| Products > Test Equipment |
| Keysight's new 34465A (6.5 digit) and 34470A (7.5 digit) bench multimeters |
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| Dr. Frank:
The linearity specifications are 1ppm of range plus 0.5ppm (34470A) / 1ppm (34465A) of reading. The passes with label (neg.) indicate that the linearity of the DUT had been tested with the 3458A being reversed, so that a possible non-linearity or asymmetry would be discriminated.. obviously there is none... the 3458A is linear to about 0.02ppm of F.S. The linearity specifications are well met. There's obviously no quality difference, in fact the 34465As seem to perform better than this particular 34470A. This also indicates, that hardware / components are identical on both instruments. Regarding this parameter, both instruments are worth 1ppm / 6 digits only. In the TrueVolt DMM manual, the resolution of the 34470A is specified better than the 34465A. Very obviously, the firmware limits the resolution of the 34465A on the main display to 6 digits and to 7 digits for the statistics display, whereas the 34470A displays 7 and 8 digits, respectively. The raw data from the A/D is transferred over the bus, as full 8 digits were output for each model. So I tried to determine the real resolution from binning the stability data. For the 3458A, you see a typical, quite narrow Gaussian distribution for the 10V measurement. At 10x magnification, an irregular binning appears, with 7 different values per 0.01ppm, which gives about 17.5nV median resolution, or 0.00175 ppm, nearly 9 digits. The 34470A shows a very similar stability distribution as the 3458A, as explained already for the Allan Deviation. Its binning equals 0.01ppm of resolution, or 8 digits, as specified. The 34465A has a much broader distribution, reflecting its worse LM399H reference, concerning noise. The binning shows exactly the same resolution of 0.01ppm, like the 34470A, therefore the Keysight specification is busted. This finally proves, that both instruments share exactly the same hardware, and only their references and the display resolution by software make the difference. As a conclusion, both instruments are very precise and stable, with many new versatile features as ACAL, OCOMP, graphic representation of readings, data logging and digitizing. Both instruments perform much better than the specification, especially after application of the firmware updates. Keysight engineers gave a very quick feedback and solution on these 3 bugs, so I'm very satisfied with my new 34465A. Frank |
| quarks:
Hello Frank, very interesting read. Thanks a lot for sharing. |
| saturation:
Thanks Dr Frank, for all the good data. |
| Vgkid:
Thanks for the very informative post, Dr. Frank. |
| dadler:
Any ETA on the 2.12 public release? |
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