While not a direct replacement for PLCs, there are some industrial automation applications built using Arduino, including prototyping, embedded systems, and low-cost PLC simulators.

Refer to our previous article about Arduino:

Introduction to Arduino: History, Hardware, and Software

In the previous article, we reviewed the Arduino platform’s hardware and software components. We also identified that Arduino is a popular educational tool that introduces students to electronics and control systems. This article will explore some applications and solutions built using Arduino. We will also learn about an interesting Arduino PLC simulator.

First, we must say that Arduino is unlikely to replace PLCs in the field of industrial automation, at least in the foreseeable future. This is because Arduino currently cannot meet the performance, capacity, and robustness levels required by many industrial automation processes. But that’s okay. Arduino is not a low-cost alternative to industrial PLCs, so they do not compete directly.

Figure 1. Although Arduino is not a replacement for PLCs, they are still used in industrial automation. Image provided by Arduino

However, this does not mean that Arduino has no space in the industry. On the contrary, the Arduino platform offers several advantages in certain applications, which we will review next.

Arduino for Prototyping

Prototyping is the first step in building new commercial products. It helps validate the functionality and feasibility of the product. The advantage of using Arduino for prototyping is the low cost of components. Before Arduino, building prototypes could easily become expensive and sometimes required advanced industrial automation hardware. Other times, not prototyping led to costly iterations during the testing phase.

Figure 2. Supplino is the first power unit built using Arduino. Image provided by Arduino

Instrumentation is one of the successful areas for prototyping with Arduino. Some instrument prototypes include data acquisition modules, compact power supplies, and sensors.

Once the Arduino prototype has been thoroughly tested, the next step is to design the commercial version of the product. In this case, the cost structure changes, and Arduino is no longer cost-effective.

The cost of prototyping with Arduino ranges from less than $100 to several thousand dollars, which is relatively low. On the other hand, installing a $50 microprocessor in a commercial product is overly expensive. Microcontrollers with the same computational specifications, priced at only a fraction of that, can be integrated with other electronics on a PCB. Producing integrated PCBs is a highly automated process compared to installing and wiring Arduino and its shields.

Embedded Systems Using Arduino

Embedded systems are one way to bring Arduino into industrial automation. Due to their low cost, Arduino can be an attractive solution for specific parts of industrial manufacturing processes. In some respects, they can also serve as prototypes and proof of concept for embedded systems solutions.

The design and implementation speed of Arduino solutions is much faster than that of PLC-based solutions, especially considering the known supply chain issues with today’s automation components.

Arduino-based embedded systems have been successful in manufacturing, primarily revolving around integrating dedicated sensors. These sensors include ultrasonic, infrared, temperature, light sensitivity, sound, voice recognition, and vibration.

Figure 3. Ultrasonic distance measuring detector prototype. Image provided by Arduino

There are also some useful Arduino-based embedded systems that can be wirelessly controlled using various protocols (including Bluetooth, RF, GPRS, and infrared).

Industrial Arduino prototypes can also be applied to motor control, including stepper, servo, and DC motor management.

Arduino as PLC

We have established that Arduino is not a replacement for industry PLCs. However, because Arduino is an open-source platform, some are pushing this technology to make it more compatible with industrial automation and propose new solutions. Controllino is one of these new solutions.

Controllinos are low-cost PLCs based on the Arduino platform. They can be programmed using the Arduino IDE, and are compatible with many Arduino shields. Controllinos are compact DIN rail-mounted PLCs that provide all the I/O functions of standard PLCs.

Controllinos also feature shielding and come equipped with many electrical protections and specifications necessary for controllers to operate in industrial environments.

Figure 4. Controllino MAXI printing “Hello World!” to an LCD. Image provided by Controllino

Again, speaking of Arduino as an educational tool, “Arduino as PLC” has an even more interesting application. The PLC simulator called “OpenPLC” allows users to program Arduino using ladder logic. This simulator is very helpful in academia as it fills another gap with Arduino: the programming language is different from the standard language used in PLCs.

Open PLC (and other similar software suites) provides a simple interface to help students focus on operands and logical programs. Once the code is complete, the simulator compiles it into Arduino code so that it is compatible with the device and can be loaded onto the device.

Arduino Ladder Logic Programming

Arduino has various applications in industrial automation; it is not just a low-cost educational platform for understanding control systems. Programming Arduino using ladder logic will be explored in more depth in the next article.