Thread Starter

Noor ul Eman

Respected Control.com,

I found your site really interesting for getting informations. Will you please let me know, What is the main difference between the existing bus systems and the new FDT/DTM?

Frank Iwanitz


bus systems are used for communication.

FDT stand for Field Device Tool, DTM for Device Type Manager. These address transparent device parameterization. What does transparent mean in this case?
To parameterize a device a fieldbus communication is used.
By using ComDTM different boards can be used in the same way, since they implement an agreed interface. The device itself is represented by a DeviceDTM. This interacts with ComDTM and a Framewokr application. The GUI for the DeviceDTM as the device itself is user dependent.

Up to now FDT exists only for PROFIbus.


There is a big difference. It is almost two completely different things.

By "bus systems" I suppose you are referring to Modbus and Profibus as well
as Fieldbus and ControlNet etc. These are technologies for networking
(hardware), i.e. wires and interface cards etc.

FDT/DTM is a software technology based on ActiveX and XML. It's a scheme for
device parameterization.

I.e. "bus" is networking hardware, while "FDT/DTM" is a configuration tool

Some of the texts I have seen can mislead the reader to believe that FDT/DTM
is a replacement for "existing bus systems" but it is not. Instead it is a
scheme that (in the long run) will be able to configure any device,
regardless of which "existing bus" technology it is connected to. Today
tools support Profibus and HART, and soon perhaps others too.

FDT is the engineering tool

DTM is a "device driver" loaded into the FDT.

We (SMAR) provide DTMs for our Profibus-PA and HART devices.