The intersection of Industrial Automation and Embedded Systems
The Arduino Pro ecosystem was created to provide a low friction path for industrializing Edge and IoT Solutions. Arduino has become the defacto platform used across industry and is synonymous with ease of use, versatility and affordability. Many Arduino based prototypes ended up evolving into commercial solutions and Arduino Pro was created with exactly that in mind.
With the launch of the Arduino Opta microPLC in the Pro series, Arduino is bringing the Arduino ethos into Industrial Automation, a traditionally niche sector. The Opta is a fully fledged Programmable Logic Controller (PLC) system that checks all the boxes for Industrial Automation professionals.
PLC’s are the workhorses at the core of Industrial Automation, which for the uninitiated has its origins in the early stages of the Industrial Revolution driven by increasing manufacturing demand that pushed the limits of productivity to a point where it became necessary to make machines do repetitive tasks without human intervention.
Early examples of automation used purely mechanical systems with much of the learnings being incorporated into the design of later electrical systems. Before the advent of solid state transistors there were electromechanical relays which enabled Engineers to implement computing systems that harnessed the power of electricity to automatically control machinery.
Relays enabled the physical realization of Boolean logic and computation which in turn lead to the implementation of complex systems that followed algorithms, which in turn was ideal for automated process control. This approach became known as Relay Logic and these hard wired relay based control systems became very popular in the middle of the last century. Installations eventually became complex with many thousands of relays used to control very large processes.
These installations consumed significant amounts of power and space. Being purely electromechanical devices, relays are noisy and required regular maintenance. Troubleshooting these installations also required skilled technicians resulting a thriving sector forming around these systems that became the roots of modern Industrial Automation.
During the era of the 3rd Industrial Revolution around the 1960’s the invention of the solid state transistor paved the way for the introduction of stored program digital computers. These new computers were relatively compact compared to relays and utilized far less power. Instead of hard wiring connections or providing a program in a physical form, these new computers were programmed using early generation programming languages much like the code we still use today. Computing systems were suddenly more compact and the programming techniques used 1st generation programming languages that were fundamentally different to the relay logic systems which Electricians and Plant Engineers became comfortable with.
Spurred by the needs of the automotive manufacturing sector in Detroit, a revolutionary innovation around the late 1960’s was invention of a type digital computer that had all the benefits of emerging digital computers but could also be programmed using a programming environment that resembled relay logic. These devices became known as Programmable Logic Controllers or PLC’s for short and were a game changer.
The programming environment became known Ladder Logic which is a visual programming language that is based on the principles of relay logic that programmers input into the system from a user terminal.
With a little training it was possible for the on site Electricians and Maintenance personal who were familiar with relay logic to quickly learn to program these systems and even convert their existing hard wired relay logic systems into Ladder Logic. The PLC effectively became a way to virtually create any relay logic system in a compact device with the only limitations being the amount of memory and processing power determining the amount of inputs and outputs that can be controlled.
PLC technicians often had no need to understand the inner working of computers nor did they have the need to learn traditional software development. The first commercial PLC’s were originally developed by Modicon for the automotive sector and they soon they became wide spread in all industries. Many more PLC manufacturers appeared with each one adding innovations, but all still iterating on the original concept.
Today PLC’s are used at the heart of every industrialized and automated process and most PLC programming is still done using Ladder Logic exactly as it was done all those years ago. PLC’s were and still are fundamentally different to work with than coding on a normal computing system and many PLC programmers have never touched coding in the sense that most people understand today.
Physical programming terminals have been replaced by software on a Laptop or PC with additional programming languages added to augment Ladder Logic. There are now other languages in addition to Ladder Logic which is abbreviated as LD. These other languages are Structured Text (ST), Instruction List (IL), Function Block (FB) and Sequential Function Charts (SFC).
Collectively these languages are standardized under the international IEC 61131–3 standard which represents an industry wide agreement on how all PLC’s should be programmed. They are primary visual programming environments and are designed specifically for the needs of process control. The only language that resembles modern coding is Structured Text which is actually derived from the Pascal programming language syntax.
These languages have helped ensure the PLC technician has access to wide variety of development techniques including text based coding languages such as ST and IL. Learning the IEC6113–3 languages means that you can essentially move between any modern PLC platform taking the same programming skills across with you. Most PLC programmers still prefer LD which is normally the starting point for learning PLC programming due to its visual nature and direct mapping to relay logic.
Many other things have been standardized in the ecosystem of devices and peripherals supporting PLC’s and the Industrial Automation ecosystem. Products all designed to be interoperable with all and have standardized performance levels in terms of safety, interfacing and reliability.
Since IEC61131–3 isn’t widely taught outside of the industry skilled PLC programmers are always in demand. This can sometimes contribute to the support cost of these systems and the actual hardware price of PLC systems ranges from a few hundred dollars to tens of thousands of dollars depending on performance level. Despite these challenges PLC’s have largely remained the trusted norm for process control in the 3rd Industrial Revolution and PLC’s are every where in process control, manufacturing, machinery and even buildings and ships are controlled by them.
On other other end of the spectrum far from industrial process control is the need to control more specific devices or products like appliances, burglar alarms, vehicle subsystems, home automation etc. These problem areas led to the creation of Microcontrollers which are tiny little computer systems packaged in a microchip which are programmed to perform one specific task.
Microcontrollers have spawned the world of Embedded Systems and this is the domain where Arduino has emerged as the standard platform providing embedded engineers with the rich ecosystem and easy to use tools for learning and prototyping.
Arduino has become synonymous with embedded systems and all kinds of developers from those starting out to seasoned engineers use Arduino as part of their daily workflow, all using some combination of the Arduino software tooling and hardware dev boards.
More recently with the advent of the 4th Industrial Revolution we have seen the rise the Internet of Things and tinyML and Arduino supports these innovations with ease.
Most PLC manufacturers have tried responding to the 4IR with some IoT extensions and enhancements but at expensive price points as they need to do R&D to fit emerging technologies into the architecture of what are largely legacy platforms. The reality is that the PLC world has largely remained the same. This is not all bad because the lack of significant change in the PLC world introduces a level of certainty and stability contrasted against the rapidly changing embedded world, which is why business have banked on the certainty that comes with PLC’s together with robust and standard ways to interface with external sensors and actuators.
The result is that embedded systems and industrial automation domains have largely remained separated from each other and while there have been attempts to use embedded systems as replacements for PLC’s this has for the most part frowned upon in the Industrial Automation space mostly due to lack of compliance with standards and proven reliability engineered into PLC’s. That was until 2023 with the launch of the Arduino Opta which represents the bridge between the Embedded and Industrial Automation domains.
The Arduino Opta is a fully functional micro PLC that supports the IEC61131–3 programming languages and is compliant with the relevant PLC standards. It has been designed in conjunction with Finder who themselves are one of the trusted names in the Industrial Automation domain.
Arduino has created a full hardware and software solution including a standalone PLC programming software package aptly called PLC IDE. On the software front PLC developers will feel at home in PLC IDE and will be able bring all the their IEC61131–3 skills directly across to the Arduino Opta. In addition there is also support for the Arduino IDE and using normal Arduino sketches allowing maximum flexibility in application development.
From a hardware perspective the Opta comes in a standard DIN Rail mountable chassis and is powered by a STM32H7 MCU that has both an Arm Cortex M7 and Cortex M4 core. This is in league with the type of computing power found in the higher end of the Micro and Compact PLC market. Being built onArm is what gives the Opta its edge over the more traditional ASIC based PLC systems specifically micro PLC’s in the same class.
The abundant available computing power is what also allows the Opta to interface to the cloud and other industrial devices using Modbus-TCP making it perfect for your next IoT project. The open nature of Arduino means you have more direct access to the underlying hardware using the Arduino IDE so you can comfortably run tinyML models on the Opta something not supported by any other PLC micro PLC product in the same class.
Being a PLC the Opta is powered by 12–24V and has 8 inputs which can act as 24V compatible Digital inputs as is the standard in PLC applications. These can also optionally be configured as analog inputs supporting 0–10V input signals inline with the 0–10V industrial standard. There are 4 relay outputs with a 10A rating which means the Opta can also directly drive bigger loads with ease.
There are also 3 versions of the Opta which characterize the additional optional connectivity supported:
Opta Lite — The entry level unit that supports just Ethernet Connectivity
Opta RS485 — The mid tier model that supports everything the Lite has with the inclusion of a hardware interface for RS485 half duplex which is useful for accessing legacy industrial systems.
Opta WiFi — The top of the range Opta model that has everything the Opta RS485 has as well as a WiFi interface which is ideal for IoT applications
Don’t let the compact size fool you as the Opta has a lot of features that easily out classes similar sized micro PLC’s and smart relays. For example if you run out of on board I/O Modbus-TCP support allows you to expand using remote I/O or even use Arduino boards as slave I/O units. Thanks to the openness provided with the Arduino IDE and the ability to run Arduino C++ based sketches as well as IEC61131–3, the possibilities are truly endless.
Use cases for the Opta include, but are not limited to:
- Machine Control
- Smart Metering
- Process Control
- Internet of Things
- Industrial tinyML/AIoT
- Interfacing existing Arduino sketches to Industrial systems
Most importantly the Arduino Opta is not just another micro PLC as it represents a paradigm shift in the world of automation. The Opta will bridge the gap from the embedded to industrial worlds seamlessly allowing developers from both of these traditionally separate domains to cross over.
There are numerous benefits for combining the technologies developed across both these domains when building robust Industry 4.0 applications. PLC Logic is ideal for control however when it comes to IoT and more recently AIoT and its inherent data processing requirements, its been harder to bring those features at a reasonable price point into the PLC space.
Similarly embedded developers haven’t had easy access to affordable industrial compliant hardware let alone access to a real PLC system to learn IEC61131–3 languages on. This presents an opportunity for embedded developers to expand their solutions across to the the world of standards compliant industrial automation.
For businesses and decision makers the benefit of adopting the Opta as a PLC solution for suitable applications is the reduced dependency on IEC61131–3 skillsets. The widespread familiarity and accessibility of Arduino means that there is immediately a larger pool of developers available to program and support Industrial Automation solutions as compared to traditional PLC systems. This translates to cost savings and making it easier to support applications in the long run. This new generation of Arduino PLC developers will also be afforded the opportunity to learn and build on their IEC61131–3 skills while producing true Industry 4.0 solutions.
In summary, the Arduino Opta represents a disruption in the world of Automation and the the point of intersection between Industrial Automation and the Embedded and Maker worlds. It will open the PLC and Industrial Automation to a larger audience and allow for more advanced and robust solutions to be implemented.
The best part is probably the cost as the Arduino Opta is also affordable compared to other PLC offerings on the market.
If you want to leverage the benefits of a thriving open community in your next Industrial project or if you are a Maker and you are curious head over to https://www.arduino.cc/pro/hardware-arduino-opta to grab one and join the Industry 4.0 revolution.
