Varec 4000 - Manual (Page 62)

Modbus Implementation Tank Gauge Transmitter
52 Installation and Operations Manual
9.6.4 The One 32-bit Register Format
Function code 65 (41 Hex) is used to read floating-point registers in this format. An example of a floating-point
register read is shown below with the a temperature of 100.0 degrees is being read from register 1 (0001 Hex).
9.6.5 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).
9.6.6 Floating Point Data
•
Hexadecimal representation: 42 C8 00 00
•
Decimal equivalent: 100.00
Floating-point registers that are defined as reserved have zero (0) as their value. A write command to a reserved
floating-point register will be ignored.
Host Request
Address
Function
Code
Start
Reg H
Start
RegL
# of
Reg H
# of
Reg L
Error
Check
01 41 00 01 00 01 XX
ATT 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 XX
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 XX
ATT Response
Address
Function
code
# of Reg
H
# of Reg
L
Error
Check
01 03 02 41 XX