Traditionally, FDT (Field Device Technology) had been associated largely with process automation and process field devices, but this is no longer the case. Suppliers in the factory automation space are now adopting FDT because they find it affords them the technical flexibility needed to deal with the wide range of product configurations their customers demand. Factory equipment suppliers and machine builders, even major ones, must comply with the system specifications demanded by end user manufacturers. As a result, they must deliver their products to support one of many different combinations of factory automation system and fieldbus. ARC spoke with one major equipment supplier that now uses FDT to increase product flexibility without adding permutations to its product design.
The factory equipment value chain
As the owner-operators, end-user manufacturers (such as global automotive companies) create the specifications for their factory production systems. Their specification decisions flow ‘up’ the value chain, while the products that equip the factory flow in the opposite direction. This complicates matters for the equipment and device suppliers further up the chain who must serve a large number of end-user customers, each with its own specifications. One major technical challenge they face is to customise their equipment as demanded by each end-user without creating a large number of product permutations that would be prohibitively expensive to develop, maintain, and support.
Equipment suppliers must usually support user-chosen factory automation systems as well as user-chosen factory fieldbus technologies. End-users usually prefer to standardise on one automation platform and as few fieldbuses as possible. This greatly simplifies the end-user’s operating and maintenance tasks over the operating life of the equipment, but the machine builders can find themselves ‘sandwiched’ between their customer’s automation and fieldbus choices. This places a premium on a supplier’s ability to be flexible. Complex machines will likely contain one or more embedded controllers supporting proprietary machine features. So the machine builder must integrate its own embedded control technology with whatever else the end user specifies.
FDT
FDT, the IEC 62453 standard, is a software interface specification for interoperability between field devices and automation systems. Its design basis is such that FDT-enabled applications within the automation system can manage field devices regardless of the device’s manufacturer and regardless of the fieldbus protocol employed. This is achieved by equipping each device with a unique software element called a Device Type Manager (DTM). FDT-enabled applications, called ‘FDT Frame Applications’, contain a fully-defined interface to DTMs, providing interoperability between any pair of Frame Applications and DTMs. Frame Applications typically operate in a Microsoft environment.
The scope of the FDT interface includes more than operating data communication. DTMs can be used over the device’s entire life cycle. Functions for device parameterisation, messaging, health monitoring, interactive functions and online help, can be integrated into a DTM. Effective implementations can provide support from commissioning to repair.
Global equipment supplier embeds FDT
ARC Advisory Group interviewed one large (over $1 billion annual revenue) global supplier of factory equipment that has begun embedding FDT into its equipment controllers. The supplier asked to remain anonymous. The supplier’s decision to use FDT was driven by its customer’s demand to support several different PLCs for factory automation and over six different fieldbuses to the various devices that are used with their equipment. The supplier’s FDT implementation presents fieldbus-independent process data both to its controller and to higher level automation systems. The company has embedded FDT into its controller to such a degree that the end user does not see it, but can use the technology to configure, commission, monitor and debug all connected devices regardless of fieldbus.
The supplier has integrated FDT into its internal product management. Each customer order now ships with a pre-configured FDT project within the equipment. Built automatically by its order management system, this covers all the manufacturer’s components in the shipment. System integrators receiving this equipment can add their own custom components to the FDT project when they integrate the equipment into a production line or machine. FDT extensibility is also a plus. The company plans to extend its own FDT implementation to include two additional fieldbuses to expand its served market. FDT represents an important strategic choice in that it ties in with the company’s corporate strategy to differentiate its equipment as being easier to customise than competing products.
The company now expects to embed FDT in the current generation of controllers for their entire product life. Asked to summarise their experience, company representatives said that the move to introduce FDT into their controllers was difficult, but they felt the difficulty was worthwhile, reporting that “it has great benefits whenever you face a wide range of fieldbus protocols.” Clearly for this major supplier, FDT plays an important role in achieving product flexibility and overcoming the difficulties often presented by fieldbus market fragmentation.
For more information contact Paul Miller, ARC Advisory Group, +1 781 471 1126, [email protected], www.arcweb.com
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