Do you know what RDM is?

Do you know what RDM is? How can it be used in LED landscape and facade lighting?

RDM Lighting Control is an extended version of the DMX512-A protocol in 2004. The RDM Control Lighting protocol is a Remote Device Management protocol, which was formulated by the American National Standards Institute (ANSI) and based on DMX512-A. DMX512-A can be regarded as a DMX for bidirectional data transmission. Under the RDM Lighting Control protocol, the control system can send requests to the lamps, the lamps can also respond to these requests, and the settings of the lamps can be changed on the console. Each RDM-compatible fixture can be identified by its built-in unique identifier; the list will most likely include the fixture model and the number of DMX fields it requires. Including the ability to remotely set the initial address of the DMX512, status monitoring, and management of these devices.

RDM system rational use environment, regardless of landscape effect design, lighting manufacturing electronic technology, engineering design, construction specifications, and many other links must be paid enough attention. Especially the RDM system network feedback signal test.

1. DMX512.-RDM belongs to two-way transmission communication and is risky

DMX512 communication is based on RS485. Usually, the host sends dynamic image signals in simplex mode. The lamp is only in the communication-receiving state. At the same time, the RS485 bus network is always in the master-slave structure. This method has extremely high reliability. The RDM system belongs to two-way transmission. Since the feedback signal needs to be sent back to the host, the master-slave structure of the RS485 bus network has been destroyed. That is to say, each lamp can be used as the host at every moment. Short, (for example about 100 meters) two-way transmission will not affect much if the RS485 bus is relatively long, the signal reflection interference is large (for example greater than 100 meters) DMX512 communication baud rate is 250K. Termination resistors have been difficult to add to ensure signal stability. Analysis: The risk of bidirectional transmission in the RDM system cannot be ignored.


2. The number of lamps and lanterns controlled by the RDM system

More than 10,000 lamps and lanterns in China’s LED landscape lighting project can often be seen. If the simplex DMX512 communication method is used, it has extremely high reliability. If the duplex DMX512-RDM communication method is used, due to a large number of lamps, higher quality requirements will be put forward in many aspects such as lamp production, communication network design, construction quality assurance, and so on. Regarding the current overall professional quality analysis of the relevant LED landscape lighting industry in my country, I hope that people in the industry must have a clear understanding.

3. RDM lighting installation environment

China’s LED landscape lighting projects are mainly used outdoors. Due to the vulnerability of the two-way transmission of the RDM system, the RS485 bus network has been exposed to the wind and the sun for a long time. Therefore, ensuring the long-term reliable operation of the two-way transmission of the RDM system brings risks. In the past, DMX512 (without RDM system) ) The control system often adopts Yutong company products, (including; system software, Ethernet switch, main control, sub-control, and signal amplifier,) need to be reconfigured after using the RDM system.

4. RDM system lamp feedback signal

Industry insiders often have misunderstandings about RDM systems and feedback signals. RDM belongs to remote equipment management, while lighting feedback signals are only part of equipment management. For example, RDM commands include: changing and setting the starting address of the DMX of the lamps; obtaining the status of the DMX equipment; information about the lamps and lantern manufacturers, etc. For the feedback signal of the lamp, it is even required that the feedback signal of the lamp has voltage, current, color temperature, the temperature of each LED light source, and the fault location of the lamp. As everyone knows, we are only dealing with a lighting lamp, not a “robot”. Therefore, the fierce collision between the technical feasibility of the RDM system and the business operation is everywhere. The fierce collision between technical feasibility and business operation tests the professional bottom line of every technical professional.

 

RDM application analysis conclusion:

It is beyond reproach that DMX512.-RDM is a mature technology. In the face of this mature technology, electronic communication engineers should be fully professional and technically prepared. From the lighting manufacturing, engineering installation, and debugging, there is a big difference compared to the non-RDM system. The RDM system and the lamps are in one line, which contains dual tasks, not only to transmit the image signal but also to take into account the feedback signal back to the

The communication system has certain risks.

At present, the most widely used lighting technology in the market that supports two-way data communication is the digital addressable lighting standard, which is widely used in indoor lighting and public lighting places. The digital addressable lighting dimming system can not only control the lights remotely but also can It also provides feedback on the status and fault conditions of the lights. It was rarely used in color matching before. As long as each bus has only 64 addresses, if the DMX-like method is used, each color occupies an address, and the connected lights The number is very small, but then DT8 technology was introduced, and the dimming and color matching of each lamp can be achieved by using only one address, and more and more dimming and color matching projects have begun to use this technology.

RELATED POSTS