Modbus-Rtu Communication Specifications (Pr. 331, Pr. 332, Pr. 334, Pr. 343, Pr. 502, Pr. 539, Pr. 549, Pr.779); Modbus-Rtu Communication Specifications; Bacnet Ms/Tp Protocol - Mitsubishi FR-F720-00046-NA Instruction Manual

Communication operation and setting

4.19.7 Modbus-RTU communication specifications

(Pr. 331, Pr. 332, Pr. 334, Pr. 343, Pr. 502, Pr. 539, Pr. 549, Pr.779)
Using the Modbus-RTU communication protocol, communication operation or parameter setting can be
performed from the RS-485 terminals of the inverter.
Parameter
Name
Number
RS-485
331 communication
station number
RS-485
332 communication
speed
RS-485
334 communication parity
check selection
Communication error
343
count
Stop mode selection
502
at communication
error
Modbus-RTU
539 communication check
time interval
549
Protocol selection
Operation frequency
779
during
communication error
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 192)
...
Specifications differ according to the date assembled. Refer to page 399 to check the SERIAL number.
* The inverter works with the initial parameter setting if a value other than the setting range is set.
CAUTION
When Modbus-RTU communication is performed from the master with address 0 (station 0) set, broadcast communication is
selected and the inverter does not send a response message to the master.
When response from the inverter is necessary, set a value other than "0" in Pr. 331.
Some functions are invalid for broadcast communication. (Refer to page 237.)
REMARKS
⋅ When using the Modbus-RTU protocol, set Pr. 549 Protocol selection to "1".
⋅ When the communication option is fitted with Pr. 550 NET mode operation command source selection set to "9999" (initial value), the
command source (e.g. run command) from the RS-485 terminals is invalid. (Refer to page 206)
234
Initial
Setting Range
Value
0
0
1 to 247 *
3, 6, 12, 24, 48,
96
96, 192, 384 *
0
2 1
2
⎯
0
0
1
0
2
3
0
0.1 to 999.8s
9999
9999
0
1 1
2
0 to 400Hz
9999
9999
Description
Broadcast communication is selected.
Specifies the inverter station number.
Set the inverter station numbers when two or more inverters
are connected to one personal computer.
Set the communication speed.
The setting value × 100 equals the communication speed.
For example, the communication speed is 9600bps when
the setting value is "96".
Without parity check
Stop bit length 2 bits
With odd parity check
Stop bit length 1 bit
With even parity check
Stop bit length 1 bit
Displays the number of communication errors during
Modbus-RTU communication. Reading only
At Fault
Indication
Occurrence
Coasts to
E.SER
stop.
After stop
Decelerates
to stop E.SER
After stop
Decelerates
to stop
E.SER
Continues
⎯
running at
Pr.779
Modbus-RTU communication is available, but the inverter
trips in the NET operation mode.
Set the interval of communication check time.
(same specifications as Pr. 122)
No communication check (signal loss detection)
Mitsubishi inverter (computer link) protocol
Modbus-RTU protocol

BACnet MS/TP protocol

Motor runs at the specified frequency at a communication
error.
Motor runs at the frequency used before the communication
error.
At Fault
Fault Output
Removal
Stop
Output
(E.SER)
Output after Stop
stop (E.SER)
Automatic
Without
restart
output
functions
Operates in
Without
normal
output
condition