DALI#

Understanding DALI Performance#

DALI (Digital Addressable Lighting Interface) is a standardized protocol for lighting control that operates at a relatively slow communication speed of 1200 bits per second. This low baud rate was intentionally chosen to ensure reliable communication over simple two-wire cables without the need for special wiring or termination resistors.

Performance Characteristics#

  • Bus Speed: 1200 bps (bits per second)
  • Command Rate: Up to 40-50 commands per second
  • Command Duration: Each command takes approximately 25 milliseconds
  • Network Capacity: Up to 64 individually addressable devices per DALI line

The slow communication speed means that addressing all 64 devices individually would require approximately 1.5 seconds. While this is acceptable for many applications, it can become a limitation when simultaneous control of multiple fixtures is required.

Optimizing Performance with Scenes and Groups#

To overcome the performance limitations of the DALI bus, the protocol includes built-in support for scenes and groups, which enable fast, simultaneous control of multiple devices with a single command.

DALI Scenes#

Each DALI device can store up to 16 programmable scenes (numbered 0-15). A scene is a pre-configured lighting level that can be recalled instantly:

  • Storage: Each driver stores its own level for each of the 16 scenes
  • Recall: A single scene command is broadcast to all devices on the DALI line
  • Execution: Each device checks its memory and, if it has a stored level for that scene, executes it simultaneously
  • Speed: All participating devices respond at once, regardless of their number

Example: A “Movie Mode” scene could dim audience lights to 10% while setting accent lights to 50% and turning off decorative lights - all with one command.

DALI Groups#

DALI supports up to 16 groups (numbered 0-15) per interface. Groups allow logical organization of devices:

  • Membership: Each device can belong to multiple groups (up to all 16)
  • Addressing: Commands can target an entire group instead of individual devices
  • Response: All devices in a group respond simultaneously to group commands
  • Hardware-based: Groups are a property of the DALI interface itself, ensuring synchronized execution

Example: All hallway lights can be grouped together, allowing a single command to control all of them at once instead of addressing each fixture individually.

Why Scenes and Groups Matter#

Using scenes and groups is essential for responsive DALI control because:

  1. Simultaneous execution - All devices respond at the same time
  2. Reduced bus traffic - One command instead of dozens
  3. Faster response - 25ms instead of 1.5 seconds for 64 devices
  4. Better user experience - Lighting changes appear instant and synchronized

Upcoming TapHome Enhancements#

New DALI Gateway Hardware#

TapHome is preparing a new DALI gateway with enhanced capabilities:

  • Integrated DALI Power Supply: Built-in 200mA DALI power source
  • Flexible Configuration: Software option to disable internal power supply and use external source when needed
  • Improved Performance: Optimized for faster scene and group operations

Software Version 2026: Advanced Group Support#

The 2026 software release will introduce comprehensive group management:

Group-Level Smart Rules:

  • Smart Rules can be applied to entire groups
  • Smart Rules can also target individual devices within groups
  • Clear priority hierarchy prevents conflicts between group-level and device-level rules

Conflict Resolution: A well-defined priority system ensures that when a group has a Smart Rule to turn off, but a child device has a rule to turn on, the system handles this intelligently without creating control loops or conflicting states.

Post-2026.1: Hardware Scene Support#

Shortly after the 2026.1 release, full hardware scene support will be introduced across the entire TapHome system, including DALI:

For DALI, this means:

  • Native Scene Programming: Direct programming of DALI device scenes through TapHome
  • Scene Recall Integration: Hardware scenes can be triggered by Smart Rules, schedules, and buttons
  • Cross-System Scenes: DALI scenes can be synchronized with other TapHome device types
  • Faster Execution: Scene recalls execute at the DALI hardware level, ensuring minimal latency
  • Scene Management: Easy configuration, modification, and backup of all 16 scenes per device through the TapHome interface

This integration will make DALI scenes fully accessible within TapHome’s automation logic, enabling complex lighting scenarios that execute with hardware-level speed and reliability.

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