FDT technology can be applied across industrial control automation, including factory automation and hybrid applications.
Overview
The automation community often assumes that FDT/DTM (IEC 62453) is mainly suited to process automation. This perception likely stems from early case studies and introductory materials that used process plants as typical examples.
In fact, when implemented correctly, FDT can be used effectively in any industrial control automation environment, including factory automation and hybrid plants that combine discrete and process automation. Whether an application uses fieldbus networks, HART field devices, remote I/O systems, drives and motor starters, or sensor networks, manufacturers can create device type managers (DTMs) for their devices.
One reason for the misconception is that many existing examples and conceptual demonstrations for FDT/DTM use field devices or control valves from process plants. This focus is understandable: field transmitters and control valves are typical examples of complex devices that benefit from comprehensive asset management, giving plant operators a unified interface to access detailed field data.
01 Better Support for Field Devices
One limitation for deploying smart devices is that some vendors require different integration software to access available data from connected field devices.
Large DCS vendors can integrate asset management into a whole-plant software suite that works smoothly with engineering tools. However, many smaller vendors, especially third-party field device and interface technology suppliers, cannot support smart field devices in their lower-cost, modular remote I/O systems targeted at machine builders.
FDT has supported nested communication since specification 1.2. Nested communication enables a DTM to communicate with devices that use the same or different communication protocols attached to different hardware. This nested capability coordinates topology and data structures and provides a unified environment for device management.
Combined with the modular framework concept, FDT nested communication enables smaller vendors to incorporate core FDT functionality into their existing engineering software solutions. Using the FDT framework, vendors can offer HART-capable, compact modular remote I/O systems that are cost-attractive. These FDT/DTM applications can serve as standalone configuration tools or as modular middleware for hardware integration, and they can be embedded into any engineering control application with minimal impact on operators.
02 Nested Communication Application Solutions
To clarify this, here are some basic FDT/DTM concepts.
DTMs generally fall into three types:
- Device DTM: operates like a hardware device driver and runs within an FDT framework application.
- Gateway DTM: acts as a device driver but also provides protocol and media conversion for industrial communication gateways.
- Communication DTM: provides communication channels for devices connected via nested communication networks (any protocol).
Nested communication allows vendors to deliver complete I/O subsystems that can be combined with any master station, power units, I/O modules, and an FDT-based integrated asset configuration and management solution. This approach can avoid costlier features—such as configurable hot-swap I/O modules and redundant power backplanes—that are seldom required in typical machine control applications.
Remote I/O subsystems are particularly well suited to the modular approach enabled by FDT/DTM. Typical remote I/O applications using FDT include:
- Communication DTMs to link remote I/O with a control system backbone network.
- Gateway DTMs to integrate the remote I/O system master. These modular DTMs allow users to replicate the I/O module structure used in the application.
- Device DTMs to support smart devices connected to the corresponding remote I/O modules.
A common implementation pairs HART-capable I/O modules with HART field devices. In this setup, an I/O module can expose information for any device connected to it, whether the device is smart or conventional.
This arrangement provides access to the full feature set of smart devices whose device-specific DTMs run in the FDT framework application, either standalone or as part of an integrated engineering application. At the same time, it supplies basic diagnostics for simple non-smart field devices, such as short-circuit and wiring-break detection for discrete DI and DO devices. In other words, it is an embedded method to provide intelligence for non-smart devices.
03 Integrated Solutions for Machine Builders
Compact modular remote I/O systems offer an attractive solution for machine builders. A machine can be designed with a universal I/O configuration and the appropriate communication master selected later. If the machine is connected to a control system that supports FDT, integration becomes much simpler.
FDT is also applicable beyond process environments for integrating complex drives, such as speed controllers, servo and motion drives, and motor controllers.
04 A Single Solution for All Fieldbus Protocols
Third-party fieldbus interface solutions designed for a specific PLC often require dedicated fieldbus configuration tools. That software maps I/O information from field devices into controller memory to create the I/O mapping table the controller uses; the controller typically does not need the additional data produced by smart devices.
When a control system uses multiple fieldbus protocols, separate configuration tools are usually required. Integrating those protocols into an FDT framework allows a single configurator to manage multiple communication protocols, simplifying the application considerably.
Communication DTMs can support new protocols and be included in a PLC programming platform's hardware catalog. This approach hides protocol details from the user interface: as long as a communication DTM supports a protocol, users can add any available device that is installed in the system. The FDT framework functions as an abstraction layer, enabling seamless access to connected devices. Each device DTM is accessed through its corresponding communication DTM.
When connecting remote I/O systems or fieldbus devices, a gateway DTM must be placed beneath the communication DTM in the topology. This arrangement allows adding remote I/O modules or specific fieldbus devices by connecting them to the appropriate gateway DTM. The main advantage is that fieldbus interface details are hidden from the framework application and presented as an abstract layer for connecting smart devices.
FDT-compliant controllers can adopt this method, using different gateway and communication DTMs for each required protocol.
05 Hybrid Plant Applications
In hybrid plants, distinct production areas may require both batch process control and machine-style automation. For example, a beverage production area might use flammable flavoring oils or spirits, which involve hazardous zones and batch processing. Typical solutions can include HART field devices, Profibus PA devices, or EtherNet/IP devices.
Local and third-party remote I/O systems can be configured with the appropriate DTMs and, when equipped with AI and AO cards that include integrated HART modems, can function as HART gateways. These systems often support Profibus-DP, EtherNet/IP, or Modbus-TCP. DI and DO cards that detect wiring breaks and short circuits for simple binary sensors can provide additional functionality.
Remote I/O systems fitted with intrinsically safe I/O cards typically support HART. These devices can host embedded FDT framework applications and be integrated into PLC configuration and programming environments.
06 Integration with Third-Party Vendor Products
A key characteristic of FDT is its openness. Even when a manufacturer does not supply a DTM for a device, viable alternatives exist.
Independent software developers have created third-party DTMs for widely used hardware, for example for Siemens DP/PA links and ET-200 remote I/O systems. With such gateway DTMs, users can use an FDT framework within a Siemens-based control system to perform typical asset management tasks for Profibus PA and HART transmitters.
While generic DTMs may not expose every device-specific function, in many applications the supported feature set is sufficient, and the advantages of a consistent configuration and management interface are apparent.
