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Electronic Theatre Controls Inc

Dimmer Property Definitions

User Defined Numer (UDN): A user defined numeric identity for a circuit which is unique within a "space". Typically UDN matches circuit numbers placed at plug strip (power distribution) outlet locations.

Name: A user defined alphanumeric identity for a circuit which can be up to 20 characters long.

Module Type: adjusts setup options for module density, ratings, and features to ensure proper operation of the circuit for the installed hardware and power devices of the module.

Slot: Numerical representation of module location within a rack.

Lug: Predefined representation of the physical location of each possible circuit in a rack. This is a display only field. Single or half density modules take up multiple lug positions in the rack even though some of the positions will not be assigned a "user defined number."

Control Mode: Determines the relationship between the control input and the output of the dimmer. Possible settings are:

Dimmable Dims according to curve within the minimum and maximum scaled voltages
Off Ignores incoming levels and will not turn on even with local overrides
Always-On Ignores incoming levels and will not turn off even with local overrides
Switched Circuit operates as a relay with output unregulated AC voltage when the control level is above the control threshold level.
Latch Lock

Latch Lock is similar to switched mode, but features an additional safeguard so that circuits can not be turned on or off so easily. The circuit only turns on when a specific control level is held for a certain time, and only turns off when the control level is held at a different level for a period of time. The level ranges and periods of time can be edited on a per dimmer basis. Latch-lock feature is useful, for example, to avoid accidental dowsing of arc lamps during shows by "running the grandmaster" down - since when you run a fader you are unlikely to remain in the right range for enough time to trigger turn-on or turn-off.

Firing Mode: Defines the type of dimming (forward, reverse, sinewave or dimmer doubled) which will be used if the circuit is required to regulate (dim) power below incoming voltage.

Fluorescent  Circuits set to fluorescent jump from an off state immediately to a predefined minimum voltage sufficient to run the fluorescent circuit at its minimum turn-on point. This control mode allows full 0-100 control fading to be scaled between a fluorescent's minimum and maximum voltage ranges specified by the 3rd party ballast manufacturer. Minimum 65V to maximum 115V ranges are adjustable to accommodate differences between ballast manufacturer's recommendations.

Curve: Curve is a mathematical function that maps control levels to RMS output voltage. The chosen curve is scaled from the minimum voltage to the maximum voltage. The control module supports the following curves:

  • Square
  • Mod Square
  • Linear
  • Mod Linear
  • Sensor 2.0.

See also Wiki article Dimmer Curvesfor more information.

Set Threshold: Minimum control level that turns a circuit on to its lowest output level determined by the "minimum scale voltage" setting.

Set Min Scale Voltage: Lowest output level of a circuit once it is turned on at its control threshold. Units of level output are shown volts. 

Note: unless preheat is active, the circuit will be off below the threshold.

Set Max Scale Voltage: Highest output level of a circuit at 100% control. Units of level output are shown volts (RMS).

Voltage Regulation When enabled, the dimmer will maintain to the desired output voltage based on the mapping of control level to scaled curve for voltage output. When disabled, the dimmer will be set to a constant firing time based on the control level. This setting defaults "on". The ability to disable regulation is sometimes useful when dimming non-tungsten loads.

Note:Changing the dimmer control mode will cause a change to default settings for curve,minimum voltage, maximum voltage, threshold and regulation. Whenever adimmer mode is set the defaults for that mode will be applied to the other dimmerproperties.

Preheat: Causes a circuit to regulate to a minimum output level measured in volts when control level is below the assigned "threshold" for a circuit. Stated simply, the preheat level is determined by setting the Minimum Scale Voltage.

Dynamic Preheat: This setting allows for the fastest possible blackouts on dimmers that has preheat enabled. It sets the amount of time (measured in seconds) that a dimmer will remain at a zero (0) volts output before returning to the preheat level. Preheat can be set from 0.5 seconds to 15 seconds and has a default of 2 seconds.

DC Output Prevent: This setting offers protection on selected dimmers for loads that are sensitive to DC buildup, which can occur under certain conditions when positive and negative half-cycles become uneven.

Inrush Protection: Defines a minimum fade time for a circuit in order to protect against large current increases (known as inrush current) in a single AC cycle. This protection is useful for high-wattage loads that may cause nuisance tripping of upstream circuit breakers and to limit peak currents in wiring and switch gear. A common use of this feature is prevention of nuisance tripping on RCD/GFCI protected circuits.

Advanced Features (AF): Enables/disables additional feedback from a circuit that provides load recording/reporting and advanced error reporting including a breaker trip, module removed, load changes, dc output and SCR failures.

(Report) No Load Errors: Enables/disables messages to report complete loss of load when a circuit is turned on. This feature is typically used in coordination with a control console for purpose of rapid troubleshooting of blown lamps and fixtures/luminaires hung on incorrect circuits.

AF Sensitivity: Resolution of the Advanced Features sensitivity reporting of load changes set in .5 amp increments starting at 1 amps.

AF Reaction (Time) Defines the hysteresis for an advanced feature error. The error must be present for the minimum set in the AF Reaction Time before an error will be reported. Five (5) seconds is the shortest amount of time and 60 seconds is the longest allowed.

Scale Load [Power]: Adjustable setting for choke correction curve based on the specified percent load of the maximum for that dimmer type. Scale Load can be set from 1% to 100% and should reflect the approximate percent load on a given dimmer to precisely match all dimmed load. The default setting is 35% which is based on a single Source Four 750w fixture on a D20 dimmer with a max scale voltage of 115Vac.

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