YASKAWA MP920 - Page 286

C.2 Sample Programs for Slave Station
C-11
C
exit(0);
}
// Prepares the response data.
mk_rsp_data( &send_len );
// Sends the response data.
// This processing will not end if the Slave cannot send the response data.
slen = send( new_sd, &sbuf[0], send_len, 0 );
if ( slen != send_len )
// The number of bytes that was sent will be returned if the sending process is successful.
{
closesocket(new_sd);
printf( "Error: Send !! -> %d\n", slen );
exit(0);
}
printf( "Hit Any Key !!\n" );
}
}
/***********************************************************************************/
/* Preparation of extended MEMOBUS response data */
/* */
/* An appropriate response for the function code (SFC=03, 06, 08, 09, 0B, or 10) of extended */
/* MEMOBUS protocol will be returned. In this sample program, an error response will be */
/* returned for other function codes as they are not supported. */
/* A dummy data will be prepared and returned for Read command. */
/************************************************************************************/
void mk_rsp_data( int *slen )
{
int i;
unsigned shortdata_size, memex_len;
/****************************************/
/* Preparation of Extended MEMOBUS Data */
/**************************************/
// MFC
sbuf[14] = 0x20;
// Fixed to 20H
// SFC
sbuf[15] = rbuf[15]; //
Send a received data.
// Set the CPU numbers.
sbuf[16] = (rbuf[16] << 4) & 0xF0;
// The destination is the source CPU. Local CPU No.: 0
// Processing for each function code
switch( rbuf[15] )
{
case 0x03:
// Read Holding Register Contents
data_size = (unsigned short)((unsigned char)rbuf[19]) << 8;
data_size += (unsigned short)((unsigned char)rbuf[20]);
data_size *= 2;
// Read data size in bytes
memex_len = data_size + 3;
// Extended MEMOBUS length for response
// data size + 3byte(MFC,SFC,CPU NO)
// Prepares a dummy data.
// Converts then sends the requested word unit data into byte units.
for( i = 0; i < data_size; i++ )
{
sbuf[17 + i] = i;
// Sets data read from sbuf[17].
}
break;