Hitachi WJ200-001S Instruction Manual page 545

Ver.3− − − − 36
Writing Holding Register [06h] , Target Register: External Register
Query:
No
1 Slave address
2 Function code
3 Register start address (high order)
4 Register start address (low order)
5 Change data (high order)
6 Change data (low order)
7 CRC-16 (high order)
8 CRC-16 (low order)
Response:
No
1 Slave address
2 Function code
3 Exception code
4 CRC-16 (high order)
5 CRC-16 (low order)
The exception Response above is caused by supposedly writing -1, but by actually writing very big data
(65535) because of designating unsigned conversion that exclude range of internal register data. If you
properly choose "Signed" format, this Query can be executed without giving exception.
Field Name
Field Name Example
(Hex)
Example
(Hex)
01
06
40
02
FF
FF
3C
7A
01
86
21
82
78
Register address value = Register
Number - 1
Since unsigned is designated, two's
compliment is not applied and
converted to 65535d