203
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.
Error response (Response message)
Error code list
∗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.
Message data mistake detection
To detect the mistakes of message data from the master, they are checked for the following errors.
If an error is detected, a trip will not occur.
Error check item
NOTE
No response message is sent in the case of broadcast communication also.
1) Slave Address
2) Function
3) Exception Code
CRC Check
(8bit)
H80 + Function
(8bit)
(8bit)
L
(8bit)
H
(8bit)
Message
Setting Description
1) Slave Address
Address received from the master
2) Function
Master-requested function code + H80
3) Exception Code
Code in the following table
Code
Error Item
Error 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
∗1
(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)
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.
Error Item
Error Description
Inverter Operation
Parity error
The data received by the inverter differs from the
specified parity (
Pr. 334
setting).
1)
Pr.343
is increased by 1 at error
occurrence.
2)The terminal LF is output at error
occurrence.
Framing error
The data received by the inverter differs from the
specified stop bit length
(Pr. 333)
.
Overrun error
The following data was sent from the master before
the inverter completes data receiving.
Message frame error
The message frame data length is checked, and the
received data length of less than 4 bytes is regarded
as an error.
CRC check error
A mismatch found by CRC check between the
message frame data and calculation result is
regarded as an error.
Summary of Contents for FR-D700 Series
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