User`s guide

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CHAPTER 8 - CFW-08 OPTIONS AND ACCESSORIES
8.25.2.2
Inverter
Configuration in
the Modbus-RTU
Network
8.25.2
Operation of the
CFW-08 in the
Modbus-RTU
Network
The CFW-08 frequency inverters operate as slaves of the
Modbus-RTU network. The communication initiates with the
masterof the Modbus-RTU network requesting a service for a
network address. When the inverter is configured to the
corresponding address, it processes the question and
answers to the master as requested.
8.25.2.1
RS-232 and
RS-485 Interface
Description
The CFW-08 frequency inverters use a serial interface for the
communicationwith the Modbus-RTU network.There are two
ways to perform the connection between the network master
and the CFW-08:
RS-232:
The interface is used for the point to point connection
(between a single slave and the master).
Maximum
distance: 10 meters (32.8 ft).
Signal levels according to EIA STANDARD RS-232C.
Three wires: transmission (TX), reception (RX) and return
(0 V).
The RS-232 module (KCS-CFW08) must be used (refer to
item 8.11).
RS-485:
This interface is used for multipoint connection (several
slaves and the master).
Maximum distance: 1000 meters (use of shielded cables).
Signal levels according to EIA STANDARD RS-485.
Mustbe used with the module RS-485(KRS-485-CFW08),
refer to item 8.13.
Note:
for connection, refer to item 8.24.7.
To ensure a correct communication in the network, you must
configure the inverter address in the network as well as the
transfer rate and the existing parity type, besides the correct
physical connection.
Inverter address in the network:
The inverter addressisdefinedthrough the parameterP308.
If theserialcommunicationtype(P312) has been configured
to Modbus- RTU, you may select the addresses from 1 to
247.
Each slave shall have a different address.
The master does not have address.
The slave address must be known, even when connection
is made point to point.