8 process data transfer, Process data transfer, Communication manual 8400 motec canopen – Lenze E84DGFCC User Manual
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Communication manual 8400 motec CANopen
Process data transfer
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EDS84DMOTCAN EN 3.0 - 11/2011
8
Process data transfer
[8-1]
PDO data transfer from / to the higher-level host (master)
The CANopen communication unit is provided with two separate process data channels
(PDO1 and PDO2) for transmitting process data. Each process data channel can transmit up
to four words (8 bytes) at a maximum.
The system bus (CANopen) transmits parameter data, configuration data, diagnostic data,
alarm messages and process data between the host (master) and the controllers (slaves)
participating on the fieldbus. Depending on their time-critical nature, the data are
transmitted via different communication channels.
Process data are transmitted via the process data channel.
The process data serve to control the controller.
Transferring process data is time-critical.
Process data are transferred cyclically between the master and the slaves participating
on the fieldbus (continuous exchange of current input and output data).
The master can directly access the process data. In the PLC, for instance, the data are
directly assigned to the I/O area.
Process data are not saved in the controller.
Process data are, for instance, setpoints, actual values, control words and status words.