ARX Dimming Protocols
Dimming options explained. Signal, Direct, Remote and various control protocols.
Dimming ARX Lighting Products
ARX products currently utilise two primary modes of dimming, dependent on the internal LED configuration of the fitting. Both current methods rely on external remote drivers.
(Note: Not all options are available in all fittings. Please verify individual product pages and datasheets for specific compatibility).
Direct Dimming / Constant Voltage (2 Wires, Parallel)
Example Spec: 24V DC (2-Wire Dimming via Remote Driver) or 24V DC 4W (Fixed Output)
In this architecture, two wires carry power to each fitting, wired in parallel. A low-voltage, constant-voltage remote driver dictates the output power according to its input control protocol (DALI, DMX, TRIAC, Casambi, etc.), or simply provides a fixed output.
- Advantage: Highly favored by installers and project managers for its simplicity, reliability, and site flexibility. Because it utilises standard parallel wiring, if one fitting fails, the rest of the circuit remains fully operational. This configuration also makes it incredibly easy to add or remove fittings on-site without needing to re-engineer the circuit design.
- Disadvantage: Because the internal LED string voltages must closely match the supply voltage (e.g., 24V DC), the physical selection of LEDs is constrained. For the lighting designer, this means ultra-narrow beam options are harder to achieve, and not all CCT (Colour Temperature) variants are kept in stock. Additionally, dimming curves may vary slightly across different types of fittings.
Remote Dimming / Constant Current (2 Wires, Series)
Example Spec: 36V DC @ 100mA Constant Current (Remote Driver)
In this architecture, the fitting contains a bare LED without an internal driver. Power is supplied via an external constant-current remote driver, requiring all fittings on the circuit to be wired in series. The dimming protocol is dictated entirely by the capabilities of the external power supply.
- Advantage: Delivers the highest possible efficiency. Powering the bare LEDs directly without internal conversion losses maximises light output per watt. It also allows for seamless integration with the ever-growing catalogue of LED COB options from major industry brands like CREE, Nichia, and Citizen.
- Disadvantage: Series wiring requires meticulous planning in large installations. Long cable runs across multiple fittings can quickly cause the combined forward voltage to exceed SELV (Safety Extra Low Voltage) limits. Due to the series circuit, a single fitting failure will break the circuit and extinguish all lights on that run. Furthermore, the bare LED components lack internal protection circuitry, making them more vulnerable to transient line voltages.
Legacy Option: Signal Dimming (3 Wires, Parallel Power + Signal)
Note: ARX no longer offers 3-wire signal dimming on new products, but it may be present in existing installations or retrofit projects.
In this legacy scheme, two wires carry power to each fitting in parallel, while a dedicated third wire carries the control signal. The signal is managed by an interface box that converts an incoming DALI, DMX, or Casambi command into the final output signal routed to each fitting.
- Advantage: Provides incredibly smooth, consistent dimming at each fitting, regardless of individual power output. Highly efficient, as the control signal directly modulates the output current of the dedicated driver inside each fitting.
- Disadvantage: Requires a 3-core cable pull to every fitting and demands significantly more upfront engineering and installation planning.