Responding To Errors - INVT DA180-S2R8SG0 Operation Manual

DA180 series basic AC servo drive
MSB. Then the LSB is extracted for detection. If the LSB is 1, the register and preset value have an
independent exclusive or relationship. If the LSB is not 0, there is no such a relationship. The
processing is repeated eight times. When the eighth bit of the current character is checked, the next
each 8-bit character is checked for an independent exclusive or relationship with register content.
Finally, register content is the CRC values for all characters in the frame.
This CRC calculation method is compliant with international standards. When editing the CRC
calculation method, you can see the standards.

8.2.6 Responding to errors

A slave device responds with a function code field and fault address to specify whether the response
is normal (that is, no error occurred) or abnormal (that is, an error occurred). In a normal response,
the slave node responds with the function code and data address or sub function code. In an
abnormal response, the slave node responds with a code that equals a normal code but starts with
logic 1.
For example, if the master node sends a request to a slave node to read the address data of a group
of servo drive function code, the following function code is generated:
In a normal response, the slave node responds with the same function code. In an abnormal
response, the slave node returns:
In addition to the function code that is modified due to the error, the slave node returns an error code,
indicating the error cause.
After receiving the abnormal response, the master node resends a message, which is typical
processing, or it changes the command based on the error.
Code Function
Invalid
01H
function
Invalid data
02H
address
Invalid data
03H
value
11H Check error
0 0 0 0 0 0 1 1 (Hexadecimal 03H)
1 0 0 0 0 0 1 1 (Hexadecimal 83H)
Table 8-6 Error codes
Modbus error codes
The function code that the upper computer receives is not allowed
for operation. The possible cause is that the function code is
applicable to new devices only or that the slave node handles such
a request in abnormal state.
The data address requested by the upper computer is not allowed
by the servo drive. Especially, the register address and transmitted
byte combination are invalid.
The received data is not within the address range, which cause
invalidity of parameter modification.
The check error message is reported when the CRC bit in RTU
-247-
Meaning
Communication