Autonics krn100 series, User Manual

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1 Modbus RTU protocol
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1.2 Read Input Status(Func02–02H)
Reads the input (1X reference) ON/OFF status in the Slave device.
(1)
Query(Master)
Slave Address
Function
(Command) Starting Address No. of Points(Number of data) Error Check(CRC16)
High Low High Low Low High
1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte
(2)
Response(Slave)
Slave Address
Function
(Command)
Byte Count
(Number of
data byte)
Data Data Data
Error Check(CRC16)
Low High
1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte 1Byte
The below example is to read the input status (ON: 1, OFF: 0) of 10EA within 10001(0000 H) to
10010(0009 H) on the Slave(Address 17) from the Master.

Query(Master)
Slave Address
Function
(Command) Starting Address No. of Points(Number of data) Error Check(CRC16)
High Low High Low Low High
11 H 02 H 00 H 00 H 00 H 0A H ## H ## H
The below example is when 10008(0007 H) to 10001(0000 H) value on the Slave is “ON-ON-
OFF-OFF-ON-ON-OFF-ON” and 10010(0009 H) to 10009(0008 H) value is “OFF-ON”.

Response(Slave)
Slave Address
Function
(Command)
Byte Count
(Number of
data byte)
Data
(00008 to 00001)
Data
(00010 to 00009)
Error Check(CRC16)
Low High
11 H 02 H 02 H CD H 01 H ## H ## H
CRC16
CRC16