Modbus Double Register Format; Overview; Table 7-1 Modbus Double Register Format Selections - Honeywell UDA2182 User Manual

Modbus Double Register Format

7. Modbus Double Register Format

7.1 Overview

Data that is 32 bits requires 2 sequential registers (4 bytes) to transfer its data. Data of this type includes
IEEE 32-bit floating point, 32-bit signed integer and 32-bit unsigned integer. The stuffing order of the
bytes into the two registers differs among Modbus hosts. To provide compatibility, the double register
format for the UDA is configurable.
To set the UDA's double register byte order, go to the Modbus menu in the Setup/Communication menu
and configure Word Swap parameter.
The selections are:
Selection
No Little Endian
Yes Big Endian
NOTE: Word Swapping only applies to Function Codes 3, 4, and 16.
16

Table 7-1 Modbus Double Register Format Selections

Description
UDA2182 Communications User Guide
Byte order
(See Figure
6-1)
3, 4, 1, 2
4, 3, 2, 1 UDA default
Notes
January 09