As your lighting requirements grow, the need to split your DMX signal may grow as well. Perhaps you’ve made do with your DMX by daisy-chaining your fixtures; however, too many fixtures in the chain and your signal path can start breaking down. In theory (and it should be in practice as well!), DMX is designed for a maximum of 32 fixtures per run, which means that – with every fixture over – the likelihood of data problems and transmission grows. At this point, converting or splitting the DMX with an opto-splitter becomes a potential solution to your problems.
What is an Opto-splitter?
An opto-splitter is a DMX data-distribution device that can be used when more than one data stream is required, or when the number of devices on a single line exceeds the maximum of 32. The “opto” stains for “optically isolated”, which basically means that any issue with one output will not affect the other outputs. The best opto-splitters have a separate transformer-isolated power supply or DC-to-DC converter for the input and each of the outputs, which provides isolation between every data link entering the unit.
Converting DMX
DMX uses 3-pin XLR jacks, although it’s not uncommon to see 5-pin XLR jacks, which are used to receive and transmit DMX signals. Sometimes, to wire up all your fixtures, you need to convert the DMX between 3-and 5-pin, and an opto-splitter will allow you to do this. While some fixtures will have both 3- and 5-pin XLR’s, converting DMX via those fixtures can be done – although if you have an opto-splitter, you don’t have to worry about this.
Splitting DMX
Sometimes, you may need to split the DMX signal. For example, when you have lights all over your facility, splitting the DMX is easier then running cables all over the place. Splitting is also beneficial if you have more than 32 fixtures on one daisy chain, if you have any extended cable run of 1800 feet or more, or if you are using multiple power panels for your lighting. Splitting DMX helps preserve signal strength, and it also creates a ‘safety’ for your lighting, in that if one fixtures isn’t working properly, the rest of your grid will still function as planned.
An opto-splitter takes the DMX signal in through the input and splits and copies the data stream. Once this is done, the split signal is electronically isolated, keeping it safe from any faults on the other lines.
Adding fixtures to your lighting grid isn’t as easy as plugging it in. Factoring in your DMX needs is equally important and having an opto-splitter on hand in case you need to convert or split your DMX and strengthen the signal is just good lighting practice.
