Application faults 44 and 49 (also indicated as "generic software fault code") are commonly related to issues in the CAN bus connection and communication. Depending on the configuration and severity of the issue, these can be either warnings (device continues to operate), or faults (device is tripped immediately).
By connecting to the device with PowerUSER, more detailed information about the faults can be found via the active faults and fault log functions. The fault displays will show a column labeled "argument" which is formed from three parts:
- First two letters of the argument code show which module the error is originating from. This is always 04 for error 44, and 01 or 02 for error 49, which all refer to the CAN bus interface of the device. In case the error indicates some other module, contact Danfoss Editron support for more information.
- The next two letters indicate the fault that occurred, see the picture below for a list of all possible faults.
- The last four letters indicate how many times this fault has occurred consecutively.
Example: error code 44 with argument 04010001 can be decoded as "RX buffer overflow which has occured once". This would indicate too many messages coming to the inverter too quickly, which has filled the RX message buffer before the device had time to process the messages.
Error 44 usually indicates failures on the CAN bus protocol level, which are commonly caused by problems such as too high CAN bus load, wiring issues, incorrect termination resistance, etc. It can also be triggered by the message timeout function, if the configured messages were not received in time. See the communication manuals for more information regarding the timeouts and message configuration. See the articles CAN troubleshooting, How to reduce CAN bus load when using J1939, or CAN bus physical layer for more information about the CAN bus functionality.
Error 49 usually indicates that the user is sending the fault clear command consecutively several times (module 2, error code 2). The fault clear command should be sent only as a singular pulse, meaning one CAN message with the fault clear command set to "true" and then immediately return it to "false". Otherwise fault 49 with module 2 and error code 2 is triggered, as clearing the faults consecutively can cause danger to the equipment or personnel in some situations. Consecutive fault reset pulses should be sent with a delay of >500 ms, otherwise error 49 is triggered.
Note that in firmware 7, the parameter network_application.fault_reset_mode (50006.50) should be switched to "Rising Edge" to prevent the error 49 from triggering in normal use (requires firmware 7.2.13 or newer).