Ordering a monitored sensing edge means getting four things right: the designator, the length, the outlet location, and the color. Sensing edges are custom manufactured and are not returnable, so this guide walks through each one before you place an order.
What a designator is, and why it matters
A monitored gate or door operator constantly checks that its safety edge is still connected and working. It does this by looking for a specific electrical value on the edge circuit. The designator is the component built into the edge that supplies that value.
Match the designator to your operator, not to the edge. The edge will be built to whatever designator you specify. If it does not match what the operator expects, the operator will read a fault and refuse to run.
Designator reference
| Code | Device | Color | Typically used by |
|---|---|---|---|
| T1 | 8.2K Ohm Resistor | Green | European operators |
| T2 | 10K Ohm Resistor | Blue | Cornell / US Gear, LiftMaster / Chamberlain, Linear, Manaras, Micanan / Napoleon Lynx, Raynor, VE Power Door, Cookson, Lawrence |
| T3 | Diode Capacitor | Red | Overhead Door Corporation |
| T4 | Capacitor | White | Linear (Transmitter) |
| T5 | 6.8K Ohm Resistor | Orange | Custom applications |
| T6 | 270K Ohm Resistor | Violet | LiftMaster CPS board |
T2 covers most of the North American market. If your operator is a LiftMaster, Chamberlain, Linear, Raynor or Cornell, T2 is the usual answer — but confirm against your operator manual before ordering.
Do you need a monitored edge or a non-monitored edge?
Monitored edges are required for UL 325 listed operators built after August 29, 2010 that have a monitored circuit. For older units and most other applications, a non-monitored edge is used.
If you are unsure, check the operator's date of manufacture on its data plate. Operators built after that date almost always require monitoring.
Outlet location — which side does the cord come out?
This is the detail that causes the most returns, and it is worth slowing down on.
The reference is from the inside looking out. Stand inside the property facing out through the gate or door opening. From that position, which side is the operator mounted on? That is your outlet location.
Get this wrong and the lead will run the opposite way across the opening. Because the edge is built to order, it cannot be exchanged.
Length
Sensing edges are manufactured to your specified length. Measure the leading edge of the gate or door where the edge will mount, and order to that measurement. If you are replacing an existing edge, measure the old one rather than the opening.
Color
Standard sensing edges are black. A chemical-resistant yellow XR5 jacket is available on many models, and yellow is often specified for high-visibility or commercial safety requirements.
Check your job specification before selecting. Color is a build option, not a stock variation — a black edge cannot be exchanged for a yellow one after manufacture.
Before you order: sensing edges are custom made and are not returnable. Confirm the designator with your operator manufacturer, and double-check length, outlet location and color.
Electric and pneumatic edges
- Electric sensing edges use conductive strips inside the profile. Compression brings the strips together and completes a circuit.
- Pneumatic edges use air pressure. Compression forces air through a hose to a switch, which triggers the operator.
Both provide reliable obstruction detection. Which one suits depends on the operator and the application.
Do I also need a control module?
Some installations need a signature module or edge interface between the sensing edge and the operator, particularly when retrofitting an edge to an operator that expects a different signal. Miller Edge signature modules such as the SM-101 and SM-102 handle 10K and T2 edges.
Not sure about any of this?
Call us at (866) 965-5599. We have been specifying and installing gate safety equipment since 1993, and we would rather spend five minutes on the phone than have you take delivery of an edge that does not fit.