Canopen - Aventics CANopen LP04 Mode D'emploi

28 AVENTICS | CANopen | R402001988–BDL–001–AC
Device description
transfer. All other devices switch to receiving mode during the
transfer. Thus the identifier determines the priority of a
message on the bus.
A transmitter sends its message to all CAN nodes, which then
decide themselves if they will process the message. A
maximum of 8 data bytes can be transferred in one telegram
due to CAN guidelines.
It is characteristic for CAN that only the layers 1 and 2 of the
ISO/OSI model, and thus the physical transfer (level, telegram
structure, timing, error recognition and synchronization of bus
access) are specified by ISO standards 11519 and 11898.
Layer 7, i.e. the significance of the data byte as user or system
data and the allocation of the identifier is determined by
manufacturer-specific profiles (CANopen, DeviceNet, SeleCAN,
SDS, layer 2).
These different protocols are not compatible with each other.
4.2

CANopen

CANopen is a CAN protocol that is based on a clear master/slave
connection. Several masters can share a physical CAN data line
and can control different slaves. A slave is, however, only
assigned to one master and can only exchange data with that
master. A master can release a slave, which can then be
requested and operated by another master.