Lenze 3241C Manual de usuario descargar pdf (Pagina 17)

API functions 3

 15

3.4.4 SDO block structure

SDO memory area header 1. DWORD

Status register 2. DWORD

BpbSdoBlockHeader

SDOs

3. DWORD

…

n. DWORD

(binary data, according to SDO

package formats)

The structure of the SDO memory area results from the different SDO package

formats. The following package formats are defined there:

Write request (BpbSdoHeader, BpbWrite)  status message (BpbSdoHeader)

Read request (BpbSdoHeader)  response (BpbSdoHeader, BpbRead)

Each SDO (FIFO telegram) starts with a header, which is identical for the IPC and the

BPB controller:

Header

Structural element Type Bits Description FIFO

Index WORD 16-31 Index of the parameter

Subindex BYTE 8-15 Subindex of the parameter

Control BYTE 0-7 Bit 7 = 0 (read) / 1 (write)

Bit 0-6 = job number

1 DWORD

Via the index and subindex, the BPB controller basically decodes the action to be

executed and, if required, generates a suitable command for the BPB master, which

the backplane bus master in turn transmits to the I/O module/s. Since a telegram on

the BPB must only contain a maximum of 64 bytes of user data, a data volume greater

than that, if necessary, has to be fragmented into several individual telegrams by the

IPC. After processing, the BPB controller sends a status message on the response FIFO

to the IPC. The response contains the job number and one byte regarding the success

of the action.

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Lenze 3241C Manual de usuario Pagina 17