How to Select a Valve Controller

It is important for process manufacturers to choose a valve controller or switchbox that will best meet their application needs. Some key aspects to consider include:

• product endurance in demanding application environments

• agency certifications

• easy installation

• maintenance requirements

• product support.

The following tips will not only help you optimize valve controller selection, but will also maximize product performance and value:

TIP 1: Choose a valve controller that’ll give you long-lasting durability
A valve controller needs to withstand demanding plant conditions. So it is usually made of strong metals like aluminum and stainless steel, with engineered resin enclosures and optional special coatings that can handle harsh environments.

It also has to guarantee two important factors – reliability and durability. That is why, valve controllers go through series of endurance tests, so that it offers high performance and also reduces potential maintenance costs. Such tests may include testing in dust chambers to see that it’s dust tight, testing against intense water pressure blasts and even complete submersion.

You can also look for those that have been tested for endurance in extreme hot and cold temperatures and are proven to resist chipping, even in corrosive environments. Products should be tested against hundreds of corrosive and caustic chemicals with various exposure times, temperatures, and concentrations and need to be proven impact- and step- resistant.

TIP 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 thru wiring. This is especially helpful when installing bus networks such as AS-Interface, which requires drop downs for each slave. Be careful not to sacrifice conduit entries for mounting solenoids, as wiring may be a difficult task.

Space is always a key consideration. Factors to consider are the width and height of the valve controller, as well as its brackets or solenoids. Also consider the height of the visual indicator, as it may be susceptible to breakage if it is not proportional to the product. The overall space required can be minimized by choosing features such as direct mounting, which can often save 3 inches max in height and remove the cost of mounting brackets.

Integrated solenoids are an excellent choice as well. They not only save space, but also see no need for additional junction boxes thus easing the installation process. Integrated solenoids are great for Class I Division 1 applications, because they don’t require explosion-proof protection in the coils, and provide extra protection for pilots and electrical components within the enclosure housing.

TIP 3: Demand product flexibility
It is important to seek valve controller suppliers that offer enough options to satisfy complex application needs. These suppliers will offer all major fieldbus protocols such as Foundation Fieldbus, Profibus, DeviceNet and AS-Interface, as well as all major sensor options such as GO Switch leverless limit switches, Pepperl+Fuchs proximity sensors, 4-20mA transmitters and mechanical limit switches.

Full-line suppliers will also have the right pilot valve options to satisfy all application needs, including solenoid valves with low power consumption, a variety of flow (Cv) rates, materials of construction to handle most chemicals and caustics and pneumatic accessories such as speed controls and manual overrides.

TIP 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 across plants worldwide, and thus operations provide 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.