I have the Edge 1040 Solar with software version 14.50
The Rally XC200 has firmware version 4.00.
So both hardwares are up to date.
On my Edge 1040 Solar, I realize that the Sensor searching for the Rally XC200 is not always continuously searching like other sensors do. For the Rally XC200, the Edge 1040 will sometime decided to continue to search for it indefinitely (which is good, all other sensors searching are also behave like this, which is desired because once the sensor is wake up or turned on, it immediately detected and connected to the Edge). Whereas at sometime the Edge 1040 will just decide it has search long enough and decided to declare the Rally XC200 sensor as "Disconnected" while other sensors are still being searched continuously.
When the Edge 1040 has declares the Rally XC200 as disconnected, no matter how I wake up my Rally XC200 by spinning the pedal or even riding it, the Edge 1040 will simply not search for it anymore. It will remain in disconnect mode until I manually click into the Rally XC200 sensor page and click Connect manually.
Why is this happening? What trigger the Edge 1040 to stop searching for the Rally XC200 and what trigger it to continuous searching for it? The Edge behavior is completely unpredictable when comes to Rally XC200 connectivity.