Omron V680 Series User Manual page 163

 Error End
Byte 0 Byte 1 Byte 2
Transaction
Protocol identifier
identifier
Copy of the transaction
Always 0000 hex
identifier that was specified
in the query
Transaction Identifier
A copy of the value that was specified in the query is returned.
Protocol Identifier
This field is always 0000 hex.
Field Length
The number of bytes inclusively from the unit identifier through the end of the data is specified.
Byte 4 will always be 00 hex.
Unit Identifier
This field is always FF hex.
Function Code
A value of 80 hex is added to the value that was specified in the query and set.
Exception Code
A code that provides information on the error is attached.
Exception code
01 hex Illegal function
02 hex Illegal data address
03 hex Illegal data value
04 hex Failure in slave device
06 hex Slave device busy
Byte 3 Byte 4 Byte 5
Field length
identifier
Always No. of Always
00 hex bytes FF hex
Range specified with the field length
Meaning
Host Communications Specifications
Byte 6 Byte 7 Byte 8
Unit Function Exception
code code
Section 7
RFID System
161
User's Manual
(Modbus TCP)