9.1 Overview of RS-485 Communication
9-5
COMMUNICATION FUNCTIONS
Chap 9
9.1.3 Connection method
• Up to 31 inverters can be connected to one host equipment.
• The protocol is commonly used in the FRENIC series of general-purpose inverters, so programs for similar host
equipment can run/stop the inverter.
(The parameters modes may differ depending on the equipment.)
• Fixed-length transmission frames facilitate developing communication control programs for hosts.
For details of RS-485 communication, refer to the RS-485 Communication User’s Manual (MEH448).
Multi-drop connection using the RS-485 communication port 1 (for connecting the keypad)
For connecting inverters in multi-drop connection, use the branch adapters for multi-drop connection as shown
below.
Figure 9.1-1 Multi-drop Connection for RS-485 Communication Port 1 (Using the RJ-45 Connector)
• The power supply for keypad is available in the RJ-45 connector for RS-485 communication
(COM port 1) (pins 1, 2, 7 and 8). When connecting other devices to the RJ-
care not to use those pins. Use pins 4 and 5 only. (refer to “9.1.2 Terminal specifications”)
When selecting additional devices to prevent the damage or malf
unction of the control PCB
caused by external noises or eliminate the influence of common mode noises, be sure to see
“9.1.4 RS-485 connection devices.”
The maximum wiring length must be 500 m.
Use the cables and converters meeting the modes for connecting the RS-
ports. (Refer to “[ 2 ] Requirements for the cable (COM port 1: for RJ-45 connector)” in “
RS-485 connection devices”)
Branch adapter for
multi-drop
Terminating resistor
switch SW2 OFF
Terminating resistor
switch SW2 OFF
Terminating resistor
switch SW2 ON
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