Mitsubishi Electric FR-D720S SC EC, Instruction Manual

Page: 374 / 512

Communication operation and settings Parameter
6 - 224
6.18.6 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.
The above parameter can be set when Pr. 160 = 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 communication. (Refer to page 6-227.)
Pr. No. Name
Initial
Value
Setting
Range
Description Parameters referred to
Refer to
Section
117
PU communica-
tion station
number
0
0
No reply to the master
—
1–247
Inverter station number specification
Set the inverter station numbers when two or more invert-
ers are connected to one personal computer.
118
PU communica-
tion speed
192
48/96/
192/384
Communication speed
The setting value × 100 equals the communication speed.
(Example: 9600bps if 96)
120
PU communica-
tion parity check
2
0
Without parity check
Stop bit length 2bit
1
With odd parity check
Stop bit length 1bit
2
With even parity check
Stop bit length 1bit
122
PU communica-
tion check time
interval
9999
0
RS485 communication can be made. Note that a commu-
nication fault (E.PUE) occurs as soon as the inverter is
switched to the operation mode with command source.
0.1
–
999.8s
Communication check (signal loss detection) time interval
If a no-communication state persists for longer than the
permissible time, the inverter will come to trip (depends
on Pr. 502).
9999 No communication check (signal loss detection)
343
Communication
error count
0 —
Displays the number of communication errors during
Modbus-RTU communication (reading only)
502
Stop mode selec-
tion at communi-
cation error
0
At fault
occurrence
Indication Fault output
At fault
removal
0
Coasts to
stop
E.PUE Output
Stop
(E.PUE)
1
Decelerates to
stop After stop
E.PUE Output after
stop Stop
(E.PUE)
2
Decelerates to
stop After stop
E.PUE Without out-
put
Automatic
restart
functions
549
Protocol selection 0
0 Mitsubishi inverter (computer link) protocol
1 Modbus-RTU protocol
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 parameter 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 (Pr. 551
≠
2), Modbus RTU
communication operation can be performed. (Refer to section 6.18.2).