Mitsubishi Electric FR-A820-00046 Instruction Manual page 846

(N) Operation via communication and its settings
Retry count setting (Pr. 121, Pr. 335)
● Set the permissible number of retries at data receive error occurrence. (Refer to page 5-642 for
data receive error for retry.)
● When the data receive errors occur consecutively and the number of retries exceeds the permis-
sible number setting, a communication fault (PU connector communication: E.PUE, RS-485 termi-
nal communication: E.SER) occurs and the inverter trips.
● When a data transmission error occurs while "9999" is set, the inverter does not trip but outputs
the alarm (LF) signal.
To use the LF signal, set "98 (positive logic) or 198 (negative logic)" in any of Pr. 190 to Pr. 196
(output terminal function selection) to assign the function to an output terminal.
Computer
Inverter
Computer
Inverter
Fig. 5-321:
NOTE For the RS-485 terminal communication, the operation at a communication error occurrence
depends on the Pr. 502 "Stop mode selection at communication error" setting. (Refer to page 5-626.)
5 - 644
Example: PU connector communication, Pr. 121 = "1" (initial value)
Inverter
Computer
ALM
Example: PU connector communication, Pr. 121 = "9999"
Inverter
Computer
OFF
LF
ALM
Data transmission error
Illegal
Illegal
Reception error
Illegal
Illegal
Reception error
ON
OFF
Parameters
Fault (E.PUE)
Reception error
ON
Normal
Reception error
ON
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