Curtis 3140 Manual – Nov. 2017
3 — CANopen COMMUNICATIONS
pg. 5
The first data byte of the NMT command is the command specifier:
Value Command Specifier
0x01 Enter the Operational state
0x02 Enter the Stopped state
0x80 Enter the Pre-Operational state
0x81 Reset 3140 (warm boot)
0x82 Reset the CANbus
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 Model 3140).
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 Model 3140 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.
LCD LAYOUT
The LCD layout is shown below. It features three large 16-segment characters, six small 16-segment characters,
an hourglass icon, percent icon, wrench (service) icon and a decimal point.