CanOpen protocol
Positioning module IMD20, IMD40
Boot-Up object
initialisation
dule s
o
ich n
MT master of
the fact that the node is available and has achieved the Pre
state. The boot-up object
s the ide
s a data byte with the firm value 0.
After a successful
, the mo
ends a b ot-up object wh
-Operational
otifies the N
use
ntifier of the guarding object and contain
0x700 +
e ID
Nod
0x00
ID
Monitoring – Guarding
e monitoring of all NMT slaves by the master (node guarding) as well as the
n of the slaves in case of a failure of the NMT master (life guarding).
er sends in regular time intervals (guard time), which can be set separately
rrect toggle bit value is
sent back or if the NMT state does not match the expected state, the master has to assume an error.
first request of the guarding object by the master and
ed off again
a rese
no
queri
e ma
itches
ms for
r.
Byte 0
The guarding includes th
automatic self-interruptio
For this purpose, the mast
for every node, a request telegram (RTR) for the guarding object of the respective slave.
The NMT slave replies within the life time (= guard time x life time factor) with the guarding object,
which contains – in one data byte - the current NMT state and a toggle bit.
Upon the first query, the toggle bit has a value of 0 and changes its value (0, 1, 0, 1…) with the
following guarding telegrams. If, within the life time, no response with the co
The guarding for a node is activated with the
can
The NM
only b
T sla
e switch
ve monitors the incoming
through
t of the
es of th
de.
ster and sw
to the fault state, if the
telegra
the life-time period fail to appea
0x700 +
Node ID
NM
a
N T S
e
T M ster
M
lav
0x700 +
No
de ID
1 data byte
RTR
toggle
bit
Bit7
0x04
Stopped
Bit 0 - 6
NMT status
0x05
erati
Op
onal
0x7F
Pre-Ope
al
Example:
the master does no longer sent a guarding request, the
d
o the fault state, when the li
la
.
ration
The module is in the Operational state. After
mo ule changes t
fe time e psed
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