Mitsubishi Electric FR-A700 Instruction Manual page 658

Communication operation and setting
To detect the mistakes of message data from the master, they are checked for the following
errors. If an error is detected, an alarm stop will not occur.
Error Item
Parity error
Framing error
Overrun error
Message frame error
CRC check error
Tab. 6-158: Error check item
You can check the cumulative number of communication errors.
Parameters
Tab. 6-159: Number of communication errors
NOTE
The number of communication errors is temporarily stored into the RAM. As it is not stored
into the EEPROM, performing a power supply reset or inverter reset clears the value to 0.
During a communication error, the minor failure output (LF signal) is output by open collector
output. Assign the used terminal using any of Pr. 190 to Pr. 196 "Output terminal function
selection".
Communication
Fig. 6-232: Output of the LF signal
NOTE The LF signal can be assigned to the output terminal using any of Pr. 190 to Pr. 196. When
terminal assignment is changed, the other functions may be affected. Please make setting
after confirming the function of each terminal.
6 - 478
Error Definition
The data received by the inverter differs from
the specified parity (Pr. 334 setting).
The data received by the inverter differs from
the specified stop bit length (Pr. 333).
The following data was sent from the master
before the inverter completes data receiving.
The message frame data length is checked,
and the received data length of less than 4
bytes is regarded as an error.
A mismatch found by CRC check between
the message frame data and calculation
result is regarded as an error.
Setting Range
343 (Read only)
Master
Alarm data Alarm data
Slave
Error count
(Pr. 343)
Signal LF
OFF
Communication error count is increased in
synchronization with leading edge of LF signal
Inverter Side Operation
Pr. 343 is increased by 1 at error
occurrence.
The terminal LF is output at error
occurrence.
Minimum Setting Range
1
Normal data
Reply data
ON OFF
Turns off when normal data is received
Alarm data:Data resulting in
Parameter
Initial Value
0
Alarm data Normal data
ON
communication error.
Reply data
OFF
I001229E