
There’s little you can do about strong fluctuations in the consumption and the quality of raw water. But what you can do is ensure that your water treatment is able to manage this intelligently. This is where networked Industry 4.0 comes into play, together with modular automation from Festo.
Modular automation with CPX
Festo has made automation technology smart. Thanks to digitalisation, we are now able to easily, securely and reliably network automated modules with each other at field level and get them to work with each other. The keyword here is “intelligent components”, which can be flexibly combined, based precisely on needs and requirements. Each module comprises all the automation components needed to manage its own processes.
Our automation platform CPX plays a leading role in the decentralised processing of signals and functional control. This gives you much better and more economical control over fluctuating water consumption and raw water quality than with a central control system. If anything is missing, whether it's a filter system or further process steps, it can simply be docked and activated (numbering-up rather than elaborate scaling-up).
Intelligence at the field level
Generally, the design and engineering of process-related systems is done as follows: you define a production quantity to be produced within a predefined time, and then you set up a process to achieve this. Everything is controlled and monitored by a centralised control system. This works well as long as the required production quantity remains the same.
But that is often precisely the opposite of what happens. Or there are fluctuations in the quality of the raw. Intervening in such a centralised automation system is extremely laborious, because it means the entire process and automation technology needs to be modified. In addition, you need someone who is proficient in precisely this special design and in programming it. On top of that, a reduced throughput can impact the product quality and jeopardise the profitability of the system. Last but not least, service and maintenance become more difficult and expensive, because you continually have to shut down and restart the system.
Your route to modular automation
Using water filtration as an example, these diagrams show in just four steps how you can turn a conventional, process-based large-scale system with centralised automation into a modular, decentralised automated solution. In this example, we will show a typical water treatment plant that was designed using requirements defined some time ago, making the plant more difficult to adapt (scale-down or scale-up). Modular automation turns it into a flexible system, allowing you to adjust the production quantity quickly and easily by removing modules (numbering down) or by adding modules (numbering up).
For our example, we’ll take the water filtration system design that has a central controller and control system and was once commonly used. The valve terminal is connected to it using a fieldbus as a remote I/O system with an integrated pneumatic part. The components for controlling the field devices are installed in the control cabinet.
Step 1: Dividing into subprocesses
These types of conventional water treatment systems can be easily modularised. To start with, the overall process is divided into subprocesses. A module is defined for each subprocess, which contains all the mechanical and automation technology components that are needed for autonomous operation.
Step 2: Modularising automation
The automation is modularised in the same way. The control cabinet components and the central controller (the process-based application software) are divided in such a way that each module is equipped with its own controllers, remote I/O components and pneumatic controllers.
Step 3: Co-ordinating the complete system
Once the modules have been connected to form a process-based system, each module makes its specific functionality available via a data interface in an encapsulated format. The operating mode, status, process measurement values, alarms, etc. can thus be read out and written so that the system functions.
In addition, you also need a process management system that co-ordinates the module functionalities across the complete system and facilitates the guidance of the processes. This can turn out to be a much leaner approach than with central controllers. As mentioned before, the process-related control functions are already contained in the modules themselves.
Step 4: Flexible adjustment of modular systems
Using the modules described, you can build systems in any design that meets your current needs and requirements, simply by adding modules that are identical in terms of construction and function. It is and remains flexible from the word “go”, in line with numbering-up instead of scaling-up.
Modular automation is relatively easy. With Festo, it is even easier. Our experts will be happy to advise you.
Arguments in favour of modular automation
The modularisation described here is based on the example of a water filtration system that used to be centrally controlled. However, the basic principle can be applied to other industry segments. And it isn't just the system operators that benefit from the flexibility that modular process automation from Festo offers. A modular concept represents a win-win situation for equipment manufacturers too.
Benefits for operators and OEMs
- Numbering-up/-down: Modular automation makes it significantly easier to modify the complete system. As a result, the engineering is completed more quickly and economically.
- Transparency: The individual modules from Festo are precisely defined units with a clear functionality.
- Flexibility: This also makes the modules easy to adapt. This simplifies and accelerates the integration of additional process steps.
- Simplicity: The modules contain their own specific application software. This reduces the complexity of the complete IT architecture.
- Autonomy: Festo modules are programmed with CODESYS in accordance with IEC 61131. This means there are no licence costs, and you are free to select the automation hardware of your choice.
- Synergy: OEMs can produce uniform modules, even in small quantities, and thoroughly test them before delivery. You thus benefit from economies of scale in terms of production and assembly, you reduce your costs and you can service the market at the right time.
Water technology is just the beginning
It’s anticipated that the design and engineering of process-based systems will drastically change. With an eye on Industry 4.0, the NAMUR Recommendation NE 148 has already formulated “Automation Requirements relating to Modularisation of Process Plants”. In other words, system operators and manufacturers across all process industries should test to see whether their systems can already be operated with modular concepts.

Valve terminal MPA-S with CPX terminal
Incredibly modular and versatile! The CPX interface on the valve terminal MPA is based on the bus system of the CPX and uses this serial communication system for all the solenoid coils and electrical input and output functions.