2002-08-27

Deep Breath

Tonight we divulge the story of the Genie(R) Excellerator(TM) garage door opener, it opens twice as fast as the normal chain drive garage door opener, but took me three times as long to install. The problems started with the prewiring of the garage and extended into a two day hot battling against safety sensors.

The garage was prewired for both openers. I hate having external wiring so this should make installation faster and more attractive. The typical garage door opener only needs two wires at each of three locations: each side of the door opening, and at the console switch.

CAT-3 networking cable was used for wiring. CAT-3 cable has six conductors (three twisted pairs) so we have extra conductors for future technology. My garage has two doors, making six runs of CAT-3 cable. Each run of three cables terminates at an opener drive unit. Unfortunately, none of the cable runs are labeled. My first obstacle was determining which run of cable to use. Fortunately, a multi-meter made order of the chaos in about 15 minutes.

I wasn’t so lucky with the optical sensors. Genie(R) includes an optical sensor which detects when objects, like children or bicycles, are blocking the path of the door and prevents the door from automatically closing on the obstacles. To operate, and infrared beam is pulsed from a sending unit to the receiver. Since the average door opening is 8 feet wide, seemingly small differences in alignment can make the sensors inoperable. The alignment procedure can be frustrating. Without infrared goggles, you can’t tell where the beam is aligned..

A friend in Ft. Worth once installed the sensors on top of the drive motor so they would be only inches apart. This saved him from the frustrating task of aligning the sensors in the hot garage, but also rendered them useless. Simply by-passing the sensors isn’t an option as the drive unit will not function without the sensor signal.

Knowing the sensitivity to alignment, I took my time and measured twice to ensure that my sensors would line up. I was quite surprised to find that my sensors did not function. I suspected the wiring, or alignment, and went off in search of the problem. After nearly six or more hours of continuity checks on the wiring, rereading the instructions, remeasuring the sensors, I called it quits.

On Sunday, I attacked the problem again. The wiring checked out so there must be a problem with alignment. I took the sensors off, measured and drilled again, but I still had the same problem, signal interference, which suggested that the alignment wasn’t spot on.

Quite fortunately I stumbled upon an solution, instead of measuring from the floor, I would measure from the ceiling. Holding the tape measure to the ceiling wasn’t a workable solution, so I turned to the time-honored technique of the plumb bob. There was a 1/2 inch difference. Measuring the distance out from the wall, another 5/16 inch error. With knowledge of the errors, I was able to shim and align the sensors. Next time I’ll measure all axes.

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