Another day of 3458a logging resistor.
As by Andreas suggestions this time I used copper wire (from ethernet cable) soldered to the end of resistor leads. I also used a clamp to reduce overheat of the resistor.
Measured resistance of the DUT in free air before to start tests. Temperate 21°C +/- 2°C circa (no way to measure it).
- DUT R with pomona leads 12K00596
- DUT R directly to binding posts 12K00592 (observed heating/cooling process when in the binding posts)
- DUT R with soldered ethernet copper leads 12K00597
I also measured the 10K resistor inside my MF calibrator before to start test and at the end of the test to be sure multimeter doesn't drift.
- start of test: 10.000061 ohm
- end of test: 10.000059 ohm
At the end of cycle I added also a log period at 25°C (steps 10 and above). Every step has same temperature and lasts 15 minutes, by this I can get resistance value averaged every 15 minutes. If you really force a bit readings you can notice a slight drift down because 25°C is still higher than normal temperature.
I give it also a run 30/65/30 without offset compensation just to check if anything changes but also this tests give me the same results.
Here are all data and charts.
READINGS - 4W - SOLDERED COPPER ETH LEADS - OFFSET COMP ON (DELAY 0.5s):
===================================================================================================
step 00 - temp. 25 °C - avg. res. 12005.837343 ohm (0026 samples)
step 01 - temp. 30 °C - avg. res. 12005.656371 ohm (0088 samples) total -15.07 ppm - -3.01 ppm/K°
step 02 - temp. 40 °C - avg. res. 12005.198936 ohm (0101 samples) total -38.10 ppm - -3.81 ppm/K°
step 03 - temp. 30 °C - avg. res. 12005.612139 ohm (0054 samples) total +34.42 ppm - -3.44 ppm/K°
step 04 - temp. 40 °C - avg. res. 12005.195729 ohm (0102 samples) total -34.68 ppm - -3.47 ppm/K°
step 05 - temp. 30 °C - avg. res. 12005.607506 ohm (0042 samples) total +34.30 ppm - -3.43 ppm/K°
step 06 - temp. 65 °C - avg. res. 12003.806769 ohm (0076 samples) total -149.99 ppm - -4.29 ppm/K°
step 07 - temp. 30 °C - avg. res. 12005.559735 ohm (0076 samples) total +146.03 ppm - -4.17 ppm/K°
step 08 - temp. 65 °C - avg. res. 12003.794508 ohm (0065 samples) total -147.03 ppm - -4.20 ppm/K°
step 09 - temp. 30 °C - avg. res. 12005.531690 ohm (0026 samples) total +144.72 ppm - -4.13 ppm/K°
step 10 - temp. 25 °C - avg. res. 12005.740309 ohm (0018 samples) total +17.38 ppm - -3.48 ppm/K°
step 11 - temp. 25 °C - avg. res. 12005.743185 ohm (0056 samples) total +0.24 ppm - +0.24 ppm/K°
step 12 - temp. 25 °C - avg. res. 12005.742822 ohm (0051 samples) total -0.03 ppm - -0.03 ppm/K°
step 13 - temp. 25 °C - avg. res. 12005.742047 ohm (0051 samples) total -0.06 ppm - -0.06 ppm/K°
step 14 - temp. 25 °C - avg. res. 12005.743028 ohm (0050 samples) total +0.08 ppm - +0.08 ppm/K°
step 15 - temp. 25 °C - avg. res. 12005.742188 ohm (0051 samples) total -0.07 ppm - -0.07 ppm/K°
step 16 - temp. 25 °C - avg. res. 12005.742950 ohm (0051 samples) total +0.06 ppm - +0.06 ppm/K°
step 17 - temp. 25 °C - avg. res. 12005.741966 ohm (0049 samples) total -0.08 ppm - -0.08 ppm/K°
step 18 - temp. 25 °C - avg. res. 12005.740597 ohm (0050 samples) total -0.11 ppm - -0.11 ppm/K°
step 19 - temp. 25 °C - avg. res. 12005.740345 ohm (0051 samples) total -0.02 ppm - -0.02 ppm/K°
step 20 - temp. 25 °C - avg. res. 12005.740984 ohm (0051 samples) total +0.05 ppm - +0.05 ppm/K°
step 21 - temp. 25 °C - avg. res. 12005.740076 ohm (0050 samples) total -0.08 ppm - -0.08 ppm/K°
step 22 - temp. 25 °C - avg. res. 12005.740010 ohm (0050 samples) total -0.01 ppm - -0.01 ppm/K°
step 23 - temp. 25 °C - avg. res. 12005.738172 ohm (0051 samples) total -0.15 ppm - -0.15 ppm/K°
step 24 - temp. 25 °C - avg. res. 12005.739758 ohm (0050 samples) total +0.13 ppm - +0.13 ppm/K°
step 25 - temp. 25 °C - avg. res. 12005.739483 ohm (0050 samples) total -0.02 ppm - -0.02 ppm/K°
step 26 - temp. 25 °C - avg. res. 12005.739246 ohm (0051 samples) total -0.02 ppm - -0.02 ppm/K°
step 27 - temp. 25 °C - avg. res. 12005.739165 ohm (0051 samples) total -0.01 ppm - -0.01 ppm/K°
step 28 - temp. 25 °C - avg. res. 12005.738020 ohm (0051 samples) total -0.10 ppm - -0.10 ppm/K°
step 29 - temp. 25 °C - avg. res. 12005.737698 ohm (0050 samples) total -0.03 ppm - -0.03 ppm/K°
step 30 - temp. 25 °C - avg. res. 12005.738319 ohm (0051 samples) total +0.05 ppm - +0.05 ppm/K°
step 31 - temp. 25 °C - avg. res. 12005.738173 ohm (0051 samples) total -0.01 ppm - -0.01 ppm/K°
step 32 - temp. 25 °C - avg. res. 12005.738530 ohm (0051 samples) total +0.03 ppm - +0.03 ppm/K°
step 33 - temp. 25 °C - avg. res. 12005.738807 ohm (0050 samples) total +0.02 ppm - +0.02 ppm/K°
step 34 - temp. 25 °C - avg. res. 12005.738572 ohm (0051 samples) total -0.02 ppm - -0.02 ppm/K°
step 35 - temp. 25 °C - avg. res. 12005.737621 ohm (0051 samples) total -0.08 ppm - -0.08 ppm/K°
step 36 - temp. 25 °C - avg. res. 12005.735601 ohm (0051 samples) total -0.17 ppm - -0.17 ppm/K°
step 37 - temp. 25 °C - avg. res. 12005.715372 ohm (0067 samples) total -1.68 ppm - -1.68 ppm/K°
READINGS - 4W - SOLDERED COPPER ETH LEADS - OFFSET COMP OFF:
===================================================================================================
step 05 - temp. 30 °C - avg. res. 12005.513999 ohm (0160 samples)
step 06 - temp. 65 °C - avg. res. 12003.726170 ohm (0119 samples) total -148.92 ppm - -4.25 ppm/K°
step 07 - temp. 30 °C - avg. res. 12005.495170 ohm (0093 samples) total +147.37 ppm - -4.21 ppm/K°