The DMX 512 agreement was first proposed by USTT (United States Society of Theater Technology), and gradually developed into a digital signal control protocol for the lighting industry. It is an international agreement. The agreement takes frames as units, and each frame of data is composed of a synchronous header and 512 bytes, and the data is sent and received in a computer serial manner, and the data transmission rate is 250KBit/second.
There are 512 bytes of serial data behind the synchronous header of the DMX 512 signal. For an all-digital dimming system, each byte of data represents the dimming brightness value, the second byte represents the brightness value of the second channel, and the second byte represents the brightness value of the second channel. 512 bytes represent the brightness value of 512 lamps. The DMX 512 agreement is the basis for digital lighting system applications.
The transmission of DMX 512 adopts RS485, and theoretically the longest transmission distance of RS485 can reach 1200 meters. But in practical application, the transmission distance is shorter than 1200 meters. How far the transmission can be done depends on the surrounding environment. In the transmission process, the signal can be amplified by adding relays, or optical fiber is used as the propagation medium, and a photoelectric converter is added at both ends of the transceiver. The transmission distance of multi-mode optical fiber is 5-10 kilometers, while the transmission distance of single-mode optical fiber up to 50 km transmission distance.
The lighting control system adopting DMX 512 agreement has the advantages of transmission distance, easy to use, reliable and good compatibility. Compatible with DMX512 lamps from different LED suppliers.
DMX 512 control system is generally composed of “HS lantern management” software, controller, decoding driver or (sub-controller) and other components.
The function of the software is to convert the content (text, pattern or animation) displayed by the LED lamp into a special file, which is the display content of the lamp. The controller reads the converted file, and sends it to the decoder (sub-controller) of each corresponding LED lamp according to the DMX agreement, and the decoder (sub-controller) drives the LED lamp.