03 (0X03) Read Holding Registers" Function - Toshiba TOSVERT VF-MB1/S15 IPE002Z Function Manual

8.4. "03 (0x03) Read Holding Registers" function

The Modbus request is used to read the values of a number (No. 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
･･･
B
B+1
Exception response format:
Byte
0
1
If the communication number that doesn't exist is read, the option returns 0x8000.
Meaning
Function Code = 03h
Starting Address Hi
Starting Address Lo
No. of Points Hi (0)
No. of Points Lo (1 - 125)
Meaning
Function Code = 03h
Byte Count (B = 2 × No. of Points)
First Point Data Hi
First Point Data Lo
････････････････
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
- 65 -
E6581741