P loop confusion

Programming Support VEXcode Pro V5 Text Tech Support
#1

Can someone help me with my p loop i cant find out what im doing wrong the code is below

int tilterPControl = ButtonR1 + 100(-1(Lift.rotation(degrees)/1.58));

Lift.spin(fwd,100,tilterPControl);

The errors are here

called object type ‘int’ is not a function or function pointer
no matching member function for call to ‘spin’

#2

What is the range of values for ‘buttonR1’? If its boolean then you are trying to add a double and a bool which won’t work

#3

the R1 value is supposed to be the input but i don’t really understand how to write a p loop in vexcode so that’s why i am confused on how to write it

#4

And I haven’t found any resources on how to write it in vexcode

#5

Which is why I sent the link in the other thread. Try something like this:

Double power;
If(buttonpressing){
    power = (target - current)*constant);
}
Else{
    Power = 0;
}
#6

well i looked into it and that’s similar to what i wrote its just that part of code that is having the issue

this is how mine is set up below

if(Controller.ButtonR1.pressing()) {
int LiftPControl = Lift + 100(-1(Lift.rotation(rev)/1.58));
Lift.spin(fwd,100,LiftPControl);
}
else if(Controller.ButtonR2.pressing()) {
Lift.spin(vex::directionType::rev, 200, vex::velocityUnits::pct);
} else {
Lift.stop(vex::hold);
}

#7

For the first Lift.spin line, LiftPControl should go in the second parameter and pct/rpm should be in the 3rd parameter

#8

Ok 1 of the 2 problems solved now this line still has an error:
int LiftPControl = Lift + 100(-1(Lift.rotation(rev)/1.58));

The error states that the called object type ‘int’ is not a function or function pointer and the red area on the code is at the start of the 2nd parenthesis

#9

What is “Lift” in your code

#10

the lift is just the tray lift motor

#11

Lift doesn’t mean anything by itself so it is producing an error in your code, try removing it

#12

still the same error

int LiftPControl = (-1(Lift.rotation(rev)/1.58));
----------------------- ^
the arrow is where the error is

#13

Try changing the int to double and add a multiplication sign in between -1 and (Lift.rotation(rev)/1.58)

#14

Ok it worked thank you so much there is just little to no reference on p loops for vexcode and i really appreciate your help

#15

introduction_to_pid_controllers_ed2.pdf (400.2 KB)

P loops isnt only specific to VexCode so that’s why there’s nothing in VexCode that references P loops. The PDF I uploaded is one of my favorite documents for learning P loops (and PID)

#16

The problem here was that when you tried to do implicit multiplication without the * symbol, the compiler interpreted that as you calling a function, as that is the same syntax as you would use to call a function that was named “100”

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#17

well yea but i didnt find an exact way on how to set it up

#18

Here’s also a link to a post that contains code with a p loop

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