Varec 2920 Installation And Operation Manual page 165

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Address Function Start Reg
Code H
01 41 00
Address Function # of Reg
Code H
01 41 00
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).
Address Function
Code
01 42
Address Function
Code
01 42
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
Start Reg # of Reg
L H
01 00
2920 FTT Response
# of Reg Data
L MSB
01 42
Host Request
Start Reg Start Reg
H L
00 0C
Data
C8
2920 FTT Response
# of Reg # of Reg
H L
00 01
MODBUSAppendix A — MODBUS Implementation
# of Reg Error
L Check
01 AD C5
Data Data Data LSB
C8 00 00
# of Reg # of Reg
H L
00 01
Data Data
LSB
00 00
Error
Check
60 0C
Error
Check
78 85
Data
MSB
42
Error
Check
27 6D
155