Electrohydraulic proportional valves from different manufacturers may be nearly identical — except for the pin assignments of their electrical connectors. That can spell big trouble.
What do Tiger the Cat and King Kong have in common? For one, you'll find animated figures of both entertaining guests at Universal Studios Florida — Tiger is an animatronic character in Fievel's Playland, and King Kong is the centerpiece of Kongfrontation. For another, both use electrohydraulic proportional valves with on-board electronics to orchestrate a variety of lifelike motions.
King Kong uses standard Vickers valves, and Tiger the Cat uses standard valves from Parker Hannifin. If maintenance technicians had to replace a Parker valve with one from Vickers or a Vickers valve with one from Parker, the mounting footprint, plumbing configuration, port connections, or geometry of the electrical connector would not prohibit doing so. What would prevent replacing a valve from one manufacturer with that from another is pin assignments of the electrical connector.
If all operational and performance characteristics are carefully evaluated, Parker, Vickers, Bosch, Danfoss, and Rexroth proportional valves with on-board electronics all can be physically interchanged within an application. Furthermore, all are available with the same electrical connector. However, pin positions on the connector for one manufacturer's valve may perform different functions from those for any other manufacturer's valve. This means that to replace a valve, you either must use one from the same manufacturer, or you have to reconfigure the pin assignments — a risky and time-consuming process. You can't just replace the valve and reattach the electrical connector because — if you're lucky — the valve will do nothing. If you're not so lucky, the valve will become damaged or malfunction, which could damage expensive equipment controlled by the valve. So if an attraction becomes inoperative due to a valve failure, it will remain inoperative until a replacement is obtained from the original manufacturer — even if an equivalent valve from a different manufacturer is on the shelf.
In an attempt to eliminate this problem, the National Fluid Power Association (NFPA), Milwaukee, formed Technical Committee T2.30.6 — Connectors for integrated amplifier proportional valves. The committee has been meeting three times a year to develop a common connector for standard industrial hydraulic proportional valves that have on-board electronics. Establishment of the committee was spearheaded by Fred H. Phillips, manager, advanced technology, Vickers, Inc., Rochester Hills, Mich. Currently, the committee is co-chaired by Mary McNamara, senior project engineer, of Parker Hannifin's Hydraulic Valve Div., Elyria, Ohio, and Greg Cameron, regional sales manager, Deutsch, Hemet, Calif., who serves as the committee's source of technical information on electrical connectors.
Specifications for a standard connector have been proposed by the National Fluid Power Assn., Milwaukee. For more information about Performance Specification T2.30.6 — Connectors for integrated amplifier proportional valves, contact NFPA at firstname.lastname@example.org.