Electronics > Metrology

Hioki DM7276-01 Precision DC Voltmeter (9 PPM)

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Alex Nikitin:
I rather like the temperature measuring feature. Strangely, if you copy data to a USB stick, the temperature measurements are what is on the screen, with 0.1C resolution. However if you request the data remotely, the resolution is 0.01C which does make a lot of difference! Below the results of an overnight run with the Hioki measuring the Fluke 731B 10V output and the room temperature at the same time. I plan to use the DM7275 together with a small DIY "temperature chamber" for tempco measurements on resistors and references.

Cheers

Alex

EC8010:
Going back to the lovely internal pictures, the difference between the 7276 and 7275 is that the black dot is in the A box on the voltage reference board whereas it's in the C box on the 7275. Looks like they graded the stability of the reference board. Which seems entirely reasonable. Perhaps more significantly, it might mean that the DMM's drift is dominated by the voltage reference rather than input stage and ADC noise/drift? If so, it might be possible to improve a 7275.

HighVoltage:

--- Quote from: EC8010 on May 22, 2024, 06:46:47 pm ---Going back to the lovely internal pictures, the difference between the 7276 and 7275 is that the black dot is in the A box on the voltage reference board whereas it's in the C box on the 7275. Looks like they graded the stability of the reference board. Which seems entirely reasonable. Perhaps more significantly, it might mean that the DMM's drift is dominated by the voltage reference rather than input stage and ADC noise/drift? If so, it might be possible to improve a 7275.

--- End quote ---

There is almost a $1000 price difference between the DM7275 (20 ppm) and the DM7276 (9ppm) models
Resolutions are the same.
You might be right, same as the differences in the Keysight 3458A models.

BTW, I used the Contact Check Function of the 7276 for the first time consciously.




chekhov:

--- Quote from: HighVoltage on May 23, 2024, 11:03:06 am ---BTW, I used the Contact Check Function of the 7276 for the first time consciously.

--- End quote ---

Eh, having so much space on display they show "NoCntct" instead of "NoContact", lame  :palm:
Also, from the first seconds this is a little bit of cheating on low voltage input - "guessed" DMM in 10M input mode.
If it was in auto or was a different similar class DMM - it's evident when the input is not connected by readings jumping all around. Of course, for automated measurements that could be much more versatile function.

MegaVolt:

--- Quote from: HighVoltage on May 23, 2024, 11:03:06 am ---BTW, I used the Contact Check Function of the 7276 for the first time consciously.



--- End quote ---
How does it work? What would it show if the battery was working?

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