Rtu Basic Function; Read Analog-Data Ai Input - Ebyte E821-RTU User Manual

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4.2 RTU basic function

4.2.1 Read analog-data AI input

Function code: 03, Read hold-register; 04, Read input-register
Address range: 30017(0x0010)~30020(0x0013)
Remark: The unit of analog input value is uA
E.g.:
Function code 0x03, read AI1 input, assuming AI1 input is 9946uA, the corresponding value should be 0x26 DA
Modbus RTU protocol read analog-data input:
01
Send Device ModBus
address
01
Receive Device ModBus
address
Modbus TCP protocol read analog-data input:
00 01
Transmiss
Send
ion
identifier
00 01
Transmiss
Receive
ion
identifier
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03
Function
code
03
Function
code
00 00 00 06
Protocol
Length
identifier
00 00 00 05
Protocol
Length
identifier
00 13
Analog-data start Read the number of
address
02
Number of bytes Analog-data input
returned
01 03
Unit Functio
identifier n code
01 03
Unit Functio
identifier n code
E821-RTU (0400-ETH)User Manual
00 01
CRC check code
addresses
26 DA
CRC check code
value
00 13
Analog-data start Read the number
address
02
Number of bytes Analog-data input
returned
75 CF
23 BF
00 01
of addresses
26 DA
value
17 17