VCS Limit code

VEX V5 General Discussion General Forum
1 
    if(Controller1.ButtonR2.pressing()) {
        LiftM1.spin(vex::directionType::fwd, armSpeedPCT, vex::velocityUnits::pct);
        LiftM2.spin(vex::directionType::rev, armSpeedPCT, vex::velocityUnits::pct);
    }
    else if(Controller1.ButtonR1.pressing()) {
        LiftM1.spin(vex::directionType::rev, armSpeedPCT, vex::velocityUnits::pct);
        LiftM2.spin(vex::directionType::fwd, armSpeedPCT, vex::velocityUnits::pct);
    }
    else {
        LiftM1.stop(vex::brakeType::brake);
        LiftM2.stop(vex::brakeType::brake);
    }

We need a limit on how far the motors can go down, how would we make a code for that?

2

This probably isn’t what you’re looking for, but why not build a physical stop? It’s a lot more consistent than a code stop :slight_smile:

3

Try using this:

if(Controller1.ButtonR2.pressing()) {
LiftM1.startRotateTo(360, rotationUnits::deg, armSpeedPCT, velocityUnits::pct);
LiftM2.startRotateTo(-360, rotationUnits::deg, armSpeedPCT, velocityUnits::pct);
}
else if(Controller1.ButtonR1.pressing()) {
LiftM1.startRotateTo(-360, rotationUnits::deg, armSpeedPCT, velocityUnits::pct);
LiftM2.startRotateTo(360, rotationUnits::deg, armSpeedPCT, velocityUnits::pct);
}
else {
LiftM1.stop(vex::brakeType::brake);
LiftM2.stop(vex::brakeType::brake);
}

I am pretty sure that this would work. It will rotate your motors towards a specific value, so all you would have to do is play around with the rotation value until you get to the desired stopping point. I hope this helps!

4

This is something that will be much different in the V5 world than with 393s. The first time I relied on a mechanical stop on the bottom of the range on a 100rpm V5 arm motor geared 1:7, I twisted the entire tower about 20 degrees. I’d use both software and hardware stops, but be very careful if you only rely on hardware.

5

And this is more generally true, which will make people learn to use the motors and stops better in VEX. You really don’t want to stop motors exclusively with physical stops. Not only does this result in a lot of stress on the stops, but it means you’re stalling your motors out, which is really not what you want to do with motors. True hard (ideally cushioned some) stops without a motor doing most of it are usually better as safety constraints. There are plenty of situations where we willingly choose to destroy motors/gears/etc. while physically stopping devices for safety reasons. I prefer to use limit switches or bumpers, slowing the motors down as you get close with encoders and making sure you’re stopped when you get there with those switches.