Bosche WTS - Page 42

User manual WTS Ver.1.16
Seite 42 von 52
FUNCTION 3: Read holding registers (PROGRAMMABLE REGISTER READING)
QUERY
Address
Function
Add. Register1
No. register
2 bytes
A
0x03
0x0000
0x0002
CRC
Tot. bytes = 8
RESPONSE
Address
Function
No. bytes
Register1
Register 2
2 bytes
A
0x03
0x04
0x0064
0x00C8
CRC
Tot. bytes = 3+2*No. registers+2
where:
No. registers= number of Modbus register to be read, starting from the Address 1° register;
No. bytes = number of data bytes to follow;
FUNCTION 16: Preset multiple registers (MULTIPLE REGISTER WRITING)
QUERY
Address
Function
Add. reg. 1
No. reg.
No. bytes
Val. reg.1
Val.reg.2
2 bytes
A
0x10
0x0000
0x0002
0x04
0x0000
0x0000
CRC
Tot. bytes = 7+2*No. registers+2
RESPONSE
Address
Function
Add. reg. 1
No. reg.
2 bytes
A
0x10
0x0000
0x0002
CRC
Tot. bytes = 8
where:
No. registers = number of Modbus register to be read, starting from the Address 1° register;
No. bytes = number of data bytes to follow;
Val.reg.1 = register contents beginning from the first.
The Response contains the number of records changed starting from the Address 1° register.
COMMUNICATION ERROR MANAGEMENT
The communication strings are controlled by CRC (Cyclical Redundancy Check).
In case of a communication error the slave will not respond with any string. The master must
allow for a time-out before response reception. If no response is received it infers that a
communication error has occurred.
In the event of a string received correctly but not executable, the slave responds with an
EXCEPTIONAL RESPONSE. The "FUNCTION" field is transmitted with the msb at 1.
EXCEPTIONAL RESPONSE
Address
Function
Code
2 bytes
A
Funct + 0x80
CRC
CODE
DESCRIPTION