mode)
10 6.9973060000 0.0000045886 10 5.0005193000 0.0000051273
2012-08-20 - 2012-08-20 80.9 3 3458A(1) 999 6.9971877711 0.0000010629 999 5.0005314107 0.0000009556
2012-08-18 - 2012-08-18 82.76 3 3458A(2) 999 6.9971967204 0.0000009491 999 5.0005410164 0.0000011941
2012-08-05 - 2012-08-05 80.96 3 7081 66 6.9972224758 0.0000030342 69 5.0005511870 0.0000006535
Average of averages 6.9972476635 5.0005362028
STDEV of averages 6.37E-005 1.18E-005

The measurements reported by Volunteer 1, taken from 2012-01-04 through 2012-01-08, are attached below.

The measurements reported by Volunteer 2, taken from 2012-04-19 through 2012-04-21, are attached below.

Volunteer 4 is providing long term drift data, taken with multiple HP3458As calibrated against a Fluke 732A. Here are some plots of his data:

TS1 2012-10-06TS1 2012-10-06


TS1 2012-10-14TS1 2012-10-14


TS1 2012-10-17TS1 2012-10-17


2012-10-202012-10-20

AttachmentSize
TS Schematic (pdf)11.8 KB
TS_data_2012-01-04--2012-01-08.csv994 bytes
TS_data_2012-04-19--2012-04-21.csv1.13 KB