Ring Topology - Danfoss iC7 Series Operating Manual

iC7 Series PROFINET
Operating Guide
Illustration 4: Example of Star Topology

2.6.3 Ring Topology

Ring topology enables the same simpler cabling and reduced cabling costs as line topology, but also reduces the damage caused
by a single cable failure in a similar manner as star topology.
When line topology is used, take precautions to avoid timeout in the PLC when more than 8 drives are installed in series. Each
drive in the network adds a small delay to the communication due to the built-in Ethernet switch. When the update time is too
short, the delay can lead to a timeout in the PLC.
-
Set the update time as shown in the table. The numbers given are typical values and can vary from installation to installation.
-
Number of drives connected in series
<8
8–16
16–32
33–50
>50
The ring topology protocol depends on the protocol in use.
For PROFINET, the Media Redundancy Protocol (MRP) is used. The MRP is designed to react deterministically on a cable failure. One
of the nodes in the network has the role of Media Redundancy Manager (MRM), which observes and controls the ring topology to
react to network faults. Usually this device is a PLC or network switch.
18 | Danfoss A/S © 2023.06
N O T I C E
Minimum update time [ms]
2
4
8
16
Not recommended
Product Overview
AQ408626183394en-000101 / 136R0280