A programmable logic controller (PLC) controls the manufacturing processes for integrated production lines and equipment. PLCs were designed to replace the need for a large bank of relays or timers in facilities with numerous inputs and outputs. Due to their durability and ability to automate multiple processes, PLCs have become a staple in modern manufacturing. In this guide, we will review the basic architecture of programmable logic controllers.


The main components of a PLC consist of a central processing unit (CPU), power supply, programming device, and input and output (I/O) modules.


The CPU is the brain of the PLC and carries out programmed operations. These operations or outputs are executed based on signals and data provided from connected inputs.

I/O Modules

PLC input modules connect various external devices, such as sensors, switches, and push buttons to the PLC to read various digital and analog parameters, such as temperature, pressure, flow, speed, etc. Output modules convert signals from the CPU into digital or analog values to control output devices.

Power Supply

The power supply provides power to the PLC by converting the available incoming AC power to the DC power required by the CPU and I/O modules to operate properly.


The PLC manufacturer typically determines PLC development software. Allen Bradley, Siemens, and GE each have their own software development platforms for programming their PLC models. Once the platform is determined, the actual programming of the PLC logic can be done in a few different methods. The most common methods of PLC programming include Ladder Logic, Function Block, and structured text.

Ladder Logic

Ladder Logic is a graphical PLC programming language and is the most common method of programming. Ladder Logic can be used to execute tasks such as sequencing, counting, timing, data manipulation, and more. Ladder Logic is structured similarly to relay logic; however, the physical switches and coils used in relay logic are replaced by the PLC’s memory locations and I/O.

Structured Text

Structured text is a text-based PLC programming language and is similar to Python, Visual Basic, or C coding languages. Programming with structured text has multiple advantages, such as the program requiring less space due to being text based instead of graphic based. Additionally, the structured text can be combined with other programming languages, such as creating function blocks containing functions written in structured text.

Function Block

Function block PLC programs are represented in the form of graphical blocks. Signals or data flow into the function block from inputs connected to the PLC. When the incoming signals or data triggers the function block’s pre-programmed function, the PLC executes one or more outputs. Function blocks can have standard functions such as timers, counters, calculating min and max values, obtaining averages, and more.

About Process Solutions

Located near Seattle, Washington, Process Solutions has over 30 years of experience providing high quality and reliable control systems. With over 100 engineers and technicians on staff and an output of over 3,000 control panels per year, Process Solutions is the Northwest largest control systems integrator. Process Solutions’ control systems services include custom control panel design, build, and commissioning, HMI programming, PLC integration, energy management and refrigeration systems, SCADA software, and machine monitoring software.

Vaclav Mydlil
Sr. Director of Advanced Automation
Vaclav leads the dynamic Energy Management and Refrigeration Division at Process Solutions. With an impressive 20 years of experience in power demand management and refrigeration control systems, Vaclav is the driving force behind one of the company’s most innovative systems.

His expertise extends to PLC and cloud-based systems, ensuring seamless integration and optimal performance. Vaclav’s commitment to excellence is underscored by his Master of Science degree, specializing in control systems and electrical engineering, which he earned from the University of Life Sciences in Prague, Czech Republic.

Beyond the office, Vaclav’s passions include kayaking, snow skiing, and woodworking. Most of all, he enjoys moments spent with his wife and three kids.
Steve Pelton
Vice President of Sales
With over 20 years at Process Solutions, Steve Pelton has held various roles, including Sales Engineer, Sales Director, and his current position as Vice President of Sales.

In addition, Steve oversees Process Solutions’ Energy Management and Refrigeration Division — ensuring the company remains at the forefront of energy-efficient solutions that cater to diverse food production applications. Steve also spearheads the strategic development of the company’s machine monitoring solutions, aligning them with client needs and market trends.

Steve’s background includes mechanical engineering, but his career trajectory has mainly focused on control systems marketing and management. His ability to bridge technical expertise with business acumen has been instrumental in Process Solutions’ growth.

Outside the office, Steve passions include conquering rugged trails on his mountain bike, perfecting his golf swing, and exploring new destinations with his family.
Matt Barnes
Chief Financial Officer
Matt, with 28 years of financial strategy and accounting experience, plays a pivotal role at Process Solutions. As the Chief Financial Officer (CFO), he spearheads the company’s growth strategy, ensuring financial stability and health.

Beyond traditional financial management, Matt also oversees strategic initiatives aimed at optimizing Process Solutions’ on-hand inventory costs and availability. By fine-tuning inventory management, Matt ensures the company can meet client needs efficiently and maintain a healthy bottom line.

Matt graduated with a degree in accounting from Western Washington University and previously served as a financial executive at a large retail corporation. Outside of work, Matt enjoys traveling, soccer and spending time with his family.
Kevin Orr
Executive Vice President
Kevin boasts an impressive tenure of over 25 years at Process Solutions. His position in the company has been multifaceted, spanning roles as a project engineer, engineering manager, and Process Solutions’ first Executive Vice President.

Under Kevin’s leadership, the food processing division has flourished, earning its reputation as of the most respected in the industry. Today, Kevin closely collaborates with executives from leading food processors and food processing equipment manufacturers across the country.

Kevin is a devoted husband and father with a passion for international travel.
Todd Busby
Chief Executive Officer
Todd has dedicated over 30 years to Process Solutions, where he has worn multiple hats—from panel builder to project engineer and sales representative.

As the CEO of Process Solutions, Todd has spearheaded significant transformations. Under his leadership, the company has diversified into new industries, acquired a world-class facility, and more than doubled its size.

Todd, a native of the Puget Sound region, is a devoted husband, father, and avid outdoorsman. When he’s not at work, you’ll find him supporting his three kids in all their pursuits or hunting and fishing in Eastern Washington.
David Crumpley
David has dedicated over 15 years to Process Solutions, where he has served as a Senior Engineer, Vice President, and now Chief Operating Officer. His multifaceted experience spans technical expertise, strategic leadership, and operational efficiency.

As the head of Process Solutions’ Water/Wastewater division, David orchestrated the modernization of the company’s internal systems and boosted operational efficiency across the organization.

In his current role as President, David continues to drive innovative initiatives aimed at expanding the company’s reach and further streamlining internal processes.

Outside of work, David enjoys spending quality time with his family and pursuing his passions as an avid outdoorsman.

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