Automated lighting fixtures are very complex little robots that dutifully follow the commands given to them by savvy automated lighting programmers. Some people refer them as "intelligent lights," however the fixtures contain little intelligence and usually rely on the programmer to send them instructions. Without us they would just sit there and do nothing! Even though these automated creatures wait patiently for our commands, they have their own ways of exerting control over us. Most every fixture type has a selection of modes that determine functions, protocols, and output. It is essential that automated lighting programmers are familiar with these modes.
DMX Protocol
The most commonly asked question about a fixture is, "How many channels does it require?" In many cases, the answer is that it depends on the mode. Fixture manufacturers try to please all their customers by anticipating how fixtures will be used. This means that a single wash light might have four different DMX modes ranging from 12 DMX channels to 28 DMX channels. The mode must be assigned (usually at each fixture) to determine the DMX protocol to be used and to map the incoming DMX to the appropriate functions. If there are fewer DMX channels in use, the functionality is more limited. For instance, smaller DMX protocols often provide lower resolution movement of pan/tilt, resulting in steppy movement; however, if you select a different mode, you can gain 16-bit control of these parameters, and that allows for much smoother movement.
It is essential that the fixture library in the console match the DMX protocol used by the fixture. Because fixtures often contain different modes, you must assign a mode to the fixture(s) and also select the correlating mode in the console. For example, a fixture set to Mode 4 would require mode 4 in the console (usually labeled "fixture name M4" or similar). Trouble can occur if you prepare your show for fixtures set in mode 4 and then the technicians set all the fixtures to mode 1. You will quickly see that you can't control the fixtures correctly.
Parameter Inverting
Most fixtures have the ability to invert the pan and/or tilt so that it pans right to left instead of left to right, ensuring that all fixtures move in the same direction when you move the encoder on your console. However, I recommend turning these functions off at the fixture level. Most automated lighting consoles provide this ability from the console without having to change the fixture mode. If you ask the crew to ensure that all fixtures have their pan/tilt invert (and swap) set to OFF, then you are guaranteed that the rig starts with a clean slate in terms of direction of movement. Furthermore, if a fixture must be swapped out for repair, any replacement fixtures should also have their pan/tilt invert modes turned off. This makes it easy for the crew to swap fixtures without having to remember the settings.
Movement Speed
Several popular brands of moving lights have a mode that allows the fixture to move faster than normal. You might ask why they don't just allow the fixtures to move at their fastest speed all the time. The manufacturers like to promote the silence of their fixtures, so they limit the speed to reduce the noise. They also understand that many situations require fast movement without regard to noise. So they offer a mode that increases the top speed of movement when enabled. It's important that automated lighting programmers are aware of this mode and request it to be enabled when desired. Your designer will praise you when he/she sees that you can move them faster than anyone else!
Furthermore, you must always check your rig before you begin programming to ensure that all fixtures are set to the same speed mode. I always grab all my fixtures and give them a big pan move, then a big tilt move. Often you will see one or two fixtures move at a different speed than the rest. You can then ask your crew to set the movement mode to match the other fixtures. If you do not catch this early you will spend many hours trying to figure out why these two fixtures respond to a ballyhoo effect differently than the others.
Even More Modes
Have you ever sent a strike or shutdown command to a group of fixtures and found one that would not respond? One manufacturer has a fixture mode that causes them to ignore some DMX control channel commands. This means that you can't shut down or strike lamps unless the fixture is set to listen to these instructions. Additionally, there are modes to cause fixtures to operate alone without a console (stand alone) or to respond to audio triggers (usually via a built-in microphone). Sometimes a mode is used to provide a smoother dimming curve or better color mixing. Other modes cause fixtures to change color or gobo wheels from scrolling to split colors/gobos. It's important for a programmer to understand the fixture modes and to ask the crew to ensure all fixtures are set to the same mode settings.
Changing Your Mode
Most automated fixtures have an LED or LCD menu that allows you to set the DMX address and fixture mode. These are fairly easy to use as long as you can decipher the abbreviations (usually four characters). Older fixtures use dipswitches, which require a chart to understand the various settings. Refer to the user manual for full details.
Remote Device Management (RDM) allows you to query a fixture about its DMX address, modes, and other settings. With RDM software you can easily change the mode directly via your laptop or console. In the future we will see the adoption of ACN in both fixtures and consoles, which will add even more functionality between the console and the fixtures. Finally there is some intelligence between our lighting fixtures and consoles!
Making the Most of Modes
Automated lighting fixtures are complex robots that often need fine tuning and always need instruction. Just as you configure your console before programming, it is essential that you configure the various mode options on your fixtures before you begin programming a single cue. Confirm the DMX protocol mode matches the fixture library in your desk. Then check that for parameter speed differences, pan or tilt inverts, features and other settings that may be adversely affected by various modes. By taking some time to understand the capabilities of your fixtures, you can guarantee that you can get the most out of them and have a successful production.
