Communication operation and setting
4.20.6 Modbus-RTU communication specifications
(Pr. 117, Pr. 118, Pr. 120, Pr. 122, Pr. 343, Pr. 502, Pr. 549)
Using the Modbus-RTU communication protocol, communication operation or parameter setting can be performed from
the PU connector of the inverter.
check time interval
Stop mode selection
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 188)
∗ When Modbus-RTU communication is performed from the master with address 0 (station number 0) set, broadcast communication is selected and the
inverter does not send a response message. When response from the inverter is necessary, set a value other than "0" (initial value is 0) in Pr. 117 PU
communication station number.
Some functions are invalid for broadcast communication. (Refer to page 235)
When "1" (Modbus-RTU protocol) is set in Pr. 549 and "384" (38400bps) in Pr. 118, parameter unit (FR-PU04/FR-PU07)
is disabled. When using the parameter unit (FR-PU04/FR-PU07), change parameter using the operation panel.
Set Pr. 549 Protocol selection to "1" to use the Modbus-RTU protocol.
When PU connector is selected as NET mode command source (when Pr. 550 NET mode operation command source selection ="2"
or "9999" (initial value) without communication option), Modbus-RTU communication operation can be performed. (Refer to page
No reply to the master
Inverter station number specification
1 to 247
Set the inverter station numbers when two or more inverters are
connected to one personal computer.
48, 96, 192,
The setting value × 100 equals the communication speed.
Example) 9600bps if 96
Without parity check
Stop bit length 2bit
With odd parity check
Stop bit length 1bit
With even parity check
Stop bit length 1bit
RS-485 communication can be made. Note that a communication
fault (E.PUE) occurs as soon as the inverter is switched to the
operation mode with command source.
Communication check (signal loss detection) time interval
If a no-communication state persists for longer than the permissible
time, the inverter trips (depends on Pr. 502).
No communication check (signal loss detection)
Displays the number of communication errors during Modbus-RTU
communication (reading only)
Coasts to stop. E.PUE
Mitsubishi inverter (computer link operation) protocol