Rockwell Automation 1747-PCINT API Software for 1746 I/O - Manual (Page 145)

OC_WriteOutputImage Library of Routines 6–91
Publication 1747-6.5.3 June 1998
Example:
HANDLE Handle;
WORD outputdata[2];
int retcode;
outputdata[0] = 0x55AA;
outputdata[1] = 0xAA55;
retcode = OC_WriteOutputImage( Handle, NULL, 6, 0, 2, outputdata );