(0X04) Read Input Registers - Hitachi HX-RIO3 Series User Manual

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A.3.4. 4 (0x04) Read Input Registers
This function code is used to read from 1 to approx. 125 contiguous input registers in a remote device.
The Request PDU specifies the starting register address and the number of registers. The register data
in the response message are packed as two bytes per register, with the binary contents right justified
within each byte. For each register, the first byte contains the high order bits and the second contains the
low order bits.
•
Request
Field name
Start of Frame
Slave Address
Function Code
Starting Address Hi
Starting Address Lo
Quantity of Register Hi
Quantity of Register Lo
Error Check (CRC/LRC)
End of Frame
•
Response
Field name
Start of Frame
Slave Address
Function Code
Byte Count
Input Register #0 Hi
Input Register #0 Lo
Input Register #1 Hi
Input Register #1 Lo
Error Check (CRC/LRC)
End of Frame
In case of address 0x0000, 0x0001 input register value: 0x0080, 0x0000.
-
Example RTU
- t1-t2-t3
0x07 0x07
0x04 0x04
0x00 0x00
0x00 0x00
0x00 0x00
0x02 0x02
- 0x71, 0xAD
- t1-t2-t3
Example RTU
- t1-t2-t3
0x07 0x07
0x04 0x04
0x04 0x04
0x00 0x00
0x80 0x80
0x00 0x00
0x00 0x00
- 0x9C, 0x6C
- t1-t2-t3
HX-RIO3 Series