How to Use DMX512 / RDM With Raspberry Pi

The Raspberry Pi can be used for lighting controls via DMX512 bus. In DMX512 bus systems RS-485 is used as the physical layer. Our RS422 / RS485 Serial HAT is a fully galvanic isolated serial communication HAT designed for use with the Raspberry Pi and the perfect choice for such kind of applications.

The following instructable will show you how to use the Raspberry Pi and our RS485 HAT for DMX512 applications.

Step 1: Bill of Material

Raspberry Pi A+, B+, B2 or B3
RS422/RS485 serial HAT
5pole XLR connectors (male & female) or 3pole XLR connectors (male & female)
hook-up wires

Step 2: Wiring of 5pole XLR

The official XLR plug for DMX/RDM is 5-pins, that is always used in professional systems.You have to connect a male and a female connector as in the picture above.

Step 3: Wiring of 3pole XLR

For semi-professional and hobby equipment there is the 3-pins XLR.

Step 4: DIP Switch Setting

Our RS422/RS485 HAT comes with 3 DIP switch banks. You have to set these DIP switches for DMX as shown in the picture above.

Switch 1:

1 OFF

2 ON

3 OFF

4 ON

Switch 2:

1 OFF

2 OFF

3 ON

4 ON

Switch 3:

1 OFF or ON *

2 OFF

3 OFF

4 OFF

*Depending of the position of the RS422/RS485 HAT in the DMX512 bus line you have to switch the terminating resistor ON or OFF. Please switch the resistor to ON position only if the HAT is on one end of the bus line. In all other cases switch the terminating resistor OFF:

Step 5: Free Up Serial Line and Enable UART

The RS422/RS485 HAT comunicates via the internal UART with the Raspberry Pi. This UART is usually connected withn the internal Bluetooth module (or with the console in older models). You have free up these UART lines.

Preventing Linux from using the serial port
http://elinux.org/RPi_Serial_Connection#Preventing...

Update : raspi-config -> 5 Interfacing Options ; Yes , No

Enable UART PL011

Add the following lines to the /boot/config.txt

# OLA UART DMX Output

dtoverlay=pi3-disable-bt

init_uart_clock=16000000

reboot

Step 6: Software for DMX512 & RDM

You will find tutorials and software packages for the Raspberry Pi On www.raspberrypi-dmx.org

The RS422/RS485 HAT can be used with the OLA UART native DMX plugin (DMX output only). Baremetal implementation (full DMX512/RDM support) is successfully tested with:

Raspberry Pi Art-Net 3 ->DMX Out http://www.raspberrypi-dmx.org/raspberry-pi-art-n...

Raspberry Pi DMX Real-time Monitor http://www.raspberrypi-dmx.org/raspberry-pi-art-n...

Raspberry Pi RDM Responder http://www.raspberrypi-dmx.org/raspberry-pi-art-n...