A significant growth in the use of FDT (Field Device Tool) in factory automation applications has prompted the FDT Group to release an annex that provides enhanced features for PLC programming tools that support the FDT standard. The Factory Automation annex provides a bus-independent interface that allows PLC engineering tools to map generic I/O signals to variables in an IEC 61131-3 program.

“Most PLC applications are conceptually based on a process image that is cyclically updated by a bus master device and accessed via the PLC system vendor’s optimised drivers for the target runtime system,” explains Manfred Brill, the FDT Group’s chairman of factory automation marketing. “This annex provides a consistent mapping of layout information between the communications DTM (Device Type Manager) for the bus master device and the PLC system.”

The new annex supports a bottom-to-top approach where first the I/O signals are configured at individual device DTMs before they are made available at the master DTM as FDT Factory Automation process channels. The annex also provides a well-defined way to identify a specific PLC fieldbus interface if there are several available.

The FDT Group has also released an annex that brings support for the Sercos III high-speed real-time communications system into the FDT standard. It supports the Sercos configuration interface and allows offline configuration of Sercos networks, including  providing process information channels for engineering systems.

Bosch Rexroth and Hilscher have both announced the availability of generic device and communication DTMs to support Sercos III products in FDT applications.

FDT standardises the communication and configuration interface between field devices and host systems and provides a common environment for accessing field device features. It allows any make or type of device to be configured, operated, and maintained via a standard interface.