I have replace a Motion Senor 1 that worked great for many years with a Motion Sensor 2. I have setup the Motion Condition to "Only at Night."

What value do I need for the Night Threshold parameter to ensure the Motion Senor 2 only turns on the light when it is "dark"?

There should be an option in your ISY MS2 device configuration for night mode only mode. You can adjust light threshold if needed. It's trial and error depending on the MS2 location. Start with the default setting

Thanks. I know from the MS1 that the sensitivity was trial and error. I was hoping someone had already gone through a trial and error effort and would have some recommendations.

The setting would be based on factors like the amount of ambient light and the location of the sensor, Each semsor setting is unique.

Turns out the factory defaults worked as desired.