Danfoss VLT AutomationDrive FC 361 Series Design Manual

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Danfoss VLT AutomationDrive FC 361 Series Design Manual Manual pdf 79 page image

11.3 RS485 Installation and Set-upRS485 is a 2-wire bus interface compatible with multi-dropnetwork topology. Nodes can be connected as a bus, or viadrop cables from a common trunk line. A total of 32 nodescan be connected to 1 network segment.Repeaters divide network segments. Note each repeaterfunction as a node within the segment in which it isinstalled. Each node connected within a given networkmust have a unique node address, across all segments.Terminate each segment at both ends, using either thetermination switch (S801) of the drives or a biasedtermination resistor network. Always use shielded twistedpair (STP) cable for bus cabling, and always follow goodcommon installation practice.Low-impedance ground connection of the shield at everynode is important, including at high frequencies. Thus,connect a large surface of the shield to ground, forexample, with a cable clamp or a conductive cable gland.If necessary, apply potential-equalizing cables to maintainthe same ground potential throughout the network, partic-ularly in installations with long cables.To prevent impedance mismatch, always use the sametype of cable throughout the entire network. Whenconnecting a motor to the drive, always use shieldedmotor cable.Cable Shielded twisted pair (STP)Impedance 120 ΩCable length Maximum 1200 m (3937 ft), including droplines.Maximum 500 m (1640.5 ft) station-to-stationTable 11.2 Motor CableOne or more drives can be connected to a control (ormaster) using the RS485 standardized interface. Terminal68 is connected to the P signal (TX+, RX+), while terminal69 is connected to the N signal (TX-, RX-). See illustrationsin chapter 7.14 EMC-compliant Installation.If more than 1 drive is connected to a master, use parallelconnections.130BA060.1168 69 68 69 68 69RS 485RS 232USB +-Illustration 11.2 Parallel ConnectionsTo avoid potential equalizing currents in the shield, groundthe cable shield via terminal 61, which is connected to theframe via an RC-link.e30bh258.1012 13 18 19 27 29 32 33 2061 68 69 39 42 50 53 54 55Illustration 11.3 Control Card TerminalsThe RS485 bus must be terminated by using a resistornetwork at both ends. For this purpose, set switch S801 onthe control card to "ON".For more information, see chapter 7.2 Wiring Schematic.Communication protocol must be set toparameter 8-30 Protocol.Appendix Design GuideMG06K102 Danfoss A/S © 03/2019 All rights reserved. 7711 11