Danfoss VLT Series Design Manual page 123

®
VLT HVAC Drive Design Guide
7.1.4. VLT HVAC Parameter Settings for Modbus Communication
The following parameters apply to the RS-485 interface (FC-port):
Parameter
ber
8-30
8-31
8-32
8-33
8-35
8-36
8-37
7.1.5. EMC Precautions
The following EMC precautions are recommended in order to achieve interference-free operation
of the RS-485 network.
Num- Parameter name
Protocol
Address
Baud Rate
PC port parity/Stop
bits
Min. response delay Specify a minimum delay time between receiving
Max. response delay Specify a maximum delay time between trans-
Max. inter-char delay Specify a maximum delay time between two re-
NB!
Relevant national and local reg-
ulations, for example regarding
protective earth connection,
must be observed. The RS-485
communication cable must be
kept away from motor and
brake resistor cables to avoid
coupling of high frequency noise
from one cable to another. Nor-
mally a distance of 200 mm (8
inches) is sufficient, but keeping
the greatest possible distance
between the cables is generally
recommended, especially where
cables run in parallel over long
distances. When crossing is un-
avoidable, the RS-485 cable
must cross motor and brake re-
sistor cables at an angle of 90
degrees.
®
MG.11.B2.02 - VLT is a registered Danfoss trademark
7. RS-485 Installation and Set-up
Function
Select the application protocol to run on the
RS-485 interface
Set the node address. Note: The address range
depends on the protocol selected in par. 8-30
Set the baud rate. Note: The default baud rate
depends on the protocol selected in par. 8-30
Set the parity and number of stop bits. Note: The
default selection depends on the protocol selec-
ted in par. 8-30
a request and transmitting a response. This can
be used for overcoming modem turnaround de-
lays.
mitting a request and receiving a response.
ceived bytes to ensure timeout if transmission is
interrupted.
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