myCNC Online Documentation

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==== Software PLC examples ====

//**NOTE**: The myCNC team recommends utilizing the examples provided in this manual (as well as other manuals in this documentation) as a starting point for your machine setup. When possible (and applicable), it is recommended to keep changes to a mininum. In general, using these examples as the basis for your PLCs/macro commands allows for an easier setup process.//

===General examples===

  * [[How to add mandatory Homing after Emergency Button and-or Servo ready alarm]]
  * [[Button to toggle select output pin with indication]]
  * [[Oil Change counter]]
  * [[Controller Peripherals Test - BV17]]
  * [[plc:Charge Pump]]

=== 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 - 
<code c 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);
};
</code>


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.

<code c 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
</code>


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 - 
<code c 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
</code>


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



<code c 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);
};

</code>


===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".
  - The procedure contains an endless loop. 
  - Variables a7382...a7385 keep previous state or "Current Jog Step Size"
  - 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


<code C 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);
};

</code>


===Switching an output ON for a certain period of time===

<code>
#define OUTPUT_TIMER 15
main()
{
count=0;
do{
a=gvarget(7373);

if (a!=0)
{
  count++;
  if (count<30) { portset(OUTPUT_TIMER); }
  else { 
            portclr(OUTPUT_TIMER); 
            if (count>6000) { count=0; };
          };
}else
{
  portclr(OUTPUT_TIMER);
  count=0;
};
}while(1);
exit(99);
};
</code>