Why can't I enable backlog feature on my Sentrius RS1xx LoRaWAN Sensor?

The Sentrius RS1xx backlog feature allows to store up until 4096 measurement in its flash memory that users can retrieve with either FIFO or LIFO mode. To enable this feature, you'll have to make sure of the following :

- Depending on how you want the backlog feature to operate (On Fail or Continious), choose either Laird or Laird2 packets format.

- Provide the RS1xx with the network time

The backlog feature only functions if the sensor has received a timestamp from the server. Every time a sensor will join the Network Server, it will ask to be provided with the network time. Please make sure the network provide its timestamp every time the sensor will request it as per Application Note - RS1xx LoRa Protocol, section 4.3 Server-to-Sensor Message : Set UTC Notification. 

More information on the RS1xx logging feature can be found into User Guide - Sentrius RS1xx Sensor Configuration section 8.9.