Controlled Products Systems Group PATRSL - Manual (Page 40)

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Loops
Loop Size Chart
The loop size is based on the width of the driveway. If the driveway is 14' wide, the loop would be a 6'x6', the
minimum. This is determined by subtracting 4' off of each side of the drive, which would leave you 6'.
See chart below for number of turns per loop size, plus lead in. The loop itself should contain between 90 &
125 feet of wire in the loop, plus lead in.
Drive Loop Number of Turns
Width Size Size 2 3 4
14' & Under 6' x 6' 96’
16' 6' x 8' 112'
18' 6' x 10' 96'
20' 6' x 12' 108'
22' 6' x 14' 120'
24' 6' x 16' 132'
26' 6' x 18' 96'
28' 6' x 20' 104'
30' 6' x 22' 112'
32' 6' x 24' 120'
The location of the loop is also important. If a loop is located too close to the gate, it will detect the gate itself,
giving false operation. If the loop is too far away from the gate a small vehicle might not be detected. Loops
should be approximately 5' from the centerline of a gate when closed. See Loop Position on previous page.
Loops
Other Loop Detector Facts
1. Always clean saw cuts thoroughly with water, air or brush to remove all debris prior to installing wire.
2. Recommended loop wire is TFFN #16 gauge stranded wire. It is available at electric supply distributors.
3. No splices are permitted in the loop or loop leads. One continuous wire should be used.
4. Lead wires should be twisted a minimum of 4 twists per foot to eliminate false sensing. Twists should begin at the edge of the
loop and continue to detector.
5. Do not use metal or sharp objects to push the loop wire into the saw cut. The slightest nick or cut in the insulation will cause the
loop to ground out and malfunction. To test for shorts, use a megohmeter or "Megger" between either loop lead and earth
ground with both leads disconnected from the detector. The resistance should be greater than 50 megohms.
6. Use siliconized caulk for backfill. Gray for concrete, black for asphalt. 25-Year life rating is preferred.
7. Never set adjacent loops on the same frequency. False activation will occur.
8. Almost all brands of detectors have an external or internal sensitivity adjustment. Usually the factory setting is sufficient if
internal adjust type. Be very careful and use extreme caution when decreasing sensitivity.
9. Most false activations are caused by an improperly installed loop or a shorted loop. The loop should be tested and validity
determined before adjusting sensitivity. See # 5 above.
10. Most detectors used in the gate business are fail-safe. This means that if the loop fails, the gate will be given a continuous signal.
When power is disconnected from a detector, the signal output is also given.
1 1 . ASB, or automatic sensitivity boost is now available on most detectors. This feature should be activated if large truck or trailer
traffic is likely.