Controlled Products Systems Group SWINGSMART DC 20 - Manual (Page 111)

Installing Photoelectric Sensors For Secondary Entrapment Protection Only
Revision E Reference 6-13
Notes about retro-reflective systems:
Correct installation and alignment of a retro-reflective photo eye and its reflector is important for trouble free
performance. Any system operating at a range greater than 16 feet is more prone to false triggering due to dirty
optics, condensation or poor weather. If care is taken in the initial mounting and alignment of the 3-inch
reflector, the chance of problems is greatly reduced. Use only through beam photo eyes for a distances greater
than 24 feet because the function of a retro-reflective photo eye will be too unreliable.
Taking steps to protect the photo eye and the reflector from being exposed to fog and being absolutely certain
the photo eye is perfectly aligned will greatly reduce any false triggering of the system. The ideal mounting of a
retro-reflective photo eye is inside an enclosure.
The ideal reflector mounting suspends it inside a 12-inch long piece of 3-inch PVC conduit. Cut the opening
of the PVC conduit at a 45-degree angle to act as a drip shield. Hold the reflector against the backside of the
PVC conduit by attaching a 3-inch male connector. Do not cement the connector. This would prevent the
reflector from being reached for future cleaning. To create a mounting base, attach a 3-inch aluminum flange
(electric meter hub) to the connector. This whole package can be mounted to any flat surface.
Locate the reflector in the center of the invisible beam of infrared light to achieve the most sensitive alignment.
The beam center is determined by the following test: while holding the reflector in your hand, slowly raise it
until the beam is no longer returned and the photo eye trips. Mark this maximum height. Now lower your
hand and determine the lower limit of the infrared beam by watching for the trip point. Mark this position as
well. Repeat the same procedure for left and right at the center elevation of the beam, as determined by the
previous test. Once the four limits have been determined, either mount the reflector in the center of the area
outlined or realign the eye for the position of the reflector. If the photo eye is realigned, be sure to perform the
centering test again to verify that the reflector is truly in the center.