0X04) Read The Input Registers (Read Ai Values) - ICP DAS USA iNS-308 User Manual

iNS-308 User Manual

7.2.4 04(0x04) Read the Input Registers (Read AI values)

This function code is used to read either the input registers or the current analog input value from
the iNS-308. These registers are also used to store the current value for the digital counter, the
number of DI channels and the number of DO channels, etc.
[Request]
Byte Description
00 Net ID (Station Number)
01 Function Code
02-03 Starting AI Address
Number of Registers
04-05
(Channels)
[Response]
Byte Description
00 Net ID (Station Number)
01 Function Code
02 Byte Count
03 Register Values
[Error Response]
Byte Description
00 Net ID (Station Number)
01 Function Code
02 Exception Code
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Size
1 Byte 1 to 247
1 Byte 0x04
Byte 02 = high byte
2 Byte
Byte 03 = Low byte
Word Count
2 Byte Byte 04 = high byte
Byte 05 = Low byte
Size
1 Byte 1 to 247
1 Byte 0x04
Byte Count of the Response
1 Byte
( n = Points x 2 Byte )
n= 1; Byte 03 = high byte
n= 2; Byte 04 = Low byte
n Byte .......
n= m; Byte m+1 = high byte
Byte m+2 = Low byte
Size
1 Byte 1 to 247
1 Byte 0x84
Refer to the Modbus Standard
1 Byte
Specifications for more details
Value
Value
Value
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