Rockwell Automation 1747-PCIS API Software - Open Controller - Manual (Page 140)

Publication 1747-UM002A-US-P - June 2000
6-80 Library of Routines
Considerations:
Supported in the DOS API library and the Windows NT API library
Example:
HANDLE Handle;
WORD outputdata[2];
int retcode;
outputdata[0] = 0x55AA;
outputdata[1] = 0xAA55;
retcode = OC_WriteOutputImage( Handle, NULL, 6, 0, 2,
outputdata );
OC_WriteSRAM OC_WriteSRAM wires data to the battery-backed user memory
Syntax:
int OC_WriteSRAM(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 the data to be written. offset specifies the offset
within the memroy to begin writing. length specifiies the number of
bytes to be written.
If offset + length points past the end of the memory, no bytes
will be written and ERR_OCPRAM will be returned.
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.