Mitsubishi Electric FR-A800, Instruction Manual

Page: 799 / 1042

Parameters (N) Operation via communication and its settings
FR-A800 5 - 619
Retry count setting (Pr. 121, Pr. 335)
●
Set the permissible number of retries at data receive error occurrence. (Refer to page 5-617 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.
I002738E
Fig. 5-313: Data transmission error
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 5-606.)
ENQ
ACK NAK NAK
LF
ENQ
ACK NAK NAK
ENQ
ACK
ENQ
ENQ
ALM
ALM
Example: PU connector communication, Pr. 121 = "1" (initial value)
Computer
Computer
Inverter
Inverter
Inverter
Inverter
Computer
Computer
Reception error
Reception error
Reception error
Reception error
Fault (E.PUE)
Illegal
Illegal
Illegal
Illegal
Normal
ON ON
ON
OFF
OFF
Example: PU connector communication, Pr. 121 = "9999"