PAS (Process Automation System) Independent Process Monitoring and Field Device Management

Summary

 

Chemical manufacturers and distributors alike are seeking better ways to more efficiently manage the assets of their operations. Advances in communication technologies and standards are now making it easier and more cost justifiable to deliver information from measurement instrumentation as well as manage these instrumentation assets more efficiently. Today, over 12 million installed process field devices allow full access to measurement and configuration data via the open HART® communication standard. However, the challenge is to get practical access to this data. Access to the information within HART communication capable devices is often not possible through legacy telemetry and automation platforms.

 

This paper describes the application of the Fieldgate HART to XML based field server and the open standard Fieldcare Field Device Tool (FDT) to gain on demand access to selected HART devices over wired and wireless Information Technology based Local Area Networks (LAN) and Wide Area Networks (WAN). Visibility of and access to field device information contributes to efforts to improve the life cycle management of process plants and associated distribution operations.

 

Challenges to improving instrumentation maintenance and asset management through legacy automation control platforms

 

"If you can’t measure it you can’t control it" is often voiced during discussions about managing the performance of manufacturing processes. This statement also applies to managing the plant and equipment that do the work of controlling a manufacturing process or managing a distribution process. Visibility to the condition and performance of measurement and actuator devices in a timely fashion is required to contribute to improved life cycle management. Implementing the capability to do remote maintenance and real time diagnostics can contribute to the reduction of plant maintenance costs.

"Remote repair, diagnostics and maintenance offers a way to reduce massive maintenance costs ... US process industries such as chemical and oil refineries could save as much as $60 billion a year" Fortune Magazine

Operations managers are challenged to maintain and improve operations while at the same time reducing the resources used to manage the operations’ assets. This is especially the case in equipment maintenance operations where fewer personnel are being asked to do a better job managing the operating equipment in the plant. As distributed operations increase the deployment of equipment in widely scattered sites (i.e. remote tank inventory monitoring), the challenge to maintain that equipment cost effectively increases.

 

Process Automation Systems (PAS) (i.e. Distributed Control Systems, Programmable Logic Controllers) are the traditional way to get information from measurement devices and effect control of motors and valves. Many plant environments have more than one control system platform installed. Even those with control systems from one vendor may have a variety of field device interface implementations to communicate with field devices. Vendors tend to offer asset management solutions built around their particular Process Automation System platforms.

 

90% of the process measurement and actuator devices installed today are able to communicate information only via the change in a 4-20mADC current loop; the control system I/O does not often support digital communication with field devices. While the 4-20mADC loop is an effective way to get and send primary process control information it does not make other information within the connected devices available to those responsible for equipment performance. Here a device problem is communicated only when the current signal drops below 4mADC and the measurement information is lost. Operators are forced to react in real time to manage the process affected by the lost information and maintenance is pushed to fix the problem.

 

The challenge is to employ a permanent cost effective information bridge from selected HART based 4-20mADC devices to the maintenance people without interfering with the existing control system.

 

The rise of Information Technology connected field devices

 

The trend to use Information Technology Ethernet TCP/IP Local Area Networks (LAN) and wireless Wide Area Networks (WAN) to support business processes is now invading process manufacturing and distribution operations.

 

Instrumentation is often grouped into critical and non critical application categories which can then be subdivided:

  • Safety and environmental

  • Asset protection

  • Operations

  • Enterprise applications

Environmental applications (i.e. EPA reporting) and enterprise applications (i.e. inventory management) do not require the millisecond update speeds or deterministic behavior required in critical control applications. No longer is it assumed that every field device must be connected to an automation platform to have value. Some facilities have found that up to 70% of their 4-20mADC measurement devices do not have any control function associated with them.  Information from non critical environmental, asset protection and enterprise instrumentation can often be conveyed directly to standard networks and associated databases via wired and wireless field gateways. The more deterministic delivery, data management, safety and security issues associated with more demanding control system environments do not need to be employed.

 

There are several 4-20mADC to TCP/IP gateways on the market designed to deliver field device information into standard LAN and WAN environments.

 

A solution for automation platform independent process monitoring and field device asset management

 

More recently, Fieldgate™, a HART to TCP/IP gateway has been developed to convey process measurement values developed within HART measurement devices via an XML file. Not only is the primary information delivered in fully defined engineering units but also the status of these devices can be continually monitored and communicated on an event driven or periodic basis. Remote servicing tools and asset management applications working at the network level can configure and manage connected HART devices. Standard Information Technology security and data management tools can be used to control access.

 

Automation vs Information Technology platforms

Automation Platform

Information Technology Platform

Deterministic, "real time"

Control supported

Milliseconds to seconds updates

Event / periodic, "time stamped"

Little to no control supported

Seconds to hours updates

Tied to Enterprise level through legacy

automation system data collection and

management

Tied directly to Enterprise driven data collection and management. Asset management can be a subnet

Automation architecture is generally a proprietary data concentrator/collector and control network. Open or proprietary industrial fieldbus and I/O interfaces to sensors.

Architecture is heavily IT standards leveraged. IP addressing driven further down toward measurement devices.

Security generally accomplished by

total isolation

Security managed via IT structures. External access allowed under defined conditions

Integration leveraged on the IT side

Integration leveraged on the

automation side.

Instrumentation is usually hardwired

Instrumentation is connected to wired

or wireless LAN / WAN

 

As shown in the diagram below both process monitoring and remote servicing/asset management of field devices can be addressed on a standard TCP/IP network by using Fieldgate as the bridge.

 

 

 

Selected HART instruments connected to a control system can be simultaneously connected to the monitoring and/or remote servicing network given appropriate security and access controls are in place. Since HART supports the access to device information via both primary and secondary masters the Fieldgate can maintain a permanent connection and still allow temporary connection of a HART communicator in the field.

 

Procedures similar to those already in place to manage maintenance access to control loop connected instruments must be extended to cover this. Secure access to instruments and valves independent of a particular automation system is managed with full control of instrument maintenance activities. Interaction with field devices by maintenance and service people is managed by process engineers and operators to ensure such interaction will not affect control of the process. If required Fieldgates and associated remote servicing/asset management applications can be isolated in the same way preventing unauthorized and potentially damaging access.

 

Investment in networking the complete proprietary automation platforms and adding HART I/O (if available) may not be possible (or necessary) to implement improvements in device asset management. Fieldgate allows one to gain access to just those devices that are important to asset management improvement.

 

Automation platforms are usually completely isolated from the enterprise Intranet and the Internet because of the potential consequences of unauthorized changes. This is to prevent digital access to the instruments and valves settings and the automation system control settings. Unless HART communications is supported via the I/O and supportive databases within the automation platform there is no value to networking the automation platform to get detailed access to HART devices.

 

Field Device Tool (FDT) standards based field device remote maintenance and asset management

 

As soon as plant equipment is commissioned, it is subject to degradation. The process, human interaction and time all conspire to compromise the function of process equipment and associated field devices. Plant/facility maintenance groups are responsible for the operational oversight and timely repair of equipment. This includes measurement instruments, actuators and other active devices. The challenge for these groups is to keep this equipment performing while also reducing the resources and personnel employed to do this. A local operator interface or handheld communicator is used for temporary on site interaction with smart field devices. What is needed is a means to interface with field devices on a continuous basis to capture preventative maintenance information and conduct and capture appropriate remote servicing activities.

 

The use of HART communication and the introduction of field buses such as Profibus and Foundation Fieldbus provide the means to interact remotely with field devices. As the installed base of Profibus and FF devices grows it will displace traditional 4-20mADC control loops. For the present and foreseeable future, the majority of remote communications with process field devices will be conducted via HART.

 

Today there are several field device remote maintenance/asset management tools. It is not uncommon for one facility to have several of these tools to cover the different devices installed. Even though these tools may support open standards device communications most are built on a proprietary platform

  • There is a limited choice of system and components with proprietary solutions

  • Third-party device integration rarely provides full functionality

  • There is a greater risk of proprietary software changes causing interoperability problems

No one likes being locked into a proprietary platform if solid open standards solutions are available. FDT (Field Device Tool) is an open, vendor-independent specification for describing, communicating with, configuring, and accessing intelligent field devices. FDT enables a supplier to provide a universal toolset for any field device from any manufacturer that complies with the specification.

 

One toolset for all the important field device communication

 

In addition to deploying the vendor and bus-independent specification, the FDT solution provides extended frame services that make the information from FDT compliant field devices available to higher level applications utilizing standard XML schema.

 

The Fieldtool Device Tool – Joint Interest Group (FDT-JIG) is addressing key issues in establishing FDT as an open core technology. For example, there is a technical cooperation between the OPC Foundation and the FDT-JIG with the prime objective of providing the end user both within process and factory automation a totally seamless, truly open and easy enterprise wide communication. Why this cooperation?

  • OPC is designed purely for communication. It is not suitable for cases, where devices need to be addressed through several different protocols.

  • FDT technology adds a "nested communication" or "stacked communication" interface to OPC to support communication to devices with several different protocols

Fieldcare - Endress+Hauser’s FDT based device maintenance and asset management toolset

 

Endress+Hauser‘s FieldCare™ maintenance tool is based on the open FDT/DTM standard and designed to support the consolidation of process field device management tools into an open multiple vendor solution. FieldCare offers:

  • Full operation of all Endress+Hauser devices, plus on-board device manuals

  • Operation of third-party devices using either vendor or generic device type managers (DTMs)

  • Full support for HART, PROFIBUS and, in future, FOUNDATION Fieldbus devices

  • Network configuration, device navigation and management of DTMs

  • Tracking of user changes

  • User management

The maintenance package includes in addition:

  • Plant wide condition monitoring of device status

  • Alarm notification via SMS, e-mail or printout

  • Open database connectivity to other software

FieldCare provides the best possible support during the commissioning, operation and maintenance of a plant. FDT (field device tool) is an open, vendor-independent specification for describing, communicating with, configuring, and accessing intelligent field devices. FDT enables a vendor to provide a universal toolset for any device from any manufacturer that complies with the specification.

 

Field Device Tool (FDT) is an open standard supported by PROFIBUS International and many major instrument and control system suppliers. The FDT Standard:

  • Can be used within an enterprise network level engineering environment, a process control system or as a device operating tool

  • Enables operation through all levels of the plant

  • Separates a system into a FDT frame application

  • DTM device and DTM communication components

  • Is communication protocol independent.

A device type manager (DTM):

  • Contains the graphical user interface for device operation

  • Can be used in any FDT frame application

FieldCare will continue to grow and be able to manage much more device information available than is usual today. To unlock this potential, an open tool with extensive capabilities is required. FieldCare intends in the future to be the key to:

  • Recording and visualization of measured values

  • Plant-wide acquisition of device management data

  • Full life-cycle management support

  • Advanced maintenance support

Endress+Hauser’s objective is to provide chemical operations with one tool covering all aspects of device and lifecycle management that arise during the commissioning and running of a plant. For more information visit http://www.endress.com

 

FieldCare and [email protected]

Web-enabled Asset Management (or [email protected] for short) is Endress+Hauser’s vehicle for open information management. All data required to secure or increase the value of an asset within a plant are collected and provided as information for the plant management directly or through interfaces to other applications. Within this framework, FieldCare provides on optional link to [email protected], ensuring seamless data flow and the availability of information at all locations. For more information visit http://www.endress.com

 

 

Conclusions

The advent of TCP/IP networks and wired/wireless infrastructures combined with open instrumentation maintenance and asset management toolsets will allow those responsible for operations in legacy plants to more effectively maintain instrumentation assets. Fieldgate™ provides a means to communicate continuously with HART devices over wired and wireless Intranet and Internet networks. The Field Device Tool (FDT) based Fieldcare™ toolset can support HART instruments as well as the growing base of Profibus and Foundation Fieldbus instruments.

 

This white paper was provided by Endress+Hauser, Inc.  Craig McIntyre(author) is the Chemical Industry Manager with Endress+Hauser, Inc. in Greenwood, Indiana.  Other positions he has held with E+H include Level Product Manager and Communications Product Manager. Previously he served as a Marketing Manager with Rosemount. Craig holds a BA in Physics and an MBA.