DMX Troubleshooting
Are you having problems with your lighting setup? Maybe one of your light fixtures isn't working properly, or your DMX console isn't communicating with your lights?
Whatever the problem might be, we'll walk you through some troubleshooting steps to help you resolve any complications.
DMX issues will stem from one of three areas: cabling, fixtures, or the DMX controller.
Cabling
If a fixture is flickering or unresponsive, the first piece of equipment you should check is the cabling. Typically, most lighting and connectivity issues are the result of faulty or incorrect cables. The cable may have been stored improperly or one of the pins inside the connector is faulty. Also, ensure that it is the right type of cable. One tip is to label 3-pin DMX cables to help you distinguish between audio cables and lighting cables. Audio cables use a different electrical standard and will result in degradation of the DMX signal. Lights will flicker or strobe and can be potentially damaged so we recommend always using quality DMX cables.
The next step for troubleshooting cables is to test each cable individually. A faulty cable could be the result of improper wrapping or a loose pin. A couple ways of testing a cable is to connect it to a working fixture or to use a cable tester. You can purchase the one our techs use here.
Fixtures
Now that you've confirmed that all your cables are working properly, its time to troubleshoot the fixtures themselves. The light itself could be faulty or you have too many lights in a single DMX run.
Let's go over a few different ways to troubleshoot.
You can use a terminator to ensure the DMX signal is being terminated at the end of the run. If the signal isn't terminated, it can bounce back causing interference and loss of control. This is very important for larger setups specifically, but it is best practice to do it for all setups.
The next step is to test the fixtures individually. Go ahead and make sure that your run isn’t too long. While DMX is rated for 32 fixtures, it is best practice to keep it to 20 to avoid signal degradation.
Break the daisy chain up into smaller groups to see if the problem persists. You can slowly bring everything back together and if the issue continues to arise, then the chain is too long. Also, ensure you are using a DMX-specific splitter for a setup of more than 32 fixtures. The splitter will isolate and split the signal allowing you to have multiple groups of 32 fixtures. Additionally, many modern fixtures have a power link feature letting you daisy chain power from one fixture to the next. Keep in mind that multi-effect lights draw more power than a standard light.
Another common issue is the DMX addressing and modes of the fixtures. If a fixture is unresponsive or cannot be controlled independently, the reason is most likely an incorrect starting address or incorrect mode.
Check to see that your light is set to DMX channel mode, not automatic, sound activation, or preset.
Also, if multiple fixtures are being controlled by one fader but different functions are being triggered, this means that they are in the same group. Finally, if a fixture has a dip switch for DMX addressing, make sure the switch is in the correct position.
For help in knowing which fixture is assigned to each DMX channel, use this DMX universe reference sheet to map out your lighting rig. Color-coated highlighters will help make distinguishing each feature easier.
DMX Controller
The final item to troubleshoot for your setup is the DMX controller. To make this easier, we'll break it down into four parts.
1) Before troubleshooting your controller, ensure that Blackout Mode is turned off. This mode temporarily disables DMX output from the controller.
2) Check the polarity on your controller. Most controllers have a polarity switch and this switch needs to be in the correct position. If a light is polarity-reversed, this should fix the issue. Most modern lights are not polarity reversed but be sure to check the controller and fixture's owner's manuals for clarification.
3) Some DMX controllers have firmware and it will need to be updated. Many connectivity issues are fixed through firmware updates. Refer to your DMX controller's user manual for clarification.
4) You can attempt a factory reset if everything else has failed to resolve the issues. A factory reset will erase all user-created data so only do this after you have tried everything else.