5 Major PLC and PCB Differences

Two acronyms surface in electronics manufacturing and automation discussions: PLC (Programmable Logic Controller) and PCB (Printed Circuit Board). They are often pitted against each other, and someone who’s new in this field would be baffled.

Both are fundamental components in the realm of electrical engineering. Both have critical roles in the operation of a wide array of devices. However, they serve different purposes. 

Understanding the differences between PLCs and PCBs is a basic requirement for engineers, designers, and tech professional. It helps them learn the nuances of electronic systems and their applications. 

We’ll elaborate on five major differences between PLCs and PCBs and why these distinctions matter.

Functionality and Application

PLC: Designed to continuously control manufacturing processes, PLCs automate specific tasks within a production line. These activities may range from machinery operation to assembly processes or any activity requiring high reliability and ease of programming. PLCs are known for their durability and ability to cope with harsh industrial environments, including excessive temperatures, vibration, and electrical noise.

PCB: Meanwhile, a printed circuit board is the backbone of all electronic devices. This platform allows mounting components and establishes electrical connections through conductive pathways and other features etched from copper sheets surface-mounted onto a non-conductive substrate. PCBs are fundamental in creating an interface for electronic components, including resistors, capacitors, and integrated circuits, to communicate and function together as intended.

Complexity and Design

PLC: The complexity of the PLC system lies in its software programming rather than hardware. PLCs are programmed using ladder logic or other programming languages to perform tasks based on input signals and predetermined sequences. Their design focuses on flexibility and adaptability, allowing them to be reprogrammed for different tasks or operational changes.

PCB: On the other hand, PCB is inherent in its design and layout. Designing a PCB involves careful planning of the circuit layout to ensure proper functionality, minimize interference, and adhere to manufacturing constraints. The complexity can range from a simple single-layer board for basic electronic devices to intricate multilayer PCB for advanced computing and telecommunications equipment.

Durability and Environment

PLC: PLCs can withstand industrial conditions, including exposure to dust, moisture, and extreme temperatures. Their enclosures meet specific industry standards, such as IP (Ingress Protection) ratings, to ensure operational reliability in challenging environments.

PCB: While PCBs can be engineered with durability in mind, their environmental tolerance is generally lower than that of PLCs. Some types are specifically engineered for harsh conditions, such as those in automotive or aerospace applications. Protective coatings and enclosures can enhance a PCB’s durability to some extent.

Cost Implications

PLC: Given their uses in industrial automation, the initial cost of PLC systems can be high. However, their adaptability, programmability, and durability often justify the cost by providing adjustable and versatile solutions

PCB: The cost of producing a PCB varies widely depending on the design complexity, the number of layers, and the materials used. High-volume production can significantly reduce the cost per unit, making PCBs a cost-effective solution for consumer electronics where price sensitivity is critical.

Adaptability and Upgradeability

PLC: PLCs’ software-based nature allows for relatively easy updates and adaptations to new processes or changes. This makes them inherently flexible and future-proof, as they can be reprogrammed and extended with additional modules to meet evolving needs.

PCB: Meanwhile, PCBs are fixed once they’re made. Their adaptability comes from the ability to redesign and iterate on the layout for future device versions. However, upgrading a PCB-based system requires replacing the board with a new design to accommodate updated components or functionalities.