Mitsubishi Electric FR-D720-008 Instruction Manual page 210

Communication operation and setting
Error response
An error response is returned if the query message received from the master has an illegal function, address or data.
No response is returned for a parity, CRC, overrun, framing or busy error.
NOTE
No response message is sent in the case of broadcast communication also.
Error response (Response message)
1) Slave Address
(8bit)
Message
1) Slave Address
2) Function
3) Exception Code
Error code list
Code
01 ILLEGAL FUNCTION
ILLEGAL DATA ADDRESS ∗1
02
03 ILLEGAL DATA VALUE
∗1
An error will not occur in the following cases.
1) Function code H03 (Read holding register data)
When the No. of Points is 1 or more and there is one or more holding registers from which data can be read
2) Function code H10 (Write multiple holding register data)
When the No. of Points is 1 or more and there is 1 or more holding registers to which data can be written
Namely, when the function code H03 or H10 is used to access multiple holding registers, an error will not occur if a non-existing holding register
or read disabled or write disabled holding register is accessed.
REMARKS
An error will occur if all accessed holding registers do not exist.
Data read from a non-existing holding register is 0, and data written there is invalid.
Message data mistake detection
To detect the mistakes of message data from the master, error item are checked for the following errors.
If an error is detected, a trip will not occur.
Error check item
Error Item
Parity error
Framing error
Overrun error
Message frame error
CRC check error
206
2) Function 3) Exception Code
H80 + Function
(8bit)
Address received from the master
Master-requested function code + H80
Code in the following table
Error Item
The set function code in the query message from the master cannot be
handled by the slave.
The set register address in the query message from the master cannot be
handled by the inverter.
(No parameter, parameter read disabled, parameter write disabled)
The set data in the query message from the master cannot be handled by the
inverter.
(Out of parameter write range, mode specified, other error)
Error Description
The data received by the inverter differs from the
specified parity (Pr.120 setting).
The data received by the inverter differs from the
specified stop bit length (Pr.120).
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.
CRC Check
L
(8bit)
(8bit)
Setting Description
Error Description
1) Pr.343 is increased by 1 at error
occurrence.
2)The terminal LF is output at error
occurrence.
H
(8bit)
Inverter Operation