Lighting Control Systems

DMX, DALI, and KNX

In modern building automation and lighting design, DMX, DALI, and KNX are three prominent control protocols, each suited for different applications and offering unique benefits. Understanding their use cases and cabling requirements is key to successful implementation.

DMX (Digital Multiplex)

Application: DMX is primarily used in theatrical, stage, and architectural lighting, where precise and dynamic control of individual fixtures is needed. It is ideal for color-changing LED fixtures, dimmers, and moving heads.

Cable Requirements:

  • Standard: DMX512-A over shielded twisted pair (STP), typically 2-core with shield (e.g. MAS1PRS485    ;  MAS2PRS485  )
  • Impedance: 120 ohms
  • Maximum length: 300 meters per segment
  • Connectors: XLR (3-pin or 5-pin) or RJ45 in architectural applications

DALI (Digital Addressable Lighting Interface)

Application: DALI is used for intelligent, energy-efficient lighting control in commercial and residential buildings. It supports individual and group control of fixtures and two-way communication for monitoring.

Cable Requirements:

  • Standard: DALI-2 over unshielded 2 Core 1.5MM (e.g. MAS2C15LSZH)
  • No specific polarity requirement
  • Voltage: 16V DC on the DALI bus
  • Max current: 250 mA (supporting up to 64 devices)
  • Maximum length: 300 meters (depending on voltage drop)
  • Typical cable: 5-core cable (L, N, Earth, DALI+, DALI− : MAS2C3G15).

KNX (Konnex)

Application: KNX is a comprehensive building automation protocol used for controlling lighting, HVAC, blinds, and more. It enables integration across devices from different manufacturers in a home or building automation system.

Cable Requirements:

  • Standard: KNX twisted pair
  • Cable type: KNX-certified cable (green), typically 2 x 2 x 0.8 mm twisted pair (e.g. MAS2PKNX)
  • Voltage: 30V DC
  • Maximum cable length: 1,000 meters (total), 700 meters max line length
  • Topology: Free, star, line, or tree

Summary

Protocol

Application Area

Cable Type

Max Length

Notes

DMX

Stage, Architectural

Shielded twisted pair, 120Ω

300 m

Needs termination at ends

DALI

Commercial, Residential

2-core bus cable (shield optional)

300 m

Bus-powered, no polarity

KNX

Whole building systems

KNX-certified twisted pair

1,000 m

Can also run over IP or RF

Each of these systems plays a critical role in delivering flexible and efficient lighting solutions, and selecting the correct cabling ensures optimal performance and compliance with standards.