Actel ARTU Series, Installation And Operation Manual

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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
Exception response format of the ARTU tetratele unit
Address Corresponding error function Exception error code data CRC check
BYTE BYTE BYTE WORD
XX XX (requested function code
+80H) 01H
、
02H
、
03H
、
04H XXXX (CRC check value)
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 Address Data CRC check
BYTE BYTE WORD WORD WORD
XX XX
（
01H/02H
）
XXXX XXXX XXXX (CRC check value)
Lower machine reply (MODBUS 01/02 function)
Address Function Data length Data CRC check
BYTE BYTE BYTE N BYTE WORD
XX XX
（
01H/02H
）
XX XXXX……. XXXX (CRC check value)
Lower machine abnormal reply (MODBUS 81H/82H function)
Address Corresponding
error function Exception error code data CRC check
BYTE BYTE BYTE WORD
XX XX
（
81H/82H
）
XX (02H address error, 03H data error) XXXX (CRC check value)
6.2.3 Read by using Modbus 03 or 04 function
Reading required by the upper computer (MODBUS 03H/04H function)
Address Function Start address Data CRC check
BYTE BYTE WORD WORD WORD
XX XX
（
03H/04H
）
XXXX XXXX
（
N
）
XXXX (CRC check value)
Lower machine reply (MODBUS 03H/04H function)
Address Function Data length Data CRC check
BYTE BYTE BYTE 2*N BYTE WORD
XX XX
（
03H/04H
）
XX
（
2*N
）
XXXX……. XXXX (CRC check value)