Ethernet Switching
The DYN servo drives with Ethernet communication such as Modbus TCP and EtherNet/IP has built-in switching technology to eliminate the need for external ethernet switches.
The DYN servo drive can monitor the IP address of the ethernet packet and forward any packets not matching it's own IP address. The end servo drive then loops the packet back to the master. This topology can be extended up to 127 servo drives on the network.
By eliminating the need for an external switch, the overall cost and complexity of the wiring can be significantly reduced. This also significantly improves communication cycle time as the servo drive can filter the packets much faster than most switch devices.
Topology
Each DYN servo drive with ethernet communication has 2 ethernet ports IN and OUT. The servo drive always reads the ethernet packets from IN port. If the IP address does not match it's own IP address, it will forward the packet to the OUT port. If the IP address matches it's own, it will process the data then send a reply (if necessary) to the OUT port.
On the last servo drive, a Terminator is installed to loop the packet back to the master. This is made possible since ethernet cables and RJ45 connectors have 8 pins but actual ethernet communication only needs 4 pins consisting of differential Rx and Tx signals.
Faster Cycle Times
In motion control, cycle times are critical. By eliminating the switch from the network, the PLC or motion controller can interface the servo drive directly without delay.
Even the fastest switch devices can introduce network latency that can affect position speed for the motor. Adding an external switch also adds another potential failure point.
The DYN servo drive can operate and automatically switches between 10 or 100Mbps speeds so it's compatible with a variety of slower or faster master ethernet devices. The DYN servo drive also uses proprietary code for generating packet protocols which significantly cuts down on how fast the drive reacts to commands and replies to commands. Typically, over ethernet, the servo drive can respond to commands in 300us and can reply to commands in 600us.
See this technology in action in the below videos. The first video shows Modbus TCP communication and second shows EtherNet/IP.
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