Sinee EM500 - Abnormal Information Response; Definitions of Exceptional Codes

EM500 Open-Loop Vector Control Inverter User Manual
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return (crcH<<8) | (crcL);
}
12.3.7Abnormal Information Response
Master wants to receive a normal response after it sends a request to slave. Inquiry
of master may results in the following four response situations:

If slave has received a request without communication error and can handle
the inquiry normally, slave will return a normal response;

If slave has not received the request due to communication error, slave cannot
return information. Slave will be seen as overtime
；

If slave has received the request but detected a communication error (for
example parity, address, frame error), it will not return a response. Slave will
be sited as overtime；

If slave has received the request without communication error but can not
handle it (example: request to read a register which does not exist), it will
return an abnormal response to report the actual situation of the error to
master
An abnormal response message has two fields that are different from the normal
response:

Function code field: in normal response, slave copies the original request
function code from the appropriate function code field. MSB of all the
function code is zero. In abnormal response, MSB of slave function code is 1.
Abnormal response function code = normal function code +0x80

Data Field: A slave can return data in the data field in normal response and
return abnormal code in abnormal response. See Table 12-4 for definitions of
exceptional codes.
Table 12-4 Definitions of Exceptional Codes
Exceptional
Code
Name
Definitions
01H
Illegal function
The function code received by slave exceeds the
configured scope (refer to 12.3.3 Function Code)