9
8-BIT vs 16-BIT
Standard DMX data structure is 8-bit, which limits
the value range between 0-255. This is the preferable
operating mode for maximum compatibility with DMX
controllers. If more precise control is required, the unit
can be operated in 16-bit mode, offering a value range
of 0-65,535. On the surface, this sounds more valuable
than 8-bit mode, however operating in this mode
assigns two DMX channels for each control, working
in pairs, requiring twice as many DMX addresses. The
first DMX channel in the pair is the COURSE adjustment
of the control, while the second channel is the FINE
adjustment. The COURSE channels operate identically to
8-bit controls, while the FINE channels in the pair adjust
in-between adjacent values of the COURSE control. To
further explain, the COURSE channel adjusts values of
0-255 while the FINE channel adjusts between only two
control values. If, for example the COURSE channel is set at value 165, the FINE channel adjusts between
165 and 166. Fortunately, most professional lighting consoles allow controls to be set up in 16-bit mode,
so a single fader manages the two channels automatically. It is recommended that 16-bit mode only be
used when the DMX controller supports 16-bit operation.
HSI vs. RGB Personality modes
HSI, also known as HSIK, stands for Hue, Saturation, Intensity and white value in Kelvin. This is the most
common method of control for full-gamut lighting fixtures, and mimics the operation from the LOCAL
control panel on the back of the fixture.
In HSIK Mode, the channel assignments are as follows, and are directly related to 8-bit or 16-bit operation:
First Channel (or channel pair for 16-bit): Output level
Second Channel (or channel pair): CCT
Third Channel (or channel pair): Color Saturation
Fourth Channel (or channel pair): Hue
The RGB Personality is technically considered RGBK, where a variable white point can be selected as
well as values of the primary Red, Green and Blue channels. This is extremely valuable in correlating RGB
operation in context with the white balance selected on the camera.
In RGBK Mode, channel assignments are as follows:
First Channel (or channel pair for 16-bit): RED level
Second Channel (or channel pair): GREEN level
Third Channel (or channel pair): BLUE level
Fourth Channel (or channel pair): CCT
