Controllino is the name of a new controller family that attracted the attention of electronics supplier Conrad Business Supplies at its trade fair premiere at SPS IPC Drives in November last year. This is a new device concept based on the Arduino open source platform. This means that Controllino is based on the same Amtel processors as the Arduino family and is also based on this platform in terms of its schematic structure and interfaces, but has also been made fit for industrial purposes by the Austrian company SG-Tronic. The main functions include a direct processor connection with 4000 V ESD protection on all connections, a range of interfaces such as SPI, I²C, RS232, RS485 and an integrated real-time clock that can be switched on and off. A USB port on the front allows for easy programming.

The Controllino family currently comprises three different models: Mini, Maxi and Mega. The Mini version offers various inputs and outputs (six relay outputs, eight analog/digital inputs and eight digital outputs) in a compact housing (94.5 mm × 59.4 mm × 36 mm). The Maxi module offers more flexibility (10 relay outputs, 12 analog/digital inputs and 12 digital outputs) as well as an Ethernet connection and a second RS232 interface. The highest specification is the Mega module, which can handle currents up to 30 A and offers 16 relay outputs, 24 analog/digital inputs, 12 high-side-switch digital outputs and 12 additional half-bridge digital outputs.

When asked what opportunities open-source-based controllers would have in the industrial environment apart from development projects, Markus Obermeier, Product Manager at Conrad Business Supplies, replies: "The Controllino devices can basically be used for the simplest switching tasks through to complex and time-critical applications, for example in food industry systems. We see no limits here and no extensive IT knowledge is required to use these controllers. However, the responsibility always lies with the person who implements the application. Of course, they should know what they are programming. This means, for example: If an application is in a safety-relevant environment, care must be taken during programming to ensure that the relevant applicable standards are adhered to."

The initial spark: a faulty coffee machine

Behind the developers of the Controllino control units is SG-Tronic, a small 8-man company from Innsbruck that focuses on customer-specific electronics development. Managing Director Marco Riedesser explains how the idea came about: "At the end of 2013, I was faced with the problem of repairing my brother-in-law's broken but very expensive espresso machine. I quickly realized that designing new electronics tailored to his needs would be too expensive. I first came into contact with the Arduino world through an internet search and quickly recognized the advantages of the platform. An Arduino board and three relays were all I needed to repair the espresso machine. But then I asked myself: Why isn't there a professional control solution based on Arduino yet?"

New for embedded world 2016 - The communication expansion modules for Controllino: The modules can be connected not only via the RS485 interface, but also via a serial interface at 3.3/5 V level.

© SG-Tronic

What followed was the launch of a Kickstarter campaign through which SG-Tronic, as a professional hardware and software developer, finally developed the first Controllino series, which was on show for the first time at the Conrad stand in Nuremberg. But what is so special about this new control platform? Marco Riedesser's answer: "An Arduino board is basically just a processor on a circuit board with just enough components surrounding it to make it run and be programmed. The pins of the processor are led out unprotected. Although today's processors are already well protected against ESD, this is not sufficient for the requirements of industrial automation. The same applies to inputs and outputs, which only supply 5?V at around 20 mA. The I/Os of the Controllino controller are different: with our PWM-capable digital outputs, we control up to 2 A per channel. This means that we can supply up to 30?A to actuators via the individual channels and are therefore able to drive suitable DC, brushless and stepper motors directly."

Riedesser cites the plug connectors on the top as another unique selling point: "These make it possible to make contact at 5-volt level, just like on an Arduino board, and thus connect to the familiar electronics world of displays, sensors, wireless modules and so on." Last but not least, Riedesser sees the IoT capability of the Controllinos as a decisive advantage over the many micro-controllers and intelligent control relays available on the market: "When a prototype of an IoT application is developed today, it is developed with the common open source platforms and not on a conventional controller that is not capable of doing so." Last but not least, Controllino offers the widest range of programming options - including IEC 61131, a graphical drag & drop interface, a real-time tool, an 'old-school' ladder diagram tool and a Labview plug-in.

When asked about his business expectations for the new control platform, Riedesser is optimistic: "In total, we are planning to produce around 50,000 to 75,000 units over the next two to three years with our expanding product range. Our industrial customers already include VW, Audi, Sony, Dyson, Mattel and Cummins - to name just the best known." In order to be able to handle this in terms of sales and production, Controllino was spun off from SG-Tronic into its own company - Controllino GmbH - in February of this year.

Also in February, SG-Tronic presented the first expansion modules for the Controllino platform at the embedded world trade fair in Nuremberg - namely communication modules for Ethernet/IP, Devicenet, Profinet/Profinet, Ethercat, Modbus TCP, Modbus RTU, CC-Link and CANopen. This means that in future the controllers can be integrated into virtually any industrial environment and also into larger systems.

Programming according to IEC 61131-3

If you want to develop software for Controllino CPUs or program these controllers, you can usually use the open source programming environment ArduinoIDE, which is based on C/C++. The open source compiler (avr-gcc) also allows the license-free generation of user code, so that developments on host systems other than Windows - for example on Linux - are also possible without any problems.

But what if the user prefers to work in their familiar IEC 61131-3 world? Logi.cals, another Austrian-based system house, has addressed this question and developed a customized solution based on its own logi.CAD 3 development environment for the Arduino platform with its limited resources in terms of computing power and processor speed. In addition, the existing logi.RTS PLC runtime system was adapted so that it can be executed on the Controllino controllers.

Using a corresponding interface, existing C code created with the Arduino IDE, for example, can be integrated directly into the PLC code generation of logi.CAD 3 in just a few steps. The Controllino-Lib was created using this technology. This library contains a large number of blocks that support the special functions of the Arduino. Some of the functions are already available in the Arduino IDE and have been transferred to the IEC 61131-3 programming world with logi.CAD 3. These include functions for controlling the PWM outputs, programming the SPI bus or connecting I/O modules via the I²C bus.

Dieter Goltz, Logi.cals: "The form factor of Controllino and the possibilities of simple IoT connection via the MQTT protocol commonly used in IT definitely speak in favor of industrial use."

© Logi.cals

So much for the technical features. But does mechanical and plant engineering really need solutions like the Controllino? - After all, the market is full of small(est) PLCs and intelligent control relays! Dieter Goltz, Managing Director of the German branch of Logi.cals, has a clear opinion on this: "The competitors of Controllino & Co. are certainly established control systems such as Logo from Siemens and Easy from Eaton. However, what makes Arduino-based solutions particularly interesting as an alternative is their unbeatable price-performance ratio. In addition, the flexibility is significantly greater and the parallel usability of 'C' and IEC 61131-3 also makes the Controllino interesting for industrial purposes. Last but not least, there are plans to connect the emBrick system from Imacs as a fieldbus. This has a special form factor and thus opens up new I/O possibilities for the controller. The modules are mounted next to each other on a base board and connected to each other via a jumper. The practical 'mixing ratio' of inputs and outputs on one module enables a precise adaptation to the task, which is also reflected in a particularly attractive price level."

When asked about the specific costs of the industrial programming solution for the Controllino, Goltz replies: "The RTS runtime license accounts for around 15?% of the sales price of the controller. Use of the logi.CAD 3 compact programming software is free of charge. If the user wants to use additional functions beyond this entry-level solution, such as integration into various version and revision control systems, they must use the 'logi.CAD 3 professional' version, which is subject to a charge."

Open source in industrial quality

PLCs and panel PCs from Industrial Shields can be programmed in the same way. This enables developers to go from prototype to industrial application with the same flexible program codes.

© RS Components

In addition to Conrad Business Supplies, RS Components was another distributor at SPS IPC Drives 2015 to address the topic of control with open source platforms.

In September last year, RS Components entered into a distribution agreement with Industrial Shields and accordingly had their product range of PLCs and panel PCs on show in Nuremberg. In detail, Industrial Shields' PLC portfolio includes the entry-level model 'Ardboc compact' based on the Arduino Leonardo board and 'M-Duino', an industrial or modular PLC based on the Arduino Mega board. Both are supplied with 12 to 24 V(DC) and can be programmed and controlled via the Arduino IDE platform. The Ardbox compact PLC is available in two different versions with up to ten I/Os including digital, analog, PNP, PWM and relay. Five versions of the M-Duino series allow up to 58 I/Os. If more I/Os are required, there is the option of communication between two controllers via an I²C bus. Other communication interfaces are Ethernet, USB, serial interface, RS232 and RS485.

The aforementioned panel PCs are touchscreens with a screen diagonal of 26 cm (10.1 inches), which are available in three different versions: HummTouch Android and HummTouch Linux enable open source programming via Android OS or Linux OS on the ARM-based Hummingboard single-board computer. Finally, the Touchberry PI is based on Raspberry PI B+ and runs on the Raspbian Linux operating system. Simple programming via the USB port is carried out using the Arduino IDE interface.