Rockwell Automation Technologies Incorporated

Anatoly Moldovansky

Sivaram Balasubramanian

Kenwood H Hall

Mark A Flood

Kendal R Harris

Anthony J Cachat

David Alan Vasko

Brian Alan Batke

Anthony Gerard Gibart

Balasubramanian Sivaram

The subject matter disclosed herein describes a method to allocate and prioritize data communications on an industrial control network. A transmission schedule including multiple priority windows and multiple queues is established. Each queue is assigned to at least one priority window, and each priority window may have multiple queues assigned thereto. A control device communicating on the control network transmits data packets according to the transmission schedule. Within each priority window, data packets corresponding to one of the queues assigned to the priority window may be transmitted. The data packets may be transmitted at any point during the priority window, but will only be transmitted if no data packet from a higher queue is waiting to be transmitted.

Method and apparatus for allocating and prioritizing data transmission

Multiple gateway devices communicating between a device level ring (DLR) network and a spanning tree (ST) network may be provided a gateway protocol that cooperatively ensures that only a single gateway is active at a given time. This cooperation may be effected by the transmission of advertise messages by gateways, the advertise messages holding precedence values so that only a single gateway having a highest precedence value is active at a given time. Loss of the advertise messages may trigger a gateway held in a backup state to assume an active gateway role.

Redundant gateway system for device level ring networks

Fault-tolerant Ethernet is provided through the use of special interfaces providing end-devices with duplicate ports that may be alternatively enabled with the same network address in the event of a fault detected by loss of the message from a beacon device. Unidirectional network errors in the direction from the end-device to the beacon devices are detected through a path check message from the end-device to the beacon device. Multiple faults may be accommodated without network interruption by adding top-level switches without increasing the number of ports on the end-devices by cross connecting a lowest level of switch.

Multiple-fault-tolerant ethernet network for industrial control

Fault-tolerant Ethernet is provided through the use of special interfaces providing duplicate ports that may be alternatively enabled with the same network address. A switching between the ports, corrects for single faults in a two-way redundant system without time-consuming reconfiguration of other end devices or the need for complex middleware in the end devices.

Fault-tolerant ethernet network

A network for an industrial control system employs a ring topology that is normally opened by a ring supervisor at the ring supervisor. Upon failure of the network, the ring supervisor reconnects the ring to provide an alternative transmission path around the failure point. High speed operation is reconciled with the ability to use commercial switching integrated circuits through a dual communication channel of communicating a network state as either closed or open using both high-speed hardware handled beacon frames and low-speed software processed announce frames.

Industrial controller employing the network ring topology

Fault-tolerant Ethernet network

A method and circuit for precisely synchronizing clocks in separate nodes on a communication network is provided by adjusting timestamps and related data in network messages. The circuit will allow a daisy-chain connection of the nodes and will forward time synchronization frames while accounting for delays in a manner that does not use boundary clocks, but does not depart from the IEEE 1588 standard protocol. The delays will be added on the fly to synchronization packets and the IP checksum and frame CRC will be adjusted. Deterministic data delivery and redundant data paths are also provided in a full duplex Ethernet network.

Time synchronization, deterministic data delivery and redundancy for cascaded nodes on full duplex ethernet networks

Systems and methods are disclosed for time synchronization of operations in a control system. Synchronization networks and devices are provided for transferring synchronization information between controllers in a distributed or localized control system, which is employed in order to allow operation of such controllers to be synchronized with respect to time. Also disclosed are synchronization protocols and hardware apparatus employed in synchronizing control operations in a control system.

System and method for multi-chassis configurable time synchronization

A transmission schedule is overlaid on the Ethernet protocol to allow use of this readily available high speed protocol for transmission of I/O data communicated in an industrial control environment and requiring a high degree of determinism. Scheduling improves load leveling and bandwidth utilization and by producing a more consistent delay may be teamed with time synchronization to produce more accurate clock synchronization.

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Pepper Pike, OH, United States of America

Anatoly Moldovansky