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plc:software_plc_examples

Software PLC examples

Endless loop for G-code program

An endless loop can be made in Software PLC procedure. PLC procedure contains an endless loop. In the loop it checks the current status of myCNC controller, if the controller is in Idle mode and ready to run a new program, it reloads G-code file (if needed), reset current program pointer and starts running g-code.

PLC code is -

ENDLESS.plc
main()
{
 
 do
 {
   do{ a=gvarget(6065); }while(a!=0);	 //wait Motion Controller ready to accept new program
   gvarset(100001,1);	                 //Reset G-code pointer to start
   timer=5; do{ timer--;}while(timer>0); //0.5 sec Pause
   gvarset(100002,1);	                 //Start G-code
 }while(1);              //endless loop
 
 exit(99);
};

If Stop button pressed, g-code will be stopped, the procedure will see Motion controller is ready for next loop entry and restart g-code again. This behaviour can be inappropriate for many applications.

A simple solution is to add global variable single/auto and check this variable in the loop.

NOT_ENDLESS.plc
main()
{
 
 do 
 {
   do{ a=gvarget(6065); }while(a!=0);	 //wait Motion Controller ready to accept new program
   gvarset(100001,1);	                 //Reset G-code pointer to start
   timer=5; do{ timer--;}while(timer>0); //0.5 sec Pause
   gvarset(100002,1);	                 //Start G-code
 }while(gvarget(400)==0);    //endless loop, if #400==0, otherwise exit from procedure
 
 exit(99);
};
//If variable #400 will be set to non-zero value, NOT_ENDLESS.plc process will be finished

In case no need to exit from ENDLESS.plc and variable #400 should be monitored constantly and run g-code when #400 is set bu user -

ENDLESS2.plc
main()
{
 do 
 {
  if (gvarget(400)!=0)                   //if #400!=0, run g-code, otherwise continue to test #400
  {
   do{ a=gvarget(6065); }while(a!=0);	 //wait Motion Controller ready to accept new program
   gvarset(100001,1);	                 //Reset G-code pointer to start
   timer=5; do{ timer--;}while(timer>0); //0.5 sec Pause
   gvarset(100002,1);	                 //Start G-code
  };
 }while(1);    //endless loop
 
 exit(99);
};
//If variable #400 will be set to non-zero value, ENDLESS.plc process will be finished

Endless loop with switch to left & right sides of working area

LEFT-RIGHT.plc
#define MAX_X	800
#define MAX_Y 800
 
main()
{
 
do
{
 
  auto=gvarget(501);	//Automatic mode
 
  if (auto)
  {
 
    do { rect_not_ready=gvarget(7369); }while(rect_not_ready==0);
 
    left_right=1;
    xmax=gvarget(7350);
    if (xmax>MAX_X){ left_right=0;};
    ymax=gvarget(7351);
    if (ymax>MAX_Y){ left_right=0;};
 
    gvarset(502,left_right); //502 - shows both sides or single side
    LR=gvarget(500);
 
    if (LR==0) //left
     {
//       gvarset(9100,1);	//show message #1
       //do{ a=portget(11); }while(a==0);	//press pedal, port 11
       //do{ a=gvarget(6065); }while(a!=0);	//press pedal, port 11
//       gvarset(9100,0);  //clear the message
 
       portclr(10);//Vacuum Left OFF
       portset(9); //
 
       portset(11);//
       portset(22);//
 
//       gvarset(9101,1); //show message #2
       //do{ a=portget(13); }while(a==0);	//press pedal, port 13
//       gvarset(9101,0); //убрать
 
       portset(10);//Vacuum Left
       portclr(9); //
       timer=5; do{ timer--; }while(timer>0);	//wait 0.5 seconds while the vacuum is working
 
       portclr(11);//выключить упоры
       portclr(22);//
 
////
//ждать пока УП завершится
       do{ a=gvarget(6065); }while(a!=0);	//wait
////
 
 
do {
      do{ a=gvarget(6065); }while(a!=0);	//wait for the system to be ready
      gvarset(100010,54);	//Дать код G54
      timer=5; do{ timer--; }while(timer>0);	//wait 0.5s for the system to switch
			n=gvarget(5220);//gets the current coordinate system number
		} while(n!=1);	//while the current system is not G54
 
       do{ a=gvarget(6065); }while(a!=0);	//wait for the system to be ready
       gvarset(100001,1);	//go to the beginning of the program
       timer=5; do{ timer--; }while(timer>0);	//wait 0.5s
       do{ a=gvarget(6065); }while(a!=0);	//wait for the system to be ready
       gvarset(100002,1);	//start the program
    }else	//right 
    {
//       gvarset(9110,1);	//show message #1
//       do{ a=portget(12); }while(a==0);	//press pedal, port 11
//       gvarset(9110,0);  //clear the message
 
       portclr(15); //Vacuum Left OFF
       portset(16); //
 
       portset(14); //
       portset(23); //
 
//       gvarset(9111,1); //show message #2
//       do{ a=portget(14); }while(a==0);	//press pedal, port 13
//       gvarset(9111,0); //clear
 
       portset(15); //Vacuum Left
       portclr(16); //
       timer=5; do{ timer--; }while(timer>0);	//wait 0.5 seconds while the vacuum is working
 
       portclr(14);//
       portclr(23);//
 
////
       do{ a=gvarget(6065); }while(a!=0);	//wait
//wait until the control program is finished
////
 
do{
      do{ a=gvarget(6065); }while(a!=0);	//wait until the program is ready
			gvarset(100010,55);	//assigns G54 coordinate system
      timer=5; do{ timer--; }while(timer>0);	//wait 0.5 seconds while the coordinate system switch is happening
			n=gvarget(5220);//obtain the current coordinate system number
} while(n!=2);//while the system is not G55
 
       do{ a=gvarget(6065); }while(a!=0);	//wait while the processor is busy
       gvarset(100001,1);	//return to the beginning of the program
       timer=5; do{ timer--; }while(timer>0);	//wait 0.5 seconds
       do{ a=gvarget(6065); }while(a!=0);	//wait for the system to be ready
       gvarset(100002,1);	//start the program
 
    };
 
       timer=20; do{ timer--; }while(timer>0);	//3 second pause
       do{ a=gvarget(6065); }while(a!=0);	//wait until the program is complete
 
		LR=LR^1;	//switch to the other side
    gvarset(500,LR);
 
  };//auto
 
 }while(1);
 
 exit(99);
};

Jog Step (0.001, 0.01, 0.1 1.0) Indication with external LED display

There are global variables which represent current jog step size

Variable Name Variable Number Description
GVAR_JOG_STEP_SIZE 5522 prepresents current jog step size (double)
GVAR_JOG_STEP_0_0001 7381 the value is “1” if Current Jog Step Size is “0.0001”, otherwize is “0” (integer)
GVAR_JOG_STEP_0_001 7382 the value is “1” if Current Jog Step Size is “0.001”, otherwize is “0” (integer)
GVAR_JOG_STEP_0_01 7383 the value is “1” if Current Jog Step Size is “0.01”, otherwize is “0” (integer)
GVAR_JOG_STEP_0_1 7384 the value is “1” if Current Jog Step Size is “0.1”, otherwize is “0” (integer)
GVAR_JOG_STEP_1_0 7385 the value is “1” if Current Jog Step Size is “1.0”, otherwize is “0” (integer)
GVAR_JOG_STEP_10 7386 the value is “1” if Current Jog Step Size is “10”, otherwize is “0” (integer)

Software PLC procedure can be made to handle LED display according to “Current Jog Step Size”.

  1. The procedure contains an endless loop.
  2. Variables a7382…a7385 keep previous state or “Current Jog Step Size”
  3. There are testing “Current Jog Step Size” global variables values, switching binary output if variables were changed and store new states in the a7382…a7385 local variables
JOG_STEP_LEDS
main()
{
 
 a7382=gvarget(7382);
 a7383=gvarget(7383);
 a7384=gvarget(7384);
 a7385=gvarget(7385);
 
 do{
 
 if (gvarget(7382)!=a7382)
 {
   a7382=gvarget(7382);   
   if (a7382==0){portclr(14);}else {portset(14);};
 };
 if (gvarget(7383)!=a7383)
 {
   a7383=gvarget(7383);   
   if (a7383==0){portclr(13);}else {portset(13);};
 };
 if (gvarget(7384)!=a7384)
 {
   a7384=gvarget(7384);   
   if (a7384==0){portclr(12);}else {portset(12);};
 };
 if (gvarget(7385)!=a7385)
 {
   a7385=gvarget(7385);   
   if (a7385==0){portclr(11);}else {portset(11);};
 };
 
}while(1);
 
exit(99);
};
plc/software_plc_examples.txt · Last modified: 2019/07/12 09:26 by ivan