Curtis 1030 Acuity Manual,
Rev. C
15
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 Specifier
01h
Enter the Operational state
02h
Enter the Stopped state
Xx
80h
Enter the Pre-Operational state
Xx
81h
Reset Acuity (warm boot)
Xx
82h
Reset the CANbus
Xx
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 Acuity).
Heartbeat messages
The heartbeat message is a very low priority message, periodically sent by each
slave device on the bus. The heartbeat message has a single byte of data and
requires no response. Once the Acuity is in the Pre-Operational state, the next
heartbeat will be issued and will continue until communication is stopped.
The heartbeat message has only one data byte. The top bit is reserved and
should be set to zero. The bottom 7 bits hold the current NMT device state as
defined previously.
4 — CANopen COMMUNICATIONS
