Installation And Set-Up - Danfoss FC 102 Design Manual

Installation and Set-up

8 Installation and Set-up
8.1 Installation and Set-up
8.1.1 Overview
RS-485 is a 2-wire bus interface compatible with multi-drop
network topology, that is, 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.
NOTICE
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.
8 8
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, including at high frequencies. Thus,
connect a large surface of the screen to ground, for
example with a cable clamp or a conductive cable gland. It
may be necessary to apply potential-equalising cables to
maintain the same earth potential throughout the network
- particularly 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
Impedance
[Ω]
Cable length
[m]
Table 8.1 Cable Specifications
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
drawings in chapter 6.8.3 Grounding of Screened Control
Cables.
If more than one frequency converter is connected to a
master, use parallel connections.
130
Screened twisted pair (STP)
120
Max. 1200 (including drop lines)
Max. 500 station-to-station
Danfoss A/S © Rev. 06/2014 All rights reserved.
Design Guide
Illustration 8.1 Parallel Connections
To avoid potential equalising currents in the screen,
ground the cable screen via terminal 61, which is
connected to the frame via an RC-link.
61 68 69
Illustration 8.2 Control Card Terminals
8.1.2 Frequency Converter Hardware Setup
Use the terminator dip switch on the main control board
of the frequency converter to terminate the RS-485 bus.
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
20 37
MG11BC02