Rockwell Automation 825-P Modular Protection System for Motors User Manual - Manual (Page 141)

Rockwell Automation Publication 825-UM004D-EN-P - November 2012 141
Modbus RTU Communications Chapter 10
The relay response to errors in the query are shownTable 77:
Table 77 - Responses to 60h Read Parameter Information Query Errors
61h Read Parameter
Text Command
The 825-P uses this function to allow a Modbus master to read parameter text
from the relay. One parameter text (setting name) is read in each query.
Table 78 - 61h Read Parameter Text Command
The relay responses to errors in the query are shown below:
Table 79 - 61h Read Parameter Text Query Error Messages
Error Error Code Returned Communication
Counter Increments
Illegal parameter to read Illegal Data Value (03h) Illegal Register
Bytes Field
Requests from the master must have the following format:
1 byte Slave Address
1 byte Function Code (61h)
2 bytes Parameter Number
2 bytes CRC-16
A successful response from the slave will have the following format:
1 byte Slave Address
1 byte Function Code (61h)
2 bytes Parameter Number
16 bytes Parameter Text (setting name)
4 bytes Parameter Unites (e.g., Amps)
2 bytes CRC-16
Error Error Code Returned Communication
Counter Increments
Illegal parameter to read Illegal Data Value (03h) Illegal Register
Illegal Write