Communication and Fieldbus

Fieldbus

Fieldbus allows a machine to be connected to other machines in an automation systems network.

Typically, this connection is referred to as a factory automation network connection.

Motion Bus

Motion requires the controller to frequently update the drive with new trajectory setpoints.

The bus involved in the motion control requires it to be able to handle rigid jitter and timing demands including high data throughput and low latency.

Ethernet

Ethernet is certainly the most popular communications bus today because it is used in most computer networks.

  • Motion control devices using Ethernet allow high-speed connections to computers without requiring special hardware.
  • This reduces the cost and time required to make high-speed connections.

EtherCAT

The EtherCAT technology overcomes the system limitations of other Ethernet solutions.

  • The Ethernet packet is no longer received, then interpreted and copied as process data at every connection.
    • Instead, the Ethernet frame is processed on the fly.
  • Each slave node reads the data addressed to it, while the telegram is forwarded to the next device.
  • Similarly, input data is inserted while the telegram passes through.
    • The telegrams are only delayed by a few nanoseconds.

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