Filter
Top Products
Modbus Double Register Format
IEEE Floating Point Formats
12 HC900 Hybrid Controller Communications User Guide Revision 4
9/03
REGISTER N
(High)
REGISTER N+1
(Low)
High Low High Low
FP L - Floating Point Little Endian Format:
S=Sign E=Exponent M=Mantissa
E0 M22 M21M20 M19 M18 M17 M16
Bit 23
Bit 16
S E7 E6 E5 E4 E3 E2 E1
Bit 31
Bit 24
M7 M6 M5 M4 M3 M2 M1 M0
Bit 7
Bit 0
M15 M14 M13 M12 M11 M10 M9 M8
Bit 8Bit 15
REGISTER N
(High)
REGISTER N+1
(Low)
High Low High Low
FP LB - Floating Point Little Endian with Byte Swapped Format:
S=Sign E=Exponent M=Mantissa
E0 M22 M21M20 M19 M18 M17 M16
Bit 23
Bit 16
S E7 E6 E5 E4 E3 E2 E1
Bit 31
Bit 24
M7 M6 M5 M4 M3 M2 M1 M0
Bit 7
Bit 0
M15 M14 M13 M12 M11 M10 M9 M8
Bit 8Bit 15
Figure 3-1 IEEE Floating Point Formats
Table 3-2 IEEE Floating Point Number Examples in FP B Format
Register N Register N+1
Value
(decimal)
IEEE FP B
MSB LSB
high low high low
100.0 42C80000h 42h C8h 00h 00h
55.32 425D47AEh 42h 5Dh 47h AEh
2.0 40000000h 40h 00h 00h 00h
1.0 3F800000h 3Fh 80h 00h 00h
-1.0 BF800000h BFh 80h 00h 00h