Monitoring
Node Guarding Protocol
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EDSMF2178IB EN 3.0
CANopen objects for configuration
CANopen Lenze
Index Subindex Designation Code Subcode Description
I−100C 0 Guard time C1827
C2327
− Change of "guard time"
I−100D 0 Life time factor C1828
C2328
− Change of "life time factor"
RTR telegram
The NMT master cyclically ("node guard time", monitoring time) sends a data telegram
called "Remote Transmit Request" (RTR) to the NMT slave.
The RTR prompts the NMT slave to send its current data.
Response telegram
The NMT slave sends a response telegram with a user data width of 1 byte. The most
significant bit of the response telegram is a toggle bit (t).
The data value (s) of the other seven bits indicates the status of the NMT slave:
Data value (s) Status
4 Stopped
5 Operational
127 Pre−operational
Identifier
Identifier = basic address (1792) + configurable address (1 ... 127)
Node life time
The "node life time" is the product of "node guard time" (object I−100C) and "life time
factor" (object I−100D).
Life guarding event
If the NMT slave does not receive an RTR telegram from the NMT master in the "node life
time", the "life guarding event" triggers a fault signal in the NMT slave. An emergency
telegram with a "life guarding event" is sent.
The controller response to a "life guarding event" is set under subcode C1882/5 / C2382/5.
If the "life guarding event" occurs, the node changes from the "Operational" state to the
"Pre−operational" state (default setting). By means of the object I−1029 a different
response can be set.
Node guarding event
The "node guarding event" should occur in the NMT master if despite the request by the
NMT master no response from the NMT slave is received in the "node life time" or the
toggle bit has not changed in the "node life time".
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