AMX RADIA RE-DM4 Operation/Reference Manual page 50

Appendix A: AMX Lighting Curves
The Radia Eclipse controllers can employ a low-end cut-off that allows the dimmer to turn on to a
specified level or to dim down to no less than a specified level. This level at which the dimmer turns on is
called the Low End Setting. This is also used to turn a light off at the low end point when dimming down
from a bright level. A low end setting of 25 applied to the standard dimming curve would prevent the
fixture from being dimmed below Level 25. From an off condition, the same fixture would dim up to
Level 25 and hold that level until the dimming curve directed the level higher.
If a fixture flickers just before it goes out, then the Low-End Setting can be used to avoid the unusable
dimming range. Setting the Low-End Setting to just above the level where flickering problem starts will
prevent the dimmer from allowing the flicker to be seen.
Dimmer manufacturers follow or adopt a level to output ratio called the Square Law curve. It is an
exponential relationship between percentage of light perceived and the percentage of light measured.
The Square Law Curve is a presumed relationship between perceived illuminance and measured
illuminance. The Radia Eclipse controller's Curve 1 is a basic Square Law Curve. From this basic curve,
AMX has developed a set of curves other than standard to accommodate the many different properties of
the various loads connected to a AMX dimmer. Multiple curves provide a user with multiple ways to
control lighting. This provides lighting designers with a more powerful lighting tool.
To demonstrate how a AMX dimmer actually performed under real conditions, we adopted a set of
uniform tests to display the output characteristics of a dimmer.
The AMX test fixture for incandescent tests was set up using a constant Voltage feed of 120 VAC to the
dimmer. The output of the dimmer was connected to (6) 100W GE lamps with a total load of 5 Amps.
All fluorescent tests were done using the RDM-HDC module connected to a (2) lamp Advance Mark VII
ballast using T-8 rapid start lamps. These curve plots are to be used as a relative guide to determining
optimum performance. Actual field performance and measurements will be similar but not equal.
FIG. 39 shows a basic dimming curve.
FIG. 39
Basic dimming curve
Each curve allows a dimmer to change its output characteristics in relation to the amount of dimming.
For example, the standard dimming curve at 50% could make a light brighter than another curve which
was also at 50%.
Each AMX Lighting control channel has three dimmer characteristics; AC dimming, DC dimming, and
switching. These are the three primary control methods for most lighting systems worldwide. The first
characteristic is the output level in volts RMS. This is represented by the following Curve charts showing
the Y-axis in (Dimmer) Output Level in Volts RMS (0-120VAC). The second characteristic is displayed
on the second curve chart with the (Dimmer) Output Level in Volts DC (0-12VDC). The third
characteristic is the turn on level for the switched (relay) aspect and is noted in text as the Relay Turn On
Level.
44 RE-DM4 and RE-DM6 RADIA Eclipse Dimmer Modules