Honeywell UDC2500 - Manual (Page 197)

Modbus RTU Function Codes
4/07 UDC2500 Universal Digital Controller Product Manual 183
Reference Type Definitions
The Reference Type definition is always 06.
See examples in Subsection 9.3.1
File Number
The file number word contains the register number from the register address structure
tables on page 3. Although the register address structure tables indicate up to 13 data
registers are available for access, only register address 3 is currently supported.
Register Address
The register address word represents the tag ID number for the parameter(s) being
accessed. The register address word is made up of two bytes—the MSB = 00 always. The
LSB contains the tag ID number. The tag ID numbers represent the parameter’s register
address(es). See Section 3 for the tag ID numbers.
Table 9-3 Register Address Format for Function Code 20
Register
Address(es)
(Decimal)
Register
Address(es)
(Hex)
Format
001 to 125 0001 to 007D analog formatted data
(2 registers – IEEE 32-bit floating point)
128 to 255 0080 to 00FF integer formatted data
(1 register – 16-bit integer)