FG_F6_MODBUS_EN_01 / 2020-06-17
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Command error handling
Reminder: a byte is 8 bits long and a word is 16 bits long
Reminder: "h" indicates a hexadecimal code, "(d)" indicates a decimal code.
Error frame
The errors are handled in the answer of the slave to a request of the master.
When an error occurs, the slaves add
80h
to the
Function number
followed by the error code:
—
Error on a
Writing N*words (10h)
request
Slave
address
Function 80h
(90h)
Error code
CRC
Byte
Byte
Byte
Word
—
Error on a
Reading N*words (03h)
request
Slave
address
Function 80h
(83h)
Error code
CRC
Byte
Byte
Byte
Word
Error codes
Hexa
code
Item
Meaning
02
ILLEGAL DATA ADDRESS
Address out of range
03
ILLEGAL DATA VALUE
Value out of limit / value not valid / parameter or bit unavailable