A diode is a standard semiconductor device integral to the safe and proper function of the door controller. It acts as a grounding tool, allowing the flow of current in one direction only. When a door strike is called, requested, or sent, the coil sends a spike (also called “kickback voltage”) down the line with as much as 50,000 volts. Without a diode semiconductor, this kickback voltage would damage the control equipment. When properly installed, the diode keeps kickback voltage localized at the lock.
Installing the diode backward for a strike can cause the Cloud Node or the door controller to reboot. A damaged or blown (dead) diode can act as if there is no diode, installed backward, or show incorrect data in the logs such as a card scan when the strike returns to the default state.
The diode MUST be installed in the direction shown in the illustrations: Gray stripe to positive (+), black to negative or ground (-). The diode MUST also be installed as close to the lock as possible. The best scenario (where possible) is directly across the screw terminals on the lock (as shown in the first image). Another option is to splice the diode in parallel (shown in image two), connecting it to the positive (+) and negative (-) strike wires; use dolphin connectors, and crimp the wires.
It's imperative to protect your equipment against this electrical kickback. To do so, the provided diode MUST be installed across the powered lock, at the strike, between positive (+) and ground (-).