03 (0X03) Read Holding Registers" Function - Toshiba PNE001Z Function Manual

7.4. "03 (0x03) Read Holding Registers" function

This Modbus request is used to read the values of a number (Number of Points) of adjacent words starting
at the address indicated (Starting Address). The values read are restored one after another, at the end of
the response (First Point Data -> Last Point Data).
Request Format:
Byte
0
1
2
3
4
Response format:
Byte
0
1
2
3
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B
B+1
Exception response format:
Byte
0
1
If the communication number that doesn't exist is read, PNE001Z returns 0x8000.
Meaning
Function Code = 03h
Starting Address Hi
Starting Address Lo
Number of Points Hi (0)
Number of Points Lo (1 - 125)
Meaning
Function Code = 03h
Byte Count (B = 2 × Number of Points)
First Point Data Hi
First Point Data Lo
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Last Point Data Hi
Last Point Data Lo
Meaning
Function Code = 83h
Exception Code =
01 (Illegal Function)
02 (Illegal Data Address)
03 (Illegal Data Value)
Notes
- 45 -
E6582051