In our last Tech Talk, we covered testing your Vivid RGB fixture and wiring a Dimwheel. This week we’re going to quickly cover ringing out pins and testing resistance with your multimeter.
Before testing Vivid Pixel with a DMX tester (which we’ll look at next week!) it’s important to be able to ring out the pins and know the polarity of your wires.
Ring Out A Pin With The Multimeter
In order to be able to determine the polarity of your pins, you need to first know which pin is which. You may need to look up a diagram of your DMX cable to find the polarity of the pins.
- Set your multimeter to continuity. (Some people know this as “beeper mode”.)
- Touch the wire you’re trying to identify to either lead on the multimeter.
- Touch the other lead to one of the pins in the DMX cable barrel connector. Be careful not to touch the other pins or the side of the connector while testing. Try each pin until the multimeter rings out.
- Once you’ve rung out a wire, mark it with tape to ID it quickly in the future.
Repeat steps 2-4 for each wire you need to ID.
Use this method ONLY to test the resistance of constant voltage static and RGB fixtures. This won’t work with constant current fixtures as it is not possible to test their resistance.
When testing for resistance take care not to touch the leads or exposed wires. Your personal resistance will mess with the multimeter’s reading.
When testing resistance of a static fixture, touch the red wire to the red lead, and the black wire to the black lead. If your fixture’s resistance is good, it should be equal to the resistance of air. (You’re looking for an open loop or infinite resistance, indicated by a 1 on the multimeter.)
For the RGB fixtures, you’ll want to test the resistance using only two of the wires. We’ve used our yellow and blue wires, but you should be able to test the resistance between any two wires and have it be an open loop.
This is what you don’t want to see when you’re testing resistance. This means your fixture is likely broken, and you’ll probably want to contact the Warranty Department.