The error register value is also part of the emergency telegram so as to indicate if other internal errors have been
detected.
The number of reported errors is given by an error counter in the pre-defined error field located at index 1003
H
, sub-
index 00
h
and the last reported error can be read from the same entry at sub-index 01
H
.
5.6 Error control services
CANopen® uses smart mechanisms to control permanently the nodes state on the bus. eNod4 supports Boot-up and
Heartbeat messages and Node guarding protocol. Using both services is not allowed. If both are configured so as to
be functional, only the Heartbeat mechanism is used.
5.6.1 Heartbeat and boot-up
eNod4 state control can be achieved through the use of Heartbeat and boot-up mechanisms :
Boot-up: this message sent by eNod4 means that its initialization phase is complete and that the
node has entered into pre-operational state. It consists in the following frame :
Heartbeat :
- producer mode : if a Heartbeat period (in ms) different from 0 is set in the entry ‘producer
heartbeat time’ of the object dictionary, eNod4 generates at this period a frame containing its state
coded on one byte. The corresponding frame is similar to the Boot-up mechanism frame:
eNod4 NMT state byte can take the different following values :
04
H
: the node is in the «stopped» state
05
H
: the node is in the «operational» state
7F
H
: the node is in the «pre-operational» state
Using Heartbeat protocol allows a NMT master to check that all nodes connected to the bus are working correctly.
- Consumer mode: eNod4 also can be configured so as to monitor the NMT state of one particular
node of the network (generally the NMT master). The node ID and a period are defined in the entry
‘consumer heartbeat time’ of the object dictionary
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