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MAY-JUN 2017

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12 INTECH MAY/JUNE 2017 WWW.ISA.ORG COVER STORY able automation engineering solutions. The position paper serves as a basis for discussion in the dialogue with manu- facturers. It describes the requirements to be met by an Ethernet fieldbus system for the process industry, taking into ac- count previous experience with existing fieldbus systems, as well as desirable fu- ture properties. Considerations include the special characteristics of the process industry, such as very long plant service life and the resulting long use of process control systems and field devices, as well as stringent requirements for safety and availability, which are special challenges for digital and networked communica- tion structures. The introduction of an Ethernet-based communication system calls for a precise definition of the re- quirements for a system that is specifi- cally designed for the process industry. In addition to the requirements described in NE 74 (NAMUR fieldbus re quire- ments) new aspects were identified. Overall concept What is needed is a modular overall concept to meet different plant require- ments, such as topological conditions, link length, bit rates, explosion pro- tection, safety instrumented systems, and the integration of existing fieldbus systems. The focus is the classical field devices of the process industry in terms of sensor and actuator systems, such as pressure, temperature, level, flow, and positioner. In addition to classical field devices, which are often also used in explosive atmospheres, the overall concept shall be integrated via the same protocols as all other equipment of the process plant, such as the motor starter, frequency converter, weighing and ana- lytical systems, as well as energy mea- suring systems and building services. It shall describe them by means of pro- files. As a result, all information will be available for processing to all systems involved and can be used consistently in engineering and configuration tools. Protocols NAMUR calls for protocols IEC 61784- 2 CPF 2/2 Ethernet/IP and IEC 61784- 2 CPF 3/5 Profinet IO CC B to become minimum binding requirements for the process industry. These protocols need to be adapted to meet the pro - cess industry's special requirements, including the following: All bus participants (e.g., field devices, process control systems, and infrastruc- ture components) must be able to com- municate with each other in an interop- erable manner without any interference to ensure long-term bus operation. The two protocols specified must be supported by all bus components in terms of mandatory functions (e.g., transmission of measuring values). In addition to the deterministic protocol specified, other standard protocols shall be interoperable (i.e., simultaneous operation with other protocols must be possible without any interaction). The same protocol shall be used irrespective of the physi - cal layer used (i.e., also for wireless or fiber optical solutions). Field-device interfaces The physical layer connects the typical sensor and actuator systems used in production plants of the process indus- try. Wired connections shall be designed as two-wire cables with signal transmis- sion and energy supply of field devices. The physical layer shall be suited for use in both explosive and nonexplosive atmospheres (which is in keeping with current fieldbus solutions). Connections Field connections will be based on NAMUR NE 74, Fieldbus Requirements. Explosion protection The large area covered by production plants calls for distribution equipment, such as switches, to be installed in haz- ardous areas. This requires components with an adequate type of explosion- proof protection. Field devices in haz- ardous areas are typically connected according to the "intrinsic safety" type of protection. Proof of intrinsic safety must be limited to a comparison of pa- l sensor verification (logical verification using adjacent sensors) l plug and play (self-configuration/ parameterization) l virtual description supporting continuous engineering l traceability and compliance l self-calibration l self-diagnosis l connectivity and communication using a unified protocol (OPC UA) l maintenance and operating functions l energy self-sufficiency (energy harvesting) l wireless sensors l sensor data access rights control l standards compatible (i.e., good manufacturing practices, U.S. Federal Drug Administration) The application of Industry 4.0 and Internet of Things concepts and tech- nologies is part of an ongoing discus- sion with ramifications throughout the entire industry. Smart sensors with embedded intelligence that can com- municate for control and integrate with enterprise business systems represent a clear system architecture change for process automation and control lever- aging advances in technology. NAMUR Working Group 2.6 NAMUR Working Group 2.6 (WG 2.6) "Fieldbus" published the position pa - per, An Ethernet communication system for the process industry on 25 February 2016 to be a basis for discussion about future systems. WG 2.6 Fieldbus is under the umbrella NAMUR work area "Automation Systems for Processes and Plants." It is addressing issues that include solutions and systems for the management, steering, control, inspection, and communication of pro- duction plants assigned to the area be- tween field and company control levels. The scope includes cross-cutting issues, such as new technologies and sustain- The application of Industry 4.0 and Internet of Things concepts and technologies is part of an ongoing discussion with ramifications throughout the entire industry.

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