Raspberry Pi in industrial automation

Industrial automation systems are complex assemblies of electronic components designed to control and monitor industrial processes.

They increase efficiency, reliability, and safety in manufacturing and other industrial operations. Industrial automation (IA) has seen remarkable growth, driven by advancements in electronics and information technology. This article will explore the current trends in industrial automation and highlight their impact on the electronics industry.

Requirements of IA

The key building blocks of an industrial automation system (figure 1) include sensors, controllers, actuators, human-machine interfaces (HMIs), communication networks, power supplies, drives, and safety systems. Sensors detect environmental changes and convert them into electrical signals. Controllers, such as Programmable Logic Controllers (PLCs) and Industrial PCs (IPCs), process input from sensors and execute control algorithms to manage actuators. The actuators, such as motors, solenoids, and pneumatic actuators, transform electrical signals into physical actions. The Human-Machine Interface (HMI) allows operators to communicate with the automation system, monitor processes, and input commands. Communication networks enable different parts of the automation system to interact with each other using protocols like Ethernet/IP, Modbus, and Profibus. Power supplies, such as AC/DC converters and uninterruptible power supplies (UPS), are essential for operating electronic components. Drives control the speed and torque of motors, using Variable Frequency Drives (VFDs) to manage motor performance. Safety systems, such as emergency stop buttons, safety relays, and light curtains, ensure the safety of operators and equipment.

Figure 1: Industrial automation system diagram (Source)

How Raspberry Pi is used for industrial automation

The Raspberry Pi is a versatile data acquisition system. It uses sensors to provide operators and engineers with intuitive, real-time visualizations of system performance by creating web-based dashboards. The many uses of the Raspberry Pi include:

• Functioning as an industrial control unit: The Raspberry Pi can potentially replace expensive and proprietary Programmable Logic Controllers (PLCs). It can be programmed to operate as a Programmable Logic Controller (PLC) for smaller-scale applications, offering tools for industrial control logic development.
• Predictive maintenance and cost reduction: The Raspberry Pi can be programmed to interact with accelerometers for monitoring vibrations in rotating machinery, allowing maintenance to detect potential issues in real-time. Additionally since AI and machine learning (ML) models run locally, latency and bandwidth requirements can also be reduced.
• Edge computing: The Raspberry Pi can process local data, making real-time decisions without a central server or cloud. This is useful for machine control or quality assurance systems. It can also run AI models for tasks like image recognition, anomaly detection, and predictive analytics, making it valuable for automated inspection systems, autonomous robotics, and real-time monitoring.
• IoT gateway: The Raspberry Pi can connect various industrial devices, sensors, and machines to the internet, enhancing system scalability. This allows engineers to monitor operations across multiple locations. Secure remote access solutions, like VPNs or SSH tunneling, can be implemented on the Raspberry Pi, minimizing the need for physical presence in hazardous or remote environments.
• Serving as an HMI system: The Raspberry Pi provides both hardware and web-based options making it a cost-effective solution for human-machine interface (HMI) systems, . Its touchscreen interface allows operators to control processes, monitor system status, and access alarms from the shop floor.

The Raspberry Pi can significantly improve energy efficiency, operational efficiency and reduce costs. By connecting the Raspberry Pi to cameras, a cost-effective CCTV system can be set up, and access control systems can be implemented using technologies like RFID, facial recognition, or biometric methods.

Raspberry Pi solution for industrial automation- compute module

The Raspberry Pi Compute Modules are compact, versatile system-on-module variants of the popular Raspberry Pi models, used in industrial and commercial applications such as digital signage, thin clients, and process automation. They offer a more streamlined and space-efficient design compared to the flagship Raspberry Pi models, making them suitable for a wide range of industrial and commercial uses. The modules come in various configurations with different memory and embedded Multi-Media Card (eMMC) flash storage capacities. The eMMC storage is soldered onto the board and includes additional features for enhanced reliability. Some "Lite" models do not include onboard storage. The Raspberry Pi Compute Module is a robust, industrial-grade device known for its small form factor, flexibility, and cost-effective performance.

Designed specifically for industrial and commercial environments, the Compute Module requires a "carrier board" for operation. The carrier board acts as an intermediary between the Compute Module and other components or devices, enabling its integration into a wide range of applications and systems.

a. Raspberry Pi Compute Module 5

The Raspberry Pi Compute Module 5 (Figure 2) is a system-on-module (SoM) that delivers the capabilities of the Raspberry Pi 5 in a form factor designed for embedded applications. It features a quad-core Arm Cortex-A76 processor, dual 4Kp60 HDMI outputs, Gigabit Ethernet, and an optional fully certified wireless module offering Wi-Fi® and Bluetooth connectivity. The Compute Module 5 is a powerful tool for modern industrial edge computing applications, offering enhanced processing capabilities for real-time process control, data acquisition, and machine learning at the edge. Its performance is reliable 24/7 and cost-effective, making it a popular choice for industrial automation and IIoT solutions. With various RAM and eMMC flash options, the Compute Module 5 enables users to harness the robust hardware and optimized software stack of the Raspberry Pi 5 in custom systems and form factors. It includes additional I/O interfaces and is available in variants without eMMC flash for greater flexibility.

Figure 2: Raspberry Pi Compute Module 5 (Source: element14, Newark)

b. Raspberry Pi Compute Module 4

The Raspberry Pi Compute Module 4 (CM4) (Figure 3) is a SoM that consists of a high-performance 64-bit quad-core processor (Broadcom BCM2711, quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz), memory, eMMC flash, and power circuitry. It allows designers to use the Raspberry Pi hardware and software stack in their custom systems and form factors. The electrical interface is provided via two 100-pin high-density connectors, and the new physical form factor has a smaller footprint due to the addition of new interfaces such as HDMI, PCIe, and Ethernet. Key features include a 64-bit quad-core processor, dual-display support, hardware video decode, up to 8GB of RAM, Gigabit Ethernet, USB 2.0, dual camera interfaces, and a PCIe Gen 2 x1 interface. The optional dual-band 2.4/5.0GHz wireless LAN and Bluetooth 5.0 have modular compliance certification, allowing the board to be designed into end products with reduced compliance testing. The CM4 also offers optional onboard eMMC storage of 8GB, 16GB, or 32GB.

Figure 3: Raspberry PI CM4 (Source: element14Newark)

Raspberry Pi IO board

Raspberry Pi IO Boards provide a way to connect a single Compute Module to a variety of I/O (input/output) interfaces. Raspberry Pi IO Boards are breakout boards designed for development or personal use, providing various functions such as powering the module, connecting GPIO to pin headers, connecting camera and display interfaces to FFC connectors, HDMI to HDMI ports, USB to USB ports, activity monitoring to LEDs, eMMC programming over USB, and connecting PCIe to connectors for storage or peripherals. Compute Modules are small, lacking ports and connectors. IO Boards provide a way to connect Compute Modules to various peripherals.

Figure 4: Raspberry Pi Compute Module 5 IO board (Source: element14Newark)

Figure 4 shows the Raspberry Pi Compute Module 5 IO board. It features a HAT footprint with a 40-pin GPIO connector, PoE header, 2x HDMI and 2x USB 3.0 ports, Gigabit Ethernet RJ45 with PoE support, M.2 M key PCIe socket, microSD card slot, MIPI DSI/CSI-2 combined display/camera FPC connectors, real-time clock with battery socket, four-pin JST-SH PWM fan connector, USB-C power (using the same standard as Raspberry Pi 5), and jumpers to disable features like eMMC boot, EEPROM write, and USB OTG connection.

A real use-case solution of using Raspberry pi compute module in industrial application

a. Revolution Pi industrial computers

Revolution Pi is an open, modular, and inexpensive industrial PC based on the well-known Raspberry Pi. It is the first truly industry-compatible IPC based on Raspberry Pi. Housed in a slim DIN-rail casing, there are three available base modules that can be seamlessly expanded with a variety of suitable I/O modules and fieldbus gateways. By using the Raspberry Pi Compute Module, the company was able to develop a robust and industry-compatible system that meets all important industrial standards, including IEC 61131-2. Depending on the application’s requirements, the RevPi base modules can be easily extended with expansion modules such as digital and analog I/O modules and fieldbus gateways.

Revolution Pi is an open system where anyone can install their own software. It comes with a customized version of Raspberry Pi OS, which includes modifications such as a real-time kernel patch and a process image. Individual applications can be programmed via Node-RED, Python, or directly in C. You can also build a custom image for your system. In addition to writing your own code, off-the-shelf software solutions such as CODESYS can be used to realize your project. The devices already have client and server capabilities for the popular Modbus RTU and Modbus TCP network protocols. Collecting sensor data, processing it, and sending the processed data to a cloud platform is one of Revolution Pi's strengths, as certified by major cloud providers.

RevPi Connect 5

RevPi Connect 5 industrial computers is a powerful device built using Raspberry Pi Compute Module 5, with faster and more versatile, ideal foundation for modern industrial edge computing. It serves multiple functions, including DIN rail mounted industrial PCs, compact PLC, edge computing devices, and IIoT gateways. The RevPi Connect 5 (Figure 5) not only incorporates the new Compute Module 5 but also introduces advanced features including up to two CAN FD interfaces — a high-speed industrial communication protocol for real-time data transmission — and two Gigabit Ethernet ports, with the option to add two more via expansion module. Revolution Pi offers a range of digital and analogue I/O expansion modules, as well as fieldbus gateways supporting popular protocols like PROFINET or EtherCAT. The CM5-based devices set new standards with enhanced CPU and GPU performance, integrated USB 3.2 controller, and improved PCIe controller.

Figure 5: Industrial-grade platform RevPi Connect 5 (Source: Revolution PI)

KUNBUS is expanding its portfolio with CM5-based devices, offering a range of solutions from entry-level variants based on Compute Module 4S, to high-performance devices featuring Compute Module 5. The RevPi Connect 5 is a compelling choice for industrial automation and IIoT solutions requiring computational power and reliability.

The open-source IIoT gateway RevPi Connect provides users maximum freedom when implementing IIoT projects, thanks to its open platform concept (including full root access). A specially modified version of Raspberry Pi OS with a real-time patch is available as the operating system. Common IIoT protocols, such as MQTT and OPC UA, are supported to transfer machine data directly to the cloud

b. One-Box.tv/pro25 from TBS-Technology

The One-Box.tv/pro25 is a compact mini server designed for continuous 24/7 operation based on the Raspberry Pi Compute Module 5. It is integrated with a Broadcom BCM2712 quad-core Cortex-A76 (ARM v8) 64-bit processor at 2.4 GHz, having RAM capacity of 2GB, 4GB, or 8GB of LPDDR4-4267 SDRAM with ECC, and storage options of 16GB or 32GB eMMC or external microSD card support. It features four PCI Express slots, allowing it to support various standard PCIe half-size plug-in cards. The slim 1U design makes it ideal for installation in 19-inch server or network cabinets, offering an efficient solution for space-constrained environments.

Figure 6: Compact mini server - One-Box.tv/pro25 (Source: TBS-Technology)

The front panel features a 128x64 dot matrix OLED display with status LEDs and buttons for quick monitoring and configuration. Connectivity options include 2x HDMI 2.0 ports, Gigabit Ethernet, and 2x USB 3.0 ports for high-speed data transfer. The Optional features include Wi-Fi and Bluetooth 5.0, with an external antenna mount on the rear panel. Power requirements include an AC input of 110V–230V, power consumption ranging from 10 to 150 watts, and up to 25 watts per PCIe slot. The One-Box.tv/pro25 is designed for robust operation, operating within a temperature range of 50 °C to 80 °C.

c. EDA TECHNOLOGY - CM4 industrial embedded computer based on raspberry pi CM4

EDA Technology offers Raspberry Pi-based industrial computer solutions, along with custom design and manufacturing services for customers in IoT, industrial control, automation, green energy, and artificial intelligence applications.

The CM4 Industrial is an embedded industrial computer based on the Raspberry Pi Compute Module 4. The system can be configured with 1GB, 2GB, 4GB, or 8GB of RAM and 0GB, 8GB, 16GB, or 32GB of eMMC storage, depending on the application, and supports booting from an SD card. It offers a variety of industrial communication interfaces and functions, including multi-channel RS232, RS485, multi-channel high-precision ADC, isolated I/O input, relay control, battery-backed real-time clock, and alarm buzzer. The device also provides robust communication capabilities with one Gigabit Ethernet interface featuring PoE functionality, a 10/100M network port, a 4G/LTE module, certified 2.4/5.8G dual-band WiFi, and Bluetooth, with support for external antennas. The CM4 Industrial supports two CSI interfaces, one DSI display interface, and one HDMI interface. Additional features include an on-board 32Mb serial Flash for storing system data, a wide power supply range, V1.4 version is 9~36V, V1.1~V1.3 version is 9~18V, and ESD protection for critical interfaces. Target Application include IOT gateway, Industrial control, Advertising display, Intelligent manufacture.

Figure 7: EDA- CM4 industrial embedded computer (Source: EDA Technology)

Figure 8: Block diagram showing the various peripherals of CM4 industrial (Source: EDA Technology)

The conventional input power supply for the CM4 Industrial is 12V, with the input range for hardware version V1.4 being 9–36V, and for hardware versions V1.1–V1.3 being 9–18V. It is recommended to use a Cat6 (Category 6) network cable in conjunction with the adaptive 10/100/1000Mbps Ethernet interface on the CM4 Industrial. The device includes both a reset button and a user button. The CM4 Industrial also features an adaptive 10/100Mbps Ethernet interface, located next to the USB Type-A double-layer socket and extended by USB 2.0. There are two USB 2.0 Type-A interfaces on the CM4 Industrial, capable of transmitting data at up to 480 Mbit/s. It is equipped with a standard HDMI Type-A interface for direct connection to an HDMI display and includes a micro SD card slot for use with CM4 Lite, supporting 4G LTE through a standard SIM card.

The CM4 Industrial shell features two standard SMA antenna interfaces, corresponding to the 4G antenna and the WiFi/BT antenna, respectively. It also includes a double-pole double-throw relay onboard, with the interface labeled J47. The CM4 Industrial has a MIPI DSI interface corresponding to the DSI1 display output of the CM4, as well as two MIPI CSI camera interfaces supporting Raspberry Pi's official 5MP–8MP camera modules. It also provides the plate_number_5 GPIO, which is compatible with Raspberry Pi HATs and supports various standard Raspberry Pi extension accessories.

The CM4 Industrial's Mini PCIe expansion interface can accommodate peripheral modules such as 4G, 5G, NPU, etc., offering 1-lane PCIe Gen2 with a speed of 5Gbps and a USB 2.0 Host interface. The gigabit network port of the CM4 Industrial supports PoE power supply. The device also supports Bluetooth 5.0 and includes a Mini PCIe slot for 4G LTE module connection, supporting a wide range of frequency bands through different 4G module variants.

d. EpiSensor energy management - Industrial IoT Gateway based on Raspberry Pi CM4

EpiSensor, in its endeavor to create an IoT energy service infrastructure layer, used the Raspberry Pi Compute Module 4 (CM4). EpiSensor is working on providing grid flexibility by aggregating multiple assets into Virtual Power Plants (VPPs) through demand response programs. VPPs aggregate distributed energy resources (DERs) for sustainable energy strategies. DERs, such as batteries, EV chargers, UPS systems, and small-scale resources like intelligent appliances, allow EpiSensor Gateway's functionality—including machine learning, device management, and advanced networking applications—to be customized.

Figure 9: EpiSensor's Gateway (Source: EpiSensor}

EpiSensor's Gateway (figure 9) is a compact but powerful and rugged device that sends data directly to the IoT platforms of customers and partners from networks of wireless sensors. It is a secure embedded computer with an IoT app store and many wired and wireless communications interfaces: ZigBee, Wi-Fi®, Bluetooth, 4G cellular, LoRa, GPS, CAN bus, and RS-485," Brendan says. EpiSensor has worked hard to automate many of the configuration steps that would normally be done by experts on customer sites, so the Gateway essentially configures and tests itself. "EpiSensor's Gateway is at the core of our advanced IoT solutions."

As the Gateway gathers data from wireless nodes in real-time, the information is made available via the Gateway web interface and mobile apps. It allows all of the nodes and sensors to be remotely monitored and managed via the API of the Gateway or using Core, EpiSensor's device management platform, making it easier for customers to run multiple energy services programs.

Figure 10: Industrial IoT Gateway system architecture (Source: Episensor)

EpiSensor’s Gateway routes data from networks of wireless sensors (figure 10) to the software platforms of customers and partners – no sensor data passes through EpiSensor servers in the process.

The Gateway can be deployed within a corporate network, or isolated automation network, behind NAT and firewalls. The data the system produces is yours, and yours only.

The huge benefit of EpiSensor’s IoT technology is that it can easily be deployed and integrated with systems on customer sites such as existing building management systems (BMS) or SCADA, as well as systems running in the cloud that provide complete energy management or demand response solutions.

EpiSensor’s Industrial IoT Gateway manages networks of EpiSensor wireless nodes and provides users with an intuitive web interface to quickly and easily build complete Industrial IoT solutions. The Gateway can be configured to push sensor data to edge or cloud software applications for archiving, and analysis and visualisation. Monitor and manage large networks of EpiSensor wireless nodes from the Gateway’s web interface. Take actions like restarting or factory resetting a wireless node, upgrade firmware, sync, and enable and configure each ‘sensor’ (which is an individual feed of data) to report data the way you want it to.

e. Sfera Labs (Strato Pi, Exo Sense Pi)- Strato: Industrial Raspberry Pi Servers

Strato Pi Max is a highly versatile industrial server based on the Raspberry Pi Compute Module 4, suitable for professional and industrial applications where reliability and service continuity are vital. It is housed in a compact DIN rail case and can be used for a wide range of applications, including data acquisition and control, home and building automation, access control, hotel room control solutions, environmental monitoring, and many others.

Figure 11 : Strato Pi - Industrial Raspberry Pi Servers (Source : Sfera Labs)

It is available in two versions:

• Strato Pi Max XL, with four expansion slots and housed in a 9-module DIN rail case
• Strato Pi Max XS, with one expansion slot and housed in a 6-module DIN rail case

Strato Pi Max XL (figure 12) is an extremely versatile industrial server based on the Raspberry Pi Compute Module 4, designed for use in professional and industrial applications where reliability and service continuity are key. It is housed in a compact DIN rail case and can be used for an extensive range of applications, including data acquisition and control, home and building automation, access control, hotel room control solutions, and environmental monitoring, among others. Both versions come pre-installed with the Raspberry Pi Compute Module 4 or the Zymbit Secure Compute Module (SCM). An optional Compute Module 4 Antenna Kit can be fitted on the top side of the enclosure and internally wired to the Compute Module.

Figure 12 : Strato Pi Max (Source: Sfera Labs)

The Strato Pi units have several hardware features that make it ideal for use in professional and industrial applications where service continuity and reliability are important requirements. Strato Pi complies with the industry standards for electromagnetic compatibility, electrical safety and emission. It can easily integrate industry standard communication buses and protocols.