Operation Selection At Communication Error Occurrence (Pr. 121, Pr. 122, Pr. 502) - Mitsubishi Electric FR-D720-0.4K Instruction Manual

4.19.3 Operation selection at communication error occurrence (Pr. 121, Pr. 122, Pr. 502)

You can select the inverter operation when a communication line error occurs during RS-485 communication from the
PU connector.
Parameter
Name
Number
Number of PU
121 communication
retries
PU communication
122
check time interval
Stop mode
selection at
502
communication
error
The above parameters can be set when Pr. 160 Extended function display selection = "0".
(1) Retry count setting (Pr.121)
Set the permissible number of retries at data receive error occurrence. (Refer to page 191 for data receive error for retry)
When data receive errors occur consecutively and exceed the permissible number of retries set, an inverter trips (E.PUE)
and a motor stops (as set in Pr. 502).
When "9999" is set, an inverter fault is not provided even if data receive error occurs but an alarm signal (LF) is output.
For the terminal used for the LF signal output, assign the function by setting "98 (positive logic) or 198 (negative logic)" in
Pr. 190, Pr. 192 or Pr. 197 (output terminal function selection).
Example: PU connector communication, Pr. 121 = "1" (initial value)
Computer
Inverter
Inverter
Computer
ALM
Example: PU connector communication, Pr. 121 = "9999"
Computer
Inverter
Inverter
Computer
LF
REMARKS
Pr. 121 is valid only when Mitsubishi inverter (computer link operation) protocol is selected. Pr. 121 is not valid when Modbus-
RTU communication protocol is selected.
How the inverter operates at a communication error differs according to the Pr. 502 Stop mode selection at communication error
setting.
Initial Setting
Value Range
Number of retries at data receive error occurrence. If the number of
consecutive errors exceeds the permissible value, the inverter will
0 to 10
come to trip (depends on Pr. 502).
1
Valid only Mitsubishi inverter (computer link operation) protocol
If a communication error occurs, the inverter will not come to trip. (NET
9999
operation mode at initial value)
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. (NET operation mode at initial value)
Communication check (signal loss detection) time interval
0.1 to
0
If a no-communication state persists for longer than the permissible
999.8s
time, the inverter will come to trip (depends on Pr. 502).
9999 No communication check (signal loss detection)
occurrence
0 Coasts to stop
0
Decelerates to
1
stop
Decelerates to
2
stop
Wrong
Reception error
Wrong
Reception
error
OFF
Communication operation and setting
Description
At fault
Indication
E.PUE
After stop
E.PUE
After stop
E.PUE
(Refer to page 163)
Fault (E. PUE)
Wrong
Reception error
ON
Wrong
Reception
error
ON OFF ON
At fault
Fault output
removal
Stop
Output
(E.PUE)
Output after Stop
stop (E.PUE)
Automatic
Without output
restart functions
Normal
OFF
183
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