Everybody’s talking about disruption and digitalization as game-changers. But are they really? From a purely technological perspective, I’d say the opposite is true. Automation experts, electrical engineers, and radio engineers have long used technologies that enable a connected world. Machines have been exchanging information since the early twentieth century, even if they only had cable connections. By the end of the 1920s, it was possible to transmit measured values to physically separate recording units via radio waves: in effect, the birth of telemetry, without which there would be no Internet of Things (IoT).
Learning from an old oil platform
The protocol on which most cloud platforms are based is also nothing new to automation experts. Message Queuing Telemetry Transport (MQTT) was developed as SCADA protocol more than 20 years ago with the purpose of monitoring unattended oil platforms in the middle of a desert – using data transmission via satellite and land-based networks instead of Wi-Fi. The result was a solution that goes far beyond a direct point-to-point connection and decouples data producers from data users. The protocol permits the transmission of very different data types and reestablishes broken connections with no loss of data, which in turn allows transmission using narrow bandwidths and unstable networks.
Projects in the cloud
Data was already floating “in the cloud” in 1999, long before “cloud” became a buzzword. You benefit from all this when your company scales the seemingly cloudy heights of IoT, big data, analytics, and real-time monitoring. You can then just lean back and follow a few simple steps to make the necessary data from your automation project available. PLCs have always exchanged process data via Industrial Ethernet field bus systems – easily and with higher data layers, thanks to interfaces and protocols like MQTT. The road has already been paved for your projects to enter the cloud with no additional software licenses or special hardware.
Function blocks for the IoT and M2M
An MQTT library with an MQTT client function is available for the Simatic S7 controller family. The S7 CPU uses this client to make the process data available to the “MQTT broker” in the cloud, such as AWS or Azure. The broker then distributes the information to additional systems that have “subscribed” to this data, including apps, analysis tools, and ERP systems used by salespeople.
Here’s how easy it is: Download the LMQTT_Client library. Create a TIA Portal project that includes the S7 CPU you want to use. Parameterize the CPU’s Ethernet interface with an IP address in the same subnetwork as the MQTT broker. If you use a cloud service like AWS, parameterize a router and a DNS server. Connect the CPU and MQTT broker via Ethernet. Then load the project’s client in the global library, select the function block necessary for your CPU, and insert it in the “Program blocks” folder via drag-and-drop. Done! The door to the cloud is now open.
Expertise for a connected world
Would you like to learn about the configuration of Simatic S7 controllers as MQTT clients in more detail? You’ll find more information in the application example from Siemens’ Industry Online Support at:
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