In RS1xx, once the alarm threshold reaches for temperature, is that data continuously sent uplink? does it keep sending

Answer

When alarm condition is reached, that reading is sent immediately. After that, a timer is started with a fixed duration of one hour. If one-hour timer expires and alarm condition has persisted, the updates to normal uplink is interrupted and single uplink is sent again with alarm data. 

The Sensor Alarm Flag set in the Options byte is only set once per hour during sending of the single set of sensor data uplink.