Curtis 1352 - NMT Messages

Curtis 1352 eXm Manual, R ev. D
15
3 — CANopen COMMUNICATIONS
The standard organization of the COB-ID puts the message type in the
upper four bits, and the Node ID in the bottom seven bits:
11 10 9 8 7 6 5 4 3 2 1
Message Type Node ID
NMT MESSAGES
NMT (Network Management Transmission) messages are the highest priority
message available. The NMT message puts the eXm into one of the four defined
states. These messages have 1 byte of data sent by the master; the slave does not
respond with any data to an NMT. The eXm state value is transmitted with
each heartbeat message.
Value State
00h Initialization (or “boot-up”)
04h StoppedXx
05h OperationalXx
7Fh Pre-OperationalXx
The NMT message identifier consists of the standard message type (NMT)
in the top four bits; the bottom seven bits must be set to zero.
The first data byte of the NMT command is the command specifier:
Value Command Specier
01h Enter the Operational state
02h Enter the Stopped stateXx
80h Enter the Pre-Operational statex
81h Reset the eXm (warm boot)Xx
82h Reset the CAN busXx
The second byte of the NMT command defines whether this NMT is for
all slaves on the bus (data byte = 00h) or for a specific node (data byte = Node
ID of the eXm)