Raw data files
 Aug  8 17:48  m1-K2001.txt                    | FX measurement on K2001
 Aug  8 17:49  m1-temperature-8-8.csv          | Temperature/Humidity for m1
 Aug  9 07:57  m2-K2001-R6581T.txt             | FX measurement on K2001, R6581 measuring Randall's 10v LTZ ref (RKMX).
 Aug  9 07:57  m2-temperature-8-8.csv          | Temperature/Humidity for m2
 Aug  9 11:59  m3-K2001-R6581T.txt             | K2001 measuring FX, R6581 measuring FX - RKMX.
 Aug  9 11:59  m3-temperature-8-8.csv          | Temperature/Humidity for m3
 Aug  9 12:44  ReadK2001-R6581T.488            | Created EZGPIB script to log temp/humidity,r6581,K2001 together
 Aug  9 20:45  m4-K2001-R6581T.txt             | K2001 measuring FX, R6581 measuring FX - RKMX.
 Aug  9 22:06  m5-K2001-R6581T.txt             | K2001 measuring FX, R6581 measuring Fluke 731B - FX.
 Aug 10 08:54  m6-K2001-R6581T.txt             | K2001 measuring FX, R6581 measuring Fluke 731B - FX.
 Aug 10 11:55  m7-K2001-R6581T.txt             | R6581 measuring Fluke 731B, K2001 measuring FX.
 Aug 10 13:51  m8-731b-K2001-R6581T.txt        | R6581 measuring Fluke 731B, K2001 measuring FX.
 Aug 10 16:04  m9-px-K2001-R6581T.txt          | Measure PX reference on both meters
 Aug 10 20:21  m10-fx-fx-K2001-R6581T.txt      | Measure PX reference on both meters
 Aug 10 21:55  m11-fx-fx-K2001-R6581T.txt      | Measure PX reference on both meters
 Aug 11 10:29  m12-fx-fx-K2001-R6581T.txt      | Measure PX reference on both meters
 Aug 11 10:57  px-1k-R6581T.txt                | px 1k resistor measurement on 6581t
 Aug 11 10:59  px-1k-K2001.txt                 | px 10k resistor measurement on 6581t
 Aug 11 11:00  px-10k-K2001.txt                | px 1k resistor measurement on K2001
 Aug 11 14:43  px-10k-R6581T.txt               | px 10k resistor measurement on K2001
 Aug 12 07:47  m13-fx-fx-cat-K2001-R6581T.txt  | Measure PX reference on both meters. Cat caused bad data 7am

Ambient conditions: air conditioning on during the day, window open at night with house fan bringing in outside air.
Actual outside temperatures from 41C to 16C. Temperature measurement using TI EVM sensor HDC1010. Thermal blanket
added around FX reference 8/11 7am.

Meters used:
1) Advantest R6581T self calibration by me to Fluke731B. 100PLC used.
2) Keithley K2001 last cal date 5/2018 by TiN, out of cal as of 5/2019. Filter=Adv(50) used.

Summary FX reference stats for logging from 8/10-8/12:
mean temperature=27.62 C, SD=2.34 C
6581T mean = 10.0000128 volts, SD=5.33 uV; K2001 mean = 9.9999839 volts, SD=6.82 uV
Raw data files: *fx-fx*txt

Summary PX reference:
Mean temperature = 27.6C, SD = 0.47 C
PX actual = 7.0456 Volts
R6581T mean = 7.045683 SD=1.1uV
K2001  mean = 7.045659 SD=4.0 uV


m1-m4: R6581T is measuring delta between my in-house LTZ reference and the FX reference. Btw it has never been temperature compensated, unlike the FX. FX is negative lead.

m5,m6: R6581T is measureing delta between Fluke731B and FX reference. FX is negative lead.