Driveway Vehicle Detection - Loops & Loop Detectors

Swing Gate Operators

There are five types listed below:

Swing Gate Operators with Arm On Top. These are the most common units and are the work horses of the industry. A high end unit can last up to 20 years. Most of these units have heavy gear reduction oil bath gear boxes. They are generally very heavy in weight, many weigh up to 100 Lbs. and are large in size. A couple of drawback to them is the arm has to be removed to remove the cover for service. Some of them have an access panel to service the controls, but you still need to remove the cover to service the mechanics. The other drawback is the arm generally ends up in the middle of your gate where it can be unsightly.

Swing Gate Operators with Bottom Arm. DoorKing is the only operator that has the arm on the bottom. In general, they are not built as heavy as the top arm units, but do last as long. The two benefits of this type of unit is that the cover pops right off to reveal the entire unit and is one of the easiest units to service

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