Lenze 3241C Manual de usuario descargar pdf (Pagina 20)

3 API functions

18 

3.4.6 PDO communication

Process data (PDO)

In order to r

ead process data from the backplane bus, the BpbReadPdo function is

used, reading the process input image. The process output image can be written to

the backplane bus by means of the BpbWritePdo function. The reading/writing of

PDOs is only possible in the Operational state.

Reading/writing the PDOs of a group is only transmitted from/to the BPB controller if

the group status is "RUNNING“. During the "INIT“ group status, the values are read as

0 (directly in the driver, not from the BPB controller).

By the BpdReadPdo and BpbWritePdo functions, a PDO block including a header

(contains the size of the PDOs and the status register) is provided or expected. In the

case of the writing access, the contents of the status register are ignored.

Abb. 3 Reading/writing the process image

DPRAM

Process output image

Process input image

RWB_Read(...)

{

...

ReadDPRAM()

...

}

RWB_Write(...)

{

...

ReadDPRAM()

...

}

BPB driver

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Lenze 3241C Manual de usuario Pagina 20