Mitsubishi Electric Q80BD-J61BT11N, User Manual

Page: 87 / 362

4 - 33 4 - 33
MELSEC
4 FUNCTIONS
(5) Program example when the standby master function is used
The following shows a program example when the standby master function is
used.
void Change_StanbyMaster()
{ short Counter; // General counter
short StNo; // Station number
unsigned short DevType; // Device type
short DevNo; // Device number
short Size; // Sending data size
short RecvBuf[10]; // Buffer for receiving
unsigned short ret; // Return value
//Turn on SB1 (switching request)
StNo = 0xFF; //Set the station number
DevType = 5; //Set the device type (SB: equivalent to special M)
DevNo = 0x1; //Set the device number
ret = mdDevSet(path,StNo,DevType,DevNo);
if(ret!=0) {
printf("SBI ON processing failed, error code:%x\n",ret);
printf("Press any key\n");
getch();
mdClose(path);
exit(0);
}
for(Counter = 0;Counter < 100;+){ // Confirm completion of switching
//Read SB (equivalent to special SM) 43)
Size = 2; // Set the size of sending data
StNo = 0xFF; // Set the station number
DevType = 5; // Set the device type (SB: equivalent to special M)
DevNo = 0x20; // Set the device number
ret = mdReceive(path,StNo,DevType,DevNo,&Size,&RecvBuf[0]);
if(ret!=0){
printf("mdReceive[SB43 read] processing failed, error code:%xYn";ret);
printf("Press any key\n");
getch();
mdClose(path);
exit(0);
}
if((RecvBuf[0] & 0x0800)!=0) // Exit from the loop if SB43 is on
break;
Sleep(100); // Wait for 100ms
}
// Confirm the time-out
if(Counter>=100){
printf("[SB43]ON conformation timed out \n");