Fluke 5450A cal result

[VintageNut]

This week I have access to a primary cal lab. My 5450A has been calibrated. I am sharing the results for the community here to view and make comments if desired.

The calibration used two MI bridges. My understanding is that the low ohms up to 10K uses a current comparator bridge. The values over 10K uses a voltage comparator bridge. There is a temp controlled pool with a Thomas 1 ohm in the pool.

[CalMachine]

Where is this lab located? That's a damn good uncertainty! 5 ppm @ 100 MOhm...   

[e61_phil]

Was this the first calibration or do you have some experience with the drift of a 5450A?

[VintageNut]

Was this the first calibration or do you have some experience with the drift of a 5450A?

I bought this 5450A from eBay a year or so ago. This is the first calibration under my ownership with no history of previous calibrations.

My plan is to have this calibrated once a year if possible.

The technician who performed the calibration said that it requires about 30 minutes per resistance. He spent an entire day calibrating the box. No way I could afford this if I was paying for it. The calibration was performed as a favor.

They are also calibrating my two 731Bs and the three high resistance bricks that I assembled.

When I get home, I can go crazy doing some bridge measurements with one or more of my DV4107 KVDs. Woohoo

[Dr. Frank]

The regular calibration process won't take a whole day, so I really wonder why it took the cal lab guy so long.
I also doubt, that this very low uncertainty certification of calibration is useful, as the resistors inside the 5450A are much less stable in time and temperature.
There's also that probable leakage problem with the electro-mechanical relays, which will falsify the calibration of the higher resistors, from 100k to 100M.
This (error - checking) validation verification has been omitted by the cal lab, as they did not follow the intended procedure.

Did you attempt to calibrate the 5450A on your own, so to validate verify the regular calibration constants versus the measured ones?

Frank

PS: Judging from the date codes inside your box, how old is your 5450A?

PPS: Adding link to my findings on error during the calibration of the 5450A:

https://www.eevblog.com/forum/blog/eevblog-544-fluke-5450a-resistance-calibrator-teardown/msg1113471/#msg1113471

[ap]

The reason these measurements take long (total time per resistor) is temperature settling and multiple measurements per resistor to build average with the MI bridges, this way you can achieve this accuracy. If all this makes sense for that unit is truely questionable, given its instability. It would have been much more valuable, having acccess to such accuracy that cheap, to use a set of precision hermetic resistors with low drift. Not sure what the 5450 has cost, but probably in the same range as a set of such resistors from VPG.

I have my 732 calibrated to 0.3ppm, and they do it over a couple of hours in a tightly controlled ambient, somehow justifying the price.

[aronake]

Was this the first calibration or do you have some experience with the drift of a 5450A?

I bought this 5450A from eBay a year or so ago. This is the first calibration under my ownership with no history of previous calibrations.

My plan is to have this calibrated once a year if possible.

The technician who performed the calibration said that it requires about 30 minutes per resistance. He spent an entire day calibrating the box. No way I could afford this if I was paying for it. The calibration was performed as a favor.

They are also calibrating my two 731Bs and the three high resistance bricks that I assembled.

When I get home, I can go crazy doing some bridge measurements with one or more of my DV4107 KVDs. Woohoo

Did you ever get this calibrated again? Would be interesting to see drift.