Like you, I was hoping the limit switches inside the operator would help identify whether the gate was open or close.
Here’s what I determined using a multimeter:
- Blue and Red are Power and Ground for the operator. Reverse polarity to either open or close the operator.
- Green is RPM for the operator motor.
- Brown and White are for the release level. Open continuity when the limit switch is engaged.
- Brown and Yellow are for the limit switches. Both open and close positions of the operator. Open continuity when the limit switch is engaged when operator is opened or closed.
I spoke briefly with a Liftmaster tech and he confirmed the limit switches inside the operator are safety switches to prevent the operator motor from going pass the set points. Limit switches are wired in parallel for open and close points.
Based on the description, Terminal P8: Open Safety Edge/Photoelectric Sensor on the LA400 functions similar as the obstruction sensors on the garage door.
I am waiting on my RATGDO to ship.