Mitsubishi Electric FR-A800 Series Instruction Manual page 688

Pr.
331 RS-485 communication
N030 station number
332 RS-485 communication
N031 speed
RS-485 communication stop
N033
bit length
RS-485 communication stop
333
bit length / data length
334 RS-485 communication parity
N034 check selection
343
Communication error count
N080
MODBUS RTU
539
communication check time
N002
interval
549
Protocol selection
N000
NOTE
• To use the MODBUS RTU protocol, set "1" in Pr.549 Protocol selection.
• If MODBUS RTU communication is performed from the master to the address 0 (station number 0), the data is broadcasted,
and the inverter does not send any reply to the master. To obtain replies from the inverter, set Pr.331 RS-485 communication
station number ≠ "0 (initial value)".
• Some functions are disabled in broadcast communication. (Refer to
• If a communication option is installed with Pr.550 NET mode operation command source selection = "9999 (initial value)",
commands (operation commands) transmitted via RS-485 terminals become invalid. (Refer to
 Communication specifications
• The communication specifications are shown in the following table.
Communication protocol
Conforming standard
Number of connectable units
Communication speed
Control procedure
Communication method
Communication
specifications
Time delay setting
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Initial
Name
value
0
96
1
1
2
0
9999
0
Item
MODBUS RTU protocol
EIA-485 (RS-485)
1: N (maximum 32 units), setting is 0 to 247 stations
Selected among 300/600/1200/2400/4800/9600/19200/38400/57600/76800/
115200 bps.
Asynchronous method
Half-duplex system
Character
Binary (fixed at 8 bits)
system
Start bit 1 bit
Stop bit length Select from the following three types:
No parity check, stop bit length 1 bit / 2 bits (depends on the setting of Pr.333).
Odd parity check, stop bit length 1 bit.
Parity check
Even parity check, stop bit length 1 bit.
Error check CRC code check
Terminator Not available
Not available
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Setting
range
0 Broadcast communication
Specify the inverter station number.
1 to 247 Enter the inverter station numbers when two or more inverters are
connected to one personal computer.
3, 6, 12, 24,
Select the communication speed.
48, 96, 192,
The setting value × 100 equals the communication speed.
384, 576,
For example, enter 96 to set the communication speed of 9600 bps.
768, 1152
0 Stop bit length 1 bit
1 Stop bit length 2 bits
0 Stop bit length 1 bit
1 Stop bit length 2 bits
10 Stop bit length 1 bit
11 Stop bit length 2 bits
Without parity check
0
Stop bit length 1 bit / 2 bits (depends on the setting of Pr.333)
With parity check at odd numbers.
1
Stop bit length: 1 bit.
With parity check at even numbers.
2
Stop bit length: 1 bit.
Displays the communication error count during MODBUS RTU
—
communication. Read-only.
MODBUS RTU communication is available, but the inverter output is
0
shut off in the NET operation mode.
Set the interval of the communication check (signal loss detection)
0.1 to 999.8 s
time (same specifications as Pr.122).
9999 No communication check (signal loss detection)
0 Mitsubishi inverter protocol (computer link)
1 MODBUS RTU protocol
page
Description
Description
Valid when Pr.N034 (Pr.334) =
"0"
Valid when Pr.334 = "0"
689.)
page 400.)
Related parameter
Pr.549
—
Pr.331
Pr.332
—
—
—
—
Pr.333
Pr.334
—
—
—
5. PARAMETERS
5.15 (N) Communication operation parameters
1
2
3
4
5
6
7
8
9
10
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