
API functions 3
19
3.4.7 PDO functions
BpbReadPdo function
Parameter
[in] HANDLE hOpen Pointer to open context (handle) for identification
[out] PUCHAR pReadBuffer PDO memory area
[in] WORD usBufferSize Size of the memory area
[out] PWORD pusActualPdoSize Size of the memory area assigned
Return values
S_OK Successful
E_HANDLE Incorrect (handle is invalid)
E_MEMORY Incorrect (BPB message memory area overflown)
BpbWritePDO function
Parameter
[in] HANDLE hOpen Pointer to open context (handle) for identification
[in] PUCHAR pWriteBuffer PDO memory area
[in] USHORT usBufferSize Size of the memory area
[out] PUSHORT pusSdoWritten Number of PDOs written
Return values
S_OK Successful
E_HANDLE Incorrect (handle is invalid)
PDO block structure
The structure of the process data results from the group configuration of the I/O
modules.
Size of the PDO memory area 1. DWORD
Status register 2. DWORD
BpbPdoBlockHeader
SDOs
3. DWORD
…
n. DWORD
(binary data, according to process
image)
After a read or write access the status register contains the current status of the BPB
and does not serve to change the status of the BPB.
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