Bus Diagnosis

The Master Operation Mode shows the actual status of the Master:

Master Main State	Description
Operate	The CANOPEN Master is in data exchange. In a data exchange the inputs of the CANOPEN Slaves are read and the output information is transferred to all CANOPEN Slaves.
Clear	The CANOPEN Master reads the input information of the CANOPEN Slaves and holds the outputs of the CANOPEN Slaves in a safe condition.
Stop	The CANOPEN Master is in the state Stop that means no data exchange takes place between the CANOPEN Master and the CANOPEN Slaves. The Master was stopped by the application program or it had to go in the state Stop because of a bus error.
Offline	The CANOPEN Master does not exist on the bus, it is not online. This can happen, if no or faulty bus parameters are set for the CANOPEN Master. Furthermore this can happen, if the correct bus parameters are set, but the application program has not activated the CANOPEN Master for data exchange on the bus.

Master Status shows individual bus errors. A pending error is displayed by a red LED. The meaning of the individual errors is described in the following:

Master State	Description
Not ready	Host Not ready shows that the application program has not started or it has stopped the CANOPEN Master.
Auto Clear	The Auto Clear Error displays that device has stopped the communication to all Slaves and it has reached the auto-clear end state.
Slave Error	The Slave Error shows that at least 1 Slave is not in the cyclic data exchange with the CANOPEN Master.
Fatal Error	A Fatal Error has occurred. Because of a heavy bus error no further bus communication is possible.
Control Error	The Control Error displays that a parameterization error has occurred.

Bus Monitoring	Description
Event	The used CAN chip has detected transmission errors. The number of detected events is counted in the CAN bus off counter and the CAN active to passive counter. The bit will be set when the first event was detected and will not be deleted until the Master is reset.
CAN active to passive counter	This value indicates a bad transmission quality at the CAN bus. This counter is based on a Transmission Rejected Error of the CAN chip, which is always reported, whenever an increased number of faulty CAN frames were detected.
CAN bus off counter	This counter counts the number of reported bus off events. A bus off event occurs whenever the CAN bus was disturbed substantially during the transmission of CAN frames and therefore the communication chip has to withdraw itself from the bus.
Timeout	A timeout was detected. The number of errors is counted in the Timeout counter and in the RX overflow counter. The bit is set if the first error occurs and can be reset only by a reset of the Master.
Timeout counter	Whenever a CAN message could not be sent within 250 msec, the transmission is aborted and the counter increases.
Rx overflow counter	An Rx overflow exists, if the Master cannot handle a CAN message before the next message is received because the bus demand is too high.