In: Electrical Engineering
Q17
a. What is FDT/DTM standard?
b. What is its function?
c. What are the three stages of FDT/DTM architecture
We’ll start at the “bottom.” Devices that support FDT Technology are supplied with software known as a Device DTM. A Device DTM can be specific to a device or a family of devices and to the protocol (HART, FOUNDATION fieldbus, Profibus, etc.) that the device uses for communication to control systems, configuration tools, and other asset management applications. In essence, the Device DTM is a software program that contains the user interface and any diagnostics and processing functions the device manufacturer chooses to provide. Although its appearance and functionality are engineered by the device vendor they conform to the FDT Style Guide to provide a common structure across all manufacturers. Device DTMs have been described as analogous to “printer drivers” in the office world, since they look the same in any PC or application they run in.
As Figure 1 suggests, the Device DTM, when rendered in the Frame
Application (more on this later), requires a means to communicate
to the device. This “middle” layer is accomplished by what is
called a Communication DTM, or more simply, Comm DTM. The Comm DTM
is provided by manufacturers of communication devices such as
gateways, communication cards and linking devices that provide the
physical connection between the device and the PC based
Application.
The final component, at the “top,” is the Frame Application. It is
somewhat analogous to a browser, but it can have some very powerful
capabilities. A DTM is represented within the Frame Application as
a graphical interface to allow the user to manage the device. A
Frame Application typically renders one device at a time, with most
supporting multiple windows, to allow the user to interact with
several devices. The Frame Application hosts the Comm and Device
DTMs to support management of all the smart devices within a
facility. Although available stand-alone from some organizations,
the Frame Application is more commonly provided within a larger
automation system within various environments, such as
configuration and engineering tools, operator interfaces or asset
management tools. For example, a Frame Application may be provided
as part of a configuration tool for a DCS. Many process control
system vendors that provide Frame Applications have embedded the
Communication DTM functionality into their system configuration and
management tools. The communication complexities of the network
infrastructure, DCS controller, I/O systems and even different
protocols are hidden, allowing the user to focus on the smart
device task at hand. With many vendors incorporating the
Communication DTMs within their respective system management tools,
FDT Technology is often used without the user being aware of the
‘name’ of the underlying technology, hidden to simplify
deployment.