Top 5 Troubleshooting Tips for Vehicle Loop Failures at Gate Entrances
Vehicle loops are a relatively simple to install and simple to use technology, especially when done by a professional. But things happen, wires get mixed up, and mistakes may occur but don't panic! Most issues with loop detectors come down to a few common issues that we have seen from our customers, thus why we've put together our most frequently asked questions and troubleshooting tips for vehicle loop failures at your gate entrances. Let's take a look!
Why did my loop detector stop detecting vehicles?
The underlying problem: It's likely that there is a loop wire breakage, poor splices, or damaged lead-in wire from shifting pavement or ground movement. This occurs most often when installing which is typically why it's important to test your loops before installation is complete.
Troubleshooting Tip:
To ensure that the loop itself has issues, you can test the loop's inductance with a multimeter/megger; compare reading against spec (typically 50–150 microhenries and ~2–5 ohms resistance) to confirm the wire itself failed vs. the detector which is easier to replace.
Why does my gate open when no vehicle is present (phantom detection)?
The underlying problem: It's common for loop detectors to show false positives and open, a phantom detection, if there are metal objects or adjacent loops nearby. Additionally, heavy vibrations from machinery can trigger your loop or a sensitivity that is set too high.
Troubleshooting Tip:
You can lower your detector sensitivity one step at a time and check for metal-to-metal contact (chain, gate arm) near the loop's sensing area.
Why is my gate closing on top of vehicles?
The underlying problem: This is most often caused by a failed/reverse-loop safety failure or an air pocket under a saw-cut loop insulating parts of the wire. This is a very dangerous issue and must be dealt with as soon as possible.
Troubleshooting Tip:
Confirm that loop is fully sealed with loop sealant/polyurethane as air pockets in the saw cut groove are a common cause of intermittent loop failure. This can be tested with a number of methods including chalk and testing fluids.
Why is my loop detecting intermittently in wet weather?
The underlying problem: Water intrusion into an unsealed or cracked saw-cut groove can disrupt the detection field and interrupt signals.
Troubleshooting Tip:
Inspect the groove for standing water and cracks; re-clean and re-seal with backer rod and loop sealant. This can be tested the same way that air pockets can be tested for.
Do I need to replace the whole loop, or just the detector?
The underlying problem: This is often a misdiagnosis of the problem as detector symptoms often get blamed on the loop.
Troubleshooting Tip:
Test by swapping the detector with a known working unit, or disconnect the loop and measure inductance/resistance to isolate which component failed.
