Honeywell UDA2182 - Unsigned;signed 32-bit Register Formats

Modbus Double Register Format
18 UDA2182 Communications User Guide January 09
Table 7-2 IEEE Floating Point Number Examples in Big Endian
Format
Register N Register N+1
Value
(decimal)
IEEE Big
Endian
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
7.3 Unsigned/signed 32-bit Register Formats
The formats descriptions below use the value 12345678 Hex as an example. Where the binary
representation is:
Byte 4 = 12 Hex Byte 3 = 34 Hex Byte 2 = 56 Hex Byte 1 = 78 Hex
Bits
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 0 0
Word Swap = Yes – Big Endian Format
The value 12345678 Hex will be represented as follows:
Bit 31 Bit 0
High
Low High Low
REGISTER N
(High)
REGISTER N+1
(Low)
Byte 4
12 Hex
Byte 3
34 Hex
Byte 2
56 Hex
Byte 1
78 Hex