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 4

The Raspberry Pi Compute Module 4 (CM4) is a System on Module (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 CM4 is loosely based on the Raspberry Pi 4 Model B and can be supplied without the eMMC fitted, known as the Raspberry Pi Compute Module 4 Lite (CM4Lite). 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 2: Raspberry PI CM4 (Source)

The CM4 can be supplied with an onboard wireless module based on the Cypress CYW43455, supporting both 2.4 GHz and 5.0 GHz IEEE 802.11 b/g/n/ac wireless and Bluetooth 5.0 BLE. These wireless interfaces can be individually enabled or disabled as needed. For instance, in a kiosk application, a service engineer could enable wireless operation and then disable it once finished.

The CM4 has an onboard antenna. If used, it should be positioned in the product so that it is not surrounded by metal, including any ground plane. Alternatively, there is a standard U.FL connector on the module (see Figure 1) for connecting an external antenna. It also includes an onboard Gigabit Ethernet PHY — the Broadcom BCM54210PE. Some major features of this PHY include IEEE 1588-2008 compliance, MDI crossover, pair skew, and pair polarity correction.

A standard 1:1 RJ45 MagJack is all that is necessary to provide an Ethernet connection to the CM4. Typical wiring of a MagJack supports PoE, with added ESD protection. The CM4 has an internal PCIe 2.0 x1 host controller. While the Raspberry Pi 4 Model B connects this to a USB 3 host controller (using the VIA Labs VLI805), the CM4 allows the product designer to choose how the interface is used.

The CM4 supports two HDMI 2.0 interfaces, each capable of driving 4K images. If both HDMI outputs are used, each can drive up to 4Kp30. However, if only the HDMI0 interface is being used, images up to 4Kp60 are possible. It also supports two camera ports: CAM0 (2 lanes) and CAM1 (4 lanes), and two display ports: DISP0 (2 lanes) and DISP1 (4 lanes), with each lane supporting a maximum data rate of 1 Gbps. The CM4 can support up to three displays of any type (HDMI, DSI, DPI) simultaneously. The CM4 also dissipates less power than the Raspberry Pi 4 Model B, requiring less passive heat sinking.

b. Raspberry Pi Compute Module 4S

The Raspberry Pi Compute Module 4 SODIMM (CM4S) is a System on Module (SoM) (figure 3) containing a processor, memory, eMMC Flash, and supporting power circuitry. These modules allow designers to leverage the Raspberry Pi hardware and software stack in their own custom systems and form factors. The SODIMM form factor compute modules have 18 additional GPIO pins compared to the standard Raspberry Pi boards, for a total of 46, providing more options for designers.

The CM4S is loosely based on the Raspberry Pi 4 Model B. For cost-sensitive applications, it can be supplied without the eMMC fitted; this version is called the Raspberry Pi Compute Module 4 SODIMM Lite (CM4SLite). The CM4S shares the same form factor as the older Raspberry Pi Compute Module 3 and 3+, which are mechanically compatible with DDR2-SODIMM. This device is intended for industrial customers migrating from the Compute Module 3 or 3+, who wish to continue using the SODIMM form factor while taking advantage of the increased SDRAM capacity.

Figure 3: Raspberry Pi Compute Module 4S (Source)

Although the Compute Module 4 is generally considered the latest Compute Module, this is not actually the case. In 2022, the Raspberry Pi Foundation decided to make the Compute Module 4S available to selected customers due to the global chip crisis triggered by the COVID-19 pandemic, among other factors. The Compute Module 4S is characterized by its use of the same processor as the Compute Module 4, featuring the Arm Cortex-A72, but it retains the familiar SODIMM design as the board form factor. This module, therefore, does not have WLAN or a PCIe interface. While the module was initially available only with 1 GB of RAM, Raspberry Pi has been offering it with up to 8 GB of RAM since 2024, and it is now available to everyone. The Raspberry Pi Compute Module 4 has undergone extensive compliance testing and meets the required standards in many countries.

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 4

The fourth generation of the RevPi Connect is equipped with the Raspberry Pi Compute Module 4. With its quad-core Arm Cortex-A72 processor and up to 8 GB of DDR4 RAM, the RevPi Connect 4 receives a significant performance boost over its predecessors, enabling its use in entirely new application areas. Due to its modular design and integrated interfaces, the RevPi Connect 4 can be utilized for a wide range of tasks, whether as an industrial PC, industrial controller, edge gateway, or IIoT device.

Figure 4: RevPi Connect 4 (Source)

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). The RevPi Connect is equipped with either the Raspberry Pi Compute Module 4 or Compute Module 4S, depending on the version. 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. 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 5: EDA- CM4 industrial embedded computer (Source)

Figure 6: Block diagram showing the various peripherals of CM4 industrial (Source)

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.

c. 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 7: EpiSensor's Gateway (Source)

EpiSensor's Gateway (figure 7) 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 8: Industrial IoT Gateway system architecture (Source)

EpiSensor’s Gateway routes data from networks of wireless sensors (figure 8) 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.

d. 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 9: Strato Pi - Industrial Raspberry Pi Servers (Source)

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 9) 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 10 : Strato Pi Max (Source)

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.