As an automated lighting programmer, I am often tasked with helping to automate the playback of a production. There are several approaches that are used in our industry for various types of automated lighting playback. There are also times when the lighting console needs to trigger other de-vices to ensure that the production is synchronized by the lighting console. Whether using MIDI, MIDI Show Control, Timecode, analog signals, or other custom triggers, it is important to understand the choices and how to use them.
Often it is important to have a lighting console triggered by another source, or to have the console trigger another source. A frequent request is to have a conventional desk trigger an automated desk or vice versa. The most common type of console triggering automation is MIDI Show Control (MSC). MSC is an enhanced version of MIDI that defines specific control messages intended for theatrical uses such as lighting, smoke machines, pyro and more. MSC messages use commands such as Go, Pause, Load and Page and modifiers such as cue number and cue list number. Because MSC is defined for theatrical use, it’s easy for most manufacturers to implement it into their existing console code.
A device ID is required for each device in a MSC system. This is similar to the DMX512 address of a fixture. It defines each specific device and ensures that each device only responds to the commands intended for it. If you want to arrange for your automated console to trigger your conven-tional console, then you need to configure each accordingly. For example, the automated desk must send out MSC messages for a specific device ID. In turn, the conventional desk must be configured to receive messages for the same device ID. If they do not match, then the triggering will not occur. In addition, it is important to consider the cue list and cue numbering. If your automated console sends out an MSC command for each cue as it is played, then it is probably sending a cue number and cue list number. Many conventional desks only have one cue list and may or may not be able to respond to a trigger for a cue list number higher than one. Be sure to read the documentation for both consoles to determine what types of MSC messages each can send and receive.
MIDI Show Control can also be used to trigger other systems such as lasers, pyro, scenery automation and more. Again the standard formatted messages such as Go, Fire, Load and Pause allow simple communication between devices. Some systems such as lasers and pyro may have addi-tional safety requirements before their systems can be triggered by an external device. Usually, human presence is required to ensure safety on stage, and this is regularly accomplished with a dead-man safety switch. However, for timing purposes, it is often best to allow triggering from the lighting console to ensure that lighting and pyro cues are synchronized. Extreme care must be taken when triggering non-lighting devices from a lighting console.
Standard MIDI uses messages that define Note ON and Note OFF commands as well as a velocity. Typically, standard MIDI is not used for de-tailed show element triggering. However, several automated lighting consoles do utilize MIDI Notes for external triggering of lighting console functions. For instance, to increase the number of physical playbacks on a console, some manufacturers allow the use of MIDI Notes from devices such as audio keyboards. The automated lighting console will have a “map file” that defines which notes are mapped to which console functions. In addition, this type of mapping is also used for full programming redundancy to allow one console to send every key pressed by a programmer to another console. This allows a backup console to mirror all actions performed on a master console. Of course, MIDI Notes can also be used to trig-ger any other type of device that accepts MIDI Note information.
Probably the most commonly used method of automating a lighting console is through the use of a timecode source. When synchronizing with mu-sic or video, this is an invaluable method to ensure all lighting cues are triggered at the exact desired time within the audio or video signal. A time-code is a sequence of numeric codes generated at regular intervals by a timing system. Typically, the formats used with lighting include MIDI Time Code (MTC), SMPTE timecode and audio CD timecode. Each of these formats will send a specific time value associated with its source such as an audio or video track. You can then use this time value to trigger cues in the lighting console. Now, whenever that specific song or video is played, the lighting console will respond to the time values and replay the cues in a perfectly synchronized way.
Most automated lighting consoles are capable of allowing the programmer to “stamp in” cue timing as timecode is input into the console. This means that you can roll the audio or video source and then manually playback your cues. As you play the cues, the desk will note the timecode value when you pressed the GO button and enter this value into the cue list structure. Then the next time the timecode source is played, the cue list will automatically replay the cue list based upon the time values you “stamped in.” Of course, human reaction time is never perfect, so you may need to edit the stamped times slightly to ensure that the triggers occur at the desired points.
Most automated lighting consoles also allow for a few other methods of automated playback. Some will use analog triggering such as a 0-10 volt source. This allows various types of systems to send a low-voltage signal that can be mapped to specific console functions. Another common source of automation within the console is clock and calendar triggers. The lighting console will use its knowledge of the date and time to schedule and trigger various cue playbacks and events. Furthermore some consoles have astronomical functionalities that allow the console to calculate and trigger at sunrise or sunset based on the console’s physical location in the world. Most consoles utilize keyboard shortcuts for quick programming from a keyboard. Programmers can take advantage of OEM products such as X-Keys or Rosco Keystroke. These hardware devices can playback specific keyboard instructions to allow various input and triggering options.
People in our industry have created many methods to allow automated lighting programmers to automate the playback of a production. Whether a console is being triggered by another device or triggering a device, it is important to understand the options. You should study your console’s user manual to determine what methods of automation are available and how to configure and use them. In addition, there are several industry resources available that provide detailed information about working with Show Control. Visit www.plsnbookshelf.com to find several books on the subject. Once everything is configured and working, it is very exciting to take your hands off the console and watch it run a show all by itself.
E-mail the author at brads@plsn.com.
