ICP DAS USA tGw-735 - 0 X02) Read the Status of the Input (Read Dis)

Tiny Modbus/TCP to RTU/ASCII Gateway
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02(0x02) Read the Status of the Input (Read DIs)
This function code is used to read the current digital input value.
[Request]
Byte
Description
Size
Value
00
Net ID (Station Number)
1 Byte
1 to 247
01
Function Code
1 Byte
0x02
02-03
Starting DI Address
2 Bytes
Refer to the Modbus address depends on your
slave device for more details.
Byte 02 = high byte
Byte 03 = low byte
04-05
Number of Points (Channels)
2 Bytes
Byte 04 = high byte
Byte 05 = low byte
[Response]
Byte
Description
Size
Value
00
Net ID (Station Number)
1 Byte
1 to 247
01
Function Code
1 Byte
0x02
02
Byte Count
1 Byte
Byte Count of Response
( n =(Points+7)/8 )
03
Data
n Bytes
n= 1; Byte 03 = data bit 7 to 0
n= 2; Byte 04 = data bit 15 to 8
.......
n= m; Byte m+2 = data bit (8m-1) to 8(m-1)
[Error Response]
Byte
Description
Size
Value
00
Net ID (Station Number)
1 Byte
1 to 247
01
Function Code
1 Byte
0x82
02
Exception Code
1 Byte
Refer to the Modbus Standard Specifications for
more details