Function Code 20 (14H) - Read Configuration Reference Data - Honeywell UDC3500 Product Manual

Modbus RTU Function Codes

9.3 Function Code 20 (14h) - Read Configuration Reference Data

Description
Function code 20 (14 Hex) is used in this instrument to read information stored in its
configuration database. Each configuration item is explicitly addressed by a file number
and register address. IEEE 32-bit floating point and 16-bit integer formats are supported.
Request and Response Formats
The Request and Response formats for Function code 20 (14 Hex) are shown below.
Details for each block reference follow.
Request Message Format
Slave
Address
Reference Reference
Type Type
Response Message Format
Slave
Address
Reference
Data
Type
CRC
Data
Byte Count
The Byte Count equals the number of bytes transmitted in either the request or response
message and will be the minimum number required in order to transmit all requested
data.
Data Byte Count
The Data Byte Count is the number of data bytes of the sub response including the
Reference Type but not including itself. A floating point sub response has four bytes of
data and one byte representing the reference type making the data byte count equal to
five.
340
Function Byte Reference
Code 14 Count Type
File Register
Register
Number Count
Address
Data
Function Byte
Byte
Code 14 Count
Count
Data
Reference
Byte Data
Type
Count
CRC
Data
UDC3500 Universal Digital Controller Product Manual
File Register
Register
Number Count
Address
CRC CRC
Data Data
Reference
Data Data
Type
Data Data Data
Data
3/07