IDEC KW2D Series User Manual page 46

1 ModbusTCP Communication (Server)
Example: Write 0 to coil relay 0007 and 1 to coil relay 0008.
Request
Function
code
0Fh
（1 byte）
ACK Reply
Function code
0Fh
（1 byte）
Example: Try to access multiple coil relays of the slave address outside the range
NAK Reply
Function code
8Fh
（1 byte）
For details on the error code, refer to "Error code" on page 4-5.
Write the value to the holding register.
The host device (ModbusTCP client) can write to the holding register of the KW2D Smart RFID Reader (ModbusTCP
Server). When writing a value to one address number, the function code is "06h". When writing values to multiple
consecutive address numbers, the function code is "10h". The function code for error is "86h" (06h+80h) in the case
of writing to one address number, and "90h" (10h+80h) in the case of writing to multiple address numbers.
Example: Write "0103h" to holding register 0008
Request
Function code Start address number
06h
（1 byte）
ACK Reply
Function code
06h
（1 byte）
Example: Try to access one holding register with a slave address outside the range.
NAK Reply
Function code
86h
（1 byte）
For details on the error code, refer to "Error code" on page 4-5.
4-4
Start address Number of bits
number to write
00h 06h 00h
（2 bytes） （2 bytes）
Start address number Number of bits written
00h 06h 00h
（2 bytes） （2 bytes）
Error code
02h
（1 byte）
Data to write
Upper
byte
00h 07h 01h
（2 bytes） （2 bytes）
Written value
Upper
Start address number
byte
00h 07h 01h
（2 bytes） （2 bytes）
Error code
02h
（1 byte）
KW2D Series Smart RFID Reader User's Manual
Number of Data to
data to write write
02h 01h 02h
（1 byte） （1 byte）
02h
Lower
byte
03h
Lower
byte
03h