Emc Precautions; Fc Protocol Overview - Danfoss VLT Micro Drive FC 51 Design Manual

RS485 Installation and Set-...

8.1.4 EMC Precautions

The following EMC precautions are recommended to
achieve interference-free operation of the RS485 network.
Observe relevant national and local regulations, for
example regarding protective ground connection. To avoid
coupling of high frequency noise from 1 cable to another,
keep the RS485 communication cable away from motor
and brake resistor cables. Keep the greatest possible
distance between the cables, especially where cables run
in parallel over long distances. The minimum distance is
200 mm (8 inches). When crossing is unavoidable, the
RS485 cable must cross motor cable and brake resistor
cables at an angle of 90°.
8 8
Min.200mm
90° crossing
Illustration 8.3 EMC Precautions for RS485
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VLT Micro Drive FC 51
8.1.5 Frequency Converter Parameter
The following parameters apply to the RS485 interface (FC-
port):
Parameter
Parameter 8-30 Prot
ocol
Parameter 8-31 Add
ress
Parameter 8-32 Bau
d Rate
Parameter 8-33 Pari
ty / Stop Bits
Parameter 8-35 Min
imum Response
Delay
Parameter 8-36 Ma
ximum Response
Delay
Table 8.2 Parameters Related to RS485 Interface

8.2 FC Protocol Overview

Brake resistor
8.2.1 Overview
The FC protocol, also referred to as FC fieldbus, is the
Danfoss standard fieldbus. It defines an access technique
according to the master/slave principle for communications
via a fieldbus.
1 master and a maximum of 126 slaves can be connected
to the bus. The master selects the individual slaves via an
address character in the telegram. A slave itself can never
transmit without first being requested to do so, and direct
message transfer between the individual slaves is not
possible. Communications occur in the half-duplex mode.
The master function cannot be transferred to another node
(single-master system).
The physical layer is RS485, thus utilizing the RS485 port
built into the frequency converter.
Danfoss A/S © 01/2016 All rights reserved.
Settings for Modbus Communication
Function
Select the application protocol to run on the
RS485 interface.
Set the node address.
NOTICE
The address range depends on the
protocol selected in
parameter 8-30 Protocol.
Set the baud rate.
NOTICE
The baud rate depends on the
protocol selected in
parameter 8-30 Protocol.
Set the parity and number of stop bits.
NOTICE
The selection depends on the protocol
selected in parameter 8-30 Protocol.
Specify a minimum delay time between
receiving a request and transmitting a
response. This function is for overcoming
modem turnaround delays.
Specify a maximum delay time between
transmitting a request and receiving a
response.
MG02K402