V2.00
KBR multicomp F144-3PH
59
19837_EDEBD
A0227-1816-1_EN
Data point description for the Modbus protocol
2 Supported Modbus commands
0x04
Read input registers
0x2B
Read device identification
The multicomp F144-3PH does not support broadcast commands.
All described Modbus commands are device-specific commands.
3 Data formats
(unsigned) short:
0x1234
Address
+0
+1
Contents
0x12
0x34
(unsigned) long: 0x12345678
Address
+0
+1
+2
+3
Contents
0x12
0x34
0x56
0x78
Rule for byte sequence: MSB before LSB
float:
Format
corresponds to the IEEE 754 standard
Representation
4 bytes
Accuracy
24 bits (
represent >7 decimal points)
Composition
24-bit mantissa; 8-bit exponent
Mantissa
24 bits (M) + 1 bit (S)
The MSB of the mantissa is always 1 => it is not saved separately!
S = sign of the mantissa:
S = 1
negative number; S = 0
positive number
Exponent
8 bits (0-255); is saved relatively to 127, i.e. the current value of
the exponent is deduced by subtracting the number 127 from
the saved value.
Curr. Exp. = saved value of exp. – 127
=> range of numbers from 128 to -127!
