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 2012-10-06
TS1 2012-10-14
TS1 2012-10-17
2012-10-20
| Attachment | Size |
|---|---|
| TS Schematic (pdf) | 11.8 KB |
| TS_data_2012-01-04--2012-01-08.csv | 994 bytes |
| TS_data_2012-04-19--2012-04-21.csv | 1.13 KB |
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