Air Valves Take on a Global Identity

ISO 15407 completes the standardization of fluid power components.

By John Garbarino and Raj Rajani
Parker Hannifin Corp.,
Pneumatic Div.

This ISO 15407-2 manifold, uses a 25-pin D-subminiature connector cable for collective wiring.

ISO 15407-2, using IsysNet serial communication modules

ISO 15407-2 manifold. Jump sizing 18-mm and 26-mm valves on the same manifold.

Although the non-electrical portion of International Standards Organization (ISO) 15407, Part 1, has existed since March 1, 2000 — and used widely in Europe and Asia — only recently has Part 2, the electrical portion, shown up as a significant blip on the radar screen in the United States. The impact of ISO 15407's two parts continue to increase as global applications require standardization.

Part 2 of ISO 15407 states that ISO pneumatic valves must be constructed to a set of specifications that require manufacturers to conform to dimensional and electrical patterns. These include the interface mounting patterns and the electrical connections resulting in interchangeable components. This applies to both single-base valves and manifolds of all types.

A little history
Standardization of valves was not that important a decade or so ago because industrial production was, for the most part, regional. Today, however, in a truly global manufacturing environment such as the auto industry, for example, an engineer in Michigan may write a machine specification, the machine may be manufactured in Germany, and then half the machines are shipped to production facilities in the U.S. and the other half to Mexico.

Other fluid power products have met standards for years. Hydraulic and pneumatic cylinders, as well as hydraulic valves, conform to both ISO and National Fluid Power Association (NFPA) standards, creating common component interfaces. Pneumatic valves smaller than an ISO size 1 did not have a standard until much later.

ISO 5599-2 (plug-in) and 5599-1 (non-plug-in) pneumatic valve standards created common interfaces. Sizes 1 through 4 have a flow coefficient (CV) of 1.1 through 7.4. Size 1, however, is a larger and more expensive valve than that required for most pneumatic applications ( cylinders with at least a 4-in. bore and 12-in. stoke), creating a gap in availability. ISO Standard 15407 fills this gap.

ISO 15407
ISO 15407, which designates the valve footprint, was developed to standardize five-port directional pneumatic control valves sized 18 mm and 26 mm, with C_Vs of 0.55 and 1.1, respectively. Two types of ISO 15407 valves exist — 15407-1 and -2. An ISO 15407-2 valve has a body-to-base plug, in which the valve plugs into the base electrically. The bottom of the valve has a female socket and the base has a male plug. An ISO 15407-1 valve is a non-plug-in design with no electrical connectivity through the base. It is an adaptation of an existing VDMA ( European) standard. Electrical connections are made via DIN connectors or M12 or M8 connections on the valve body or coil.

Until recently, no standard valves in these sizes were available to designers. ISO 15407 valves typically can control cylinders with a bore to 4 in. and a stroke to 12 in. with adequate speed. Probably 50% of applications for pneumatic valves fall within in this range.

The absence of these valve sizes in ISO configurations led to a proliferation of proprietary valves from many manufacturers. Proprietary valves benefit manufacturers by creating a captive customer base by selling a brand name product with features that guarantee future business. Furthermore, proprietary designs generally do not lend themselves to component standardization. Increasing globalization and the demand for standard platforms and interchangeable valves are changing the landscape of the pneumatic valve designs the same way open operating systems changed computer designs.

Users held a false perception that purchasing ISO-compliant valves would be too expensive for many applications. However, leading pneumatic valve manufacturers recognize that globalization is here to stay and are introducing ISO 15407 pneumatic valves and redesigned ISO 5599 valves that satisfy the ever-growing demand for standardization.

ISO 15407 user benefits
From the user's viewpoint, ISO 15407 means standardized air valves will be readily available from manufacturers around the globe. In conjunction with ISO 5599 for Parker, standardization will be in place for a complete range of sizes, including ISO 15407 sizes 18 and 26; and ISO 5599 sizes 1, 2, and 3. Flow ranges will be from 0.5 to 6.6 C_V. Benefits to users include:
Standardization. With dimensional and electrical components standardized, users can write specifications that meet a standard, rather than relying on a single brand name. Dimensional requirements address the footprint for valves and bases; bolt locations, thread depths, and number of bolts; electrical connection location and configuration; and pin spacing. If an international company has facilities around the world, standardization ensures interchangeability with valves from multiple suppliers. Standardization increases performance quality and enhances electrical options and connectivity possibilities.
Reduced risk. If business conditions change, and quality, delivery, or performance issues arise with one valve supplier, user can easily change brands because proprietary limitations will be eliminated. However, performance characteristics must be checked before a substitution is made and any adjustments made before operating.
More freedom and flexibility. Standardization facilitates choice. Users may still have brand preference, but ISO-compliant valves will meet quality and interchangeability criteria. Users will have be able to deal with multiple valve manufacturers anywhere in the world.

Communication, connectivity
Communication and connectivity are critical issues when implementing fluid power control applications. The prevailing trend is toward the use of EtherNet Industrial Protocol — which supports real-time messaging — as the standard for air valve control. EtherNet IP is based on commercial, offtheshelf EtherNet communication chips but uses an open protocol at the application layer. EtherNet IP nodes show a 40% annual growth rate; ControlNet, 8.1%, (IMS European Union); DeviceNet sales exceed 5 million nodes globally.

Each of these three networks has application strengths and weaknesses, appealing to different types of users and industries. They use a common application layer, or common industrial protocol (CIP). This ensures common user experience on all networks.

Implementing a standard interface to communicate and exchange data will provide users around the world with interchangeable physical hardware — such as I/O modules, valve driver modules, and the backplane used for power distribution — and the software for communication between the valve's pneumatic and electronic components.

The goal of EtherNet/IP standardization will be to enable the same module to interact with the five main valve families: ISO 15407 sizes 18 mm and 26 mm; and ISO 5599 sizes 1, 2, and 3.

Parker Hannifin will be the first manufacturer to use EtherNet/IP with its line of ISO pneumatic valves. Its communication network is called IsysNet (See box for more information).

What will the future bring?
Although the 15407 standard has been in effect for a short time, it will be some time before all pneumatic valves in the field are 15407 compliant. There can be thousands of valves in a single plant, and it's not uncommon for global manufacturers to have 50 plants in different countries around the world. It would be economically impossible, and probably pointless, to retrofit valves before they need to be replaced. It will be an evolutionary process for ISO 15407 valves to become the dominant valve in operation. Product performance, customer service, and quick delivery will still be the drivers in a customer choosing a valve supplier.

It's apparent, however, that global manufacturers want standardization. Engineers and end-users will change specifications for new machinery to use ISO 15407 valves and, over time, they will populate plants around the world. There are too many consistency and quality benefits for 15407 not to become the standard for all pneumatic valves.

For more information, visit www.parker.com/pneumatic or call (269)629-5000.