Datalog run GPIB code running on Pi3 + E5810A with DP160 scanner, sample time 656 seconds

xDevs.com Volt is calibrated on incoming data from Day 1. Uncertainty of voltage measurements ~±0.3 ppm to SI.
CELL1 output = reference 9.99991544 VDC, measured median 9.99991314 VDC, delta -0.230 ppm, U=±0.3 ppm
CELL2 output = reference 9.99996553 VDC, measured median 9.99996581 VDC, delta +0.028 ppm, U=±0.3 ppm
CELL3 output = reference 9.99998606 VDC, measured median 9.99998635 VDC, delta +0.029 ppm, U=±0.3 ppm
CELL4 output = reference 9.99997163 VDC, measured median 9.99997108 VDC, delta -0.055 ppm, U=±0.3 ppm

Photo of measurement setup:

Result CSV-data

Workflow:

* RPI accesses DMMs via GPIB and reads data.
* Data is formatted by python script into DSV string and written/append to file on FTP
* DSV-file is visible publicly on https://xdevs.com/datashort/
* Page http://xdevs.com/datalog_mm/ runs D3.js javascript library to read DSV file test.log to input data
* D3.js plots SVG graph online :)