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0198441113586, V2.01, 11.2008
IL•1F CANopen DS301 3 Basics
Fieldbus interface 49
Structure of the NMT message After a request from the NMT master, the NMT slave responds with one
data byte.
Figure 3.31 Acknowledgement of the NMT slave
Bits 0 to 6 identify the NMT state of the slave:
•4 (04
h
): "Stopped"
•5 (05
h
): "Operational"
•127 (7F
h
): "Pre-Operational"
After each "guard time" interval, bit 7 switches toggles between "0" and
"1", so the NMT master can detect and ignore a second response within
the "guard time" interval. The first request when connection monitoring
is started begins with bit 7 = 0.
Connection monitoring must not be active during the initialization phase
of a device. The status of bit 7 is reset as soon as the device runs though
the NMT state "Reset communication".
Connection monitoring remains active in the NMT state "Stopped".
Configuration Node/Life Guarding is configured via:
• Guard time (100C
h
)
• Life time factor (100D
h
)
Slave
Master
05h
05h
COB-ID
704h
704h
Node-ID=04h
704h
704h 85h
704h
704h 05h
guard
time
Bit 7 6
...
0
000000
11
Bit7 6 0
85h
0000 0
111
==