What is RDM and what is its important role in Stage lighting?

If you have been using lighting for some time, you may hear the term RDM or remote device management.

RDM is a killer way to work with your fixtures that are in the air while you’re on the ground.

I love RDM because it allows me to change critical fixture settings from afar!

Will stage staff or operators place two lights at the same address?

Will some or all of your fixtures be in error mode when the lighting fixtures are added?

With RDM, you can easily change any of these content issues or even more at any time!

Depending on your RDM controller, you either can work with 1 fixture at a time, or make changes to a number of fixtures very quickly.

Before using RDM, if you want to access the functions and diagnostics of your fixed device, such as DMA address, control mode, light hours, and fan speed, you must be next to the fixed device - no matter how high it is on the ground or in the air!

It allows us to bid farewell to this restriction and thank our friend, RDM!

Do you know how RDM plays a role in stage lighting:

RDM, or remote device management, works by sending pulses of data down the DMX line in-between the “normal” DMX commands.

While the DMX protocol originally left pins 4 and 5 of the XLR connector open for “future use”, RDM actually doesn’t use them either!  This is one of the most common misconceptions of RDM.

RDM actually communicates down the same lines as your DMX data (that’s pins 2 + 3, for those playing along at home).

These RDM messages place themselves in the “dead air” between DMX messages to get back to your controller.  On the technical level, RDM messages are only sent when requested by the controller – so it’s not a constant barrage of extra information!

Many consoles and devices allow you to scan for RDM on an as-needed basis, or leave your RDM functionality on full-time, though that can cause some issues (more on that later!).

How can you use RDM:

To use RDM, you need 2 pieces or more puzzle pieces to succeed.

You need an RDM-enabled DMX controller, and you’ll need fixtures that are RDM compatible and compliant.  If you use DMX splitters, these will also need to be RDM-enabled and compliant as well.

At the time of this writing, and probably into the future, older and cheaper fixtures aren’t compatible with RDM.  But more and more join the RDM club every year!

Working with RDM is simple!  Just turn on RDM and do a discovery scan to find your fixtures.  Once this has finished, you can go ahead and check on your fixture’s vital signs or change options.

RDM Controllers:

RDM controllers come in 3 primary flavors – handheld devices, consoles, and PC software.  Each has its own primary use, but the underlying technology of RDM is the same.

Our lights with RDM function:

LED Fresenl spotlight: CB series(VG-CB200W /VG-CB300W /VG-CB400W-C /VG-CB300W-D /VG-CB100W .etc)

LED Leko Ellipsoidal Profile Spot Light: ERS series(ERS200A/ ERS400A/ERS400G.etc)

LED Cyclorama Lights:VG-LB250G/VG-LB2400/VG-LB2600

Handheld Devices:

Handheld DMX testers have been around for years and are great troubleshooting tools for technicians.  They can test your cables, test signal strength and even output basic DMX control. RDM-enabled handheld devices have even more power!

On the positive side, they are able to quickly and easily identify and modify fixtures.  Some can even fully control fixtures without setting a unique DMX address.

These tools are great for use in the shop or in the field to test and check a few lights at a time.  What these units are not made for is changing or monitoring lots of fixtures at once – it’s just not their intended use!

Some of the most popular handheld controllers are:

City Theatrical DMXCat: This battery-powered tester plugs directly into your DMX light and is controlled via a smartphone app.  It allows you to discover RDM, test individual lights, send out DMX signal and more!  Here’s my full review of the DMXCat – I love this thing!

The Swisson XMT-350 is the most serious RDM and DMX testing tool on the market.  Not only can it discover and set RDM modes and addresses, it can easily set the addresses for many fixtures at once – all you have to do is tell it the order!  Testing cables, finding DMX flickers and more – the XMT-350 can do pretty much anything you need out of a DMX and RDM tester!

Consoles and Console Software

RDM Having the ability to talk back and change settings on your fixtures from your console is actually really handy.

Once we had the rig up, I was able to simply identify each light in the RDM screen and then go ahead and set the addresses as needed.

While every console implements RDM differently, having RDM at the console allows you to easily re-configure your lights and monitor temperatures, lamp hours and error messages.

Non-Console Software

Lastly, we have the non-console software.  These are similar to a handheld tester, but have the benefit of being able to modify a large number of fixtures very quickly.  Of course, you need a PC to access them, so it’s not as portable.

Here are some popular pieces of software that can work with RDM:

DMX Workshop:  This free program from Artistic License allows you to discover your RDM enabled fixtures via Art-Net, change DMX modes and more!  Simply connect your computer to your Art-Net node, and you’ll press “Discover RDM” from the Node list screen.  You’ll then be able to identify and modify any fixtures that you discover!

ENTTEC RDM Controller: The free “Lite” version of this program allows you to discover and work with RDM via the ENTTEC USB Pro Mk II or DMX USB Pro.  The interface is much easier to use than the DMX workshop program, and the full license allows you to do some advanced monitoring and control changes.

Issues with RDM Systems

We are currently in the process of using RDM throughout the lighting industry. But the promotion is still ongoing, and you may encounter some common issues when starting to use RDM. (You can contact us at any time to solve any problems)

Non-Compliant Fixtures

We have discussed that not all fixed devices comply with RDM, but it is important to note that even if RDM has been introduced for such a long time, some non compliant fixed devices may flash, gate, or fully open.

This means that you may not be able to keep RDM monitoring on full time if your lighting rig isn’t comprised of all RDM-compliant fixtures.

DMX Splitters

It’s also really important that you upgrade all of your DMX splitters to RDM-compliant ones – if not, the RDM data simply will not get passed through back to your controller!

Thankfully, brands like ENTTEC, Elation, and Doug Fleenor Design have come into the market already with cost-effective RDM splitters.

RDM is changing the way we manage and monitor our lighting rigs for the better!  No longer do you need to actually access your lights to check vital signs and make simple control changes.

The future lies with those who equip themselves with the tools to manage their lighting rig the easy way – RDM!