Danfoss VLT AutomationDrive FC 361, Руководство по конструкции

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11.3 RS485 Installation and Set-up
RS485 is a 2-wire bus interface compatible with multi-drop
network topology. Nodes can be connected as a bus, or via
drop cables from a common trunk line. A total of 32 nodes
can be connected to 1 network segment.
Repeaters divide network segments. Note each repeater
function as a node within the segment in which it is
installed. Each node connected within a given network
must have a unique node address, across all segments.
Terminate each segment at both ends, using either the
termination switch (S801) of the drives or a biased
termination resistor network. Always use shielded twisted
pair (STP) cable for bus cabling, and always follow good
common installation practice.
Low-impedance ground connection of the shield at every
node is important, including at high frequencies. Thus,
connect a large surface of the shield to ground, for
example, with a cable clamp or a conductive cable gland.
If necessary, apply potential-equalizing cables to maintain
the same ground potential throughout the network, partic-
ularly in installations with long cables.
To prevent impedance mismatch, always use the same
type of cable throughout the entire network. When
connecting a motor to the drive, always use shielded
motor cable.
Cable Shielded twisted pair (STP)
Impedance 120
Ω
Cable length Maximum 1200 m (3937 ft), including drop
lines.
Maximum 500 m (1640.5 ft) station-to-
station
Table 11.2 Motor Cable
One or more drives can be connected to a control (or
master) using the RS485 standardized interface. Terminal
68 is connected to the P signal (TX+, RX+), while terminal
69 is connected to the N signal (TX-, RX-). See illustrations
in
chapter 7.14 EMC-compliant Installation .
If more than 1 drive is connected to a master, use parallel
connections.
130BA060.11
68 69 68 69 68 69
RS 485
RS 232
USB
+
-
Illustration 11.2 Parallel Connections
To avoid potential equalizing currents in the shield, ground
the cable shield via terminal 61, which is connected to the
frame via an RC-link.
e30bh258.10
12 13 18 19 27 29 32 33 20
61 68 69 39 42 50 53 54 55
Illustration 11.3 Control Card Terminals
The RS485 bus must be terminated by using a resistor
network at both ends. For this purpose, set switch S801 on
the control card to "ON".
For more information, see
chapter 7.2 Wiring Schematic .
Communication protocol must be set to
parameter 8-30 Protocol .
Appendix Design Guide
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