DALI, KNX, DMX, 0-10 V and the wireless meshes, with the numbers that decide which one a Gulf project can actually commission. The Bluetooth SIG's own lighting specification family is called NLC Profiles, for Networked Lighting Control, which is a coincidence we are going to enjoy.
Four ideas to carry into the next specification conversation you have.
0-10 V is two protocols wearing one name. In ANSI E1.3 the controller sources the current; in IEC 60929 Annex E, and ANSI C137.1 for LED drivers, the driver sources it and the controller sinks it. No 0-10 V standard fixes one dimming curve either: IEC 60929 sets only the end points and ANSI C137.1-2022 allows linear or logarithmic, which is why PNNL fed 23 LED streetlights identical control voltages and measured about 53 percentage points of spread in relative power draw.
A DALI-2 subnet carries 64 control gear AND 64 control devices, 128 addresses on one pair. The bare "64" figure is DALI version-1. Polarity insensitivity is a DALI-2 requirement with an exception that bites: devices containing a bus power supply are marked DA+ and DA-. And the curve is logarithmic, so level 127 is 3.1% light, not half; half the light is level 229.
KNX twisted pair is ISO/IEC 14543-3-6. Part 3-7 is radio, and parts 3-10 and 3-11 in the same numbering family are energy-harvesting protocols that are not KNX at all. Every KNX ISO part is still Edition 1.0, dated 2006 and 2007, so KNX Secure cannot be in the ISO/IEC text. And ANSI/ASHRAE 135, which KNX literature lists among its credentials, is BACnet.
Wireless is real, and it now has a standards track: the Bluetooth SIG's NLC Profiles, seven of them including HVAC integration. What to check is the assurance level. Proprietary meshes are candid about it: interoperability is achieved by every product running the same vendor's firmware, which is a feature and a lock-in at the same time. Casambi is one of them: it runs its own mesh on a Bluetooth LE radio, not the SIG's, and one network holds up to 250 units. Ask who holds the commissioning licence and the project file at handover.
Per IEC 62386, ANSI E1.11-2024, the KNX TP1 system documents, the Bluetooth Mesh Protocol and the CSA and Casambi published limits. Where no publisher gives a figure, none is printed.
| Protocol | Capacity | Speed, feedback and listing |
|---|---|---|
| 0-10 V | no addresses | One-way analogue level. Two interfaces share the name, and there is no public listing |
| DALI-2 | 64 + 64 | 1200 bit/s, two-way, DALI Alliance public database. 250 mA and 300 m per subnet |
| DMX512 | 512 slots | 250 kbit/s, 32 unit loads per link, 44 updates per second at a full universe. Two-way with RDM; what a BMS sees depends on the gateway. No certification programme |
| KNX TP | 64 or 256 per segment | 9600 bit/s, two-way. 64 per segment with TP1-64 devices, 256 with TP1-256, within the supply current and device mix. KNX Association public database |
| Bluetooth mesh (NLC) | 32,767 addresses | Per network, one per element, not per luminaire. Bluetooth SIG qualified product database |
| Zigbee | 250 kbit/s | IEEE 802.15.4 mesh with no published network maximum. CSA certified products search |
| Casambi | up to 250 units | Its own mesh on a Bluetooth LE radio, not the SIG's; up to 250 nodes per network (127 on Classic). No independent certification |
Five corrections that change what goes into the specification.
DALI-2 is a certification programme, not a protocol version. The protocol is IEC 62386; DALI-2 is granted to a specific product with a specific GTIN, firmware and hardware version, and the DALI Alliance's product database is the certificate: "DiiA does not issue test reports or product certification documents." A company cannot be DALI-2. Note also that "DALI-8" does not exist; it is a garbled reference to device type 8, which is colour.
The DALI Alliance gives 300 m as the recommended maximum between any two devices, on 1.5 mm² cable at a total bus supply current of 250 mA. Lunatone and Tridonic give the reason: at most 2 V drop on the line. Thinner cable reaches that drop sooner: worst case, with the full current at the far end, 0.5 mm² reaches it at 112 m. Size the run from the voltage drop first, then check it against 300 m. On a D4i run count the supplies too: each D4i driver's bus supply is on by default, four at 60 mA reach 250 mA, and from the fifth luminaire the supplies must be switched off. The DALI Alliance's guide adds that a closed loop should not be used.
SASO's January 2020 workshop on SASO 2927:2019 lists the driver programme for street, road and tunnel luminaires as "DALI (preferable) or 0-10V dimmable", with a 7-pin NEMA socket "capped (short-circuited)" on the fixture base. That sets the permitted options; it says nothing about how much of either is installed. The standard's own text is sold by SASO and AMD2:2023 exists, so check the current edition before quoting a clause. The bridge from that socket to digital control has a name: D4i, which the DALI Alliance states is compatible with ANSI C136.41 sockets and Zhaga Book 18. The current edition of the socket standard is ANSI C136.41-2025.
ANSI E1.11-2024 Table 6 caps a full 513-slot universe at 22.7 ms, 44 updates per second, on a 250 kbit/s EIA-485 line terminated with 120 Ω and limited to 32 unit loads per link. The 1 ms figure circulates everywhere and is simply wrong. Cite DMX512 as ANSI E1.11-2024 and RDM as ANSI E1.20-2025, not the 2008 and 2010 editions almost every article still cites. RDM adds feedback on the same pair: the controller discovers fixtures by binary-tree search over 48-bit unique IDs and can ask them for status, sensor readings and faults. Whether a BMS sees any of it depends on the gateway: most expose levels or programmed points, not fixture health.
Datasheet examples: the Lunatone DALI-2 PS bus supply (24033444) is rated -20 to +55 °C, IP20; the MDT STC-0640.01 KNX power supply 0 to +45 °C; the Casambi CBU-ASD-LR node -20 to +50 °C, its output derated from +40. These are product ratings, not protocol limits: in a 40 to 50 °C corridor or car park, choose parts rated for the space or cool the enclosure. Check the mains rating too: the CBU-ASD-LR input is rated 50 Hz only, and Saudi mains is 60 Hz. PIR sensing needs contrast as well: the Lunatone DALI-2 CS Corridor (88793325) quotes its 5 m range at a temperature difference above 8 °C and needs at least 4 °C, so a body close to ambient is harder to detect.
Each one has a published answer: a database entry, a datasheet line or a contract clause. None of them can be met with an adjective.
1. Is the exact product build in the DALI Alliance or KNX database?
2. How many head-end objects does the gateway expose, for how many fixtures?
3. Which sensor instance types cross it?
4. What is each device's rated ambient where it will be installed?
5. Who holds the commissioning software licence and the project file at handover, in writing?
Question 5 is the lock-in question: an ETS licence and project file on KNX, a configuration backup on DALI, a vendor account on a proprietary mesh.
With one correction to how that is worded. A company cannot be DALI-2 certified: certification is granted to a specific product build, and the DALI Alliance's public database is the certificate. NLC's own control systems page states DALI, KNX, DMX, Bluetooth and LoRa against IEC 62386, which is the accurate way to put it. Ask any integrator, including us, for the database listing of the actual products proposed, the gateway's head-end object count, and who holds the commissioning licence at handover.
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