Modbus Rtu Communication Specification - Mitsubishi Electric 800 Series Instruction Manual

4.5

MODBUS RTU communication specification

• Parameter setting, monitoring, etc. can be performed using MODBUS RTU communication protocol.
• To make communication between the personal computer and inverter, setting of the communication specifications
must be made to the inverter in advance.
Data communication cannot be made if the initial settings are not made or if there is any setting error.
Pr.
Pr. Name
group
RS-485 communication
331 N030
station number
RS-485 communication
332 N031
speed
RS-485 communication

N033
stop bit length
RS-485 communication

333 stop bit length / data
length
RS-485 communication
334 N034
parity check selection
Initial
Setting range
value
0 Broadcast communication
Inverter station number specification
0
1 to 247 Set the inverter station numbers when two or more inverters are
connected to one personal computer.
3, 6, 12, 24, 48, Set the communication speed.
The setting value  100 equals the communication speed.
96 96, 192, 384, 576,
768, 1152 For example, if 96 is set, the communication speed is 9600 bps.
0 Stop bit length 1 bit
1
1 Stop bit length 2 bits
0 Stop bit length 1 bit
1 Stop bit length 2 bits
1
10 Stop bit length 1 bit
11 Stop bit length 2 bits
Without parity check
0 The stop bit length is selectable between 1 bit and 2 bits (according
to Pr.333).
2 With parity check at odd numbers
1
Stop bit length 1 bit
With parity check at even numbers
2
Stop bit length 1 bit
Description
Valid when Pr.N034 (Pr.334) = "0"
Valid when Pr.334 = "0"
PARAMETER
4
59