CANopen Module Specification
31
Doc.Id. HMSI-168-91
Anybus X-gateway CANopen - PROFINET
Doc.Rev. 2.10
6.4 Error Control
It is strongly recommended to monitor the network. The Anybus X-gateway CANopen can use either
Heartbeat or Node Guarding. At an error event from any of these, the active I/O data is frozen, as no
new data will be available.
6.4.1 Heartbeat Mechanism
The Heartbeat Mechanism is used to monitor the nodes in the network and verifies that the nodes are
available. A heartbeat producer periodically sends a message. The data part of the frame contains a byte
indicating the node status. The heartbeat consumer reads these messages. If a message fails to arrive
within a certain time limit (defined in the object directory of the devices, objects 1016h and 1017h, 33),
a heartbeat event is registered by the consumer. The ERROR LED on the front of the Anybus X-gate-
way CANopen and the status word will indicate the event. An EMCY object (8130h) is also transmitted
on the CANopen fieldbus. If the module is configured as a slave and is in OPERATIONAL state, it will
go to PRE-OPERATIONAL state and wait for the user to take action. If it is in master mode, it will
take action according to the settings in the master objects.
The Anybus X-gateway CANopen can act both as heartbeat consumer and as heartbeat producer simul-
taneously.
6.4.2 Node Guarding
The NMT Master transmits guarding requests. If an NMT Slave has not responded within a defined time
span (node lifetime) or if the communication status of the slave has changed, the master takes appropri-
ate action according to its configuration.
If Life guarding (the slave guards the master) is supported, the slave uses the guard time and lifetime
factor from its Object Dictionary to determine the node lifetime. If the slave does not receive a guarding
request within its lifetime, a node guard event is registered. The ERROR LED on the front of the An-
ybus X-gateway CANopen will indicate the event. An EMCY object (8130h) is also transmitted on the
CANopen fieldbus.
If the guard time or the lifetime factor are 0 (default), the Slave does not guard the Master. The guarding
can be initiated at boot-up or later.
Note
: The NMT master can monitor a slave either by heartbeat or by node guarding. Only one of these
mechanisms at a time can be active. Heartbeat is preferred and if heartbeat is enabled in a slave, any node
guarding for that slave is disabled.
6.4.3 Emergency Object (EMCY)
The Emergency Object is used for error reporting on the CANopen network when a fatal fault has oc-
curred. The error codes are saved in a list in the Communication Profile Object 1003h, see page 32, and
a message is produced on the CANopen network. A list of emergency error codes, that can be produced
by the module, is available in “CANopen Emergency Codes” on page 48.
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