Rockwell Automation 20-COMM-K CANopen Adapter User Manual
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Glossary
20-COMM-K CANopen Adapter User Manual
Publication 20COMM-UM012B-EN-P
O
Objects
The CANopen specification defines an object as “an abstract representation
of a particular component within a product.”
Object Dictionary
Any CANopen device has a unique object dictionary, which is the interface
to the application. The object dictionary contains all data types used in the
device, the communication parameters, the application data, and the
configuration parameters. To gain access to the object dictionary, Process
Data Objects (PDOs) and Service Data Objects (SDOs) are used.
P
PDO (Process Data Objects)
Process Data Objects (PDO) are used to transmit any process data. The
process data are transmitted without any protocol overhead and by using the
producer/consumer model. PDO transmission is not confirmed. Each PDO
has a unique CAN identifier. The maximum length of a PDO message is 8
bytes.
PDO Mapping
The PDO mapping defines which application objects are transmitted within
a PDO. It describes the sequence and length of the mapped application
objects.
Polled I/O Data Exchange
See Remote Transmission Request.
PowerFlex 7-Class (Architecture Class) Drives
The Allen-Bradley PowerFlex 7-Class family of drives supports DPI and
includes the PowerFlex 70, PowerFlex 700, PowerFlex 700H, PowerFlex
700S, PowerFlex 700L, and PowerFlex 7000. These drives can be used for
applications ranging from 0.37…3000 kW (0.5…4000 HP).
Producer/Consumer Network
On producer/consumer networks, packets are identified by content rather
than an explicit destination. If a node needs the packet, it will accept the
identifier and consume the packet. The source therefore sends a packet once
and all the nodes consume the same packet if they need it. Data is produced
once, regardless of the number of consumers. Also, better synchronization
than Master-Slave networks is possible because data arrives at each node at
the same time.