boot-up. This initialization process can be represented by a node state transition diagram, as
shown in Figure 10-5.
Figure 10-7 Node state transition diagram
Note:
The letters in brackets in the figure indicate the communication objects that can
be used in different states.
a: NMT d:emergency b:node guard e:PDO c:SDO f:Boot-up
You can switch between various modes through NMT management messages. Only the
NMT-Master node can transmit NMT Module Control messages. All slave devices must
support NMT Module Control services, and NMT Module Control messages do not need to
be answered. After the device is initialized, it automatically enters the Pre_Operational state and
sends a Boot-up message. The NMT message format is as follows: NMT-Master→NMT Slave(s)
Table 10-20 Format of NMT managing message
When Node-ID=0,
all NMT slaves are addressed.
CS is the command word, and its value is shown in Table 10-
15.
Table 10-20 CS value table
Description of emergency message
When a fatal error occurs inside the device, an emergency message will be triggered, and the
application device will send it to other devices with the highest priority. An emergency message
consists of 8 bits.
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