Beckhoff CX-B510 Series, Руководство пользователя

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CANopen system overview
CXxxxx-M510/B510 13 Version: 1.0
At the time of the first guarding message of the slave the toggle bit has the value 0. Subsequently, the toggle
bit alternates after each guarding message and enables lost messages to be detected. The remaining seven
bits contain the node state, thereby transferring the slave status to the master.
Node State Status
4 = 0x04 Stopped
5 = 0x05 Operational
127 = 0x7F Pre-Operational
Sample
The guarding message for node 27 (0x1B) must be requested by a remote frame having identifier 0x71B
(1819
dec
). If the node is Operational, the first data byte of the answer message alternates between 0x05 and
0x85, whereas in the Pre-Operational state it alternates between 0x7F and 0xFF.
Guard time and life time factor
If the master requests the guard messages in a strict cycle, the slave can detect the failure of the master. In
this case, if the slave fails to receive a message request from the master within the set Node Life Time (a
guarding error), the slave assumes that the master has failed (the watchdog function).
In this case the slave sets its outputs to error state, sends an emergency telegram and returns to pre-
operational state. After a guarding time-out the procedure can be triggered again with a new guarding
message.
The node life time is calculated based on the following parameters:
• guard time (object 0x100C) and
• life-time factor (object 0x100D)
Life time = guard time x life time factor
If one of the two parameters is 0 (default), the master is not monitored (no life guarding) (see: CAN node
[
}
36] tab).
Heartbeat: Node Monitoring without Remote Frame
If the heartbeat method is active, the devices automatically send their respective status messages cyclically.
In contrast to the guarding method, the heartbeat method does not involve sending of remote frames,
resulting in less bus load. The master also sends its heartbeat telegram cyclically, enabling the slaves to
detect a master failure (see:
CAN node [ } 36] tab).
The toggle bit is not used with the heartbeat method, and the devices send their respective status cyclically.