Products > Test Equipment
Keysight's new 34465A (6.5 digit) and 34470A (7.5 digit) bench multimeters
splin:
From the 34465A and 34470A specs the noise adder for 1NPLC is 1ppm of range + .5uV = 6ppm for the 100mV range = 600nV
At 10NPLC the expected RMS noise would be 600/sqrt(10) = 190nV. That compares to:
34470Admm2018 136nV34465AHKJ 180nV34470AHKJ 200nV34465AHighVoltage 80nV34470AHighVoltage 190nV
So most are pretty close to the spec except HighVoltage's '65A which is surprisingly good.
[EDIT] FWIW The 3458A equivalent spec is 54nV - the difference being mostly due to the ADC.
I estimate the 34470A's input amplifier is approx 4X noisier and the the ADC is around 14X noiser.
eplpwr:
--- Quote from: splin on January 12, 2019, 03:30:42 pm ---How come the 34470A is only showing 6 1/2 Digits?
--- End quote ---
On the 100 mV range, 34470A defaults to 6 1/2 digits. You can manually change this to 7 1/2 digits with "Digit Mask" button in DCV mode, which also results in an additional digit of resolution in the statistics window (Avg, Stddev et al).
HighVoltage:
OK, repeated the histogram noise test on 4 instruments at the same time over night.
The temperature span was about 1 degree.
Since I only have one good short block, I used a single short cable on the voltage input of all instruments.
It seems the test results from earlier are repeatable.
I am not sure why my 34465A has such little noise, compared to the two 34470A's
All standard settings, 10 NPLC
1. Room temperature measurement with 5k thermistor on a 34461A
2. Noise 34461A = 130 nV StdDev
3. Noise 34465A = 100 nV StdDev
4. Noise 34470A-1 = 160 nV StdDev
5. Noise 34470A-2 = 130 nV StdDev
dmm2018:
--- Quote from: Dr. Frank on January 03, 2019, 03:16:42 pm ---
The calibration process is done at about 23°C, even @ Keysight in Malaysia, where your instrument might have been calibrated (see your cal certificate).
Highest uncertainty is achieved only at this calibration temperature. Otherwise, correction calculations using T.C.s apply.
Frank
--- End quote ---
Today installed BenchVue and tried retrieving the "temperature of last calibration" (as described on pp. 242 of 34460-90901 Operating and Service Guide) using the following SCPI command:
CALibration:TEMPerature?
Returns the temperature of the last calibration in °C.
The returned temperature of last calibration of my Keysight 34470A (L) is 25.41 °C.
According to the Certificate Of Calibration, I think the meter was calibrated @ Keysight (Malaysia). Is it normal that the Keysight 34470A was calibrated at 25.41 °C?
e61_phil:
25.41°C would be the internal temperature and not the lab temperature
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