How fast can the RS186/RS191 detect a change of the door magnet open/close sensor?

Answer

The latency of the RS1xx Sentrius LoRa sensor with external magnet open/close sensor is limited by the following reasons:

1) The RS1xx uses two internal dwell times to detect a door open and close. These can be set in the Sentrius smartphone app to a minimum of 5 seconds (which is also the default setting). So any state change faster than 5 seconds will be suppressed and a change or the open/close sensor state won't be transmitted faster than 5 seconds.

2) Independent of the dwell time the RS186 (EU868 region) faces a minimum LoRa uplink interval due to regulatory 1% duty cycle limitations of the 868MHz frequency band. At the maximum data rate (SF7BW125) the airtime is roughly 60msec, which then adds a dead time of 99x60msec=5.94sec. So from this we get a minimum cycle time of roughly 6 seconds. At the minimum data rate (SF12BW125) the airtime is roughly 1480msec plus a dead time of 99x1480msec=2.4min giving a minimum cycle time of roughly 2.5min.

So the latency of a door open/close state detection plus transmission for the RS186 would be 6 seconds at best case (maximum LoRa data rate SF7BW125) and 2.5min at worst case (minimum LoRa data rate SF12BW125).

The latency of the RS191 is not limited by duty cycle restrictions and hence end up at 5 seconds latency purely due to dwell time.