Thursday, November 23, 2006
The value of Profibus in the Process Industries
The adoption of fieldbuses in manufacturing continues to grow rapidly, especially in the heavy process industries such as oil and gas and chemical where the penetration of fieldbuses is still small. Manufacturers are realising the benefits of homogeneous fieldbus architectures that enable industrial networking across domain boundaries from simple sensors to complex field instrumentation. Profibus, with its common communications layer, many application profiles, and breadth of media alternatives, offers manufacturers a solid long-term value proposition to help protect their automation investments.
The value proposition of fieldbus has changed from the initial perceptions of the marketplace.
Benefits such as reduced wiring and installation costs are apparent, but often mask the long-term benefits of fieldbus and device networks.
According to ARC research, the greatest benefits of fieldbus and device networks are realised in the areas of maintenance and operations, long after a plant has been commissioned.
In other words, fieldbus itself is often not the cost-saver, but merely an enabler to a new level of asset management effectiveness that can significantly reduce operating costs and help manufacturers achieve operational excellence.
Many of the benefits of fieldbus are still being discovered as users gain more experience with these technologies in real world plant settings.
In typical process industries such as oil and gas or bulk chemicals, fieldbuses can contribute significantly to the achievement of operational excellence by enabling the sharing of critical information about the condition of devices.
A fieldbus simplifies the gathering of data for Plant Asset Management (PAM) systems that watch over devices, tracking their 'health', and even detecting problems before they occur - a process known as predictive or proactive maintenance.
Profibus, which conforms to the international IEC 61158 standard for fieldbus, is the most widely used industrial network to connect control systems with field devices.
To meet the special needs of the process industries for intrinsic safety and bus power with two-wire technology, Profibus offers MBP-IS (Manchester Coded, Bus Powered, Intrinsic Safety) transmission technology as well.
All variants of Profibus share a common communications layer; the differences are a function of the required network media and application profile.
This single communication layer simplifies network configuration and diagnostics in all areas of the plant by providing a seamless link between all manufacturing domains.
Profibus DP is used to network I/O and intelligent devices due to its fast response time and may also serve as the fieldbus 'trunkline'.
With data rates up to 12 Mbps, more devices can be connected to the network than with other fieldbus solutions.
For hazardous areas, Profibus PA employs an intrinsically safe physical layer that provides bus power to devices on two-wire technology.
Field instruments such as pressure or temperature transmitters, flow meters or control valves are networked using Profibus PA.
Because DP and PA share a common communication layer, PA segments can be coupled as extensions to a Profibus DP backbone network via segment couplers that are transparent to the bus protocol.
The HART protocol has become a de facto standard in the process industries, and ARC estimates that the majority of intelligent, microprocessor-based field instruments installed today are HART-compatible.
Unlike other fieldbus solutions, Profibus allows for direct integration of HART devices.
In view of the large number of installed HART devices, the Profibus HART specification was developed to enable the mapping of the HART client-master-server model on Profibus.
Installed in the engineering or asset management stations, a communications channel allows transparent remote access to diagnostic information and parameters.
Profibus Targets Process Industries.
Fieldbus technology is gaining traction in the process industries not only due to perceived benefits such as lower installation costs, but also other benefits such as enabling sophisticated tools like predictive maintenance through the use of intelligent asset management.
Profibus in particular offers a unique value proposition to various process industries.
Chemicals and Petrochemicals.
The chemical industry produces a wide range of products for consumer use as well as preliminary products for other industries such as automobile and building materials.
These industries employ a variety of different manufacturing processes - from batch processes in fine and specialty chemicals to continuous processes in bulk chemicals.
In addition, discrete applications such as filling, packaging and labeling are often integrated into these processes, especially in the manufacture of consumer products.
Chemical plants tend to be large, centralised facilities that place special demands on automation equipment and machines over lifecycles often in excess of 15 years.
A single plant may employ thousands of simple actuators and sensors in addition to a wide range of more complex field instruments and analytical devices.
These devices produce and consume large numbers of analogue process and control variables that are communicated between controllers and devices.
Many plants also employ smart motor control centres to provide controlled motion for mixers, pumps, valves and transportation equipment.
Plant equipment must be designed to operate in dusty, corrosive and often explosive environments.
High availability of automation systems means employing redundant control systems and networks and is critical in chemical manufacturing, especially in continuous processes that may run for years without stopping.
To meet these requirements, Profibus offers a large number of redundancy options such as two redundant, separate copper lines or fault tolerant optical ring structures.
The use of a fieldbus in chemical manufacturing offers users a number of tangible benefits.
In most cases, networking field devices via a fieldbus can cut documentation, installation and material costs substantially.
As a rule of thumb, the larger the application, the greater the benefits from a fieldbus, which is why many new projects or 'bulldozer' revamps are planned around a fieldbus architecture.
Start-up costs can also be lowered due to a reduction of the time needed to perform loop checks, while non-fieldbus legacy devices can be networked via remote I/O blocks that connect to the fieldbus.
Finally, field devices can be calibrated more conveniently over the fieldbus rather than on-site, both during start-up and at regular calibration intervals during normal operations.
Profibus architecture is especially suited to meet the demands of chemical manufacturers.
Data transfers rates of up to 12 Mbps allow a fast exchange of large data quantities between controller and devices, while the typically long distances between devices in a chemical plant can easily be bridged using repeaters and a fiber-optic bus medium.
Profibus offers wide range of application-specific profiles to meet specific needs, such as PROFIdrive for motion applications or PA Devices for intelligent field instruments that can take advantage of the network's high data rate while allowing a larger number of devices to be connected to the network than other fieldbus solutions.
PROFIsafe is profile for safety components that allows safe communication up to safety level SIL 3 according to IEC 61508.
Users can also protect their investment in existing 4-20 mA or HART devices by directly interfacing these to Profibus.
By far the most important advantage of Profibus for chemical manufacturers is its single communication layer, which allows integrated communication across all network media from the field level to the control level.
This seamless communication provides the basis for asset management software to monitor the performance of field devices, helping to predict faults in advance and reduce maintenance costs.
The value proposition of fieldbus has changed from the initial perceptions of the marketplace.
Benefits such as reduced wiring and installation costs are apparent, but often mask the long-term benefits of fieldbus and device networks.
According to ARC research, the greatest benefits of fieldbus and device networks are realised in the areas of maintenance and operations, long after a plant has been commissioned.
In other words, fieldbus itself is often not the cost-saver, but merely an enabler to a new level of asset management effectiveness that can significantly reduce operating costs and help manufacturers achieve operational excellence.
Many of the benefits of fieldbus are still being discovered as users gain more experience with these technologies in real world plant settings.
In typical process industries such as oil and gas or bulk chemicals, fieldbuses can contribute significantly to the achievement of operational excellence by enabling the sharing of critical information about the condition of devices.
A fieldbus simplifies the gathering of data for Plant Asset Management (PAM) systems that watch over devices, tracking their 'health', and even detecting problems before they occur - a process known as predictive or proactive maintenance.
Profibus, which conforms to the international IEC 61158 standard for fieldbus, is the most widely used industrial network to connect control systems with field devices.
To meet the special needs of the process industries for intrinsic safety and bus power with two-wire technology, Profibus offers MBP-IS (Manchester Coded, Bus Powered, Intrinsic Safety) transmission technology as well.
All variants of Profibus share a common communications layer; the differences are a function of the required network media and application profile.
This single communication layer simplifies network configuration and diagnostics in all areas of the plant by providing a seamless link between all manufacturing domains.
Profibus DP is used to network I/O and intelligent devices due to its fast response time and may also serve as the fieldbus 'trunkline'.
With data rates up to 12 Mbps, more devices can be connected to the network than with other fieldbus solutions.
For hazardous areas, Profibus PA employs an intrinsically safe physical layer that provides bus power to devices on two-wire technology.
Field instruments such as pressure or temperature transmitters, flow meters or control valves are networked using Profibus PA.
Because DP and PA share a common communication layer, PA segments can be coupled as extensions to a Profibus DP backbone network via segment couplers that are transparent to the bus protocol.
The HART protocol has become a de facto standard in the process industries, and ARC estimates that the majority of intelligent, microprocessor-based field instruments installed today are HART-compatible.
Unlike other fieldbus solutions, Profibus allows for direct integration of HART devices.
In view of the large number of installed HART devices, the Profibus HART specification was developed to enable the mapping of the HART client-master-server model on Profibus.
Installed in the engineering or asset management stations, a communications channel allows transparent remote access to diagnostic information and parameters.
Profibus Targets Process Industries.
Fieldbus technology is gaining traction in the process industries not only due to perceived benefits such as lower installation costs, but also other benefits such as enabling sophisticated tools like predictive maintenance through the use of intelligent asset management.
Profibus in particular offers a unique value proposition to various process industries.
Chemicals and Petrochemicals.
The chemical industry produces a wide range of products for consumer use as well as preliminary products for other industries such as automobile and building materials.
These industries employ a variety of different manufacturing processes - from batch processes in fine and specialty chemicals to continuous processes in bulk chemicals.
In addition, discrete applications such as filling, packaging and labeling are often integrated into these processes, especially in the manufacture of consumer products.
Chemical plants tend to be large, centralised facilities that place special demands on automation equipment and machines over lifecycles often in excess of 15 years.
A single plant may employ thousands of simple actuators and sensors in addition to a wide range of more complex field instruments and analytical devices.
These devices produce and consume large numbers of analogue process and control variables that are communicated between controllers and devices.
Many plants also employ smart motor control centres to provide controlled motion for mixers, pumps, valves and transportation equipment.
Plant equipment must be designed to operate in dusty, corrosive and often explosive environments.
High availability of automation systems means employing redundant control systems and networks and is critical in chemical manufacturing, especially in continuous processes that may run for years without stopping.
To meet these requirements, Profibus offers a large number of redundancy options such as two redundant, separate copper lines or fault tolerant optical ring structures.
The use of a fieldbus in chemical manufacturing offers users a number of tangible benefits.
In most cases, networking field devices via a fieldbus can cut documentation, installation and material costs substantially.
As a rule of thumb, the larger the application, the greater the benefits from a fieldbus, which is why many new projects or 'bulldozer' revamps are planned around a fieldbus architecture.
Start-up costs can also be lowered due to a reduction of the time needed to perform loop checks, while non-fieldbus legacy devices can be networked via remote I/O blocks that connect to the fieldbus.
Finally, field devices can be calibrated more conveniently over the fieldbus rather than on-site, both during start-up and at regular calibration intervals during normal operations.
Profibus architecture is especially suited to meet the demands of chemical manufacturers.
Data transfers rates of up to 12 Mbps allow a fast exchange of large data quantities between controller and devices, while the typically long distances between devices in a chemical plant can easily be bridged using repeaters and a fiber-optic bus medium.
Profibus offers wide range of application-specific profiles to meet specific needs, such as PROFIdrive for motion applications or PA Devices for intelligent field instruments that can take advantage of the network's high data rate while allowing a larger number of devices to be connected to the network than other fieldbus solutions.
PROFIsafe is profile for safety components that allows safe communication up to safety level SIL 3 according to IEC 61508.
Users can also protect their investment in existing 4-20 mA or HART devices by directly interfacing these to Profibus.
By far the most important advantage of Profibus for chemical manufacturers is its single communication layer, which allows integrated communication across all network media from the field level to the control level.
This seamless communication provides the basis for asset management software to monitor the performance of field devices, helping to predict faults in advance and reduce maintenance costs.
# posted by Medical Information : 3:43 AM
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