SD710 Series Servo Drive User Manal Chapter 11 Communication
10
EMCY
○
○
Boot-Up
○
NMT
○
○
○
Note
:
○
indicates valid
For
example, to
turn on the drive's SDO operation (drive node address is 1), a command word of 80 can be sent.
Frame format
Cob_ID
RTU
0
1
2
3
4
5
6
7
data frame
00
0
80
01
-
-
-
-
-
-
11.2.2.4 NMT error control
NMT error control is mainly used to detect whether the devices in the network are online and the state they are in, including
node protection/life protection and heartbeat. In practice, life protection and heartbeat are not allowed to be used at the
same time, and the time for node protection/life protection and heartbeat should not be set too short to avoid increasing
the network load.
(1) Node/life protection
Node protection is where the NMT master periodically queries the NMT slave status via remote frames; lifetime protection
is where the slave indirectly monitors the master's status via the interval of remote frames received for monitoring the
slave. Node protection follows a master-slave model, where each remote frame must be answered.
The objects associated with node/lifetime protection include the protection time 100Ch and the lifetime factor 100Dh. The
value of 100Ch is node protection remote frame interval under normal circumstances(Unit: ms), and the product of 100Ch
and 100Dh determines the final time for master queries. Under normal circumstances, node protection is all possible.
Lifetime protection is activated when both node 100Ch and 100Dh are not 0 and a node protection request frame is
received.
Figure 11-3 Link Diagram
The NMT master sends a node protection remote frame every period of 100Ch time, and the slave must answer, otherwise
the slave is considered dropped; if the slave does not receive a node protection remote frame within 100Ch × 100Dh time,
the master is considered dropped.
The NMT master sends remote frames in the format shown in Table 11-15.
Table 11-15 Node Protection Remote Frame Messages
COB_ID
RTR
NMT
salve 1
NMT Master
NMT
Slave 2
NMT
Slave 3
NMT
Slave 4