Photocell configuration for CB11

[Malcolm]

Thanks for your reply. I thought this would make more sense but the Liftmaster instructions stated:
"EN12453 specifies that a pair of photocells must be installed at a height of 200 mm and activated to “Close”; a second pair must be installed at a height of 200 mm and activated to “Open”. A third pair of photocells can be optionally installed and activated to “Close” and “Open”."