Floating-Point Number According To Ieee 754 - Siemens SENTRON 3WL10 Manual

Data structure

5.2 Floating-point number according to IEEE 754

5.2 Floating-point number according to IEEE 754
Float32 (FP32) and Float64 (FP64) are stored in accordance with the following tables:
Representation of the 32-bit floating-point number (single precision) in accordance
with IEEE 754
0 ... 7 8 ... 15
M M
Mantissa
Modbus register address +1
Low byte High byte
Representation of the 64-bit floating-point number (double precision) in accordance
with IEEE 754
0 ... 7 8 ... 15 16 ... 23
M M M
Mantissa
Modbus Modbus
register address +3 register address +2
Low byte High byte Low byte
Representation of the system time or the time stamp
0 ... 7 8 ... 15 16 ... 23
M M M
4th byte 3rd byte 2nd byte
Fraction Fraction Fraction
of the of the of the
second second second
Modbus Modbus
register address +3 register address +2
Low byte High byte Low byte
You will find the Modbus map in Chapter Register addresses (Page 37).
36
16 ... 22
M
Modbus register address +0
Low byte
24 ... 31 32 ... 39 40 ... 47
M M M
Modbus
register address +1
High byte Low byte High byte
24 ... 31 32 ... 39 40 ... 47
M M M
Highest 4th byte 3rd byte
byte Seconds Seconds
Fraction
of the
second
Modbus
register address +1
High byte Low byte High byte
Communication 3WL10 Air Circuit Breakers & 3VA27 Molded Case Circuit Breakers
23 24 25 ... 29
E E E
Exponent
High byte
48 ... 52 53 54
51
M E E E
Exponent
Modbus
register address +0
Low byte
48 ... 52 53 54
51
M E E E
2nd byte
Seconds
Modbus
register address +0
Low byte
System Manual, 06/2019, L1V30499596021-01
30 31
E V
55 56 ... 63
62
E E V
High byte
55 56 ... 63
62
E E V
Highest byte
Seconds
High byte