Fluke 5520A Multi-Function Calibrator - Performance tests at 8845A & DMM4040

[Kiriakos GR]

Here I have to share a rare find. 

They are several DC voltage sources out there, these able to output DC voltage for DMM performance tests.
But only the real thing, an Fluke 5520A Multi-Function Calibrator.
This is able to push the envelope at 100V up to 1000V of DCV output.

My lucky and or rare find, this demonstrates display resolution performance of 8845A & DMM4040, along of 8846A & DMM4050.
Another interesting detail, this has to do with DMM +/- accuracy specification at DC 1000V range.
At 6 1/2 display resolution, 1000V range, the number of insignificant digits this becomes two.

It appears that this seller of Fluke 5520A (in China) he feels pride, when DMM4040 this verify voltage output at these three examples.

Fluke 5520A Out --- 8845A & DMM4040 Confirmation
4.00000    ---  4.00007
800.000    ---   800.090
1000.000  ---   1000.088

Due this article, you are able to see of what a calibration engineer (calibrator operator) can see, at high voltage DC performance tests. 
In my surprise, under the 1000V, the DMM delivers seven digits resolution.   

[overvolt]

Lots of zeros, I got dizzy ..