Lenze DDS System bus CAN for PLC - Manual (Page 33)

System bus (CAN) for Lenze PLC devices
General information
2−21
l
PLC−Systembus EN 2.0
2.10 Monitoring mechanisms
In the CANopen communication profile (CiA DS301, version 4.01) two optional monitoring
mechanisms for ensuring the function of system bus nodes are specified, "Heartbeat" and "Node
Guarding".
Note!
The "Heartbeat" and "Node Guarding" monitoring mechanisms are supported by the
9300 Servo PLC, Drive, PLC and by the ECSxA axis module as of V6.0.
The initialisation and execution of the monitoring mechanisms is carried out by means of the
functions/function blocks of the LenzeCanDSxDrv.lib function library.
( ^ 11−1)
2.10.1 "Heartbeat"
The "Heartbeat" monitoring mechanism is a Producer−Consumer−oriented method which does not
require an enquiry message and where each node is able to monitor the state of all other nodes.
Request
Request
Indication(s)
Heartbeat
Producer
Time
Heartbeat Producer Heartbeat Consumer(s)
r s
Heartbeat
Event
Heartbeat
Consumer
Time
1 8
r s
1 8
Indication(s)
r:
Stopped
Operational
Pre-Operational
Boot-Up Event
reserved
s: State of the heartbeat producer:
4
5
127
0
Fig. 2−7 "Heartbeat" monitoring mechanism
·
A node (Producer) signalises its communication status by cyclically transmitting a so−called
"Heartbeat" message.
·
This "Heartbeat" message can be received by one, several, or by all the other nodes
(Consumer), and thus they can monitor the respective node.
·
If the responsible, monitoring node (Consumer) does not receive the "Heartbeat" message
from the node to be monitored (Producer) within the set monitoring time
(HeartBeatConsumerTime), a "Heartbeat" event is displayed in its application.