Installation And Set-Up; Network Connection - Danfoss VLT HVAC Drive FC 102 Design Manual

Installation and Set-up

7 Installation and Set-up
7.1 Installation and Set-up
RS-485 is a 2-wire bus interface compatible with multi-drop
network topology, i.e. 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 one network segment.
Repeaters divide network segments. Note that each
repeater functions 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 frequency converters or a
biased termination resistor network. Always use screened
twisted pair (STP) cable for bus cabling, and always follow
good common installation practice.
Low-impedance ground connection of the screen at every
node is important. Connect a large surface of the screen to
ground with a cable clamp or a conductive cable gland. If
needed, 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 frequency converter, always use
screened motor cable.
Cable: Screened twisted pair (STP)
Impedance: 120 Ω
Cable length: Max. 1200 m (including drop lines)
Max. 500 m station-to-station
Table 7.1 Motor Cable Specifications

7.1.1 Network Connection

One or more frequency converters can be connected to a
control (or master) using the RS-485 standardised interface.
Terminal 68 is connected to the P signal (TX+, RX+), while
terminal 69 is connected to the N signal (TX-,RX-). See
chapter 5.6.2 Safety Ground Connection and
chapter 5.7.3 Grounding of Screened/Armoured Control
Cables.
If more than one frequency converter is connected to a
master, use parallel connections.
MG16C202
Design Guide
Illustration 7.1 Parallel Connections
To avoid potential equalizing currents in the screen,
ground the cable screen via terminal 61, which is
connected to the frame with an RC-link.
61 68 69
Illustration 7.2 Control Card Terminals
Danfoss A/S © Rev. 05/2014 All rights reserved.
RS 232
68 69 68
+
USB
-
RS 485
39 42 50 53 54 55
Remove jumper to enable Safe Stop
12 13 18 19 27 29 32 33
69 68 69
7 7
20 37
169