Kuhnke Electronics Instruction Manual

CANopen
Master & Slave:
One unit in the network must provide the CANopen
master functionality.
CANopen masters can monitor CANopen slaves and
manipulate their status.
With regard to data exchange, master and slaves have
equal rights.
Ventura Remote PLC can act as a CANopen master.
Bus communication:
As opposed to "station-based" data transfer, which
defines as the exchange of messages between two
specified stations, the transfer of CAN messages is based
upon the so-called "producer/consumer principle", i.e. a
message sent by one of the stations (producer) can be
received and read by all of the other stations (consumers).
To sustain this approach, messages are not labelled with
a target address but with a unique "message identifier".
CANopen distinguishes between two types of basic
communication objects.
SDO
Service data objects (SDO) are used for configuring and
setting the parameters of CANopen slaves, for example.
SDOs are exchanged as acknowledged data transfer
operations with two CAN objects being sent through a
point-to-point connection between two network nodes
every time. The appropriate object dictionary item is
addressed by its index and subindex.
PDO
Process data objects (PDO) speed up the exchange of
process data.
PDOs are configured with reference to object dictionary
items.
There are various ways of transferring process data
objects, i.e. in response to an event, cyclically or after
request as broadcast objects without extra protocol
overhead. Every PDO can carry a maximum of 8 byte
user data.
170 E 700 GB