The Lighting Command Language
QLab 4 uses a textual light command language which you can use to control your lighting instruments. At its core, every light cue contains a plain block of text which is interpreted as this command language. The basic formats of a command are as follows:
instrument = value instrument.parameter = value group = value group.parameter = value
Note that spaces in a lighting command are always optional.
10=53 is the exact same thing as
10 = 53.
When a command omits a parameter, QLab fills in the default parameter as specified by the instrument's definition. Typically, this default parameter is intensity but it can be any parameter. So, if instrument 20 uses an instrument definition that sets the default parameter to intensity,
20 = 75 is the exact same thing as
20.intensity = 75.
When a command refers to
group.parameter, the value of that command is passed to all instruments within the group that have that parameter. So the command
group.blue = 50 would set the
blue parameter of any instruments in that group to
50. Instruments which do not have the given parameter are ignored.
QLab supports both percentage values and "raw" DMX values. Individual parameters of instruments can be set to use one or the other in their definitions. If a parameter uses percentage value, QLab will accept decimal numbers on the command line. QLab will round your entry to the nearest DMX level equivalent.
For example, if instrument
1 in your workspace is a conventional dimmer set to accept percentage values, and you enter
1 = 10.7, QLab will round down to
10.7% is mathematically closest to DMX level
25, and the exact representation of
25 in DMX is
An instrument or group can be set to the reserved value pass to explicitly prevent them from being adjusted by the current cue. Consider a show with a group called
backlight, and three instruments in the group called
right. If a cue consists of the following commands:
backlight = 75 center = pass
right would be set to
center would be left un-adjusted.
instrument = home or
instrument.parameter = home sets the instrument or parameter to its home value, as specified in the instrument definition. For example, the included "dimmer" definition has a home value of
0, so setting an instrument that uses the dimmer definition to home turns it off. The included "DMX iris" definition has a home value of
100, so setting an instrument that uses the DMX iris definition to home opens the iris all the way.
The up arrow key scrolls through the history of the command line, providing an easy way to experiment with a level. For example:
1 = 80 |Enter| |Up| 70 |Enter| |Up| 75 |Enter|
Instrument 1 is set to 80, then 70, then 75, and reentering the
1= is not necessary.
A lighting command can also refer to a range of instruments:
1 - 3 = 50 10, 12, 14 = 75
The range will be expanded to its constituent commands before being added to the cue, or applied to the Dashboard. Thus, the commands above would appear in a cue as:
1 = 50 2 = 50 3 = 50 10 = 75 12 = 75 14 = 75
You can alternately define an "ad-hoc" group by enclosing a range in brackets:
[1 - 3] = 50 [10, 12, 14] = 50
Bracketed commands remain as single commands in the cue, and behave just like groups.
Starting with QLab 4.1, you can instruct a cue to "pull" a value from another cue when it's run. Those familiar with the idea of palettes or presets on other lighting consoles will find this concept familiar.
To pull levels from one cue into another, enter
cue and the number of the cue you want to pull as the level for a light command. For example:
10 = cue A
This command sets instrument 10 to whatever values it has in cue A. If instrument 10 is not recorded in cue A, then this command has no effect. If instrument 10 is a multi-parameter instrument, the above command will set all the parameters of instrument 10 to the values they're set to in cue A. You can also be more precise, if you like:
10.zoom = cue A
This command sets only the zoom parameter of instrument 10 to the value stored in cue A. If cue A contains light groups, you can pull the whole group or only part of the group into the new cue by making use of the fact that QLab interprets light commands sequentially. Consider a workspace where group1 contains instruments 1, 2, 3, and 4.
group1 = cue A 3 = pass 4 = 75
This series of commands combines together to give you the following results:
1 = (whatever it is in cue A) 2 = (whatever it is in cue A) 3 = (left alone) 4 = 75
If cue A is updated, any cues which pull from it will receive the updated values the next time they run. In this way, you can think of a pull command as being "linked" to the cue that it pulls from. To "break" this link, and make the command stop pulling from the source cue, you can click the Expand button next to the light command in the inspector. This copies the pulled level into the current cue, and turns that command into a normal light command.