Skip to main content
Biamp Systems

Wiring LED's and relays to the Logic Box and Voltage Control Box

Besides providing the capability of using external devices, such as switches and potentiometer to control Audia and Nexia, there’s the possibility of having the audio system control external devices such as LEDs and Relays or drive logic inputs of other devices. Since LEDs and Relays are analog devices, these need to be connected to Audia/Nexia thru a Logic Box or Voltage Control Box. This note covers the details on wiring LEDs and Relays to the Logic Box and Voltage Control Box. 

Wiring an LED

Since the Logic Box and Voltage Control Box cannot supply voltage, you will need an external power supply. As explained above, logic inputs can sink up to 24V. However, a 12V supply should be sufficient for most applications. To wire an LED to a Logic Box or Voltage Control Box, do the following connections as shown in the diagram below:

  1. Connect the negative terminal of the power supply to the ground terminal on the Logic Box or Voltage Control Box 
  2. Connect the positive terminal of the power supply to a 1.2K ohms resistor
  3. Connect the resistor to the LED’s Anode (long lead)
  4. Connect the LED’s Cathode (short lead) to the Logic Box or Voltage Control Box logic input

logicbox-led.jpg

Wiring a relay

Wiring a relay is in essence very similar to wiring an LED. The only difference is that a resistor is not needed but a diode needs to be connected between the terminals of the relay coil to suppress high voltage transients that are generated when the relay turns off (note that some relays already have this diode built in). To wire a relay to a Logic Box or Voltage Control Box, do the following connections as shown in the diagram below:

  1. Connect the negative terminal of the power supply to the ground terminal on the Logic Box or Voltage Control Box
  2. Connect the positive terminal of the power supply to one of the relay’s coil terminals
  3. Connect the other relay coil terminal to the Logic Box or Voltage Control Box logic input
  4. Connect the diode’s Anode to the logic input of the Logic Box or Voltage Control Box
  5. Connect the diode’s Cathode to the positive terminal of the power supply 

logicbox-relay.jpg

Further reading

Once the device is physically connected to the Logic Box, you'll need to program it.  See Logic Box Programming for more information.

  • Was this article helpful?