Modbus Function Code Description; Exception Response Format Of The Artu Tetratele Unit To An Erroneous Command Received; Status Of The Used Modbus 01H/02H Function; Read By Using Modbus 03 Or 04 Function - Actel ARTU Series Installation And Operation Manual

Note: Dial switch status description: 1: OFF, 0: ON

6.2 Modbus function code description

6.2.1 Exception response format of the ARTU tetratele unit to an erroneous command received

Address Corresponding error function
BYTE BYTE
XX XX (requested function code
+80H)
Exception codes are defined as follows:
01 Illegal function code (the received function code is not supported);
02 Illegal data location (the specified data location is out of the scope of the instrument);
03 Illegal data value (data values received to host are out of range of the corresponding address);
04 Slave station device failure (data values received to host sent are not currently allowed to be written).

6.2.2 Status of the used Modbus 01H/02H function

Reading required by the upper computer (MODBUS 01H/02H function)
Address Function
BYTE BYTE
XX XX（01H/02H）
Address Function
BYTE BYTE
XX XX（01H/02H）
Lower machine abnormal reply (MODBUS 81H/82H function)
Address Corresponding
error function
BYTE BYTE
XX XX（81H/82H）

6.2.3 Read by using Modbus 03 or 04 function

Reading required by the upper computer (MODBUS 03H/04H function)
Address Function
BYTE BYTE
XX XX（03H/04H）
Address Function
BYTE BYTE
XX XX（03H/04H）
Exception response format of the ARTU tetratele unit
Exception error code data
BYTE
01H、02H、03H、04H
Address
WORD
XXXX
Lower machine reply (MODBUS 01/02 function)
Data length
BYTE
XX
Exception error code data
BYTE
XX (02H address error, 03H data error)
Start address
WORD
XXXX
Lower machine reply (MODBUS 03H/04H function)
Data length
BYTE
XX（2*N）
CRC check
WORD
XXXX (CRC check value)
Data CRC check
WORD WORD
XXXX XXXX (CRC check value)
Data CRC check
N BYTE WORD
XXXX....... XXXX (CRC check value)
CRC check
WORD
XXXX (CRC check value)
Data CRC check
WORD WORD
XXXX（N） XXXX (CRC check value)
Data CRC check
2*N BYTE WORD
XXXX....... XXXX (CRC check value)
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