
4th edition, 9-11-2018
7000.05050, 4th edition, 9-11-2018
7000.05050
CANopen protocol description
30
3.8.2.1
Node guarding
The node guarding object interrogates the instantaneous state of the device. To do this, the
master sets a remote frame with a request for the guarding identifier of the node to be
monitored. The node to be monitored responds with the guarding message which contains
the current status of the node and a toggle bit.
Fig. 8:
Diagram of the node guarding protocol
t: Toggle bit
Initially 0, changes its value at each guarding telegram
s: Status
s = 0x04 (4d): Stopped
s = 0x05 (5d): Operational
s = 0x7F (127d): Pre-operational
If a node life time > 0 is set (objects 0x100C and 0x100D) and no node guarding request is
made by the master within the set node life time, a node guarding error is set. The response
to a node guarding error is set by the FAULHABER error register (object 0x2321) (see
Tab. 14). The default is to send the emergency message 0x8130.
indication
indication
response
indication
response
request
request
NMT Master
NMT Slave
COB-ID = 1792 + Node-ID
COB-ID = 1792 + Node-ID
0
1
0
1
confirm
confirm
indication
Node Guarding Event
if guarding error
Node
Life
Time
Node
Guard
Time
Remote transmit request
Node/Life Guarding
Remote transmit request
7
t
6…0
s
7
t
6…0
s