Omron C200HW-CORT21-V1, Operation Manual

Page: 26 / 144

Communication
Section 1-3
9
1-3-1-2 Mapping parameters
PDO mapping
Granularity
The mapping parameters define which application objects in the
Manufacturer Specific or Standardised Device Profile Area are allocated to
the PDO.
Each PDO can have up to 8 bytes of data allocated to it, and the minimum
granularity of an application object is 1 bit. Thus a maximum of 64 application
objects can be allocated to one PDO.
Example The following figure shows an example of how process data is transmitted
over the CANopen network. To keep the complexity of the figure to a
minimum, the PDO definition in this figure is symbolised and not indicated by
object entries that define the communication parameters and mapping
parameters.
The data located at index 2000h, copied from the PLC memory, is mapped to
TPDO1 ~ TPDO4; one byte per PDO. In the PDO, the data is preceded by a
message identifier (ID) that characterises the message on the bus. The
PDOs are transmitted over the CANopen network, and every node in the
CANopen network will receive these messages. Depending on each PDO
identifier, a node may decide to process the data, or ignore it.
The frequency and timing of the transmissions depend on the TPDO's
transmission parameters.