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Operating Instructions
Chapter
6
Flexi Soft Gateways
8012664/XB29/2013-06-11
© SICK AG • Industrial Safety Systems • Germany • All rights reserved
137
Subject to change without notice
Fieldbus gateways
6.2.4
NMT — Network management
The NMT broadcast object is used to start, stop or initialise CANopen devices. For this
purpose one device in the CANopen network must take over the role of the NMT master.
Usually this is the PLC. All other devices are regarded as NMT slaves. NMT services are
broadcast services, for which the slaves do not generate a reply.
All NMT objects start with the CAN ID 00h.
Broadcast service for an NMT slave with address N:
CAN ID
DLC
DATA
00h
2
OP
N
Broadcast service for all NMT slaves:
CAN ID
DLC
DATA
00h
2
OP
0
OP
NMT operation
Explanation
80h
Change to “Pre-Operational”
After booting an NMT slave automatically enters the Pre-
Operational state. In this state, communication is allowed via
SDO, but not via PDO. The NMT slave can be changed from
another state to this state.
01h
Change to “Operational”
The Operational state is reached from the Pre-Operational
state. In this state communication via PDO is possible and
the CANopen slave reacts to Sync commands.
Note:
On transition to NMT Operational state, each slave
sends a TxPDO with the transmission type = 255, so that the
NMT master is informed of the current input configuration.
02h
Change to “Prepared/Stopped”
Communication via SDO or PDO is not possible in this state,
and there is also no reaction to SYNC commands.
81h
Change to “Reset Node”
Triggers a re-initialisation of the CANopen functionality in the
NMT slave.
82h
Change to “Reset Communication” Triggers a re-initialisation of the CANopen functionality in the
NMT slave; the toggle bit for Node guarding is set to 0.
Example for resetting all communication:
The following NMT object (CAN ID = 00h) has 2 data bytes (DLC = 2). Data byte 1 contains
the “Reset communication” command (82h) while data byte 2 addresses this command to
all devices in the CANopen network (address = 0):
CAN ID
DLC
DATA
00h
2
82h
0
Tab. 100: Network manage-
ment for one NMT slave with
address N
Tab. 101: Network manage-
ment for all NMT slaves
Tab. 102: Example NMT
object for resetting all
communication