Danfoss MCA 122 Modbus TCP Operating Instructions Manual

Danfoss MCA 122 Modbus TCP Operating Instructions Manual Manual pdf 11 page image

2.1.3 TopologyThe MCA 122 features a built-in Ethernet-switch, thus having two Ethernet RJ-45 connectors. This enables the possibility forconnecting several Modbus TCP options in a line topology as an alternative to the typical star-topology.The two ports are equal, in the sense that they are transparent for the option. If only one connector is used, either port canbe used.AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT130BA903.10Illustration 2.4 Star TopologyAutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT AutomationDriveVLT130BA904.10Illustration 2.5 Line TopologyNOTICEFor line topology, refer to 2.1.5 Recommended Design Rules. In a line topology all frequency converters must be powered,either by mains or by their 24 V DC option cards, for the built-in switch to work.NOTICEObserve that mounting frequency converters of different power-sizes in a line topology may result in unwanted power-offbehaviour.Smaller frequency converters discharge faster than bigger frequency converters. This can result in loss of link in the linetopology, which may lead to control word timeout.To avoid this, mount the frequency converters with the longest discharge time first in the line topology.How to Install MCA 122 Modbus TCPMG90P202 - VLT® is a protected Danfoss trademark 72 2