Siemens SINAMICS V20 Operating Instructions Manual page 172

Communicating with the PLC
7.2 MODBUS communication
Exception Responses
If an error is detected through the MODBUS processing, the slave will respond with the FC
of the request, but with most significant bit of the FC high and with the Exception Code in the
data field. However, any error detected on the global address 0 does not result in a response
since all slaves cannot respond at once.
If an error is detected within the received message (for example, parity error, incorrect CRC
and so on), then NO response is sent to the master.
Note that if a request with FC16 is received which contains a write that the inverter cannot
perform (including write to a zero entry), other valid writes will still be performed even though
an exception response is returned.
The following MODBUS Exception Codes are supported by SINAMICS V20:
Exception Code
01
02
03
04
The table below shows the cases in which an Exception Code is returned:
Error description
Unknown Function Code
Read registers, which are out of boundary
Write register, which is out of boundary
Read request of too many registers (>125)
Write request of too many registers (>123)
Incorrect message length
Write to a read-only register
Write register, error in parameter access
Read register, error in Parameter Manager
Write to a zero entry
Unknown error
Basic inverter settings
Parameter Function
P0010 Commissioning parameter
P0970 Factory reset
172
MODBUS name
Illegal function code
Illegal data address
Illegal data value
Slave device failure
Setting
= 30: restores to factory settings
Possible settings:
= 1: resets all parameters (not user defaults) to their default
values
= 21: resets all parameters and all user defaults to factory
reset state
Note: Parameters P2010, P2021, P2023 retain their values
after a factory reset.
Meaning
The function code is not supported – only FC3,
FC6 and FC16 are supported.
An invalid address was queried.
An invalid data value was recognized.
An unrecoverable error occurred while the device
was processing the action.
Exception Code
01
02
02
03
03
03
04
04
04
04
04
Operating Instructions, 11/2016, A5E34559884-006
SINAMICS V20 Inverter