Roadtesting Arduino Opta - my first Arduino Micro-PLC

Table of contents

RoadTest: Review the Arduino Opta Micro-PLC

Author: MARK2011

Creation date:

Evaluation Type: Evaluation Boards

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: VersaMax Micro; TSX Micro Schneider; Siemens LOGO; Moeller/Eaton EASY; SBC PLCs

What were the biggest problems encountered?: Some doubts running Arduino PLC IDE. I was unable to program Arduino Opta in that environment. I had constant hang-ups/ freezing. An essential procedure of Memory-partitioning wasn't clearly communicated (or I didn't read instructions carefully)

Detailed Review:

Review of testing the Arduino Opta Micro-PLC

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I just wanted to take a moment to say a huge thank Arduino, Finder and element14 Team for inviting me to participate in the Roadtest project and for providing the Arduino Opta Micro-PLC.

It’s been an exciting and insightful experience, and I really appreciate giving me that chance to dive into such a great product.

The Opta has proven to be a fantastic tool, and I’ve enjoyed testing its features and capabilities.

I’m looking forward to sharing my findings and seeing how this technology will continue to shape the future of automation.

Thanks again for this wonderful opportunity — it’s been a pleasure to deal with this interesting device

Introduction

The Arduino Opta Micro-Programmable Logic Controller (PLC), developed in collaboration with Finder, represents a cutting-edge solution for industrial automation and the Industrial Internet of Things (IIoT),  offering robust hardware, support for IEC 61131-3 programming, and IoT connectivity options. Combining the reliability and flexibility of the Arduino platform with industrial-grade performance and security, the Opta PLC is designed to meet the needs of modern automation systems. It offers a range of capabilities for real-time control, connectivity, and secure cloud integration, making it an ideal choice for applications across various industries, from manufacturing and process control to predictive maintenance. Testing the Opta allowed me to evaluate its key features, such as input/output functionality, connectivity, and compatibility with industrial communication protocols like Modbus. This was possible because I received the Opta variant with Modbus for testing.

If I have to start, it's best to begin at the beginning. And the beginning lies in the story of two companies.

Finder is an Italian company founded in 1954, specializing in the design and manufacturing of high-quality industrial automation components, including relays, timers, and PLCs. Known for its innovative products, Finder has been at the forefront of providing solutions for control systems, with a focus on reliability and ease of use. The company's PLCs, are designed for industrial automation and IoT applications, combining advanced features with user-friendly programming environments.

Arduino is an open-source electronics platform founded in 2005, designed to make it easy for people to create interactive projects. It consists of hardware (microcontroller boards) and software (Arduino IDE), enabling users to program devices to interact with sensors, lights, motors, and other electronics. Arduino’s simplicity, accessibility, and community-driven development have made it a popular choice for hobbyists, educators, and professionals in fields such as automation, robotics, and IoT.

This report documents the testing of the Arduino Opta Micro-PLC, focusing on its core features, performance, and functionality. The primary objective of the testing was to evaluate its programming capabilities, I/O performance, real-time control, security features, and communication protocols, including Modbus RTU and Modbus TCP. Additionally, the integration of IoT connectivity, secure OTA firmware updates, and the device’s compliance with industrial standards were tested to ensure the Opta’s suitability for industrial environments.

The results of this testing confirmed the performance, reliability, and potential use cases of the Arduino Opta Micro-PLC in various automation and IoT-driven applications. The report outlines the testing process and results for the Arduino Opta Micro-PLC, specifically the model equipped with Modbus protocol support. The aim was to evaluate its performance, connectivity, and compatibility within automation tasks requiring Modbus communication, using the RS-485 interface. The findings provide insights into the capabilities and reliability of the Opta Micro-PLC in Modbus-enabled environments.

The  Modbus is a serial communication standard and has become a de facto standard communication protocol and is now a commonly available means of connecting industrial electronic devices. In Modbus RTU and Modbus ASCII RS485 is used as the physical layer. It is possible to use an Opta as Slave (and with some restrictions also as Master) in Modbus applications, but a RS485 interface is needed.

Modbus protocol support is a key feature that enables reliable and standardized communication in industrial automation. Modbus offers benefits such as easy integration, interoperability with various devices, and robust data exchange over RS-485, making it ideal for real-time monitoring and control. My testing focused on assessing the performance and connectivity of the Opta Micro-PLC within Modbus-based systems.

 

The Arduino Pro Family

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The Arduino Pro Family is a collection of industrial-grade development boards and embedded solutions designed to bring the power of Arduino's open-source ecosystem to the world of industrial automation and the Industrial Internet of Things (IIoT). These products are aimed at professionals in sectors such as manufacturing, automation, energy, and smart cities, offering a combination of reliability, performance, and flexibility.

Arduino has traditionally been known for its accessible, hobbyist-friendly platforms, but the Arduino Pro Family is specifically engineered for more advanced and professional applications, with a focus on industrial use cases. The key to its success is its ability to bring easy-to-use development tools alongside rugged, reliable hardware designed for industrial environments.

The Arduino Pro family includes boards and modules for a variety of industrial applications:

  • Edge control
  • Machine learning
  • Industrial automation
  • Process monitoring
  • IoT applications

With products like the Arduino Opta, Portenta, MKR, and Industrial Shields, the Arduino Pro Family provides powerful processing, real-time control, data collection, and IoT communication capabilities that can be deployed in factory automation, remote monitoring, predictive maintenance, and much more.

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Leading Products in the Arduino Pro Family

a. Arduino Opta Micro-PLC

The Arduino Opta is one of the flagship products in the Arduino Pro Family and a true industrial-grade programmable logic controller . It is developed for real-time control in industrial environments and integrates with both traditional and IoT-based systems. The Opta is designed with robust industrial communication standards like Modbus RTU (RS-485) and Modbus TCP (Ethernet), and it is particularly suited for applications like smart buildings, process control, and automated production lines.

b. Arduino Portenta Series

The Portenta series is designed for applications that require higher processing power and advanced capabilities such as machine learning and edge computing. The Portenta H7 features a dual-core Arm Cortex-M7 and M4 processor, providing the processing power necessary for AI and real-time control tasks as Machine Learning at the Edge; supports various communication protocols such as Ethernet, Wi-Fi, Bluetooth, and LoRa.

c. Arduino MKR Series

The MKR series is a family of smaller, low-power boards designed for IoT applications. While these devices are not as rugged or powerful as the Opta or Portenta series, they offer great flexibility for remote monitoring, control, and sensor networks in industrial environments. The MKR boards are optimized for low-power operation, which makes them ideal for battery-powered sensors or long-term monitoring applications. Support Wi-Fi, LoRa, NB-IoT, and GSM.

 

The Arduino Pro line is designed for more demanding industrial and commercial applications, and the Arduino Opta Micro-PLC fits this profile perfectly. While traditional Arduino boards such as the Uno or Mega are great for prototyping and simple applications, the Opta Micro-PLC offers much higher performance, which is essential for complex industrial tasks.The lower-end Arduino models rely on simpler microcontrollers like the ATmega328P, which offer lower clock speeds and less processing power, making them unsuitable for real-time industrial applications. Other Arduino Pro devices, such as the Portenta H7, may offer similar levels of processing power but lack specialized industrial communication features like RS-485 or high-power relay outputs, which make the Opta specifically suited for PLC applications.

 

The Arduino and Finder Partnership: A Key to Industrial-Grade Reliability

The collaboration between Arduino and Finder represents a strategic partnership that combines Arduino's open-source platform and Finder's expertise in industrial automation and switching technology. This partnership aims to deliver powerful, secure, and reliable industrial solutions for automation systems, smart factories, and IIoT applications.

a. Finder’s Expertise in Industrial Relays and Switchgear

Finder is renowned for its high-quality industrial relays and switching technology, with decades of experience in providing reliable solutions for industries like automotive, energy, telecommunications, and process control.

  • High-Power Switching: Finder's relays and switching devices, integrated into products like the Arduino Opta, enable the control of high-power machinery and industrial systems, ensuring safe and efficient operations in demanding environments.
  • Durability and Reliability: Finder’s components are designed to withstand harsh environments, including extreme temperatures, moisture, vibrations, and electrical noise, which are common in industrial and automation settings.
b. Arduino Opta: Combining Arduino’s Flexibility with Finder’s Durability

The Arduino Opta Micro-PLC is a perfect example of how the Arduino-Finder partnership enhances the capabilities of industrial automation systems. By integrating Finder’s industrial-grade components with Arduino’s flexible and programmable platform, the Opta provides both ease of use for developers and reliability for industrial systems.

  • Relay Integration: The Opta comes equipped with high-power relay outputs (up to 3 kW), making it suitable for controlling industrial machinery, motor drivers, and other high-power devices.
  • Secure Communication: The inclusion of Microchip’s secure element (ATECC608B) in the Opta ensures secure communication for IoT integration, which is essential for industrial environments where data security and device integrity are critical.
  • Ease of Integration: Arduino’s vast ecosystem of libraries and tutorials makes it easy for engineers to integrate the Opta with existing industrial systems, while Finder’s industrial expertise ensures that the product meets rigorous industrial standards for durability and performance.
  • Scalable IoT Solutions: The partnership helps Arduino create IoT-enabled industrial devices that can be easily scaled to meet the needs of both small-scale automation projects and large industrial networks.

Unboxing

 

The film below captures the exciting unboxing experience of the Arduino Opta Micro-PLC! The device arrived securely and neatly packed, and its sleek, professional design immediately impresses. Every detail, from its aesthetic build to the robust packaging, highlights its quality and readiness for applications. A promising first look at a powerful tool for automation!

Video: 01.unboxing.OPTA.

The unboxing process assessing summary:

    Packaging: Condition of the OPTA and packaging integrity was perfect.

    Inclusions: In the box I found OPTA device, shorted “Getting started” manual (leaflet), no additional accessories

    Visual inspection: All looked great, no physical damage or defects.

 

Documentation Review and Assessment

 

Overview of User Manuals, Technical Documentation, and Installation Guides for Arduino Opta Micro-PLC

Although the box only contains a simplified manual, Arduino Opta Micro-PLC is supported by extensive documentation, easily accessible on the product page

The Arduino Opta is designed for industrial automation and IIoT (Industrial Internet of Things) applications, and as such, it comes with a comprehensive set of user manuals, technical documentation, and installation guides to ensure smooth setup, configuration, and operation. These documents provide crucial information for both engineers and developers to get the most out of the device.

Here is a breakdown of the key user manuals, documentation, and installation guides that support the Arduino Opta Micro-PLC

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https://docs.arduino.cc/hardware/opta/#tutorial

Opta User Manual

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The user manual for the Arduino Opta Micro-PLC provides a comprehensive overview of the device covering its major hardware and software elements, its capabilities, and step-by-step instructions on how to use it for applications. This manual is targeted toward users who are setting up and operating the device in their systems.

https://docs.arduino.cc/tutorials/opta/user-manual/

 

  • Introduction to the Arduino Opta: This section introduces the Opta Micro-PLC, explaining its purpose, industrial use cases, and the key features that make it suitable for automation and IoT systems.
  • Hardware Overview: It details the physical components of the device, such as the STM32H747XI microcontroller, I/O ports, Ethernet interface, and RS-485 terminal connector for Modbus RTU communication.
  • Setup Instructions: Provides step-by-step instructions for connecting the Opta to power, mounting it on a DIN rail, and connecting it to sensors and actuators via its I/O ports.
  • Using the Opta with Arduino IDE: Explains how to use the Arduino IDE to program the device, including how to write and upload Arduino sketches to the device for automation tasks.
  • Troubleshooting: Provides common troubleshooting tips, such as how to address issues with communication, firmware, and I/O ports.

Technical Documentation

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The technical documentation provides a more in-depth exploration of the Opta Micro-PLC's features, capabilities, and specifications, including detailed descriptions of the hardware architecture, communication protocols, and software features. This documentation is mainly aimed at engineers, system integrators, and developers who need to integrate the Opta Micro-PLC into industrial automation systems.

  • Device Specifications: Technical specifications including the microcontroller (STM32H747XI) with its Cortex-M7 and Cortex-M4 cores, RAM, flash memory, I/O specifications, and more.
  • Pinout and Wiring Diagrams: Detailed pinout diagrams and wiring examples for connecting the device to industrial sensors, actuators, and other equipment.
  • I/O Mapping: Information on how the analog and digital I/O ports are mapped and configured for use with external devices. It includes details on relay outputs and their maximum load ratings (e.g., 3 kW).
  • Communication Protocols: Information on how to configure and use Modbus RTU (RS-485) and Modbus TCP (Ethernet) for industrial communication. It includes register maps, addressing schemes, and example configurations for Modbus networks.
  • Security Features: Documentation on the ATECC608B secure element and how it handles encryption, secure OTA updates, and 509 compliance for secure IoT applications.
  • Ethernet Configuration: Provides detailed information on configuring the Ethernet interface for communication with cloud platforms, such as Arduino Cloud, and integration with other industrial IoT platforms.

Installation Guides

The installation guide for the Arduino Opta Micro-PLC provides step-by-step instructions for setting up the device in an industrial environment. It includes detailed instructions on physical installation, wiring, and network configuration.

  • Physical Setup:
    • Instructions for mounting the Opta on a DIN rail or panel mount.
    • Steps for properly connecting the device to an external power supply and ensuring the correct voltage and current for operation.
    • Diagrams for proper wiring of I/O devices, including sensors, actuators, and relays.
  • Communication Setup:
    • Modbus RTU configuration over RS-485 and Modbus TCP configuration over Ethernet.
    • How to configure Ethernet communication for cloud connectivity and IoT applications.
    • Instructions for integrating the Opta with other industrial devices through the Modbus protocols.
  • Software Setup:
    • Guides for setting up the Arduino IDE to program the Opta.
    • Instructions for installing necessary libraries and setting up the Opta as a target device within the Arduino IDE.
    • Guide for using the Arduino Cloud for remote monitoring and management of the Opta Micro-PLC.
  • Firmware Update Process:
    • Instructions for performing over-the-air (OTA) firmware updates, ensuring the device stays up to date with the latest features and security patches.
    • Details on the secure boot process and how the ATECC608B chip ensures secure firmware updates.

Arduino Sketches, Libraries, and Tutorials

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In addition to the user manual and technical documentation, Arduino provides a variety of sketches, libraries, and tutorials specifically designed for the Opta Micro-PLC. These resources make it easier for users to get started with the device, configure it for their specific needs, and implement automation logic using both Arduino programming and IEC 61131-3 PLC languages.

  • Arduino Sketches: Example programs to get started with I/O control, relay switching, and Modbus communication. These sketches serve as a foundation for users to build more complex control systems.
  • Libraries: Official Arduino libraries designed to interface with the Opta's peripherals, including the Ethernet, Modbus, and secure element libraries, as well as various I/O functions.
  • Tutorials: Step-by-step tutorials on how to implement automation logic, how to use Modbus RTU and Modbus TCP, and how to connect the Opta to Arduino Cloud for remote monitoring.

Documentation of Cloud Integration and IoT

As IoT plays a central role in the Opta Micro-PLC’s capabilities, there are specific guides and documentation focused on integrating the device with cloud platforms such as Arduino Cloud and third-party IoT services.

  • Cloud Integration: Instructions on how to connect the Opta to Arduino Cloud for remote monitoring and data visualization through intuitive dashboards.
  • OTA Updates: Guide to setting up over-the-air firmware updates, ensuring the device is always running the latest version of its firmware.
  • Security Protocols: Documentation on securing the IoT communication between the Opta and cloud services using 509 certificates and encrypted channels.

 

Last not least

Opta comes with convenient leaflet containing basic information, diagrams etc

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OPTA Documentation Summary

I tried to assess clarity, depth of information, and comprehensiveness in guiding users through initial setup, programming, and advanced configurations.

I also checked whether the documentation provides sufficient information on used standards, IoT integration, and Modbus RTU/TCP usage.

The Arduino Opta Micro-PLC is supported by a wide range of user manuals, technical documentation, and installation guides designed to help users set up, program, and integrate the device into industrial systems with ease. These resources cover everything from hardware setup and communication protocols to cloud integration and security features. Combined with Arduino sketches, libraries, and tutorials, these documents ensure that both beginners and advanced users can effectively utilize the Opta for automation and IIoT applications.

Familiarization with Arduino Opta

 

I spent time  (much more than I expected and planned) exploring and understanding the Arduino Opta Micro-PLC hardware, features, and key specifications

 

Hardware Overview of Arduino Opta Micro-PLC

 

A PLC (Programmable Logic Controller) is an industrial digital computer designed to control machinery and automate processes. It is highly reliable, can be programmed to perform specific tasks, and interacts with input/output devices like sensors, switches, and motors to execute complex control functions in manufacturing, automation, and other industrial environments.

The Arduino Opta Micro-PLC is an industrial-grade Programmable Logic Controller  developed by Arduino in partnership with Finder. It is designed to meet the needs of automation and Industrial Internet of Things (IIoT) applications, with a focus on reliability, connectivity, and security. The Opta integrates high-performance components, extensive I/O capabilities, and robust communication interfaces to provide a flexible solution for industrial environments. Below is a detailed overview of the key hardware components of the Arduino Opta Micro-PLC

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STM32H747XI Microcontroller

At the heart of the Arduino Opta Micro-PLC is the STM32H747XI (Dual-core Cortex-M7 + Cortex-M4) microcontroller, a powerful and efficient solution from STMicroelectronics. This microcontroller plays a critical role in the device’s performance, handling real-time control, processing, and communication tasks.

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  • Processor Architecture: The STM32H747XI features a dual-core ARM Cortex-M7 and Cortex-M4
    • Cortex-M7 The primary core operates at a clock speed of up to 480 MHz, providing high computational power for real-time control, complex calculations, and data processing.
    • Cortex-M4 A secondary, lower-power core runs at up to 240 MHz and is optimized for handling lower-power tasks, such as sensor data acquisition and auxiliary functions.
  • Memory: The microcontroller features substantial onboard memory to support the processing needs of the Opta, including flash memory for firmware storage and RAM for data handling during runtime. Processor incorporate high-speed embedded memories with a dual-bank flash memory of up to 2 Mbytes, up to 1 Mbyte of RAM (including 192 Kbytes of TCM RAM, up to 864 Kbytes of user SRAM and 4 Kbytes of backup SRAM),
  • Multitasking: The dual-core system allows for multitasking, where the Cortex-M7 handles critical control functions and the Cortex-M4 handles auxiliary tasks, providing better resource management and overall system responsiveness.
  • Peripherals: enhanced I/Os and peripherals connected to APB buses, AHB buses, 2x32-bit multi-AHB bus matrix and a multi layer AXI interconnect supporting internal and external memory access.
  • three ADCs, two DACs, two ultra-low power comparators, a low-power RTC, a high-resolution timer, 12 general-purpose 16-bit timers, two PWM timers for motor control, five low-power timers, a true random number generator (RNG). The devices support four digital filters for external sigma-delta modulators (DFSDM). They also feature standard and advanced communication interfaces.

I/O Modules

The Arduino Opta Micro-PLC is equipped with a comprehensive set of I/O modules that allow it to interact with a variety of industrial devices, sensors, and actuators. These I/O ports enable the Opta to be used in a wide range of automation tasks, from simple control processes to complex monitoring and actuation.

  • Digital Inputs/Outputs: The Opta features several digital I/O ports capable of handling high-speed signals for controlling devices such as relays, switches, and actuators.
    • 4 Digital Output Ports - Relay Outputs: There are four high-power relay outputs that can handle up to 3 kW for switching industrial machinery or controlling high-voltage devices such as motors, solenoids, and other.
    • 8 Analog/Digital Input Ports : can be configured for either analog or digital inputs providing feedback for control applications.
      • DI ports accept binary signals from sensors, switches or contact closure
      • AI ports allow it to read data from analog sensors, such as temperature sensors, pressure transducers, flow meters or any other device requiring continuous measurement.These analog inputs can handle 0-10V signals, depending on the configuration. This makes the Opta suitable for sensor-based control systems in industries like manufacturing, energy, and building automation. These enable the Opta to perform closed-loop control applications, such as PID control for temperature, humidity, or pressure regulation, enhancing its suitability for complex industrial processes.
    • Status LEDs: The Opta includes onboard LEDs to indicate power, connectivity, and operational status, making it easy to troubleshoot and monitor device states at a glance.

Communication Ports

Communication plays a central role in the Opta Micro-PLC, as it is designed to be integrated into industrial networks and IIoT ecosystems. The Opta supports multiple communication ports for both local and cloud-based connectivity.

  • Ethernet (Modbus TCP): The Opta Micro-PLC features an onboard 10/100 Mbps Ethernet transceiver, which provides Modbus TCP This allows it to communicate with other devices on the network or connect to cloud platforms for remote monitoring and control. The Ethernet port uses a standard RJ45 connector, making it easy to integrate the Opta into existing network infrastructures. Ethernet connectivity is essential for Industrial IoT (IIoT) applications.
  • RS-485 Interface ( for Modbus RTU protocol) provided in my Opta RS485 Variant) : In addition to Ethernet, the Opta also supports RS-485 communication via an onboard terminal connector, easy accessible through a terminal block. This interface is commonly used for industrial protocols like Modbus RTU or other custom RS-485 protocols, allowing the Opta to communicate over long distances in harsh industrial environments. The RS-485 interface enables the Opta to be part of larger industrial networks, interfacing with machines, PLCs, and sensors.

Other Connectivity Options

  • USB-C Port:
    • The Opta features a USB-C port primarily for programming and data logging. While it is not used for operational control, it provides a convenient interface for interacting with the device during setup, firmware updates, or diagnostics. The USB-C port simplifies setup and development. It does not power the relays, so an external power supply is needed for full functionality.
  • Cloud Connectivity:
    • Using its Ethernet port, the Opta is capable of cloud connectivity for remote monitoring and control, making it a perfect fit for cloud-based IIoT Integration with platforms like Arduino Cloud allows for the creation of intuitive dashboards for real-time control and monitoring.

Secure Element (ATECC608B)

Security is a critical aspect of industrial IoT devices, and the Arduino Opta Micro-PLC incorporates advanced hardware-level security features to protect both the hardware and software. One of the key security features is the ATECC608B secure element from Microchip Technology. ATECC608B ensures that the device can communicate securely over the network. This is particularly important for IoT applications, as the Opta can manage secure communication and encryption to prevent unauthorized access and ensure the integrity of the data exchanged between devices and cloud services.

  • Cryptographic Protection: The ATECC608B provides strong cryptographic functions for secure communication and device identification. It supports advanced algorithms such as ECDSA (Elliptic Curve Digital Signature Algorithm), AES encryption, and SHA hashing, ensuring that sensitive data remains protected during communication and storage.
  • Industrial IoT Security: The secure element is specifically designed for IoT devices, enabling 509 certificate management and secure boot functionality. This ensures that only authorized firmware can run on the Opta and that all data transmitted via the device is securely encrypted, making it ideal for industrial applications where data integrity and confidentiality are paramount.
  • Over-the-Air (OTA) Firmware Updates: The ATECC608B also supports secure OTA firmware updates, ensuring that the device can be updated remotely while maintaining security standards and preventing unauthorized access.

 Power Supply and Form Factor

  • Power Supply: The Arduino Opta Micro-PLC requires an external power supply to operate, typically operating within a range of 12V to 24V DC. The device is designed to handle power requirements typical of industrial applications, providing reliable operation even in demanding environments.
  • DIN Rail Mounting: The Opta is designed for easy installation in industrial environments. It is compatible with standard DIN rail mounting, which is commonly used in industrial control systems. This allows for convenient and secure placement in control panels or electrical cabinets.Opta measures approximately 115mm x 75mm x 58mm (L x W x H), which is suitable for installations in compact spaces like control panels.

These components collectively make the Arduino Opta a capable, reliable, and secure micro-PLC for a wide range of industrial applications, including automation, control, and IoT integration.

 

Pinout Overview

The documentation  and following film provides detailed pinout diagrams for the Arduino Opta Micro-PLC, essential for understanding its connectivity and configuration. Each pin's function is clearly outlined, covering digital and analog I/O, power, communication interfaces (such as Modbus/RS-485; Ethernet), and more.

Video: 02.OPTA.pinout.

 

Assessment of Build Quality, Connectivity Options, and Physical Dimensions of the Arduino Opta Micro-PLC

The Arduino Opta Micro-PLC is designed with industrial automation and Industrial Internet of Things (IIoT) applications in mind. As such, it needs to meet stringent standards for both build quality and connectivity, while also having physical dimensions that make it suitable for installation in real-world industrial environments.

The build quality of the Arduino Opta Micro-PLC reflects its industrial-grade design, engineered to withstand the rigors of industrial environments.

Durability and Materials: The Opta Micro-PLC is constructed using robust materials that ensure long-term reliability and resilience in industrial settings. It is designed to operate in environments subject to vibrations, temperature fluctuations, and electromagnetic interference (EMI). The plastic housing is sturdy yet lightweight, ensuring that the device can withstand physical impacts and moderate environmental stresses without compromising performance.

Compliance with Industrial Standards: The Opta is designed to meet industrial standards for automation and control, which includes compliance with various safety and electromagnetic compatibility (EMC) standards. This ensures that the device is reliable and safe for use in demanding environments such as factories, manufacturing plants, and other industrial sites.

Thermal Management: Proper heat dissipation is essential for ensuring that the device operates within its optimal temperature range, especially considering the high-performance STM32H747XI microcontroller. The Opta features a well-ventilated design that helps dissipate heat efficiently, even under load.

Industrial Certifications: The device benefits from the Finder brand's long-standing experience in manufacturing industrial automation products. This translates to high-quality design and testing, ensuring the Opta is built to last and perform in critical applications.

 

Basic Functionalities of Arduino Opta Micro-PLC

The Roadtest of the Arduino Opta Micro-PLC focused on validating its core functionalities, such as input/output operations, Ethernet communication, and relay switching, which are critical for its use in industrial automation and IoT applications. Below are the results and observations from testing these basic functions

Please forgive me for the fact that the testing environment I have prepared is quite primitive, but it was fully sufficient to complete even quite advanced projects.

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The primary testing field included

Input/Output Operations

  • Digital Inputs/Outputs
  • Analog Inputs
  • Relay Outputs

Ethernet Communication

  • Network Connectivity:
  • Modbus TCP Communication:
    • to be further described, not reported yet

General Observations

  • User Interface: The Arduino IDE and available (I use free) Modbus tools for configuration and testing were easy to use and well-supported. The interface provided quick access to all necessary settings for programming and testing the device. Unfortunately when getting started with Arduino PLC IDE I experienced crashes and software freezes.
  • Device Stability: The Arduino Opta remained stable throughout the tests, with no failure.. Communication was smooth, and I/O operations did not suffer from interruptions or delays during extended tests.

I am pleased to confirm that  Arduino Opta Micro-PLC demonstrated good performance during testing, with successful results in key areas such as input/output operations, Ethernet communication, and relay switching. The digital I/O, analog inputs, and relay outputs performed reliably and accurately. The communication via Ethernet and Modbus was seamless, making the Opta suitable for integration into existing automation and IIoT systems. Initial problems with PLC IDE have been solved

 

Go Through Available Examples and Tutorials

Arduino IDE was assessed as the primary programming environment for the Arduino Opta in my Roadtest.

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The Arduino IDE (Integrated Development Environment) is a user-friendly software platform used to write, compile, and upload code to Arduino boards.

It supports a wide range of programming languages, primarily Arduino C/C++, and simplifies the process of developing and testing projects by providing a straightforward interface and extensive libraries.

 

I admit that I have been testing with great pleasure many simple examples included with OPTA libraries in Arduino IDE, in manuals and available on the internet. It took a lot of time but I got to know OPTA very well.

Starting from very basic programming (LED blinking, analog readings, etc.). I went far further through advanced examples involving Ethernet, Modbus RTU, cloud integration, and real-time control.

Regardless of the level of advancement of the tasks,tutorials and examples are easy to follow, well-documented, and mostly error-free.

 

Tutorials, and Libraries are easy to Use, well supported, and useful

Honestly, I saw that the documentation, manuals, tutorials and shared examples were developing during my roadtest.

 

The Arduino IDE test stage of my roadtest helped me to evaluate that  mostly tutorials and examples from manual effectively help to leverage Opta’s industrial capabilities, including I/O control, Modbus communication, and cloud connectivity.

 

 

In this section, I explored various test examples and sample programs developed using the Arduino IDE for the Arduino Opta Micro-PLC. These examples provide hands-on insights into the capabilities of the Opta, demonstrating how its digital and analog I/O, Ethernet connectivity, and Modbus communication can be leveraged for industrial automation and IoT applications. By evaluating these test programs, we will gain a deeper understanding of the device’s functionality, ease of use, and integration potential in real-world scenarios.

To shorten the already too extensive report, I will show my experiences in videos.

 

Installation of the Arduino IDE and getting started with programs for Arduino Opta Micro-PLC

Video: 03.OPTA.ArduinoIDE

Programmable Inputs and Relays

Simple programs in Arduino IDE implementing Digital Inputs and Digital OutputsArduino Opta Micro-PLC

 

Digital Inputs

the use of I1, I2, and I3 input  terminals as digital inputs

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Analog Inputs

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Video: 04.OPTA.IOs

Ethernet Communication

Web client

 

Initialize Ethernet with DHCP:

  DHCP assigned IP 192.168.1.213

connecting to www.google.com...

connected to 142.250.203.196

HTTP/1.1 200 OK

 

Web Server

 

Ethernet WebServer Example

server is at 192.168.2.177

Ethernet WebServer Example

server is at 192.168.1.177

new client

GET / HTTP/1.1

Host: 192.168.1.177

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:130.0) Gecko/20100101 Firefox/130.0

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8

Accept-Language: pl,en-US;q=0.7,en;q=0.3

Accept-Encoding: gzip, deflate

Connection: keep-alive

Upgrade-Insecure-Requests: 1

Priority: u=0, i

client disconnected

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Testing  use of the onboard Ethernet PHY transceiver: the Ethernet library

The sketch enables an Opta to connect to the Internet via an Ethernet connection. Once connected, it performs a GET request to the   ip-api.com  service to fetch details about the device's IP address. It then parses the received JSON object using the Arduino_JSON library to

Extract key IP details: IP address, city, region, and country.

This data is then printed to the Arduino IDE's Serial Monitor.

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install Arduino_JSON library

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Retrieving the MAC Address of an Opta Device

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Getting Started with Interrupts on Opta

The Opta micro PLC is designed to operate in several industrial environments involving crucial processes. These processes require controllers to be responsive and precise to manage sensitive tasks and capable of handling large sets of conditions within defined parameters in real-time. Asynchronous operations or spontaneous events are the kind of process that requires immediate attention at a given moment. Therefore, interrupt management is critical to control and optimize these event classes.

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The interrupt, a basic yet vital feature, is available on Opta to handle time-sensitive and unexpected events based on state changes.

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Details in the film below

Video: 05.OPTA.Interrupts

What was missing?

At this stage of the test I realized that a large part of Manual Opta is related to full version of The Opta containing WiFi

or the expansion module  Arduino Pro Opta Ext D1608E / D1608S

Real-Time Clock (RTC) example runs with WiFi only

Analog RTD Input Mode, also no luck.

The Analog Expansion input channels can be used for temperature metering with PT100 RTDs... but only in external module  D1608.

in basic OPTA RTC input isn't available

Arduino Micro-PLC OPTA:                    image

Expansion Module D1608 image

Typically, PLC systems have a modular structure, allowing expansion modules to be connected to the PLC base in various configurations.

In addition to this standard approach, there are also compact PLCs designed for specific and sometimes limited applications.

These controllers integrate a fixed number of I/O and communication modules. However, this doesn’t rule out the possibility of expansion by adding standard modules.

The Arduino Opta Micro-PLC falls into this second category.

I shouldn’t be particularly picky or demanding, but while I understand the limitations of a compact design, I can’t help but miss "on-board" 4–20mA inputs and outputs.

Growing up with the belief that the 4–20mA standard is the most popular in automation systems, its absence feels notable.

Of course, this functionality can be achieved by adding one or more D1608 extension modules. However, doing so significantly increases the overall project cost.

Testing RS485

RS-485 Communication Standard

RS-485 is a serial communication standard designed for multi-point systems, making it ideal for industrial environments where devices need to communicate over long distances.

Features of RS-485

  • Differential Signaling: RS-485 uses differential signaling, where two wires (A and B) carry opposite signals. This method allows for higher noise immunity, making it suitable for industrial environments with electrical interference or long cable runs.
  • Long-Distance Communication: RS-485 can transmit data over long distances (up to 1200 meters or 4000 feet) without significant signal degradation, making it ideal for large-scale systems or dispersed devices.
  • Multi-Device Connectivity: RS-485 supports multi-drop communication, which means multiple devices (up to 32 devices) can be connected on a single bus. This makes it a scalable solution for complex systems with many devices.
  • Half-Duplex Communication: RS-485 typically supports half-duplex communication, meaning that data can be transmitted in both directions, but not simultaneously. This is a cost-effective and efficient setup for most industrial control systems.

Video: 06.OPTA.RS485.1

Overview of Modbus RTU over RS-485

  • Master-Slave Architecture: Modbus RTU operates on a master-slave or client-server architecture. The master device (usually a PLC or HMI) initiates communication, and the slaves (sensors, actuators, other devices) respond to queries.
  • Data Transmission: Modbus RTU uses a binary format for transmitting data, which makes it more efficient than other protocols like Modbus ASCII, which use human-readable text.
  • Polling and Response: The master sends a polling request to the slave device, and the slave responds with data. If the slave device is unable to respond correctly, it sends an exception code.
  • Supported Data Types: Modbus RTU supports a range of data types, including Discrete Inputs, Coils, Input Registers, and Holding Registers, enabling interaction with digital and analog devices.

  

Video: 07.OPTA.RS485.2

Evaluate the ease of integration with third-party PLCs and devices using these protocols.

Assess Modbus libraries and their documentation support in the Arduino IDE.

Ensure smooth data exchange between Arduino Opta and external devices (e.g., external Modbus I/O module).

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Video: 08.OPTA.Modbus RTU


Arduino PLC IDE

After a long time of experimenting with Opta programming in Arduino IDE, it was time for a real automation tool - Arduino PLC IDE

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Video: 09.OPTA.PLC IDE

At the very beginning  I experienced problems with the behavior of OPTA and Arduino PLC IDE.

Arduino PLC IDE hung while trying to run OPTA programming

The solution in the film below


Video: 10.OPTA_PLC IDE_faults

And although I still had to perform the memory partitioning procedure in a few cases,
I can admit that the Arduino PLC IDE is an extensive but very convenient tool for programming the OPTA PLC

Video: 11.OPTA_PLC IDE_programming

Example of programing in classic automation languages: Ladder, FBD, ST, SFC, and IL of the family of the IEC 61131-3 languages.

Arduino PLC IDE provides all above for easy programming

https://en.wikipedia.org/wiki/IEC_61131-3

        Ladder Diagram (LD)


Video: 12.OPTA_PLC IDE_Ladder

 

        Function Block Diagram (FBD)

        Structured Text (ST)

        Sequential Function Chart (SFC)

        Instruction List (IL)


Video: 13.OPTA_PLC IDE_FBD

 

Using Arduino PLC IDE for Modbus RTU projects

Video: 14.OPTA_PLC IDE_Modbus

GO TO SCADA

Project of implementation of Arduino Cloud in Opta

Video: 15.OPTA_Arduino_Cloud

Attempt to Compare: SCADA vs Industrial IoT

Supervisory Control and Data Acquisition (SCADA) and Industrial Internet of Things (IIoT) are two crucial technologies in modern industrial automation and control systems. Both technologies have similar objectives—monitoring, controlling, and optimizing industrial processes—but differ significantly in their architecture, capabilities, and implementation. Here's a detailed comparison of SCADA vs. IIoT:

  • SCADA (Supervisory Control and Data Acquisition): SCADA refers to a centralized control system used to monitor and control industrial processes, such as manufacturing, energy generation, water treatment, and transportation. It typically involves a central server, remote RTUs (Remote Terminal Units), PLC controllers, and HMIs (Human-Machine Interfaces) for real-time data acquisition and control.
  • IIoT (Industrial Internet of Things): IIoT refers to the integration of internet-connected devices, sensors, and actuators into industrial systems to collect, analyze, and act on data for improving operations, efficiency, and productivity. IIoT is part of the broader IoT (Internet of Things) concept, but it focuses specifically on industrial applications like manufacturing, supply chain optimization, and predictive maintenance.
  • SCADA System Components:
    • Centralized Control (SCADA Server): A centralized system that processes data from field devices.
    • RTUs/PLCs: These devices collect data from sensors and send it to the SCADA server for processing.
    • HMIs: Interfaces that allow operators to interact with the system.
    • Communication Network: Typically involves proprietary communication protocols to connect the SCADA server with field devices.
  • IIoT System Components:
    • Sensors and Devices: Collect data from industrial processes, such as temperature, pressure, or humidity.
    • Edge Devices: Process and aggregate data closer to the source, often running analytics locally.
    • Connectivity: IoT devices are connected via common network protocols such as Ethernet, Wi-Fi, LoRa, 5G, etc.
    • Cloud Platforms: IIoT systems are often integrated with cloud services for data storage, advanced analytics, and machine learning.

Communication Protocols

  • SCADA:
    • SCADA typically uses proprietary communication protocols (like Modbus, DNP3, or Profibus) for communication between the central server and field devices.
    • These protocols are designed for real-time control and monitoring in industrial environments.
  • IIoT:
    • IIoT relies on open communication standards such as MQTT, AMQP, and HTTP, and often uses Wi-Fi, Ethernet, LoRa, and 5G for connectivity.
    • The use of open protocols allows IIoT devices to connect to cloud platforms and integrate with other IT systems for data analysis and decision-making. 

Data Handling and Analytics

  • SCADA:
    • SCADA systems are designed for real-time data collection and monitoring. They typically store historical data for process analysis, but the main focus is on operational control and visualizing real-time data on HMIs.
    • SCADA systems use historical trending to monitor system performance and alarms/alerts for abnormal conditions.
  • IIoT:
    • IIoT enables data collection from a variety of sensors and devices and integrates this data into cloud-based platforms for advanced analytics, including predictive maintenance, machine learning, and AI-driven insights.
    • The large volume of data collected in IIoT systems is processed through edge computing or in the cloud, allowing for in-depth analysis and long-term forecasting beyond real-time data handling.

Scalability

  • SCADA:
    • SCADA systems are typically centralized with a fixed infrastructure, which may become difficult to scale in large, distributed systems. Adding new devices or expanding the network requires changes to the SCADA server and communication protocols.
    • Expansion is usually limited to the capabilities of the proprietary hardware and software used in the system.
  • IIoT:
    • IIoT systems are highly scalable due to their use of cloud computing and open-source technologies. New devices can easily be added to the network without disrupting the entire system. The cloud allows IIoT systems to scale seamlessly with minimal on-premise infrastructure.
    • Edge devices and sensors can be added independently, and their data can be sent to centralized cloud platforms for processing and storage.

Control vs. Data Analytics

  • SCADA:
    • SCADA is primarily focused on control. It provides operators with real-time information to monitor processes and make decisions that can trigger actions such as opening/closing valves, starting/stopping motors, and activating alarms.
    • SCADA is heavily oriented around real-time control and alarm management.
  • IIoT:
    • IIoT focuses more on data analytics and optimization. While IIoT devices can provide real-time data, their strength lies in the ability to collect large amounts of data over time and use analytics to drive predictive maintenance, performance optimization, and decision-making.
    • IIoT emphasizes data-driven decision-making rather than manual or real-time control.

Both SCADA and IIoT are critical technologies for industrial control, but they have different strengths:

  • SCADA systems excel at real-time control, monitoring, and alarm management within a centralized system.
  • IIoT offers advanced data analytics, remote monitoring, predictive maintenance, and scalability through cloud integration and the ability to process data from many connected devices.

While SCADA remains essential for legacy industrial systems requiring high control fidelity, IIoT is the next frontier, offering enhanced flexibility, intelligence, and the ability to connect and analyze vast amounts of industrial data. Many industries are gradually transitioning from traditional SCADA systems to IIoT-driven architectures, leveraging the strengths of both technologies for optimal performance and efficiency.

Assess which system (SCADA or IoT) is more suitable for certain types of industrial applications.

Evaluate scalability, maintenance, and data storage needs.

When evaluating SCADA versus IoT (IIoT) for industrial applications, it's important to consider the nature of the application, scalability, maintenance needs, and data storage requirements. Both systems have strengths in specific areas, but their suitability depends on factors such as the size of the operation, the level of automation, data processing needs, and the type of industry.

Comparison of the Arduino Opta Micro-PLC with Competitors

The Arduino Opta Micro-PLC stands out in the industrial automation market, offering a unique blend of flexibility, real-time performance, security, and ease of use. To provide a comprehensive evaluation, let's compare the Arduino Opta with some of its notable competitors in the Micro-PLC and Industrial IoT (IIoT) space, such as:

  1. Siemens LOGO! PLC
  2. Rockwell Automation’s Allen-Bradley Micro800 PLC
  3. Schneider Electric’s Modicon M221 PLC
  4. WAGO 750-880 Series

The Arduino Opta Micro-PLC offers superior flexibility, IoT connectivity, and advanced security features compared to many competitors. It is especially strong in cloud-based applications and real-time control, making it an ideal solution for Industry 4.0 and IIoT environments. While Siemens LOGO!, Rockwell Micro800, and Schneider Modicon M221 provide strong industrial functionality, Opta leads in ease of use, cloud integration, and security, making it a standout choice for future-proof automation systems.

When comparing the Arduino Opta Micro-PLC to its competitors, it is important to evaluate both initial costs and the potential long-term savings in terms of ease of programming, maintenance, scalability, and integration. While initial cost is a key factor in any decision, long-term operational and maintenance savings can greatly influence the overall value proposition of the system.

Arduino Opta Micro-PLC offers excellent value for small to medium-sized industrial applications, particularly for those requiring IoT capabilities and cloud-based integration. Its lower initial cost, combined with ease of programming, Arduino ecosystem integration, and advanced IoT features, makes it a highly attractive option for long-term savings. Remote monitoring and OTA firmware updates can greatly reduce maintenance costs over time.

Summary of Results and General Conclusions

This report summarizes my RoadTesting and evaluation of the Arduino Opta Micro-PLC.

The work began with an overview of the PLC, including a review of available documentation, manuals, and examples, followed by an analysis of its technical design and components. I conducted several tests and ran numerous examples, starting with the Arduino IDE and progressing to the Arduino PLC IDE. My focus included I/O communication, RS485, and Modbus RTU integration with external devices. Finally, I developed a project utilizing the Arduino Opta PLC with Arduino Cloud.

Despite encountering several challenges, particularly with the Arduino PLC IDE freezing, these issues were resolved, I greatly appreciate the Opta PLC for its ease of startup and programming, its universality, and its flexibility in adapting to various applications.

I extend my gratitude to the project sponsors and apologize for the significant delay in completing this Roadtest.

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Anonymous