When the sensor starts up it loads configuration from the internal memory  and merge it with user configuration. When the configuration is done the sensor writes the new configuration to the NFC chip. The sensor always writes new configurations to the NFC chip when something changes in the sensor or if NFC data is corrupted by a NFC writer or phone. The sensor always writes new configuration to NFC chip at startup. When configuration is done the sensor tries to join the network if OTAA (Over The Air Activation) is enabled.The sensor led flashes orange  when it tries to join a network. The sensor tries to join the network every 10 second and increases the join timer at every failed attempt by 10%,  up to maximum 1 hour. After startup,configuration and join the sensor enters sampling mode.