DMM versus temperature comparison - Page 1
Forum section: electronics / general

author: rigrunner
author_rank: Frequent Contributor
timestamp: November 25, 2017, 05:21:19 pm
content: It's the time of year when my lab temperature gets to wander about at the chillier end of things and i thought it would be interesting to see how the different DMMs compare with lab temperature change. All i've done is set the EDC to 10V and take a measurement at 30 minute intervals with NPLC at 100 for the HP meters. Both of the 3457A are soft calibrated when the temperature change is +/- 1C.The 3456A is remarkable and the Datron 1071 would make a pretty good thermometer

author: Andreas
author_rank: Super Contributor
timestamp: November 25, 2017, 05:36:35 pm
content: Hello,as comparison:My K2000 has around 0.5ppm/K in the 10V range.https://www.eevblog.com/forum/metrology/project-pimp-a-keithley-2000/msg1106839/#msg1106839And no significant correlation to temperature in the 100 mV range.with best regardsAndreas

author: rigrunner
author_rank: Frequent Contributor
timestamp: November 25, 2017, 06:02:43 pm
content: Using the down temperature slope from reading 89 onwards the DMMs here show:3456A: -0.5ppm/K3457A-1: +0.83 ppm/K3457A-2: -1.16 ppm/KD1071: -2.0 ppm/KI'd expect the 3457As would be slightly better in their 3V range. I wasn't going to check any other ranges but now that you've mentioned it i might flip the EDC to 100mV and log a little data there too.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 25, 2017, 06:18:12 pm
content: How do you know that your 10V reference supply was stable during the change of temperature?

author: rigrunner
author_rank: Frequent Contributor
timestamp: November 25, 2017, 06:37:57 pm
content: Quote from: HighVoltage on November 25, 2017, 06:18:12 pmFor this set of measurements i don't know the stability of the 10V. All i was interested in was a comparison of the meters,. Whatever drift the EDC has is included in the measurements. Before i switch my 1271 over to the new build LTZ i can measure the 10V over a temperature range and get an idea of it's drift.

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: November 26, 2017, 06:45:52 am
content: I looked at temperature sensitivity of Keithley DMM7510A and 34470A for periodic temperature changes on a timescale of 1000 sec:https://www.eevblog.com/forum/metrology/dmm-adc-noise-comparison-testing-project/msg1330643/#msg1330643For 34470A the measured sensitivity for these relatively fast temperature changes was about 0.8 ppm/K, while for DMM7510 it was 0.4 ppm/K. The specs for steady-state temperature change are 2 ppm/K for 34470A and 0.15ppm/K for DMM7510.Someone must have done this for a 3458A?

author: 3roomlab
author_rank: Frequent Contributor
timestamp: November 26, 2017, 08:03:37 am
content: Quote from: rigrunner on November 25, 2017, 05:21:19 pmhow about sticking the VREF in a wine box?https://www.eevblog.com/forum/metrology/dmm-adc-noise-comparison-testing-project/msg1136604/#msg113660

author: Dr. Frank
author_rank: Super Contributor
timestamp: November 26, 2017, 12:13:51 pm
content: Quote from: maxwell3e10 on November 26, 2017, 06:45:52 amWell, yes, it's described here:https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg1336575/#msg1336575,how to determine the 3458As T.C., and how to design a reference which is relatively independent from temperature changes, serving as a fix point for such measurements.I've got a 3458A which has +0.4ppm/K, and Tins both 3458As are less than 0.1ppm/K.Frank

author: rigrunner
author_rank: Frequent Contributor
timestamp: November 26, 2017, 05:10:24 pm
content: Quote from: 3roomlab on November 26, 2017, 08:03:37 amI've got a wine cooler similar to the thing Dave showed in episode #101 but the EDC is too large to fit insideI will redo the measurements with an LTZ in the cooler when i've put the next one together.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: November 26, 2017, 06:49:43 pm
content: R6581T: +1...+1.2 ppm/K (w/o selfcal)D1271: +0.5 ppm/K (w/o selfcal)S7081 #1: +0.06 ppm/K (20K span, LTZ mod + Cu mod)S7081 #2: +0.03 ppm/K (20K span, LTZ mod + Cu mod)S7081 #3: -0.55 ppm/KHP 34401A: +0.1 ppm/KK2100: -1...-1.5 ppm/KD1071: +0.8 ppm/K

author: e61_phil
author_rank: Frequent Contributor
timestamp: November 28, 2017, 08:33:22 am
content: I've attached a measurement from a Solartron 7081 I had some time ago. It was measured against my Fluke 5440B (10V). It gives a bit less than 0.8ppm/K