Mitsubishi Electric FR-D720S SC EC Instruction Manual page 374

Communication operation and settings
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.
Pr. No. Name
PU communica-
117
tion station
number
PU communica-
118
tion speed
PU communica-
120
tion parity check
PU communica-
122
tion check time
interval
Communication
343
error count
Stop mode selec-
502
tion at communi-
cation error
549
Protocol selection
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.)
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).
6 - 224
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 invert-
ers are connected to one personal computer.
Communication speed
48/96/
192 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
RS485 communication can be made. Note that a commu-
0 nication fault (E.PUE) occurs as soon as the inverter is
switched to the operation mode with command source.
Communication check (signal loss detection) time interval
9999 0.1
If a no-communication state persists for longer than the
–
permissible time, the inverter will come to trip (depends
999.8s
on Pr. 502).
9999 No communication check (signal loss detection)
Displays the number of communication errors during
0 —
Modbus-RTU communication (reading only)
At fault
occurrence
Coasts to
0
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)
After stop Output after Stop
E.PUE stop (E.PUE)
Automatic
After stop Without out-
restart
E.PUE put
functions
Parameter
Refer to
Parameters referred to
Section
—