Transmission speed of 250kbps.

The bit rate is the number of bits Per Second(BPS) that are transmitted. The baud rate is closely related to the construction specification. And the high baud rate signal has relatively poor anti-interference ability.

DMX512 NOTE

In practical operation, it is not enough to understand the feature of DMX512, In order to avoid engineering accidents, we also need to remember the following five points for attention:

1、  The transmission distance of the super-five network cable is no more than 100 meters;

2、  when the distance between the controllers exceeds 100 meters, use optical fiber;

3、  EIA485 specifies that each repeater should carry no more than 32 nodes;

4、  The wiring of each control loop must follow the bus structure layout;

5、  Signal line and power line should be laid separately.

                                   

Murphy’s law states that no matter how improbable, bad things will happen. Even if you follow the steps and standards to use the DMX512 control system. You will always encounter a variety of problems.

Common problems and solutions in project debugging.

1.    How to do the whole control circuit lamp random flash.

       Confirm that the controller signal output is normal.

When the entire control loop lamp is out of control, if possible, the temporary controller should be used to test whether the circuit is controlled or not.

a.    Controlled-Problem with original controller signal output(or wiring file problem, or port hardware problem, or port wiring problem)

b.    Uncontrolled-continue to troubleshoot

c.    Cut off the light after the first light, test the first light separately to determine whether it is controller problem or the signal interference from light   behind it. At this point, the first light is usually OK.

       Troubleshoot trouble spots or lamps

When the controller signal output is normal, slowly add lamps  to find out the nodes or lamps that lead to abnormal circuit signal, dichotomies are usually faster.

2.     Individual lamps are not controlled in a control loop

 Verify that the controller wiring is in place

        The wiring file of the controller shall have the same number of lamps as the number of lamps installed on site.

        Test with full wiring file

        Use test program to undertake controlling test first, That is, single -port wiring files from 1 to 512 channels full fill.

a.     Random flash lamp is controlled. At this time, the problem can be solved by re-coding the circuit lamp;

b.     Individual lamps are still not controlled, check whether the wiring of signal output terminal of uncontrolled lamps is correct or there is    qualityproblem of the lamps themselves;

3.    When need to add a signal amplifier?

One function of the signal amplifier is to amplify the signal and restore the weakened signal to its original strength. The other function is to  isolate the signal and prevent damage to the controller caused by lamp failure.

    In standard case, according to EIS485 protocol, every 32 nodes need to add a signal amplifier. In order to avoid in rainy days or other circumstances the lamps signal is weak, thus the lamps random flash.

More than 32 DMX decoders need to be connected with a signal amplifier, the signal amplification can not be more than 5 times.

When the signal wire is longer or wire quanlity causes such a recoil effect, can try connect 0.25W  90-120Ω terminal resistance to the DMX decoder end line or the signal terminal of power supply to solve the problem.

4.    How many nodes can be attached to the output port of the controller with amplifier?

In the current EIA485 protocol, the general recommendation is to add an amplifier to 32 nodes. However, in actual operation, it can be more than 60 nodes, but there is a security risk of unstable signal.

It is important that we generally advise our customers to add signal amplifiers when the DMX more than 32 pcs.

5.   Can the signal still transmit if the signal line didn’t shield.

Domestic project are used the network line to be signal line, usually not shielded, the transmission distance will be certainly be discounted. But it depends on what the project is. The longest distance can generally reach about 100m, therefore, we will advise customers to use DMX signal line, which is better to use shielded twisted signal line.

6.    What to do if the DMX loops are out of sync ?

There are several different ports in the same controller, among which the output signal of some individual ports will have obvious delay. In this case, it is necessary to reset the parameters of the controller. The most likely reason for this situation is that the parameters of the controller itself cause the output frequency of each port to be different. Which results in the signal output of each port being out of sync.

7.   If the transmission rate is reduced, will synchronization be affected?

The transmission rate of DMX512 IS 250Kbps, which cannot be reduced, if the transmission rate is reduced, it will be another system, and another system will have another protocol. Which will not have any impact on the synchronization of lamps.

Following:

1.   Traditional DMX dialing address method diagram:
                                  


                              


                               

2.    New digital tube DMX address setting method:

The decoder has3 keys, respectively M, +, -; long press “M” for 2 seconds to enter.

Three-digital-display indicates the current setting value; different value indicates different operating status.

DMX Slave Mode: The value is: 001-512, such as: “001”.

                                                                                               

3.    Schematic diagram of DMX512 decoder connection

       1）  Wiring diagram of Master Mode:(Only one decoder is allowed to work as a master)

                  

2）Wiring diagram of Slave Mode:

* More than 32 DMX decoders need to be connected with a signal amplifier, the signal amplification can not be more than 5 times.

*When the signal wire is longer or wire quanlity causes such a recoil effect, can try connect 0.25W  90-120Ω terminal resistance to the DMX decoder end line or the signal terminal of power supply to solve the problem.