Modbus RTU Function Codes
Example #2
The following is another example of a request and response message using Function code 20.
Request Message (Read LSP #1 = ID Tag 39 and LSP #2 = ID Tag 53) 02 14 0E 06 00 03 00 27 00 02 06 00 03 00 35 00 02 (CRC16)
Where:
02 | = | Address |
14 | = Function Code 20 (14 Hex) | |
0E | = | Byte Count |
06 | = Reference Type (IEEE Floating Point) | |
00,03 | = File Number (Access Data Value) | |
00,27 | = Register Address (Standard Access LSP #1 - ID Tag 39) | |
00,02 | = Register Count to read (Floating Point Data) | |
06 | = Reference Type (IEEE Floating Point) | |
00,03 | = File Number (Access Data Value) | |
00,35 | = Register Address (Standard Access LSP #2 - ID Tag 53) | |
00,02 | = Register Count to read (Floating Point Data) | |
(CRC16) |
|
|
This is the response to the above request.
Response Message
02 14 0C 05 06 43 C8 00 00 05 06 44 60 00 00 (CRC16)
Where:
02 | = | Address |
14 | = Function Code 20 (14 Hex) | |
0C | = | Byte Count |
05 | = Data Byte Count (Sub Message Length) | |
06= Reference Type (IEEE Floating Point)
43C8 00 00 = 400.0 (Value of Local Setpoint #1)
05 | = Data Byte Count (Sub Message Length) |
06= Reference Type (IEEE Floating Point)
4460 00 00 = 896.0 (Value of Local Setpoint #2) (CRC16)
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