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Streetlights play a crucial role in ensuring public safety and security. While investing in modernizing public lighting infrastructure, municipalities and city authorities seek LED streetlights that deliver optimal illumination as well as future-ready smart city capability. Furthermore, some decision-makers aspire to achieve advance functions that are built on the smart street-lighting infrastructure, such as, motion sensing, remote monitoring and scheduling street lights, monitoring air quality, tracking pedestrian and vehicular traffic, and offering EV charging facility.

Interoperability clearly plays a significant role in achieving this. Interoperability here means that a controller or motion sensor from vendor A or B, must seamlessly pair and work with a streetlight fixture from vendor X, Y or Z.

Interchangeability | Interoperability – Zhaga (book 18) global standard

Key mission of Zhaga Consortium is to standardize interfaces of the LED luminaires in order to achieve interchangeability and interoperability. Launched in 2018, the standardized Zhaga (book 18) socket enables universal luminaire compatibility.

  • Zhaga socket allows quick tool-free installation of a Zhaga controller on to any Zhaga certified street light luminaire.
  • Thanks to this universally accepted standard, specifiers and municipalities do not have to worry about the compatibility between an outdoor lamp controller (OLC)/ motion sensor and a streetlight fixture.
  • Zhaga socket based street light fixtures are particularly suitable for cities that wish to have ‘controls’ ready street lights, but do not want to install an LMS system right now.

Zhaga (book 18) socket interface has rapidly replaced the traditional NEMA 7-Pin (ANSI 136.41) standard in Europe and several other countries.

  • While Nema receptacle based luminaire mandates installation of a shorting cap, Zhaga socket based luminaire do not need any shorting cap.
  • Zhaga interface deliver 24V DC clean auxiliary power for OLC. This is unlike the AC grid voltage from the Nema receptacle. DC power to OLC significantly improves the OLC’s as well as entire luminaire’s lifetime and reliability.
  • Zhaga (book 18) sockets are available from multiple suppliers such as TEAmphenolTridonic and Longjoin – to name a few. Furthermore, majority of streetlight OEMs deliver Zhaga certified streetlight fixtures.

At Tvilight, we believe that intelligent lighting is imperative for cities and citizens. We aim at making our products easily accessible, so that cities can effortlessly and economically become smarter and sustainable. We offer both Nema as well as Zhaga based controllers. List of our Zhaga (book 18) supported intelligent outdoor light controllers (OLC) / streetlight controllers (SLC) include:

Zhaga Street Light Controller
Zhaga-D4i Street Light Controller

Plug & Play Interface for Smart, Future-Ready Street Lights

DALI Alliance (also known as DiiA, or Digital Illumination Interface Alliance) is an equally important standardization body that aims at improving the interoperability and functionalities of public lighting infrastructure. DiiA’s D4i DALI standard protocol for intelligent, IoT-ready street luminaires ensure excellent software compatibility between the OLC’s and the streetlight fixture.

D4i offers standardized data model, wherein D4i certified LED drivers deliver over 60 standardized data-points to monitor the complete street lighting infrastructure, including the LED module(s), LED Driver, underground Power-Grid as well as the Lamp Controller. Such a level of standardized data model is a major leap forward and an excellent news for municipalities, utilities and asset managers.

Furthermore, D4i certified drivers offer auxiliary power (24V). This enables the lamp controller to work on clean protected DC power, instead of direct grid AC power. This, in turn, significantly improves the lifetime and reliability of a Zhaga OLC.

With the latest introduction of the new Zhaga-D4i (ZD4i) interface standard, a combined effort between the DALI Alliance (DiiA) and the Zhaga Consortium, streetlight standardization goes even a step forward. This standard ensures future-proof plug-and-play interoperability between the streetlight controller and the LED luminaires.

The ZD4i supports dual certification. Meaning that a certified product has a standardized Zhaga book 18 interface, as well as it also adheres to DiiA’s DALI-2 and D4i standards. Such smart lighting products are clearly plug-and-play, interoperable, cost effective and future-ready.

Smart Street Lighting – Zhaga-D4i Data

Intelligent Street Lights

Zhaga is the New NEMA

Zhaga D4i Smart Streetlight in action

Want to see how Zhaga D4i works in practice?

City of Dortmund already installed over 20.000 smart streetlights and will reach 30.000 by end of year 2023.

A bicycle highway in Mechelen (Belgium) uses our ingenious plug-and-play Zhaga controller and Zhaga motion sensor with D4i certified streetlight luminaire. Learn more about this project at: Motion sensor smart street lighting in Belgium.

So, what is our recommendation?

Here are the key takeaways:

  1. Zhaga ready streetlight luminaires are a safe choice. A marginal higher investment will make your public lighting infrastructure future-ready.
  2. Choose either for single Zhaga socket (for controls only option) or dual Zhaga sockets (for both, control as well as motion sensor capability). Prominent street light luminaire suppliers support single as well as dual Zhaga sockets.
  3. Select Controls vendor that can offer full range of Zhaga products, both RF Mesh as well as IoT. Ensure that Zhaga controller supports DALI D4i communication protocol.

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About Tvilight

TVILIGHT PROJECTS B.V. is a European market leader specializing in motion sensors, wireless lighting controllers, and a complete portfolio of street light management software – to manage, monitor, operate and maintain citywide public lighting infrastructure. Our smart lighting platform and open API allow integration to city’s preferred software platform and thus constitute an open, reliable and future-proof base for Smart Cities and the Internet of Things. The company has installed over 800 projects globally across 25+ countries, including iconic cities and critical infrastructure around the world. Tvilight’s international projects include Amsterdam Airport Schiphol, Dutch Railways, Port of Moerdijk, Seoul, Beijing, as well as some of the largest German cities such as Düren, Münster, Cologne, Dortmund, and Berlin. To discover more about us and our products, visit