Chapter 4. Data Communication Protocol of the CANopen
23
4.2.5 The frames enabling communication by NMT status
Pre-
operational
Operational
Stopped
PDO
X
O
X
SDO
O
O
X
SYNC
O
O
X
TIME
O
O
X
EMCY
O
O
X
Node
control and
error
control
O
O
O
4.3 Error Control Protocols
Error Control Protocol is the Protocol that checks if the CANopen
devices connected with the Network are properly working.
Error Control Protocol consists of two types; Node/Life Guarding
Protocol and Heartbeat Protocol.
4.3.1 Protocol node/life guarding
Node/Life Guarding is used to check if CANopen Device is properly
working.
Master transmits RTR Frame to the NMT Slave in a routine manner
(Preset Node Guard Time). Upon receipt of RTR Frame, the Slave
device responds RTR Frame that it works properly together with its
own NMT State.
