Control Network (Cnet) is a high-speed data communication highway between nodes in the Symphony™ Enterprise Management and Control System. Cnet provides a data path among Harmony control units (HCU), human system interfaces (HSI), and computers. High system reliability and availability are key characteristics of this mission-critical communication network. Redundant hardware and communication media bolster reliability in a way that the backup automatically takes over in the event of a fault in the primary. Extensive use of error checking and message acknowledgment assures accurate communication of critical process data.
Cnet uses exception reporting to increase the effective
bandwidth of the communication network. This method offers the user the flexibility of managing the flow of process data and ultimately the process. Data is transmitted only when it has changed by an amount which can be ususer-selectedor when a predetermined time-out period is exceeded. The system provides default values for these parameters, but the user can customize them to meet the specific needs of the process under control.
bandwidth of the communication network. This method offers the user the flexibility of managing the flow of process data and ultimately the process. Data is transmitted only when it has changed by an amount which can be ususer-selectedor when a predetermined time-out period is exceeded. The system provides default values for these parameters, but the user can customize them to meet the specific needs of the process under control.
Features and Benefits:
■Fast plant-wide communication network: Cnet provides fast response time to ensure timely information exchange.
■Efficient data transfer: Message packing and multiple addressing increase data handling efficiency and throughput.
■Plant-wide time synchronization: Time synchronization of Cnet nodes throughout the entire control processensuress accurate data time-stamping.
■Independent node communication: Each Cnet node operates independently of other nodes.Requires no traffic directors; each node is its own communication manager.
■Accurate data exchange: Multiple self-check features,s including positive message acknowledgment, cyclic redundancy checks(CRC), and checksums insure data integrity.
■Automatic communications recovery: Rack communication modules provide localized startup/shutdown on power failure without operator intervention. Each type of interface supports redundancy.
The communication interface units transfer exception reports and system data, control, and configuration messages over Cnet. Exception report
ed data appears as dynamic values, alarms, and state changes on displays and in reports generated by human system interfaces and other system nodes. Exception reporting is automatic at the Harmony controller level. Specifically, the controller generates an exception report periodically
to update data, after a process point reaches a defined alarm limit or changes state, or af ter a significant change in value occurs.
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Cnet-to-Cnet Communication Interface
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INNIS01 Network Interface Slave Module
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Cnet-to-HCU Communication Interface
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INNPM12 Network Processing Module
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Cnet-to-Computer Communication Interface
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INICT03A Cnet-to-computer transfer |
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Multifunction Processor Interface Module
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IMMPI01 Multifunction Processor Interface Module |
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Rack Communications Mounting Hardware
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IEMMU21 Module Mounting Units
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