1.5.6 FC Protocol
An RS-485 interface is standard on all Danfoss frequency converters allowing for up to 126 units in one network. The FC protocol has a very simple design
described in
Serial Communication
. For applications where data transmission speed is of less importance, the RS 485 interface provides a good alternative
to the faster fieldbus solution.
The FC protocol can also be used as a service bus for transfer of status information and parameter setup. In this case it is combined with normal time
critical I/0 control via digital inputs.
1.6 Good Installation Practice
1.6.1 Flexible Installation Options
A major benefit of Danfoss’ decentralised concept is saving installation cost partly due to the clever two-part design of the FCD 300.
All electrical installation is done inside the installation box prior to mounting the electronic part. Subsequently the electronic part is plugged into the
installation box, fixed, and the drive is ready for operation.
Power line looping
The FCD 300 serie facilitates internal power line looping. Terminals for 4 mm
2
power cables inside the enclosure allows connection of up to 10+ units.
FCD 300 can be mixed along the line. Average load must not exceed 25 A.
24 V control back up
External 24 V (20-30 V) DC can be connected in the EX and EB versions for back-up of control circuits. This way communication and programming
possibility are maintained even during power down. The terminals are dimensioned for up to 2.5 mm
2
and are doubled for looping.
The T63 and T73 installation boxes have additional looping terminals for 2 X 24 V with 4 mm
2
. Connected sensors can be supplied separately from the
control back up supply.
VLT
®
Decentral FCD 300 Design Guide
1 The Decentral Concept
MG.90.S1.02 - VLT
®
is a registered Danfoss trademark
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