1.5 Introduction: Solution Concept

The FDT concept defines the interfaces between device-specific software components provided by the device supplier and the engineering tool of the control system manufacturer. The device-specific software component is called DTM (Device Type Manager).

The FDT concept can apply to any other application for handling field devices. However, the focus of the current version of FDT lies on engineering, commissioning, diagnostics and documentation of fieldbus-based control systems. Basic functionality is defined to achieve Audit Trail for applications like Asset Management.

The Device Type Managers are supplied by the device manufacturer together with the device. The following properties are characteristic for the DTM:

• It is generally no standalone tool
• ActiveX interfaces defined by the FDT-Spec.
• All rules of the device known
• All user dialogs contained
• User interface (multilingual including help system)
• Parameter validity check (also depending on other device-specific parameters)
• Automatic generation of dependent parameters
• Definition of the processing sequences of complex calibration, matching and setting procedures for high-quality field devices
• Reading and writing of parameters from/to the field device
• Diagnostic functions customized for the device
• Provision of the type-specific data for establishment of communication
• Provision of device/instance-specific data e.g. to be used in function planning
• Device / instance specific documentation
• No direct connection to any other device
• No information on the engineering environment
• Support for one or more device types

The quantity of functions (optimized by the device manufacturer for its device) listed here depends on the functional capabilities of the device. A DTM covers at least one field device. DTMs can, however, also cover device families (for example, pressure transducers), for example on the basis of Profiles or the entire palette of a manufacturer. Communication (via the various bus systems of a control system) and data management are handled via the interfaces of the engineering tool. Within the framework of overall system planning or plant management, a DTM must always be integrated into the appropriate engineering tool. Parallel standalone operation may be implemented in special cases for example when migrating from a standalone tool to a DTM. For reasons of data consistency, parallel operation of standalone solutions and DTMs running in the system’s engineering tool accessing the same devices are not intended. Standalone operation may typically be used for testing purposes in a plant’s workshop.

A DTM is installed as a component of an engineering tool or any other application that manages the device instances, provides the communication mechanisms and commissions the associated component with device-specific tasks. In the following, those applications are referred as ‘Frame Applications’.

The following requirements apply to Frame Applications:

• No device-specific knowledge necessary
• Manages all device instances and stores instance data
• Creates the device communication and connection (tool routing)
• Guarantees system-wide consistent configuration
• Makes multi-user and server/client operation possible
• Takes care of data versioning