Products > Test Equipment

Keysight's new 34465A (6.5 digit) and 34470A (7.5 digit) bench multimeters

<< < (91/145) > >>

Alex Nikitin:
I left both meters (34465A and 3458A) to run overnight measuring the LTZ1000 reference voltage. The Keysight meter did drift about -3ppm, while LTZ1000+HP3458A combination did show a drift of less than 0.7ppm. However ACAL on Keysight did get it back at <1ppm difference from the HP. It looks like a regular ACAL is a necessity here unless the drift would stabilize after a while. By the way, when I've powered the 34465A for the first time and let it run for an hour, it was about +35ppm off at 10K before I've done ACAL. Here are two graphs from the overnight logs (same scale, 1ppm/div). The Keysight has about 4-5 times larger p-p noise.

Cheers

Alex

Dr. Frank:

--- Quote from: Alex Nikitin on October 06, 2016, 01:59:25 pm ---Received the 34465A today. After ACAL it agrees within 1ppm with our HP3458A Opt002 meter (calibrated in January) on my self-made 10K reference and on 7.16V from LTZ1000 . Quite impressive for both meters to agree that nicely.

Cheers

Alex

--- End quote ---

Hello Alex,
congrats on your new 34465A.
Your 10V / 10k check is to be expected, and proves that it arrived in undisturbed condition.

Check the Test Report of your instrument.. it has been adjusted and verified to < 1ppm uncertainty in DCV and Ohm modes.
As you probably received it within about 3 weeks, and it had not been powered on in between, practically no drift occurred.
So you might take these readings as an additional calibration verification of your 3458A, about +/- 1ppm after ACAL.´

The difference in noise levels of the 34465A vs. the 3458A arise directly from the LM399H vs. their internal  LTZ1000A references.

Your 0.7ppm drift of the 3458A vs. the external LTZ1000 is quite high, maybe your room temperature changes too much; <= 0.2°C change is required.

Frank

Alex Nikitin:

--- Quote from: Dr. Frank on October 07, 2016, 11:57:21 am ---
--- Quote from: Alex Nikitin on October 06, 2016, 01:59:25 pm ---Received the 34465A today. After ACAL it agrees within 1ppm with our HP3458A Opt002 meter (calibrated in January) on my self-made 10K reference and on 7.16V from LTZ1000 . Quite impressive for both meters to agree that nicely.

Cheers

Alex

--- End quote ---

Hello Alex,
congrats on your new 34465A.
Your 10V / 10k check is to be expected, and proves that it arrived in undisturbed condition.

Check the Test Report of your instrument.. it has been adjusted and verified to < 1ppm uncertainty in DCV and Ohm modes.
As you probably received it within about 3 weeks, and it had not been powered on in between, practically no drift occurred.
So you might take these readings as an additional calibration verification of your 3458A, about +/- 1ppm after ACAL.´

The difference in noise levels of the 34465A vs. the 3458A arise directly from the LM399H vs. their internal  LTZ1000A references.

Your 0.7ppm drift of the 3458A vs. the external LTZ1000 is quite high, maybe your room temperature changes too much; <= 0.2°C change is required.

Frank

--- End quote ---

Hi Frank,

Thank you!

1) The calibration date on the 34465A is 30th of June, so over 90 days ago :( .

2) Yes, according to the calibration data the unit was calibrated to less than 1ppm error on 10V DC and 10K.

3) Yes, the lab is not temperature controlled, with at least 3-4C temperature variation overnight. Also my LTZ1000 reference is on an open board with only a foam cup. I will move it into a proper case soon  ::) . It is probably sufficient for my current needs though.

Cheers

Alex

Dr. Frank:

--- Quote from: Alex Nikitin on October 07, 2016, 12:11:56 pm ---..

1) The calibration date on the 34465A is 30th of June, so over 90 days ago :( .

..
Cheers

Alex

--- End quote ---

The DCV drift is dependent on the instruments uptime. If it's not used so often, it may as well have its initial uncertainty.
Mine is from about June 2015, I think, and it's still within about 1ppm.

HighVoltage's 34470A, which is running 24/365, showed a drift of +5ppm only, after about 10 months.
This is also typical for the LTZ1000A reference, at 95°C.

The Ohm ranges, as their components are running on RT, won't drift as much, and the 34470A was also found to be within 1ppm for 10kOhm.

So your observation is an indicator, that your instrument is still in very good condition; 3 months of operation is nothing.

Ah yes, you should try to get the 2MB option for free.. I also got it this year, despite mine was an elder one.

Frank

Alex Nikitin:
Hi Frank,


--- Quote from: Dr. Frank on October 08, 2016, 08:01:57 am ---The DCV drift is dependent on the instruments uptime. If it's not used so often, it may as well have its initial uncertainty.
Mine is from about June 2015, I think, and it's still within about 1ppm.

HighVoltage's 34470A, which is running 24/365, showed a drift of +5ppm only, after about 10 months.
This is also typical for the LTZ1000A reference, at 95°C.
--- End quote ---

Thank you - I thought that the 34465A has LM399? In my case this unit will be running 24/7, same as the HP3458A. At home I have two K2015 which are also running 24/7 for last four years (and were used for many years before I bought them). LM399s in both Keithley meter are very stable, drifting not more than a couple of ppm per year (if that - I will have a chance to check soon).


--- Quote from: Dr. Frank on October 08, 2016, 08:01:57 am ---The Ohm ranges, as their components are running on RT, won't drift as much, and the 34470A was also found to be within 1ppm for 10kOhm.

So your observation is an indicator, that your instrument is still in very good condition; 3 months of operation is nothing.
--- End quote ---

3 month of sitting on a shelf at Farnell in this case!


--- Quote from: Dr. Frank on October 08, 2016, 08:01:57 am ---Ah yes, you should try to get the 2MB option for free.. I also got it this year, despite mine was an elder one.

Frank

--- End quote ---

Yes, I've ordered the extended memory option as soon as I've received the meter!

Cheers

Alex

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod