NMT state machine
The NMT state machines support different states and the
highest prior CAN message transmitted controls the transition
to the states by the NMT Master.
Node guarding
Mechanism used in CANopen and CAL to detect bus off or
disconnected devices. The NMT Master sends a remote frame
to the NMT Slave that is answered by the corresponding error
control message.
Node ID
Unique identifier for a device required by different CAN-based
higher-layer protocols in order to assign CAN identifiers to
this device, e.g. in CANopen and DeviceNet. In the pre-defined
connection set of CANopen some of the CAN message
identifiers are derived from the assigned Node ID.
Object Dictionary
Heart of each CANopen device containing all communication
and application objects.
Operational state
In the NMT
Operational
state all CANopen communication
services are available.
PDO mapping
In PDOs, there may be mapped up to 64 objects. The PDO
mapping is described in the PDO mapping parameters.
Pin assignment
Definition of the use of connector pins.
Pre-defined connection
set
The pre-defined connection set is a default assignment of CAN
message identifiers to CANopen communication objects. Some
CANopen communication objects are distributed in broadcast
(NMT message, Sync message, Time message) and others are
transmitted between NMT Master device and dedicated NMT
Slave devices (PDO, SDO, Emergency, and Error Control). This
default assignment guarantees that the CAN message
identifiers are uniquely assigned in the network, if the node-ID
has been assigned uniquely.
Pre-operational state
In the NMT
Pre-operational
state no CANopen PDO
communication is allowed.
Process Data Object
(PDO)
Communication object defined by the PDO communication
parameter and PDO mapping parameter objects. It is an
unconfirmed communication service without protocol
overhead.
Producer
In CAN networks a transmitter of messages is called a
producer.
Protocol
Formal set of conventions and rules for the exchange of
information between nodes, including the specification of
frame administration, frame transfer and physical layer.
Receiver
A CAN node is called receiver or consumer, if it is not
transmitter and the bus is not idle.
Redundant networks
In some safety-critical applications (e.g. maritime systems),
redundant networks may be required that provide swapping
capability in case of detected communication failures.
Remote frame
With a remote frame another node is requested to transmit
