Products > Test Equipment
Fluke 8050A calibration
bob91343:
I have one of these that seems accurate except on the 20V dc range. As it happens, there seems to be no adjustment for that.
I have searched the diagram and there is no pot for the 20V range. The calibration procedure skips that range.
Not that it's terribly far off, maybe around 0.2% at most, but I'd like to trim it.
Does anyone know about this?
med6753:
First make sure your supply voltages are in spec. There is interaction between R11 (2V cal) and R5 (200V cal) and you may have to adjust for best compromise. Or you can play with the U5 jumpers on table 4-10 on page 4-11 of the manual.
Above all, how accurate is your source voltages?
bob91343:
Allthe voltage ranges appear to be in spec except the 20 V range.
However I will open it again and measure the voltages. There do not seem to be any precise voltages, at least from my schematic perusal. And no adjustments.
Can you explain what this is all about? If I can't adjust the power supply I don't know how to correct the error if any. And I will have to look for the tolerances on the supply voltages.
med6753:
The power supply voltages should be within +/- 10%. If not, investigate the cause.
By "source voltages" I am referring to the standards you are using to calibrate it. What is it? Is it a traceable standard? If not then your source voltages are suspect.
If the 2V range and the 200V range are properly set then the 20V range will automatically fall into place. If not then there is the possibly, although unlikely, that one of the precision resistor networks (U1 - U5) has drifted.
Fungus:
--- Quote from: bob91343 on July 28, 2020, 03:31:29 am ---I have searched the diagram and there is no pot for the 20V range. The calibration procedure skips that range.
Not that it's terribly far off, maybe around 0.2% at most, but I'd like to trim it.
Does anyone know about this?
--- End quote ---
You need to calibrate it on the the 200V range, the 20V is derived from that with precision resistors.
Feed it a voltage while it's on the 20V range and twiddle R5. The reading on screen should change.
For me the 20V range is the most useful so I'd "Lego" two 9V batteries together and use the 18V output to match it against my best meter while the 8050A is on the 20V range... :-DMM
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