Valve Basics: How to Select a Valve Controller

Choosing the best valve controller or switchbox starts with understanding the unique demands of each application.

Steve Sikora, P.Eng., SAMSON Controls Canada, Senior Applications Specialist

When it comes time to select a valve controller, there are numerous factors that must be considered based on the demands of the application for the valve. The following includes some key issues to understand to optimize valve controller selection while maximizing product performance and value.

Consideration 1: Choose products engineered for endurance
Reliability and durability are extremely important when choosing a discrete valve controller. Valve controllers must be rugged to withstand demanding plant, environmental and process conditions. Look for products that have been tested for endurance in extreme hot and cold temperatures and are proven to resist deterioration or chipping, even in corrosive environments or abusive conditions.

Manufacturers should provide endurance testing for millions of cycles to ensure that product performance and reliability. Choosing products that are tested tough increases life-cycle performance and reduces potential replacement or maintenance costs. Endurance tests may include testing in dust chambers to ensure the product is dust tight, testing against intense water pressure blasts or even complete submersion.

Products are tested against hundreds of corrosive and caustic chemicals with various exposure times, temperatures and concentrations, and need to be proven impact- and step resistant. These extreme test conditions should instill confidence that the product is durable enough for your application.

Standard materials of construction include aluminum, stainless steel and composite enclosures, often with options for special coatings to handle unusually harsh environments. Ideally, seek suppliers that proactively design products to pass the intense testing criteria of the various major certification agencies, and have the vision to anticipate trends and future requirements.

Consideration 2: Seek savings beyond downtime
Sometimes it’s the little things that make a difference. For example, having two dedicated conduit entries on your valve controller enables easy wiring. This is especially helpful when installing bus networks such as AS-Interface, which requires drops for each slave. Be careful not to sacrifice conduit entries for mounting solenoids as this limits wiring ease.

Space is a critical consideration when selecting a valve controller. Evaluate the total installed footprint, including the controller, brackets, solenoids and the height of the visual indicator, which should be proportional to the unit to reduce the risk of damage. Features such as direct mounting can reduce installed height by up to 3 inches while eliminating mounting brackets. Integrated solenoids further minimize space requirements, simplify installation by eliminating separate junction boxes, and are well suited for Class I, Division 1 applications by providing enclosed protection for pilots and electrical components without requiring explosion-proof coil protection.

Consideration 3: Demand product flexibility
Choose a discrete valve controller supplier with a comprehensive product offering to meet a wide range of application requirements. Look for support for major fieldbus protocols, including Foundation Fieldbus, Profibus, DeviceNet and AS-Interface, along with sensor options such as leverless limit switches, Pepperl+Fuchs proximity sensors, 4–20 mA transmitters and mechanical limit switches. Suppliers should also offer a full range of pilot valve options, including low-power solenoid valves, multiple flow (C_v) ratings, corrosion-resistant materials for harsh chemical environments, and pneumatic accessories such as speed controls and manual overrides.

Consideration 4: Identify suppliers with global certifications
Many process manufacturers have plant operations located around the world. As plants expand globally, there is increased need around the world for products with multiple certifications. Choosing products with global certifications makes it easier to standardize global operations and create greater efficiencies and reduced costs. Standardized plants that operate the same regardless of location help improve product quality and service levels, reduce operations and training costs and increase purchasing leverage.

Global process manufacturers should seek suppliers with all major agency certifications (UL/CSA, c-ULus, CENELEC/ATEX, CE Mark, etc.), ideally in the same model. The reduction to a single part number can significantly increase cost savings. Suppliers should also offer solutions for all major hazardous area classifications, including Zone 0 (Intrinsically Safe), Zone 1 (Flameproof/Explosion Proof), and Zone 2 (Non-Incendive), as well as General Purpose applications. It is important to choose a supplier that is aware of global certification requirements and offers products to meet these varying needs.

Making the right selection

Selecting a valve controller or switchbox should be a deliberate decision, not simply left to supplier preference. Evaluate manufacturers based on their experience, global certifications, product testing and long-term technical support. By clearly specifying the features your application requires — such as improved performance, a smaller footprint, standardized components, and simplified installation and maintenance — you can reduce unnecessary costs while improving long-term reliability. Investing time upfront in the selection process helps ensure consistent performance, lower lifecycle costs, and greater confidence in your operation for years to come.

This article was originally written by Deanna Dessify. It has been reviewed and slightly updated by Steve Sikora, SAMSON Controls Canada.