0X02) Read Discrete Input - ICP DAS USA PIR-130-AC User Manual

3.3 02 (0x02) Read Discrete Input

This function code is used to read the value at address 1xxxx.
Request
Byte Description
00 Address
01 Function Code
02 - 03 Starting Address
04 - 05 Number of
Addresses
Requested
*N = Number of addresses requested
Response
Byte Description
00 Address
01 Function Code
02 Byte Count
03 Value from the
Requested Address
*N = (Number of addresses requested / 8)
Error Response
Byte Description
00 Address
01 Function Code
02 Exception Code
PIR-130-AC/DC User Manual Ver. 1.4.0, 2020/07/28
Length
Value
(in Bytes)
1 1 to 247
1 0x02
2 0x0020 to 0x003F
2 0x0001 to 0x0001 + *N
Length
Value
(in Bytes)
1 1 to 247
1 0x02
1 *N
*N
Length
Value
(in Bytes)
1 1 to 247
1 0x82
Refer to the Modbus standard for more
1
details.
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