4.20.3 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
Number of PU
check time interval
Stop mode selection
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 188)
Retry count setting (Pr.121)
Set the permissible number of retries at data receive error occurrence. (Refer to page 223 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
any of Pr. 190 to Pr. 192 (output terminal function selection).
Example: PU connector communication, Pr. 121 = "1" (initial value)
Example: PU connector communication, Pr. 121 = "9999"
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.
Number of retries at data receive error occurrence If the number of
consecutive errors exceeds the permissible value, the inverter trips
0 to 10
(depends on Pr. 502).
Valid only Mitsubishi inverter (computer link operation) protocol
If a communication error occurs, the inverter will not come to trip.
RS-485 communication can be made. Note that a communication
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
If a no-communication state persists for longer than the permissible
time, the inverter trips (depends on Pr. 502).
No communication check (signal loss detection)
Coasts to stop
Communication operation and setting
Fault (E. PUE)