It all started with the first version of a single-board computer called “Raspberry Pi”, developed by a charitable foundation in Great Britain. Since its launch in 2012, originally designed as a low-cost tool for students, the Raspberry Pi has become an incredible success. On its fifth birthday at the end of February, the foundation announced its latest product, the Raspberry Pi Zero W — credit card-sized board PC with wireless LAN and Bluetooth, priced at only $10!
Around this compact and inexpensive computer, a worldwide developers’ community and a whole ecosystem have been established and the community is still growing. More than eight million IT experts and hobbyists around the world are developing and modifying applications, devices, software and accessories for the Raspberry Pi family.
For industrial applications, a compute module series was introduced in 2014. The latest versions are the Raspberry Pi Compute Module 3 (CM3) and 3 Lite (CM3L). They are DDR2-SODIMM-mechanically-compatible systems on module (SoM) containing processor, memory, eMMC Flash (CM3 only) and support power circuitry. These modules allow designers and developers to leverage the Raspberry Pi hardware and software stack for their own custom systems and form factors.
Visiting Germany’s SPS IPC DRIVES fair last October, I was impressed by companies offering open, modular and comparatively cost-effective industrial PCs based on the Raspberry Pi Compute Module. For example, Kunbus, a company specialized in fieldbus and industrial Ethernet products in the automation sector, presented its solution called Revolution Pi. According to the company, the solution is ready for tough industrial environments as a “real” industrial PC that meets the EN61131-2 standard. It can be complemented with IO modules and suitable fieldbus gateways for connecting it to an industrial network. USB, Ethernet and HDMI connections are already on-board. The power supply uses industry standard 24 volts. The industrial computer runs with the Raspi standard operating system called Raspbian. Thanks to root access, users can run their own programs. In co-operation with various software producers, they also offer control and SCADA software that turn it into a small industrial controller.
Another example is the company MASS, which offers a ready-to-run panel PC with a 7-inch capacitive multi-touch display (800 x 480 pixels, 10-finger operation) and solid metal housing built for harsh industrial environments.
Raspberry PI modules offer flexible programming, customizable signal types and easy adaptation to existing installations — real benefits to the industrial world. Another advantage of such systems is that they are great low cost and flexible alternatives to usual industrial devices, for example, by adding remote control and monitoring functionality to small legacy industrial systems.
But there are still concerns about the use of such development boards in the industrial environment. The three most common are:
- Robustness in industrial environments
- Industrial standard communication protocols
Addressing these concerns, there are already several ruggedized versions available and more will follow.
Safety is probably the most controversial and discussed topic about such solutions. There is no simple answer; it depends on many factors and requires a change in the mind-set of engineers. The safety of an industrial application does not only depend on the IPC or PLC — it’s a matter of the integrity of the whole system. How the systems, software and safety are implemented has to be considered during the design phase of a project.
Flexibility is a big advantage of such boards. The Modbus foundation has developed and published specific libraries to allow the boards to communicate via their protocol. Modbus is a serial communications protocol developed by Modicon (now Schneider Electric) for its programmable logic controllers (PLC). It has become a common standard and is adopted by many automation manufacturers such as Omron, Schneider and Mitsubishi. Modbus allows many different devices connected to the same network to communicate together regardless of the manufacturers. With the arrival of IIoT, interoperability of devices from different manufacturers has become even more important.
We are convinced that Raspberry PI in their ruggedized version can be a valuable and reliable alternative to well-established industrial devices (e.g. to connect legacy industrial systems to the IIoT). At this week’s Embedded World show in Nuremberg Germany, we expect to see more solutions based on Raspberry Pi modules and we are looking forward to seeing industrial use cases.