The search for “modbus poll key full” typically comes from users who have reached the end of their 30-day trial period. They are looking for a way to unlock the complete set of features. The legitimate “key” is the purchased from the developer, and the “full” version is the perpetual, licensed version of the software.
To change a value, double-click the register value and enter a new number. You can write to Coils or Holding Registers. modbus+poll+key+full