External power supply - SmartRelay 3 system

The readers (up to three readers per controller) are connected to the controller at the designated points. The power for readers is provided from an own power supply unit. A common reference potential is required for data transmission between controllers and readers. As a result, the earth systems in power supply units, the power supply and the controller must be connected. Using an external power supply unit avoids potential problems with voltage drops between controllers and readers.

Option 1: Using a earth connection

This configuration uses just one of the two earth connections available on the reader. Since the two earth connections are connected to one another electrically, it does not matter which one is connected to the earth. It is sufficient to assign one earth connection to the controller. This establishes a common reference potential, allowing data transmission to take place. Since the earth connections on the controller are connected to one another electrically, it does not matter which one is connected to the earth (see Controller for details). The diagram shows all possible earth connections between the readers and the controller. However, it is sufficient if one earth connection on the controller is connected to the reader earth systems.

Option 2: Using two earth connections

This configuration uses both earth connections available on the reader. The power supply unit's earth is wired to one earth connection, the controller's earth to the other earth connection. This establishes a common reference potential, allowing data transmission to take place. Since the earth connections on the controller are connected to one another electrically, it does not matter which one is connected to the earth (see Controller for details). It is sufficient if one earth connection on the controller is connected to the readers' earth systems.

This configuration is ideal if you wish to reduce the number of branches in the wiring. Both configurations function in exactly the same way.