
20 06/05
4.8.3 Emergency message, reaction
If a slave on the system bus suffers a fault, it transmits the emer
ency tele
ram. The
emergency telegram marks the node ID for the identification of the failed node via its
identifier and the existing fault message via its data contents (8 bytes).
After a fault has been acknowledged on the slave, the latter again transmits an emer-
gency telegram with the data content zero.
The emergency telegram has the identifier 128 + node ID ( = 129 ... 191)
he system bus master evaluates the emer
ency tele
rams of the slaves. Its reaction
to an emergency telegram can be set with
Emergency Reaction 989.
Operation mode Function
0 -Error The system bus master receives the emergency
telegram and switches-off
1 -No Error The Emergency Telegram is displayed as warning.
Operation mode - parameter 989 = 0 – Error
Behavior of the system bus master in
Emergency Reaction 989 = 0 / Error:
As soon as the system bus master receives an emer
ency tele
ram, it also breaks
down and reports the failed node on the basis of its ID via the kind of error. Only the
node is reported, not the cause of the error.
The fault message on the system bus master via
Current error 260 is 21nn with nn
= node ID (hexadecimal) of the slave in which a fault switch-off exists.
In addition, the system bus master reports the warning Sysbus (0x2000) via the pa-
rameter
Warnings 270 Bit 13.
If a fault switch-off occurs on a number of slaves, the first slave to transmit its emer-
gency telegram is displayed on the system bus master.
Operation mode - parameter 989 = 1 – No Error
Behavior of the system bus master in
Emergency Reaction 989 = 1 / No Error:
As soon as the system bus master receives an emer
ency tele
ram, it reports the
warning Sysbus (0x2000) via the parameter
Warnings 270 Bit 13.
Note: In both cases, the Boolean variable SysbusEmer
ency with source number
730 is set to TRUE in the system bus master. It can be used in the system
bus master and (in transmission via a TxPDO) in the slaves for a defined
shutdown.
SysbusEmergency is also set if the system bus master breaks down.
Resetting of SysbusEmergency is done with the fault acknowledgment.
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