Modbus-Rtu Communication (Pr. 331, Pr. 332, Pr. 334, Pr. 343, Pr. 539, Pr. 549) - Mitsubishi Electric FR-A700 Instruction Manual

Parameter
6.23.6 Modbus-RTU communication (Pr. 331, Pr. 332, Pr. 334, Pr. 343, Pr. 539,
Pr. 549)
Using the Modbus-RTU communication protocol, communication operation or parameter set-
ting can be performed from the RS-485 terminals of the inverter.
Pr. No. Name
RS-485 communication
331
station number
RS-485 communication
332
speed
RS-485 communication
334
parity check selection
Communication error
343
count
Modbus-RTU communica-
539
tion check time interval
549
Protocol selection
NOTES When Modbus RTU communication is performed with "0" (initial value) set in Pr. 331 "RS-
485 communication station number",broadcast communication is selected and the inverter
does not send a response message to the master. When response from the inverter is nec-
essary, set a value other than "0" in Pr. 331. Some functions are invalid for broadcast com-
munication. (Refer to page 6-470.)
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 section 6.22.3.)
FR-A700 EC
Initial Setting
Description
Value Range
0 Broadcast communication is selected
Specify the inverter station number.
0
Set the inverter station numbers when
1–247
two or more inverters are connected
to one personal computer
Set the communication speed.
The setting value × 100 equals the
3/6/12/24/
communication speed.
96 48/96/192/
For example, the communication
384
speed is 9600bps when the setting va-
lue is "96".
Without parity check
0
Stop bit length: 2bits
With odd parity check
2 1
Stop bit length: 1bit
With even parity check
2
Stop bit length: 1bit
Display the number of communica-
0 — tion errors during Modbus-RTU com-
munication. Reading only
Modbus-RTU communication can be
0 made, but the inverter will come to an
alarm stop in the NET operation mode.
Set the interval of communication
9999
0.1–999.8 s check time.
same specifications as Pr. 122)
No communication check (signal loss
9999
detection)
Mitsubishi inverter (computer link)
0
protocol
0
1 Modbus-RTU protocol
Communication operation and setting
Parameters referred to
—
Refer to
Section
6 - 467