Modbus-Rtu Communication - Mitsubishi Electric FR-E700 Series Instruction Manual

Communication operation and setting
6.19.5

Modbus-RTU communication

(Pr. 117, Pr. 118, Pr. 120, Pr. 122, Pr. 343, Pr. 549)
Using the Modbus RTU communication protocol, communication operation or parameter setting can
be performed from the PU connector of the inverter.
Pr. No. Name
PU communication sta-
117
tion number
PU communication
118
speed
PU communication par-
120
ity check
PU communication
122
check time interval
Communication error
343
count
Stop mode selection at
502
communication error
549
Protocol selection
The above parameter can be set when Pr. 160 "User group read selection" = 0.
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 com-
munication. (Refer to page 6-261.)
NOTES 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 parame-
ter using the operation panel.
When using the Modbus-RTU protocol, set Pr. 549 "Protocol selection" to "1".
When PU connector is selected as NET mode operation 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 section 6.19.2).
6 - 258
Initial Setting
Description
Value Range
0
No reply to the master
Inverter station number specification
0
1–247 Set the inverter station numbers when two or more inverters are con-
nected to one personal computer.
Communication speed
48/96/
96 The setting value × 100 equals the communication speed.
192/384
(Example: 9600bps if 96)
Without parity check
0
Stop bit length 2bit
With odd parity check
2
1
Stop bit length 1bit
With even parity check
2
Stop bit length 1bit
RS-485 communication can be made. Note that a communication fault
0 (E.PUE) occurs as soon as the inverter is switched to the operation mode
with command source.
0.1 Communication check (signal loss detection) time interval
0
– If a no-communication state persists for longer than the permissible time,
999.8s the inverter will come to trip (depends on Pr. 502).
9999 No communication check (signal loss detection)
Displays the number of communication errors during Modbus-RTU com-
0 —
munication (reading only)
At Fault
Occurrence
0/3 Coasts to stop
0
Decelerates to
1
stop
Decelerates to
2
stop
0 Mitsubishi inverter (computer link) protocol
0
1 Modbus-RTU protocol
At Fault
Indication Fault Output
Removal
Stop
E.PUE Output
(E.PUE)
Output after Stop
After stop E.PUE
stop (E.PUE)
Automatic
After stop E.PUE Without output restart
functions
Parameter
Refer to
Parameters referred to
Section
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