The io-key

Introduction to IoT (gateways)

Access my devices from every place in the world? The Internet of Things (IoT) networks the devices of the world. How will the data get into the network?


The key to networking is Gateways which, in short, establish the connection between the device on the edge, i.e. the local border of a system, and the global network. Purpose is to establish connectivity between the Operative Technology (OT), i.e. physical systems such as sensors or entire machines, and Information Technology (IT). The latter is intended to integrate the data in a virtual image of the physical system to implement monitoring and/or control of the system.

In the course of the Industry 4.0 approach the virtual image of the devices is also applied for industrial processes thus opening up new options for producers. The extension of automated processes and the improved flexibility by data analysis in a broad scope and the related improved controllability of production processes are just two of many applications of the Industrial Internet of Things (IIoT). The functional principle of IIoT gateways frequently only differs by the architecture of the existing OT system.

How to find the appropriate IIoT gateway for your own application?

Edge controllers or edge computer applications can be frequently found in large production lines. These systems are linked to an existing control device, e.g. a PLC, and forward the data in the form of switching signals to a cloud platform. In this case the switched inputs and outputs can be monitored and controlled by remote access. Edge computers pre-model process parameters of production from these binary signals already and then transmit them compressedly to a monitoring platform. In addition further interfaces and individualised software solutions for large-scale IIoT projects are often integrated here.

A broad variety of gateways for bus systems mainly differing by the supported communication protocol, e.g. ProfiNet or CANopen, is available for selection to implement the digitalization of process data on field level. These gateways “collect” the data of different sensors and actuators and send it via a connection to a local network via (wireless) LAN to the global internet.

If no comprehensive infrastructure in the form of controls is available or if the existing system architecture shall not be modified (retrofitting), gateways directly establishing the connection as “sensor to cloud”* are used. Smart sensors have an integrated gateway especially for this type of communication that makes available the process data online with different protocols via the mobile network. These sensors are predominantly used in Smart Home applications. To connect industrial sensors with the IIoT directly, the sensors use external gateways which also establish the connection with the IIoT via Ethernet or wireless LAN and/or the mobile network. The first type of connection depends on a local network. If it is not possible or difficult to set up such network due to external conditions or if an independent way of transmission is required, a gateway which communicates via the 2G network and Narrowband IoT is used.

The latter is a special wireless network based on LTE (4G) technology. The frequency band is characterised by its long wavelength achieving high penetration of buildings of the radio waves. That way it is also possible to transmit data in the basement while the data volume however is limited. In another extension level of this network the so-called Cat-M1 technology also based on LTE is useful although it has no equivalent penetration of buildings but significantly higher data transmission volumes and more stable radio cell switching. This is why the Cat-M1 technology is frequently mentioned in connection with the future of the IIoT.

You will find additional information about different mobile communication technologies in the following table:

Designation 2G 3G 4G 5G NB-IoT Cat-M1 Zigbee
Technology GSM UMTS LTE 5G LTE NB1 LTE CatM1
Frequency band Approx. 900 MHz Approx. 2 GHz 0.8/ 1.8/ 2.6 GHz 3.4 – 3.8 GHz 180 kHz 1.4 MHz 868/ 915 MHz, 2.4 GHz
Data transmission up to 234 kBit/s up to 42 MBit/s up to 3 GBit/s up to 10 GBit/s approx. 150 kBit/s 375 kBit/s, 1 MBit/s
Application Mobile telephony, SMS Mobile internet VoIP, online gaming Mobile communication, industrial automation, autonomous driving Internet of Things, low-consumption appliances Internet of Things, mobile devices Domestic / industrial automation
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