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The Differences Between Industrial PCs and PLCs

Updated: Apr 16, 2022

Automation is one of the critical factors to increase factory throughput and reduce costs for the manufacturing industry. Technological advancements such as relays, PLCs, and industrial PCs (IPCs) are pushing forward industrial automation that changed how machines and human labor interact. Therefore, this blog will talk about the two-control system hardware that is widely used in industrial automation, PLCs, and industrial PCs. We will also discuss which type of two-control system may be the most appropriate based on your application's needs.

What is a PLC?

To begin with, let's discuss how Programmable Logic Controllers (PLCs) were widely used for automation processes in manufacturing plants. Back in the 1970s, PLCs were a game-changer for automation systems. PLCs were designed to replace relay panels and switch boxes.

PLCs have been upgraded with a more rugged design, scalable features, and programmable systems. In addition, PLCs' programming language, known as ladder logic, allows PLCs to be highly customizable for machine automation. This robustness and versatility made PLCs a popular choice to replace older relays and switch boxes.

What is an Industrial PC?

The development of personal computers (PCs) is increasing along with the exponential advancement of semiconductor chips. As computer chips become more powerful, smaller, and cheaper, industrial PCs are gaining interest within the automation industry. Industrial PCs can cover the supervisory control that PLCs offer, but with more workloads such as HMI, gateways, AI applications, and more. Industrial PCs are able to perform these workloads' consolidation because of the performance accelerators such as GPUs, TPUs, VPUs, NVMe SSDs, and more. Being able to consolidate workloads reduces its hardware footprint on the factory floor. That being said, further below, we will discuss similarities and differences between industrial PCs and PLCs.

What is the difference between IPC and PC?

Regular PCs and industrial PCs share pretty similar basic components such as CPUs, RAMs, SSDs, and GPUs. However, industrial PCs are built and designed to withstand extreme environmental conditions, from extreme temperatures to shock and vibration exposures. A normal PC will quickly fail when encountering some of the harsh environments. Some designs and build materials that allow industrial PCs to be incredibly rugged are fanless designs, one-piece chassis, and industrial-grade materials. Moreover, industrial PCs are versatile. Not only do they support the latest technologies, but they also support legacy technologies that are commonly found in factory automation, such as serial ports, COM, M12 connectors, DIO, GPIO, and many more which has led to the rapid increase of industrial PCs in manufacturing automation.

What are the Differences Between Industrial PCs and PLCs?

7 Distinctions

1. Operations

A PLC comes with a real-time operating system that constantly monitors input from connected devices and then executes decision commands according to its program. In addition, PLC's operating system (OS) is designed specifically for performing tasks related to control. Thus, PLCs typically do not require antivirus programs or registry cleaners, which increases the processing throughput during operations.

Industrial PCs can perform the same tasks as PLCs but with an operating system that enables them to run various applications and programs that are not available for PLCs. With these capabilities, IPCs are more than just control purposes. Industrial PCs can consolidate workloads which reduces hardware footprint. However, the operating system of an IPC such as Windows and Linux are susceptible to cyberattacks, but current antivirus software and firewalls are advanced enough to mitigate this risk.

2. Programming

The next difference between industrial PC and PLC is how programs are developed and executed. PLCs generally implement a scan-based program execution, whereas industrial PCs are typically event-driven software. For instance, a PLC software logic is specified in the IEC 61131-2 standard like ladder logic or other proprietary vendor languages. In contrast, industrial PCs function on the well-known Windows or Linux operating system using programming languages such as C/C++/.NET. Therefore, industrial PCs are much easier to program due to their popularity among developers. They can also allow the system to interface with more machinery and devices thanks to the universal programming language like C++ compared to ladder logic that needs special training to learn.

3. Security

Security is one of the detrimental factors in manufacturing automation, where some companies can lose millions of dollars if not taken seriously. There are two fundamentals of security an industrial system should deal with. First, blocking attacks from external access that is not authorized. Second, limiting users' access based on their rights or designation. In the past, PLCs were known to be secure from malware attacks. However, some attackers started developing malware to target PLCs, just like what happened to Stuxnet when their Siemens PLCs were breached. Despite that, industrial PCs are also vulnerable to malware attacks and require comprehensive protection from software antivirus or hardware modules. Some industrial computers utilize TPM (trusted platform module) 2.0 embedded on the motherboard to encrypt data, keeping it safe from online and offline threats.

4. Build Quality

As for build quality, both PLCs and Industrial PCs are designed to operate in extreme environments. Since industrial PCs are different from normal desktop computers or workstations, Industrial PCs are incredibly rugged. Here are some of the industrial features of industrial PCs:

  • Fanless Design

  • Wide Temperature Range

  • Shock and Vibration Resistant

  • High IP Rating

  • Expandable Modules

  • Rich I/O with legacy technology support

For build quality, PLCs and industrial PCs are pretty well matched. However, industrial PCs are winning when it comes to their compact size. PLCs are often bulky and have a limited mounting option. Some PLCs can also overheat when they get mounted because their heat dissipation is obstructed. In contrast, industrial PCs are relatively small and have various mounting options, including VESA mount, rack mount, and din rail options. In addition, some industrial PCs are equipped with power ignition management and can be deployed for in-vehicle applications.

5. Expansion Capabilities

Both PLCs and industrial PCs are required to control various devices for control, monitoring, and communication. Therefore, both PLCs and industrial PCs are equipped with multiple COM ports and other I/O capabilities, including legacy technologies. Some of the common industrial communication protocols are CANbus, Modbus, Profibus, EtherCAT, and EhterNET/IP. Even though both can support these technologies, most PLCs already have these technologies built-in. On the other hand, industrial PCs are built with expansion slots to increase their versatility. Hence, industrial PCs have a higher threshold for the amount of I/O they can handle. In addition, industrial PCs also feature various COM ports, LAN, USB, and HDMI ports. These features enable industrial PCs to consolidate workloads from different hardware more than just PLCs. For instance, industrial PCs can run HMI applications by themselves, whereas PLCs require a separate HMI application before they can display anything to a display panel. What makes industrial PCs even more special is they are able to support a myriad of expansions from wireless cards, 5G modules, SSD storage, to GPU accelerators.

6. Processing Power & Storage

Since PLCs' microprocessors are designed specifically for a dedicated function, PLCs are powerful controllers for automation controls. PLCs can manage high-speed I/O and have no problem tackling smaller automation applications. However, automation projects are getting more advanced and compute-heavy. This is where industrial PCs come in. Industrial PCs utilize more storage and a full processor like workstation computers that can run computing and storage heavy applications. Additionally, thanks to the help of performance accelerators such as GPUs, TPUs, CPUs, and VPUs, industrial computers can perform intelligent computation like in the intelligent assembly lines that collaborate with machine vision applications.

7. Cost

In short, the cost comparison between PLCs and industrial PCs is PLCs have a lower cost for smaller applications, while industrial PCs have a higher initial cost. However, as the applications get more complex and compute-heavy, the cumulative cost of PLCs may exceed industrial PCs. While PLCs' initial costs are less expensive, the price increases exponentially when additional computing power or peripherals are needed. In contrast, industrial PCs cost more initially but cost much less when requiring an upgrade in computing power and expandability.

Summary – Industrial PC vs PLC

Both PLCs and industrial PCs have their own place when you're selecting a programmable controller for your industrial automation system. PLCs are a better fit to run more minor automation systems with a strict set of functions. Moreover, PLCs are rugged, cost-effective, and highly secure for industrial deployments. On the other hand, industrial PCs are great for solutions with high demand in computing and storage. Industrial PCs have a lower total cost of ownership (TCO) for complex tasks requiring versatility from the controller. PLCs are secure because they don't have wireless connectivity, whereases industrial PCs are also as secure because of today's cybersecurity software while hardware for industrial standards is very reliable. Some applications can use both PLCs and industrial PCs in their operations to balance each other's costs and benefits. At the end of the day, it depends on what functions are implemented in your manufacturing process.

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