Gateways are important components in building automation network architectures. As intermediaries between the various devices and communication protocols, they ensure smooth data exchange.

In line with the large number of devices and protocols in building automation (BA), the universal gateways from MBS are literally "universal": they include not just individual bus protocols, but all common bus protocols that can be implemented within the scope of the available physical interfaces. Whether mounted as a component on a top-hat rail in a control cabinet or as an edge device in a virtual environment - the universal gateways cover all hardware interfaces as well as all communication protocols. Not only can they link up to five bus systems, they also offer a wide range of data points with a minimum of 25 to a maximum of 40,000.

Many communication protocols, a single interface

It is obvious that building automation cannot do without gateways. This is because all devices are networked, monitored and controlled via a bus system. It provides a common line system between the various participants - such as sensors, actuators, DDC or control technology - on which data can be transmitted. Since the internet protocol has been used in the GA, the terms communication or bus protocol have become established among experts.

There are so many different systems for technical reasons: Depending on the intended use, the requirements are very different. For example, when transmitting meter data with the M-Bus, the data lines are used simultaneously to supply the meters with power.

But historical developments also play a role: for example, at the field level, sensors were initially used for data collection that worked with analog signals. Since the 1980s, digital sensors have also been increasingly used here. Initially, wired systems and power lines were used for networking. With the introduction of the Internet Protocol (IP) in GA, IP-based networks are increasingly being used, which are now being supplemented by wireless technologies.

There is also a fundamental distinction between closed and open bus systems. Closed systems are proprietary, i.e. manufacturer-specific, and can only be used on the devices of the corresponding manufacturer. Open systems, on the other hand, allow different devices from different manufacturers to be interconnected, which offers both technical and economic advantages. Corresponding bus protocols for building automation have been standardized by separate consortia and continue to be adapted to current requirements.

BACnet, KNX, LON, DALI, M-Bus ...

These include the following systems:

Around 25 million devices currently exchange data via BACnet (Building Automation and Control Networks). With BACnet Secure Connect, the manufacturer-independent communication standard has had its own security architecture since 2019.
A popular communication protocol at field level in Europe is the KNX Konnex bus, the successor to the European installation bus EIB. This standard transmits data on twisted two-wire cables, but also via radio or IP.
The LON (Local Operating Network) field bus standard with the LonTalk communication protocol was one of the most popular technologies worldwide. It enables interdisciplinary networking and can still be found in many properties today, often in the area of individual room control.
DALI (Digital Addressable Lighting Interface) is a tried and tested bus system for the installation, control and communication of all components of a lighting system, for example to adjust light colors or dim luminaires.
The M-Bus (meter bus) is used in the field to record consumption data. It works according to the request-response or master-slave principle; communication is organized via voltage modulation.
Modbus originates from the field of programmable logic controllers (PLC). The standard is based on a client/server architecture: The client - e.g. a PC - can be combined with several servers - such as measurement and control systems.
The OCF standard is currently being developed to pave the way for the future viability of classic GA. Around 500 members of the OCF (Open Connectivity Foundation) industry group are currently developing specifications for the Internet of Things (IoT).
MQTT (Message Queue Telemetry Transport) is the most important network protocol for machine-to-machine (M2M) communication. It is often used to transfer data from properties to the cloud services of different operators.
Thread is an open radio protocol for wireless data transmission between devices with low power consumption and low data transmission rates. Thread offers native IP support for uncomplicated connection to the Internet.

... CAN, Profinet, OPC UA

There are also other bus protocol drivers that are primarily used in industrial automation:

CAN (Controller Area Network) is used for cable-based, digital data exchange. This standard forms the basis for CANopen, a protocol for modern automation technology.
With Profinet, distributed control elements can be linked to a central controller. The open industrial Ethernet standard defines the decentralized field devices as IO devices (input/output) that are controlled by an IO controller.
The Open Platform Communications Unified Architecture (OPC UA) is a platform-independent architecture for manufacturer-independent data exchange in the industrial environment and in the Internet of Things (IoT).

If you were to add the proprietary communication protocols to this list, it would grow to well over 100. This shows once again very clearly why building automation cannot do without its "interpreters".

Indispensable translators

As far as the technical structure is concerned, the Universal Gateways from MBS are based on the following concept: At the center is the data point manager (DP manager) as a neutral instance that mediates between all installed, enabled bus protocol drivers. When data arrives, the relevant bus protocol driver first passes this data to the DP manager. Depending on the programming, the DP manager assigns it to one or more target protocols. There is also an interface for a serial bus and an IP interface, which can be used to run several IP protocol drivers simultaneously. Most frequently, a universal gateway mediates between two different buses.

It depends on the bus systems which hardware interfaces are used. In order to meet the different technical requirements, MBS offers its gateways in two series - the X-series and the A-series. As they are based on a firmware platform, they are as versatile as they are flexible. And thanks to the modular design, specific add-on boards can be installed directly in the device. The product list shows which bus protocols can be combined with the X series. With 20,000 or 40,000 data points, the A series is the most powerful device on the market, but is only a third of the size of conventional devices. With these gateway series, a solution is possible for almost every customer-specific requirement.

Incidentally, the data point of a gateway does not denote a specific object or a specific value or similar. To understand its definition, you should know that each bus protocol defines it differently: In BACnet, for example, a data point designates the name and value of a specific BACnet object. In KNX, on the other hand, there are no individual names, but rather group addresses plus values. Depending on the system, data points can also be physical or virtual. In control technology, on the other hand, this is understood to mean a fade-in point that is defined with a setpoint and actual value component. These definitions differ greatly - in technical, administrative and financial terms.

Data point and data point manager

In the workflow of the MBS gateway, the data point is defined as the forwarding of information from one bus protocol to another. If you imagine a gateway that "interprets" between two systems, then a separate technical address is defined in each. Each of these two addresses represents a data point. If data comes in with the first bus protocol, the value of the data point belonging to this technical address changes. The neutral DP manager now becomes active by forwarding this change to the technical address of the second communication protocol, the second data point.

Forwarding information from one bus protocol to another is counted as one data point with the MBS universal gateways.

The Universal Gateways cover all trades: from air conditioning, fresh water supply and waste water disposal to access control, lighting control and fire detection, as well as general control tasks plus actuators. The Krefeld-based manufacturer has been offering them since the mid-1990s. Since then, their modular design has enabled great flexibility.

From the field to the cloud

With this extensive experience, MBS is also responding to the current changes in the world of building automation. For example, the demand for solutions that link different systems is currently increasing. With the development of cloud-based services, these links are extending beyond individual properties and into the Internet of Things. MBS is responding to this trend by further developing its universal gateways into edge devices using the MQTT bus protocol. The Krefeld-based manufacturer will also follow the trend towards digital wireless communication - with Thread - in the future.

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Universal gateways | Interpreters for building automation