Honeywell HC900 User Manual page 24

Modbus Double Register Format
Unsigned/signed 32-bit Register Formats
FP LB – Little Endian Byte Swap Format
The value 12345678 Hex will be represented as follows:
Bit 15 Bit 8 Bit 7 Bit 0 Bit 31 Bit 24 Bit 23 Bit 16
Byte 2 Byte 1 Byte 4 Byte 3
56 Hex 78 Hex 12 Hex 34 Hex
Low High Low
High
REGISTER N REGISTER N+1
(High) (Low)
16 HC900 Process Controller Communications User Guide Revision 13
April 2017