FAQ&Troubleshooting of DMX512 during setting

Common problems and solutions in engineering debugging

 What should I do if the lamps in the whole control circuit flash randomly and uncontrollably?

1. Confirm that the controller signal output is normal

When the whole control loop lamp is out of control, if conditions permit, first use a temporary controller to test whether the loop is under control;

a. Controlled - there is a problem with the original controller signal output (or wiring file problem, or port hardware problem, or port wiring problem);

b. Uncontrolled - continue to investigate;

c. Disconnect the lights after the first lamp, and test the first lamp separately to determine whether it is the controller problem or the signal interference caused by the following lamps;

At this time, the first light is often OK.

2. Troubleshoot faulty nodes or lamps

When the signal output of the controller is normal, slowly increase the lamps and find out the nodes or lamps that cause the abnormal loop signal; usually the "dichotomy" is faster.

The random flashing of individual lamps in a control loop is uncontrolled

1. 

1.Verify that the controller wiring is in place

The number of lights in the wiring file of the controller should be consistent with the number of lights installed on site.

2. Test with full wiring file

First use the test program to control the test, that is, the single-port wiring file is filled from 1-512 channels.

a. The random flashing lamps are under control. At this time, re-write the code for the circuit lamps, and the problem can be solved;

b. Individual lamps are still uncontrolled, check whether the wiring of the signal output terminals of the uncontrolled lamps is correct or the lamps themselves have quality problems.

3. When do you need to increase the signal amplifier?

One function of the signal amplifier is to amplify the signal and restore the weakened signal to the strength of the starting point; the other function is to isolate the signal to prevent damage to the controller caused by the failure of the lamp.

Under standard circumstances, according to the EIA485 protocol, a signal amplifier needs to be added for every 32 nodes.In order to avoid the signal of the lamps becoming weak in rainy days or other situations, the phenomenon of random flashing of lamps will occur.

4. How many nodes can the output port of the sub-controller with the amplifier take?

In the current standard specified in the EIA485 protocol, the general recommendation is to add an amplifier to 32 nodes. But in actual operation, it can also exceed 60 nodes, but there will be a security risk of unstable signal.

5. If the signal line is not shielded, can the signal still be transmitted? If yes, how far is it?

Many domestic projects use network cables as signal lines, which are basically unshielded, and the transmission distance will definitely be discounted, but it depends on what project is used to make a decision. The longest distance can generally reach about 100m.

6. What should I do if the time between DMX circuits is not synchronized?

There are several different ports in the same demultiplexer, and some of the individual ports output signals will have obvious delay. At this time, what needs to be done is to reset the parameters of the controller. Because the most likely cause of this situation is the parameter problem of the controller itself, which causes the output frequency of each port to be different, which causes the signal output of each port to be out of synchronization.

7. If the transmission rate is reduced, will the 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. Another set of systems will have another set of protocols, which will not have any effect on the synchronization of the lamps.