Mitsubishi Electric FR-D720S SC EC, Instruction Manual

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Communication operation and settings Parameter
6 - 234
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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.
Error response (Response message)
An error will not occur in the following cases:
– 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.
– 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.
NOTE No response message is sent in the case of broadcast communication also.
Slave Address Function Exception Code CRC Check
(8 bits)
H80 + Function
(8 bits)
(8 bits)
L
(8 bits)
H
(8 bits)
Message Description
Slave address Set the address received from the master.
Function The master-requested function code + H80 is set.
Exception code The code in the following table is set.
Tab. 6-76: Description of response data
Code Error Item Description
01
ILLEGAL FUNCTION
(Function code illegal) The set function code in the query message from the master cannot be
handled by the slave.
02
ILLEGAL DATA
ADDRESS
(Address illegal)
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)
03
ILLEGAL DATA VALUE
(Data illegal)
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)
Tab. 6-77: Error code list
NOTES 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.