Limit Switches

Technical Programming
1

How can we go about thoroughly programming the limit switches to control a specific motor using MPLab,
ex: if ((dig_in03)) { pwm03 = p3_y; } else { pwm03 = 127; }
Is that the correct way?

Any help would be greatly appreciated, Thanks!

2

You’re up a bit late, aren’t cha? (Or early? Do programmers ever get to see the sun?) :cool:

I think it’s **rc_**dig_in03.

Here’s some code we had from last year, using joystick 2 y-axis to move the grabber arm up or down (like your lower arm with the motor at the elbow). We had a limit switch (LS) at the top and bottom to stop the motor, but allows it to go the other way even if it reaches the limit switch.

   //-------------------------- ARM WORK 3 -------------------------------------
   //Arm desired direction is from JoyStick2, Y-axis. UP goes fwd, DOWN is back.
   //pwm05 is the motor. LimitSwitch 5 and 7 is fwd and back stop points.
   //Change pwm numbers of motor, LS, and Joystick as need be.
   if (p2_y >(127+50))                          //If Joystk2 Y pushed up - arm forward
      {
      if (rc_dig_in05 == 0)                     //is LS5 not pressed?
         { pwm05= 127+3; }                     //  No- turn motor on!
      else
         { pwm05= 127; }                        // Yes- turn motor off!
      }
   else if (p2_y < (127-50))                    //If Joystk2 Y pulled back - arm backwrd 
      {
      if (rc_dig_in07 == 0)                     //is LS7 not pressed?
         { pwm05= 127-3; }                     //  No- turn motor on!
      else
         { pwm05= 127; }                        // Yes- turn motor off!
      }
   else
      { pwm05= 127; }                           //Turn motor off

Of course if you’re doing autonomous, don’t use the joystick! :wink: Just remember to cover all possibilities (all if/ifelse/else’s) so you know at the end the motors are on or off.

This wasn’t our final code, but it did work at the time. As always YMMV.

One of the main causes of the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs.

3

Hey, thank you so much! It worked!