The first steps in the field of system automation with programmable logic controllers (VPS) and their structure with hard-wired logic - including electro-mechanical contactors - led to an acceleration of processes for the first time. However, troubleshooting was very complex and required a lot of experience. The replacement by PLCs was another major milestone. Thanks to the possibility of digital programming, the logic could be controlled depending on the system status and process step. Since then, technology has developed rapidly - Siemens has now established the latest TIA generation of its Simatic S3, S5 and S7 controllers on the market.

The application and programming also changed with the PLC generations - from the Simatic S5 environment with a blue background to the Simatic S7 tool with more clarity and extended programming options to the current step towards the TIA portal, which changed both the programming environment and access to the data structures. From then on, these data structures could be used via optimized access using purely symbolic names instead of absolute addresses, which facilitates the subsequent logical addition of data blocks. However, other points have also been adapted and supplemented since the first release of the TIA generation.

Digitized production

'ControlPlex CPC20' enables intelligent power distribution and maximizes system availability through extensive diagnostic functions.

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In the past, feedback contacts were relatively uncommon in automation technology; their main purpose was to ensure the safe and smooth operation of the system. Subsequently, the main focus was on the visualization of error states, which were displayed to maintenance personnel on monitors. This constant progress is noticeable for plant operators through increased availability, both through a more transparent process and faster troubleshooting. This brought the benefits of signaling and visualization further into focus and triggered the digital transformation of production.

Terms such as Digital Factory, Industry 4.0 or Internet of Things have become an integral part of current automation projects. Many companies set themselves the goal of combining optimum quality with a stable output quantity of manufactured products, and to achieve this, transparency had to be increased in all processes. The additional connection of process and measured value data - 'machine sensing' - to higher-level ERP or MES systems or directly to the cloud now enables further data analyses and provides a concrete basis for decision-making for predictive maintenance. An important part of this is the integration of the 24 V (DC) control voltage throughout the entire process chain. Topics such as energy management or the condition monitoring of machines and systems are among others located here.

The 'ControlPlex' systems from E-T-A with intelligent overcurrent protection including power distribution fall within this range of topics. The two bus controllers of the systems collect data from the electronic circuit breakers, such as load currents and status information from the field level, and make it available to higher levels. This allows the main function of an electronic fuse to be used - fast and safe disconnection in the event of a fault - while the measurement and status information also increases transparency.

Counteracting rising training costs

The various communicative devices from different manufacturers generally require time-consuming familiarization - for understanding the system architecture and efficient integration into the field level as well as into higher-level systems. This often leads to investments in digital and transparent products being approached rather hesitantly due to the supposedly excessive effort involved.

In order to keep training costs as low as possible, the two 'ControlPlex' systems 'CPC12' and 'CPC20' offer the option of 'desk commissioning' without PLC and programming: an additional RJ45 socket enables the visual display of measurement data and parameters via a standard IP address of the integrated web server. In addition, 'on/off/reset' control of the individual channels is possible. This allows pre-tests and prototypes to be realized within a very short time. The standard Rest API interface in JSON format on the same port enables further implementation in an ERP system, an MES or a cloud solution, which promotes the acquisition of machine and production key figures.

The fieldbus connection

In mechanical engineering, the focus is on flexible adaptation, with engineering costs playing a major role. Consequently, the devices used in the control cabinet must also support flexible adaptation, especially with regard to a possible switch to a different control manufacturer and a different communication protocol. Such a change can be realized more easily if the devices used support different fieldbus interfaces with the same form factor. The 'ControlPlex' systems, for example, support fieldbus interfaces such as Profinet, Ethernet/IP, Ethercat and Modbus TCP/IP. This results in simplified integration into the automation of the systems.

With their various fieldbus interfaces, the aforementioned bus controllers form the heart of the 24 V (DC) power distribution system. In addition to the web server view, users can also access pre-implemented software and image modules for the various automation portals - for example, for Profinet implementation in the TIA Portal - to reduce the time required to familiarize themselves with the systems. Once individual variables and system constants have been connected, this library block with the corresponding data block helps to interpret and access the prepared data. Additional function blocks and functions are automatically loaded into the project in order to execute and control the required functions in the background. They are divided into modules that are as small and manageable as possible.

The author: Stefan Gleinig is an application developer for automation technology in the Automation & Process Control division at E-T-A Elektrotechnische Apparate in Altdorf near Nuremberg.

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From batch size 1 to series production of a production plant, software developers as well as users and maintenance staff benefit from the identical structure of the plant visualization and the web server. The screen module integrated into the library provides the basis for this. Parameters and displays are automatically assigned via a single data interface on the screen module, enabling a user-friendly flow of information. An integrated histogram can be connected for further analysis. This allows the current and voltage curves of overload and short-circuit events to be evaluated in just a few steps. The seconds before and during a detected event are recorded and analyzed. The monitoring tool thus gives on-site personnel a deeper insight into the situation in the system and enables faults to be rectified more quickly.