Lenze 931K - Manual (Page 42)

CANopen communication
Network management (NMT)
Telegram structure
5
l
42 KHB 13.0002−EN 4.1
5.5.2 Telegram structure
11 bits 4 bits User data (2 bytes)
1st byte 2nd byte 3rd byte 4th byte 5th byte 6th byte 7th byte 8th byte
Identifier
Data
length
CS NI
Via the NMT, commands can be sent to one or all drive controllers. Each command consists
of two bytes. The first byte contains the command code (command specifier, CS) and the
second byte contains the node address (node ID, NI) of the addressed drive controller. Via
the node address zero, all nodes of the network can be addressed simultaneously. It is thus,
for instance, possible to reset all drive controllers simultaneously. The drive controllers do
not acknowledge the NMT commands. The successful execution can only be inferred
indirectly e.g. from the switch−on message after a reset.
The NMT states of the CANopen nodes are defined in a state diagram. Via the CS byte in the
NMT message state changes can be initiated. These changes are mainly orientated
towards the target state.
In the NI parameter, the node address of the drive controller has to be specified. If all nodes
of the network are to be addressed (broadcast), the parameter must be set to zero.
)
Note!
Communication via process data only is possible with a state change to
operational"!
Example:
For changing the state of all nodes on the bus from "pre−operational" to
operational" via the CAN master, the following identifier and user data must
be set in the telegram:
ƒ Identifier: 00 (broadcast telegram)
ƒ User data: 0100 (hex)