Need the ability to choose less than 1/8 inch rain detection

I read the following:
“To prevent severe equipment damage, never connect the Rain Sensor to any power source greater than 24 VAC.”

I’m connecting the Rainbird WR2 to the Rachio, so how does that relate to the power source? If you know that the rain sensor is connected to the Rachio, then presumably you know if it’s greater than 24 VAC, so why even write that?

Or do you mean never connect the Rachio to a power source greater than 24 VAC if a rain sensor will be connected to the Rachio? I’m confused.