Page 5 - Stephen Kidwell

Typically, the slide gate operator is installed next to the opening of the gate. This is called a standard or front installation.

Some sites will not allow the gate operator to be installed next to the opening due to vegetation or structures, etc. In this case, the operator should be installed at the back end of where the gate opens into. This "rear installation" would require the drive chain to be routed differently and to have external idler pulleys mounted to guide the chain.

• In a standard installation, the drive chain is connected on each end of the gate and the sprocket movement pulls the gate side to side.
• On a rear installation, another idler pulley would be added and the chain loops around the pulley to pull the gate from the same spot.

The picture below shows the difference between front and rear installations.

(Article & Diagram Courtesy of LiftMaster)

Vehicle detector loops are like large metal detectors which detect all metal vehicles including bicycles. Loops in gate systems need to be installed correctly and are one of the most common causes of automation system failure. The most common type of failure is due to leakage to ground which occurs when moisture penetrates the insulation of the wire. Poorly spliced loop wire or splices which are not watertight are other common points of loop failure. An indication your EXIT loop has failed is when the gate will not close. See our Loop Troubleshooting Article for more information.

There are 2 basic components to this type of driveway vehicle detection; the Loop Detector & the Loop.

Loop Detectors:

Loop Detectors are the "brains" of the system. They are control module components which are installed on the gate operator control or circuit board and operate in tandem with the loop. Loop Detectors control what type of actions are taken when the presence of a vehicle detected. There are 2

Most common problem on the loops is a short to ground. This happens when the wire is abraded or nicked and moisture creates an electrical path to ground. This usually occurs in splices, if there are any. If the incorrect type of wire was used during the installation, this can also cause a leak to ground condition.

To Check Leakage, disconnect loop from detector. Use a multi-meter to measure the resistance from one loop wire to ground (stick long nail in dirt if operator does not have ground). Be sure that other loop wire is floating (not connected). If there is less than 10 Meg Ohm leakage to ground, loop is faulted. Most loop leakage to ground occur in wet conditions. The loop may work fine during the dry season.

To Check Loop Continuity, connect two meter leads to two loop leads. You should only read a few ohms at most. If resistance is higher, the loop is faulted. This usually indicates that loop is severed.

Check Loop Detectors: If loop passes test, replace detectors. If you have

By Jeff Harris, Systems Specialist

Inductive loops or "sensing loops" as they are commonly referred to, have become an integral part of automatic gate systems and other aspects of our everyday life. For example, every time you pull up to a stoplight, you "trigger" a loop, which in turn engages a timer or switching device to change the lights and get you on your way. Loops are used to stop or reverse a moving gate, to allow free exit from or entrance to a site, or as an "arming loop" to allow entrance with the use of a transmitter or some other access control device.

A loop is made from a continuous run of wire with no splices, which is typically wound in a rectangular shape and saw cut into the existing pavement. In some instances, prefabricated or "pre-formed" loops can be installed before paving or pouring concrete on the roadway. The ends of the wire are brought back to the gate operator and attached to a loop detector. The lead-in or "home run" from the corner of the loop to the detector