Controlled Products Systems Group HRG 220-A ST - Manual (Page 55)

Installation and Maintenance Manual
41
Installing Photoelectric (Non-contact) Sensors (continued)
Supervised Connection:
If the photo eye being installed has a true NC output (one that is NC when the photo eye is powered,
aligned and set for Light Operate) then a supervised connection is recommended. A supervised
connection will signal a system Fault and prevent gate operation if either the open or close photo eye
connection ever becomes an open circuit or a short circuit. The Installer Menu item [PC_0] must be
changed to [PC_1] to enable this feature. See Description of Functions available in the Installer Menu.
Photo Eye Function:
A tripped photo eye will prevent the gate from starting in either direction if the gate is stationary. If
tripped while in motion, the standard function is to pause the gate motion and then automatically restart
again if the photo eye is clear within five seconds. An optional setting in the Installer Menu will cause a
2 second reversal of travel.
Alignment:
Most photo eyes require careful optical alignment in order to aim the emitter beam to the center of the
receiver or reflector. In order to avoid false triggering, it is important to carefully align the system,
especially with retro-reflective photo eyes. The best way to assure true centering of the beam is with
some trial testing where the emitter is shifted to move the beam left and right and up and down until the
range of the invisible cone of the infrared beam is known. Photo eyes usually provide alignment aid
LED’s for this setup, but they can be hard to see. HySecurity has provided a unique feature that causes
our buzzer to chirp when the photo eye enters and exits alignment. See User menu 9. Set the Installer
menu item [PE_0] to [PE_1] and the buzzer will provide an audible indication both when the beam is
broken and remade.
Notes about retro-reflective systems:
Correct installation and alignment of a retro-reflective photo eye and its reflector is important for a trouble free
installation. 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.
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 and enclosure of some sort.
The ideal mounting for the reflector is suspended inside a twelve-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, so that the
reflector can be 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.
A last tip
– if you coat the reflector with common dishwashing detergent, or some other anti-fogging
compound, it will reduce fogging from atmospheric moisture.