You want to monitor values of a PLC, controller, OPC, HMI or SCADA that is Master Modbus RTU and write in spreadsheets from Google (Google Docs), In this case we will monitor the value of potentiometer V0 PLC from 0 to 100%:
Potentiometer V0 (0-1000 SCALE 0 -100%)
ESP8266 Connection Script and Google – Google Spreadsheets
-01 ESP8266 connecting with Google Script and connection with the spreadsheet from Google (Google Docs) Direct.
Based on the library HTTPS Redirect for ESP8266 of electronicsguy Github I have set and have made several improvements, I created the following tutorial full to Connect ESP8266 with (Google Script) and (Google Spreadsheets)