Miller Edge sensors are available in a variety of models to easily adapt to any motorized door or gate. All electrically activated edges operate on the same basic principle referred to as a Normally Open (N.O.) electrical configuration.

• The outer covering houses 2 electrically conductive flexible contact elements
• The contact elements are separated by a soft perforated foam cushion.
• When touched, the edge compresses causing the contacts to touch.
• An immediate electrical signal is sent to the motor control unit to stop and/or reverse motion.
  
  

A 2-conductor electrical configuration complies with UL-325 and the 2009 International Building Code for gates

Effective August 31, 2010, the UL-325 safety standard will require motorized doors installed with momentary contact on the down control to require the installation of a monitored reversing device.

With a monitored device, the motor controls are able to check for the presence and operation of the reversing system. There are multiple ways to monitor a Sensing Edge depending upon what the controls monitor (some brands check for resistance or a certain electrical pulse).

The following diagram shows a basic 4-conductor electrical configuration. In this configuration, a lead wire is attached to each end of the top contact element. The motor controls send voltage in through one wire; the voltage travels through the contact element and back out the wire attached to the opposite end. When the same voltage is received back to the controls, the motor "knows" there is continuity in the circuit. The same process is repeated with the bottom contact element.