This news contains information about another open-source industrial computer based on an inexpensive module—in this case Raspberry Pi. Again I ask (not predicting, but wondering) whether the new wave of engineers inevitably coming into this market will prefer something, small, inexpensive, programmable in familiar languages, and flexible due to advances in networking?
Phytools, a leading IIoT value-added reseller, announced Oct. 11 the publication of its first Revolution Pi White Paper, presenting the seven-year history and technical details of this revolutionary open-source industrial PC (IPC) in an easily-digestible medium. Built on the open, customizable, and commercial-off-the-shelf premise of Raspberry Pi, RevPi ruggedizes the versatile microcomputer for use in industrial applications.
IIoT-enabled IPCs like RevPi are ideal for automation, data connectivity, motion control, robotics support, machine visualization, and many more applications. From 2016 to the present, RevPi has cemented its place in the market by incorporating features such as:
- Modular form factors
- Operating system (OS) determinism
- A wide variety of input/output (I/O) modules
- Communications gateway functionality
- DIN-rail mounting capability
- And extensive support for third-party software, such as CODESYS soft PLC
The latest revision—RevPi Connect 4—was released in August 2023, equipped with a Broadcom BCM2711 processor and support for WLAN and Bluetooth communications. This most recent lineup addition also comes with a battery-buffered real-time clock and easier I/O expansion with a plug-and-play GUI.
RevPi base modules come equipped with USB, Ethernet, and HDMI connections. The two USB 2.0 sockets are each capable of supplying 500mA at 5V, alleviating the need for an external USB power supply when connecting parallel devices. The onboard RJ45 Ethernet connection is industrially hardened with suppressor circuits, and a micro-HDMI socket is included for connecting a monitor with sound output.
The RevPi delineates itself from Raspberry Pi with a portion of its operating system dedicated to deterministic control. Most PLCs in industrial settings leverage a real-time OS (RTOS) to ensure deterministic program execution through a dedicated routine, a rigorous treatment which is used to provide the robust and predictable performance necessary to avoid equipment failures and human harm.
A general-purpose PC OS is more versatile than that of a PLC because of its shareable—and usually more powerful—computing resources, which empower multi-tasking, customization, and processor-intensive operations. However, this flexibility presents a greater risk of OS disruption if one or more tasks becomes corrupted or overloads the processor, potentially leading to delays, instability, or a complete crash.
Revolution Pi uses a split OS, providing the determinism of an RTOS, along with the versatility of a standard OS. As a result, RevPi can be developed into an industrially viable small control system, a large scale IIoT platform, or elements of both simultaneously. Its scheduler—which controls the execution of tasks by the operating system—can be configured extensively to avoid networking or software resource delays, ensuring the best performance for real-time control and other critical or time-sensitive tasks.