| Products > Test Equipment |
| Keysight's new 34465A (6.5 digit) and 34470A (7.5 digit) bench multimeters |
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| TiN:
Since measurement in comparison were taken different time, perhaps in case of 34465 some EMI/RFI coupling to resistor? |
| HighVoltage:
The noise seems to be high. What I have noticed with my 34470A on resistance measurements is noise injected from nearby WiFi, or wireless phones, so I make sure to take these kind of measurements far away from any known noise and test the place, before I start. |
| Alex Nikitin:
As far as I can tell, it is not EMI/RFI, the variations were present even overnight, with doors closed and nobody/ nothing in the lab to interfere. As a side note - if I do an ACAL during one of the far out variations (as you may see on the graph some large shifts are long lived), than the value returns to accurate, with ACAL correcting up to 10 ppm. Below the overnight (18 hours) run using a different 10K W/W resistor (UPW25). When I've looked at it this morning it was not a pleasant sight, so I've re-run the measurements using the LT450C - with the same result :( . Cheers Alex |
| saturnin:
@Alex I am just repairing one of my DMMs (an ohms stability issue). As part of tests I have made, I measured short-term stability of my 10K standard (two Fluke 19.995K 0.03% resistors in parallel). The measurement was performed by healthy K2000. Its 24hour spec is 26 ppm (34465A has 25 ppm). Therefore, I would expect 34465A should perform very similar to my K2000 in 2h interval. I have PC, WiFi, and smartphone within 1.5m from my DMM and yet the measured variation of 10K resistance is no more than 2ppm (max. temp change was 0.4°C)... |
| Alex Nikitin:
It looks like our 34465A is failing the noise spec on 10K. I'll talk to Keysight on Monday. It would be nice if somebody with the 34465A would repeat this resistance test (10K, 100NPLC, 10 sec logging interval). Cheers Alex |
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