Rockwell-automation 1747-PCIS API Software - Open Controller Manual de usuario descargar pdf (Pagina 112)

Publication 1747-UM002A-US-P - June 2000

6-52 Library of Routines

Return Value:

Considerations:

Supported in the DOS API library and the Windows NT API library

Example:

HANDLE Handle;

WORD outputdata[2];

int retcode;

retcode = OC_ReadOutputImage( Handle, NULL, 6, 0, 2,

outputdata );

/* Read slot 6 data, first 2 words, directly from the output

image */

/* table to outputdata buffer */

OC_ReadSRAM

OC_ReadSRAM reads data from the battery-backed user memory.

Syntax:

int OC_ReadSRAM(HANDLE Handle, BYTE *bufptr,

DWORD offset, DWORD length);

Description:

The battery-backed memory may be used to store important data that

needs to be preserved in the event of a power failure. The size of the

available memory in bytes may be obtained using OC_GetDeviceInfo.

handle must be a valid handle returned from OC_OpenScanner.

bufptr points to a buffer to be receive the data. offset specifies

Name: Value: Description:

SUCCESS 0 output image was read successfully

ERR_OCACCESS 2

handle does not have access to scanner

ERR_OCPARAM 8 parameter contains invalid value

ERR_OCSCANCFG 14 scanner has not been configured

ERR_OCSLOT 12 slot number is invalid

IMPORTANT

It is recommended that the integrity of data stored in

the user memory be verified by some means. The

OC_CalculateCRC function may be used to generate

a 16-bit CRC that may be used for this purpose.

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Rockwell-automation 1747-PCIS API Software - Open Controller Manual de usuario Pagina 112