Fluke 8846A DMM and the Hidden VA high precision Power Meter mode

[Kiriakos GR]

Fluke 8846A this is an advanced and high precision multimeter, that I do own and admire for it significant pack of features.

For an unknown reason, Fluke Corporation leaved as undocumented, the function at DC mode, of VA high precision Power Meter mode.
Fluke 8846A at DCI mode (primary measurement display), and due the activation of it 2ND Meas (second measurement display), this now measure simultaneously DCV and DCI (due three wires connection with the load).

The undocumented VA mode  this is hidden within 2ND Meas additional menu option.

1) Note: Feel free to read 8846A User manual -> Measuring DC Current -> DCI/DCV. 
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Fluke 8846A accuracy specifications for DC: 
10 V  range 0.0024 + 0.0005
100 V range 0.0038 + 0.0006

(three wire mode for VA, + 20mV burden voltage)
10 V range 0.0044 + 0.0005
100 V range 0.0058 + 0.0006

400 mA  range  0.05 + 0.005
3A   range  0.1 + 0.02
10A  range 0.15 + 0.008 

I am not an mathematician, but combined or total VA error, this is never greater than a Class 0.2 DC Watt meter
(at any combination of voltage and current range in use, at FLUKE 8846A). 
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Why would some one to care about this detail?

In the application of power measurement, and for power efficiency calculation, the 8846A it can become your eyes at the DC side (Load), for a single DC rail measurements.
For the AC side (source), you will always need a modern single phase (bench top) power meter, Class 0.5 or better. 

2) Note: Such a combination of instrumentation, it would warranty power efficiency calculation with no greater error of 1%     

3) Note: 8846A include analog and digital filter, its one it can assist in favor of noise removal, and or VA averaging = a more stable measurement that you may trust. 

It is well known that integration speed at DMM, this slow down at dual mode measurements.
But with the use of programmable DC load, and at very specific load conditions (10% 50% 80% 100%), these are stable loads and the performance of 8846A this it can not be challenged.

[Kiriakos GR]

Here I will present some facts about  Fluke 8846A -> DCI Mode -> 2ND MEAS

Available options:
DCI & ACI
DCI & mV / V
DCI & mVA / VA 

2ND MEAS this has a resolution of seven Digits at maximum.
Demonstrated example:  1.107241 mVA = Power (milliwatts)
Resolution drops to six digits, when it measure for example 55.2321 mV instead.
While at 2ND MEAS   mVA / VA digits are small in size, the measurement it is there. 

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For power efficiency calculation, the 8846A it can log due windows PC software it VA measurement along the time stamp.
My digital AC power meter this also support data log due it own windows PC software.
Therefore I will simply collect two recorded measurements,  AC Watt  + DC VA them be at identical time stamp.
And with that data at hand, I will be able to find the efficiency ratio.     


Note: At this demonstration I did use my VA portable calibrator,  so to deliberately use the 400mA INPUT of the instrument, with out any fear that I will blow any fuse. 

[overvolt]

Fluke 8846A this is a truly impressive instrument! 

But it is a fact, the team whom wrote the user manual, it did a poor job.