Field Device Tool

from Wikipedia, the free encyclopedia

Field Device Tool ( FDT ; German  " Field device tool " ) is a manufacturer-independent concept in automation technology, which the parameterization of field devices allows different manufacturers with only one program.

FDT introduction

FDT is a specification for a software interface. This software interface describes the data exchange between an application and software components for field devices. FDT is standardized as the international standard IEC 62453 and ISA103.

FDT is used both in process engineering systems and in factory automation. The concept supports both simple field devices (with few parameters) and complex devices (with many parameters and modules).

In order to keep the variety of device operating tools low for the user, FDT pursues the main goal of bringing together different device software (DTMs) in a common frame application ( FDT Frame Application ). The various field devices can be accessed from this central framework application and configuration can be carried out with the corresponding DTMs.

The FDT concept can be explained clearly using a printer and the associated device driver with an integrated graphical user interface. The latter always appears in any Office application in the same way and with the same functionality. With FDT, the manufacturer provides a device driver (DTM) for the field device that allows access to the device from any FDT application via a graphical user interface. This enables the users to access all device functions made available by the DTM and to configure, operate and maintain their devices.

FDT supports a large number of communication protocols as well as communication via nested communication protocols .

With the help of the standardized interface between DTMs and the framework application, the DTMs can be used in a wide variety of framework applications regardless of the system.

Why is standardized device integration important?

Device integration has been a much discussed topic for years. In addition to process data, today's intelligent field devices provide more and more information and functions. Crucial for the user: A standardized system environment for the central administration, commissioning, configuration and maintenance of all field devices. A corresponding standard must be independent of manufacturer and communication protocol so that the best device can be selected for the respective application. In addition, the solution must ensure seamless data exchange between field devices and the higher-level automation system. In order to be able to guarantee the operators long-term investment protection, only an open technology such as FDT comes into question. Last but not least, FDT paves the way for uniform device drivers. Only a single DTM is required for each device for integration into existing FDT systems. The universal application also lowers the development costs for the manufacturer.

This is possible because the FDT specification ensures interoperability. This means that every DTM can be used in every FDT frame application, regardless of the manufacturer. FDT technology does not require any specific adjustments to the field devices, such as firmware or hardware, but only a communication interface to the device and can therefore be used universally.

The FDT technology maps the communication protocol supported by the device and the device properties completely on the PC. Thus, a DTM is able to carry out parameterization and configuration even without a device - offline - and to transfer them to the device at a later point in time. FDT is not only suitable for new systems, but also for subsequent introduction into existing systems - without having to intervene in the installed devices. The users can simply use their existing network. For the existing devices only DTMs and of course an FDT frame application have to be installed.

Current state of the art

With the new FDT2 specification, the FDT Group ensures the implementation of current user requirements. Due to the downward compatibility, the use of all FDT 1.2.x DTMs is still possible, thus guaranteeing investment protection over the life cycle of a system. Downward compatibility is ensured by the fact that FDT frame applications support both FDT 1.2.x and FDT2 and take over the transformation of the communication between the components of different versions. The Microsoft .NET technologies as a basis make the FDT technology more independent of the hardware and different Windows operating systems. In addition, the possibility of using WPF ( Windows Presentation Foundation ) opens up the way to new design options for graphical user interfaces (GUIs), such as B. finger operation, as users from the private sector of smartphones or tablet PCs are used to, or generally the use of modern UI design.

DTMs and FDT frame applications are optimized in particular through the introduction of so-called common components. The common core components increase the stability of the application and improve the interaction of the individual components. The interoperability is ensured because the specification was actually implemented only once in two components, which have been intensively tested and certified by the FDT Group. They also allow a consistent development of the standard software components. This accelerates the time-to-market for certified FDT products and reduces costs for device manufacturers. Stricter specifications for certification and recurring manufacturer tests (interoperability tests in which manufacturers of DTMs and frames meet and test their components mutually) have significantly improved the interoperability of FDT.

At the same time, work is being carried out to support further standardized communication protocols in FDT. The following are currently described in annexes (additional documents to the standard): Profibus DP, Profibus PA, Hart, Foundation Fieldbus H1 / HSE, Interbus, Profinet, Modbus TCP / RTU / ASCII, Ethernet / IP, Ethercat, Devicenet, Controlnet, IO-Link , AS-Interface, Canopen, SercosIII, CC-Link and ISA100; further protocol descriptions follow. An annex describes how the protocol-specific communication on the fieldbus must be mapped on the software side in the DTM so that DTMs from different manufacturers can interact.

Consistent device access

FDT offers the user many advantages. The technology can particularly show its advantages in systems in which different types of field devices and communication protocols, mostly from various manufacturers, are used on the different levels of the automation pyramid.

The greater the variety of device types used, the more difficult and time-consuming the configuration is in everyday plant life. The effort is particularly high when the manufacturers work with proprietary parameterization and configuration tools that are not standardized. In order to enable data exchange between these tools and the engineering systems of the controls, data conversion is often necessary, which requires special know-how. Consistent data, documentation and configurations become a real Sisyphean task for users. This is different with tools such as FDT, which can be seamlessly integrated into the system tools of the automation system. So z. For example, the cyclic data traffic of the controller can be configured in an integrated manner. The universal technology enables end-to-end device and system integration across all levels of the automation pyramid and regardless of the communication network used.

The advantages at a glance

  • Planning, commissioning, diagnosis and maintenance with direct access to all field devices from a central workstation
  • Consistent access to the devices, regardless of the given network structures and communication protocols, from both central and decentralized locations
  • Exchange of common data between system tools (engineering or plant asset management system (PAM)) and / or device-specific user interfaces
  • Central data management and security as well

Management of multi-user systems

  • Possibility of use in system tools (e.g. engineering tool, control system) as well as stand-alone configuration tools in the workshop and maintenance area

What FDT can do

However, FDT supports much more than just the configuration or parameterization of devices. Each phase of the life cycle of a system requires specific functions that FDT makes available to users.

Offline engineering

FDT enables offline engineering without devices as early as the planning phase. To do this, you enter the parameterization data of the devices in the associated DTM and save them in the project file of the FDT frame application. Once the devices have been installed, the data is then simply downloaded. This significantly shortens the commissioning time of a system.

Network scan

FDT frame applications can automatically recognize field devices connected to the bus. This scan function enables the system topology to be generated or checked automatically. The network scan also provides the fieldbus addresses of the identified devices. The FDT projects of existing plant topologies can be generated automatically from the field devices by scanning and data upload.

Topology import / export

FDT defines a method for the exchange of topology information between FDT frame applications. The export information also contains application-specific data from the respective DTMs. This function can be used, for example, to archive historical data records from DTM instances. With the mutual export / import of projects, these can be exchanged between different framework applications without further conversion.

Audit trail (process and device history)

Operator interventions can be traced using an audit trail. A kind of logbook documents who made which changes and when - an essential function in system validation.

Consistent data storage

FDT frame applications provide a database for the consistent data management of all devices in a system in a single project file. All project data can be saved (backup) and restored (restore) centrally.

User management

FDT specifies a uniform user management with individual access rights for defined users or user groups: observers, operators, maintenance and planning engineers and administrators. This ensures that certain functions of the DTM or the FDT frame application are only accessible to authorized users. Sensitive functions and data can be protected and unnecessary data hidden for certain operations.

Plant documentation

All parameters and "nameplate information" of the installed devices are required for the documentation of a system. A uniform interface ensures that this data can be accessed electronically and processed or output for the desired type of documentation. The option to print (also as PDF) the device information in standardized templates is typical.

Diagnoses and online values

The DTM allows online access during the runtime of the system and shows diagnosis, status monitoring or measured values ​​of the device or the process.

Applications over the entire life cycle

DTMs offer many advantages over the entire life cycle of a system. Manufacturer-specific device functions such as status monitoring and messages, interactive functions and graphic objects, trend curves, echo curves, time curves or device-specific online help can be integrated into a DTM. Device manufacturers can support the user via DTMs - from commissioning aids and diagnostic options to maintenance and repair instructions. For example, a project view can show the structure of the plant under the aspect of communication between PC and field devices. Colored symbols can mark the current status of a system and thus accelerate maintenance or error analyzes.

Plant planning and project planning

The framework application offers a clear and well-structured device catalog for planning and configuration tasks. Optionally, the view of the device catalog can be adapted with filter functions. The framework application is free to further support the work of the plan. For example, in the context of a communication DTM it can be displayed which device DTMs (or corresponding devices) can be connected.

Installation

The be-all and end-all of every commissioning is the device parameterization. With the online parameterization function, those device parameters are configured that can also be defined without a connected device, i.e. offline. With the online parameterization, parameters of connected field devices, such as B. control parameters, change. Additional online functions (trend displays, envelope curves, etc.) optimally support commissioning with regard to the device and application.

Plant operation and maintenance

It is important to work in a time-optimized manner during operation and maintenance. FDT frame applications can offer the simultaneous processing of several devices in one operation. After selecting the relevant devices, the desired function, such as reading out the device status, is automatically started for all. The often tedious reading and writing of parameters in field devices can also be carried out automatically and for several devices or a specific part of the system in one operation. Plant operators and maintenance personnel also need current status information on the field devices in the plant. With the help of the appropriate FDT frame application, you can z. B. query a predefined set of field devices once or cyclically for their status information. Filter functions increase the clarity and facilitate display and evaluation. Modern field devices provide a large amount of diagnostic information - usually both specific and standardized in accordance with the Namur recommendation NE107. Using the corresponding device DTM, users can then identify maintenance requirements and, in the event of maintenance requirements, query more detailed information from the sensor and take suitable measures at an early stage. Is z. If, for example, the signal-to-noise ratio of a radar sensor is getting smaller, product build-up on the antenna could be the cause. The cleaning of the antenna can then be planned specifically.

The problem and the solution

A modern field device offers the possibility of parameterization and diagnosis with computer programs that have been specially developed for the respective field device. In order not to have to install many different programs on a PC, the FDT concept was developed by field device manufacturers.

FDT frame application

The FDT frame application creates a common runtime environment for DTMs from different manufacturers. All frame applications are basically fieldbus-neutral, support various communication protocols and thus fulfill one of the most important requirements of the user for device integration. You manage all device instances and save their data. In addition, they guarantee a system-wide uniform configuration and allow both multi-user and single-user applications. FDT frame applications from different manufacturers are available on the market as configuration or engineering tools, operating consoles or PAM tools.

A widespread framework application is PACT ware , developed by a consortium of field device manufacturers and system suppliers. Other supporting programs are, for example, FieldCare from Endress + Hauser , fdtCONTAINER from "M&M", the "Field Device Expert" in the "Foxboro DCS" process control system from Schneider Electric or integration into the control systems from ABB .

Device Type Manager

A DTM is not an independent program, but only works in conjunction with an FDT frame application. In terms of content, it represents a specific device or a communication component with its properties and functions, including the user interface. From a framework application, the DTMs enable operation with "their" devices or communication components located in the system. A user can call up the functions of the connected devices via the associated DTMs.

“Device drivers” make it easier for the user to work with field devices, as he does not need any special knowledge of the bus systems used and their communication protocols. Since essential parts of the user interface are defined in the DTM Style Guide, all devices have the same look and feel. The big advantage: intuitive and simple operation and configuration of the devices.

Device DTM

Device DTMs (Device Type Manager) are device-specific and contain data, functions and logic elements of the device. Depending on the level of implementation, the driver includes a simple graphical user interface for setting the device parameters up to extensive applications for diagnosis and maintenance, e.g. B. a logic for device calibration. Device DTMs are usually developed by the device manufacturer and are part of the scope of delivery of the device. The development of the DTMs is often outsourced by the manufacturers to specified service providers who have specific tools and development processes. In contrast to the freedom of content design of a DTM, its interfaces to the frame application are made mandatory by the FDT specification.

The three groups of DTMs

  • Manufacturer-specific device DTMs offer the largest range of functions and optimally support a device or an entire device family from a manufacturer. These DTMs are often provided with additional functions such as B. expand more extensive parameterization and diagnosis options, network analyzes or history displays.
  • Compared to manufacturer-specific device DTMs, interpreter DTMs have a smaller range of functions. You use existing device description files created for a specific device, e.g. B. EDD (Electronic Device Description) or IODD (IO Device Description). As a rule, such DTMs are graphically and functionally less convenient due to the limited properties of the device description language EDDL. Examples are the " ioddINTERPRETER DTM ", which interprets the DDs of IO-Link devices and with the help of which these devices can be parameterized. There are various other interpreter DTMs, etc. a. for EDDs.
  • Generic, i.e. universal DTMs do not represent a device or a device group from a manufacturer, but rather defined commonalities between devices from different manufacturers. This includes the protocol-compliant parameters that are the same for all devices of a protocol class (e.g. Hart or Profibus PA devices) and can therefore be described in a single DTM. With a generic Hart DTM z. B. These are the parameters that can be reached using the term "Universal and Common Practice Commands". With a generic Profibus profile DTM, this affects all profile parameters of a field device. Generic DTMs usually have very few or even only one entry in the device catalog of the frame application.

DTMs for communication components

Similar to the field devices, the network infrastructure components involved in the communication, e.g. B. communication adapters, gateways or bus couplers represented by appropriate DTMs. A common feature of these device drivers is the communication channel which they make available to the assigned device DTM and which maps the specific services of the respective network protocol in corresponding software interfaces. Depending on the design of the associated hardware components and the location in the network, a distinction is made between two DTM categories:

  • Communication DTMs (CommDTM) are the first DTMs that become active when communication is established from an FDT frame application.

They represent the corresponding communication hardware - e.g. B. in the form of a PC card. The communication DTM makes the functions of the corresponding communication protocol available to the connected device DTMs or gateway DTMs and forwards queries in the function of a driver to the hardware, where they are transferred to the device.

  • Gateway DTMs are used between the communication DTM and device DTMs, provided that there are transitions between different network protocols on the communication path between the communication adapter and the field device. Your task consists in the configuration of the necessary hardware components for the network transition as well as - in the case of online communication - in the implementation of the communication services of one protocol requested by the assigned device DTMs into the corresponding services of the other protocol.

Gateway DTMs enable the communication path to the field device including the necessary transitions between different protocols, such as B. RIOs, IO-Link hubs etc. and thus form the basis for establishing vertical communication - the so-called nested communication.

Uniform look and feel

The graphic surface of the DTMs is the daily work tool for the user of the FDT technology. The clear and uniform design for all manufacturers and device types can help to increase work efficiency. The rules for the structure of the user interface are laid down in the DTM Style Guide. The style guide conformity is also part of the certification results.

The aim of the FDT Group is to design and make all the basic functions of a DTM look the same, but on the other hand not to restrict the task and process-related representations. The Style Guide stipulates the division of the user interface into general and task-related areas, provides a library of icons and their meaning and a glossary of terms and standard messages in at least eight languages.

Independent of the network protocol

FDT is primarily an interface definition that traditionally comes from the field of PROFIBUS and HART , but is fundamentally independent of the communication protocol. There are now additions to well-known protocols such as Foundation Fieldbus, Interbus , the CIP protocol family, Modbus , IO-Link , PROFINET , AS-Interface , CANopen . Support for other protocols is in the works.

Nested Communication ( nested communication )

If DTMs are available for the gateway devices between different bus protocols, a field device can be addressed and (centrally) configured regardless of the type of communication path. The manufacturer of the device DTM does not have to bear any expenditure for the superimposed communication paths. So is z. B. a DTM for a HART device regardless of whether the HART device is connected to the PROFIBUS via a multiplexer or the HART-capable analog input of an IO card. The implementation of the communication via the different superimposed networks is taken over by the associated gateway DTMs.

Use of FDT in practice

... for system operators

The user benefits of FDT are complex and unfold over the entire life cycle:

  • Free choice of device
  • Comprehensive device data help to optimize the efficiency of the processes
  • Supports all tasks over the entire life cycle from offline engineering to preventive maintenance
  • Shorter installation times and higher system availability
  • more safety in system operation
  • open and future-proof

... for device manufacturers and system providers

FDT technology also offers device manufacturers and system providers real added value:

  • Less effort for development
  • Protection of investments and know-how
  • Efficient and flexible

organization

At the beginning of 2003, companies such as ABB , Endress + Hauser , Invensys , Siemens and Metso Automation founded the FDT Joint Interest Group . These companies formed the Steering Committee of the FDT JIG. In November 2004, Omron also joined the Steering Committee. The FDT Joint Interest Group was a not-for-profit international collaboration of companies in the field of industrial automation, which had set themselves the task of promoting the spread of FDT technology and establishing it worldwide. As the membership grew, the FDT Joint Interest Group became more difficult to organize and manage and it was decided to reorganize it as a legally independent organization.

For this reason the “FDT Group” was founded in September 2005 as a non-profit association under Belgian law. The FDT Group AISBL holds the trademark rights to "FDT" and "FDT2" and has taken over the maintenance, further development and distribution of the FDT technology. The FDT specification is provided free of charge by the FDT Group. Today more than 80 organizations are members of the FDT Group.

The FDT specification is today administered, maintained and further developed by the FDT Group AISBL (Association Internationale Sans But Lucratif). The FDT Group is an association of end users, manufacturers, universities and research institutions in the field of automation technology. The tasks of the international, not-for-profit association of companies from process and production automation also include the creation of guidelines, such as B. DTM Style Guide or FDT Life Cycle Policy. The main objective is to establish the FDT standard as an open, manufacturer-neutral interface description for device integration in engineering, automation and PAM systems, and to develop and maintain new ones. In addition, through cooperation with other organizations, the FDT Group operates the classification of FDT in the requirements landscape and the generation of additional benefits through harmonization and coordination of standards. Cooperations have been established with the OPC Foundation and the FieldComm Group, among others. The FDT Group provides development tools as well as support, training, practical tests and documentation for users of the technology. The FDT Group ensures the quality in the form of the interoperability of the products via a specified certification test process.

The FDT Group consists of a Board of Directors, an Executive Committee and several specialist committees. The members elect the board of directors, which in turn sets up the executive committee. The working areas of the specialist committees are: marketing, technology, user forum as well as associations and standards.

Working and project groups are part of a committee. If necessary, the executive committee will set up new, topic-related working groups that, for example, develop protocol extensions (annexes). A project group is subordinate to the working group and only exists until the defined project goal has been achieved.

Test and certification

In order to ensure the high quality of DTMs for end customers, the FDT Group decided in 2004 to introduce a tool with which compliance with the interface specification can be checked. The dtmINSPECTOR program contains almost 250 official tests that check the behavior at the interfaces.

Certification process

Certification tests must be carried out by an audited and accredited test laboratory. If the DTM passes all tests, the manufacturer can submit the test report generated in the process to the FDT Group Certification Office for certification. If the certificate has been issued, the manufacturer may use the "FDT certified" logo for the DTM.

Web links