MODBUSAppendix A — MODBUS Implementation
Varec, Inc. 155
Example of Floating-point Data
• Hexadecimal representation: 42 C8 00 00
• Decimal equivalent: 100.00
Function code 66 (42 Hex) is used to write floating-point registers. An example of a floating-
point register write is shown below with the value 100.0 being written into the Advisory High
Temperature Alarm Setpoint, register 12 (000C Hex).
Example of Floating-point Data
• Hexadecimal representation: 42 C8 00 00
• Decimal equivalent: 100.00
Floating-point registers that are defined as reserved will respond with undocumented values.
A write command to a reserved floating-point register will be ignored.
Host Request
Address Function
Code
Start Reg
H
Start Reg
L
# of Reg
H
# of Reg
L
Error
Check
01 41 00 01 00 01 AD C5
2920 FTT Response
Address Function
Code
# of Reg
H
# of Reg
L
Data
MSB
Data Data Data LSB Error
Check
01 41 00 01 42 C8 00 00 78 85
Host Request
Address Function
Code
Start Reg
H
Start Reg
L
# of Reg
H
# of Reg
L
Data
MSB
01 42 00 0C 00 01 42
Data Data Data
LSB
Error
Check
C8 00 00 27 6D
2920 FTT Response
Address Function
Code
# of Reg
H
# of Reg
L
Error
Check
01 42 00 01 60 0C
To Next Page
Loading...