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Hello and welcome to the VEX Classroom. My name is Lauren Harter, and in this video, we're going to be talking about Mastering the Workcell. Oftentimes, when you build your Workcell, you go through the mastering process to ensure that all of your joints are in master and that everything is functioning properly. However, as you continue through the labs and use your Workcell, you may need to remaster it or notice that one or more of your joints falls out of master. This video will cover the troubleshooting steps you should take when you need to remaster your arm after it's already built.

I'm going to walk you through all of those things. What should I start with? What are some small things I can check first before I actually need to take the arm apart? And what are those troubleshooting steps? The first thing we're going to talk about is checking our connections and hardware. Sometimes, when something falls out of master, it may be as simple as a cable coming unplugged. So, we're going to check things as far as that goes.

The next step is identifying which joint is out of master. To do that, we have two different example projects: the arm install example project, which is covered in the build instructions, and the arm mastering projects. What exactly is the difference between the two? When would I use one over the other, and how do they deal with actually mastering the arm itself?

Before we get started with anything, let's talk about the number one thing we want to check before we realize that we need to take the arm apart as far as remastering our arm goes. The first thing we want to check, no matter what, is whether the mastering jig is actually in the arm. When I go to check and see that my arm is out of master, a lot of times, people just forget to put the jig back in. Of course, when your jig is not in place, you'll notice that the arm is going to extend a lot further. When we're checking for mastering, we are checking that the arm is actually in this home position with the jig put in. So, we obviously want to check that that's in first. Again, a lot of people just forget to actually put the jig in before we check to see if everything is still in master.

The next thing we want to look at is the three-wire cable connection. A lot of times, when we're checking the potentiometers, especially, we have a lot of three-wire cables throughout here. We have cables going not only potentially to sensors but also to the potentiometers. To get the potentiometers actually connected to the brain, there is a three-wire cable connection there and an extender. A lot of the times, we notice that it isn't actually plugged all the way into the brain because these three-wire ports on the side of the brain require you to push them in all the way. One thing to check is to make sure that everything is actually plugged in all the way.

The second thing is to ensure they are in their correct ports. If I accidentally plugged in one of the potentiometer three-wire cables into the incorrect port, I could get readings showing that something is not connected or not in master when, in fact, I just plugged it into the wrong port. When checking for that, we want to make sure joint one is in A, two is in B, three is in C, and four is in D. Just make sure that all of those are there as well.

Something else you can check is if I actually go to the device's screen. From the brain, there is a little connector here at the top that allows me to see all of the three-wire ports there.

Thank you for watching this video on Mastering the Workcell. I hope you found it helpful. If you have any questions or need further assistance, please feel free to reach out. Happy building!

So that's also something that you can check if you want to see if something is even plugged in at all. So that's another thing that we can check to see, is this even reading? Is the potentiometer even reading on the brain and things of that nature.

Next thing that we want to check with our three-wire cables is, are they actually connected correctly? So when I connect the three-wire cables together, you'll notice that there are two different sides to that cable. We don't want to connect them inverted that you see there in the image to the bottom. We want to make sure that the gold side is paired with the gold side, and the black side is paired with the black side. If you accidentally flip them, you may be getting some readings on your brain that you either not expected, or it may be showing that something's out of master, but actually it's just a bad connection. So definitely something to look at again, as we are checking our connections, as far as the three-wire cables go.

Next thing that we want to check is our motor connections. So as you can see, all of our potentiometers have a shaft that connect from the motor to the shaft, and the shaft actually goes into the potentiometer. And that's something that you may notice is that if our cables are not connected correctly here, we may be getting some values on the brain that are not expected. Two things that we definitely want to check for, is number one is the smart cable all the way plugged into the motor. One thing to note is that if it is not all the way plugged in, you will hear a click when it is all the way plugged in. And also the ends of the cables, the actual plastic components actually turn red when they are powered on. So again, if everything is turned on and you don't see that it's red, there may be a connection that's missing there.

Another thing is you do want to make sure that the joints and the potentiometers associated with those shafts and motors are connected to the correct motor. So again, if my smart cables are not correctly connected to the right motor, I may be getting some readings there that are not accurate. So joint number one is going to be in smart port one all the way down to joint four being connected to smart port four. Now, when I'm talking about the smart ports, I also mean connecting them to the brain at the top here. So again, want to make sure one through four, those are actually connected correctly with the actual motors themselves.

The next thing that we want to look at is the center lock beam versus the flat bearing. So this is something that I've actually seen. As feedback happened to a couple of individuals, is that if you choose the wrong piece or you think that they're the same, but they're actually not, you can often think that the flat bearing and the center lock beam are the same because they are kind of the same shape. But you'll notice in that image there to the left of the flat bearing, center hole is actually circular. And the center lock beam, center hole is square. So if you accidentally swap these in the building instructions that you see there on the right, if you have a shaft going through there, it will freely spin in the circle because it's not being caught in the square portion of the center lock beam. So just something to keep in mind there as well, to make sure, especially that when you are building the Workcell that these parts are being used correctly. Because again, just depending on what you're doing, you know, if I'm trying to actually turn the actual turntable of the Workcell with the shaft, but it's in a circular flat bearing, it's actually not going to catch and turn the turntable as intended. So definitely something to check out if you are experiencing your turntable of your Workcell, either not spinning or spinning incorrectly as far as when it twists and that actually has to do with joint one being out of master.

Thank you for your attention, and I hope this information helps you troubleshoot effectively. If you have any further questions, feel free to reach out.

Is definitely something to keep in mind there as well. Another thing to look at is that the shaft is fully inserted into the potentiometer. So again, this deals with joint one. You'll notice that the shaft here that actually goes into the motor is connected to the motor there. It actually goes all the way through the potentiometer and it needs to actually catch in the potentiometer in order to give those readings that it's actually spinning.

If you note that the shaft isn't actually all the way through, and it's not in the potentiometer, you may be getting that it's not actually moving, but it may just not actually make contact with the potentiometer. So you want to make sure that that is actually fully seated in there.

All right, with all that being said, that's checking our hardware and also making sure our connections are correctly connected. Now that's all stuff that we want to check before we actually get into, do I need to take the arm apart? Do I actually need to make changes to the actual arm itself? So those are all things that can be quick fixes that again, you definitely want to troubleshoot and check before we do any changes to the arm itself.

Now that being said, we want to identify which joint is actually out of master. There is joint one, and then there are joints two through four. So depending on which joint is actually out of master, there are two different processes that we have. Joint one has its own process on how to remaster it and joints two through four have their own process on how to remaster those. So you have to make the decision on which one is actually out of master. Is it joint one which follows a singular process, or is it joint two through four, which follow a different process and use the arm install example project?

We actually do have a knowledge base article that walks you through how to fix both of those. So again, are you fixing joint one or are you fixing joints two through four? This article actually walks you through all of those things, depending on which one is actually out of master, but I'm going to explain them in a little bit more detail here and kind of different tips and tricks that you can use as you're distinguishing them.

Going back to identifying which one is actually out of master, there are two example projects that we have that people either get confused, or they're not sure what to use when. The one that we have on the left is the arm install example project. You can see that all four joints and the potentiometer values there that we're seeing, if they're in and out of master, are displayed. But at the bottom, you can also see that Coast, Hold, and Target are also being displayed.

The arm install project is actually used to maneuver the arm to actually have the motor spin and put it back into master. So this one's actually going to manipulate the arm. This one is also used in the build instructions when you build the arm for the first time. The one on the right, the arm mastering example project, is just used to tell you if any of the joints are out of master. It's not going to give you the option to actually move any of the motors or the gears associated with them and the shafts and things of that nature. It's only going to display if the joints are out of master or not.

So that's the main difference between the two. Both of them are going to show you the values that you're going to get from each joint. However, the arm mastering one is only going to display those values for you while the arm install is actually going to give you the option to manually move those motors and actually code them to go back into master.

That being said, in a classroom setting and something that we have throughout our STEM labs is we have the arm mastering to check.

Thank you for your attention and dedication to mastering these processes. We hope this information helps you in your troubleshooting and maintenance tasks.

If you have any further questions or need additional support, please don't hesitate to reach out.

Because again, then you can just get a quick reference on if anything is out of master without having the option to actually go through and have to change anything. Take the arm apart and actually go through and move the motors.

Now, one thing why the arm mastering there on the right is actually really helpful is because the arm install project that you see there on the left, that one, you don't want to move anything pertaining to the arm, especially when the jig is in. You don't want to actually hit Target and move those gears and motors and things of that nature with the arm attached, because you could potentially damage the arm.

So using the example project on the right, that arm mastering one, that allows you to see if anything is out of master without having to worry about accidentally hitting anything or damaging the arm. So there is a reason that we have both of them. One is for, okay, I actually, the one on the left, the arm install, is actually used for, okay, I need to actually take the arm off. I need to put everything back. I need to move the motors, which attach to the gears. Well, the one on the right is just for displaying.

So when I'm talking about actually moving the motors, we have the shafts here attached to the motors, which also have gears associated on those shafts. And they can connect to the red gears that actually manipulate the arm. Now, if I hit Target with all of that attached, that can put a lot of strain on the arm, because again, we have the mastering jig in. So we're basically trying to move things, but we're also blocking it with the jig being in.

So again, I can't stress enough how important it is that you do not want to use the arm install project to move these motors with the arm attached.

All right, that being said, after you know what the differences between the two example projects, let's identify which joint is failing. If joint one is failing, you do not need to take the arm off if joint one is failing. If joint one is failing, that means that this shaft that goes through potentiometer one here, which is associated with joint one, that just needs to be lowered down. And you basically need to spin it until it goes back into the range that you want.

So we have some animations here in this article that kind of explain that. So again, dropping that shaft down so it's no longer attached to the base up here, which allows me to spin the potentiometer without affecting the base of the turntable. So once I do that and I drop that down, the next thing that I want to do is I want to turn the shaft with the potentiometer so that I get the range that is desired.

Now, when you're doing that, something that I do recommend is having either the arm install project actually on or the mastering on. It doesn't matter, as long as I can actually see the values on the screen. If you are using the arm install, you need to make sure you're in Coast because that means I can freely move anything on the arm and nothing's going to potentially break. It does not lock the motors. It does not move the motors. So being in Coast is a safe space to be.

Now, when I'm actually doing that, again, I want my arm to be facing forward. I don't want to actually spin this and then do all those changes and get an in master, and then this now be the home position. I need to actually have the arm centered. I need it to be facing the brain. And when I do that again, I'm going to drop that shaft down. I'm going to spin it, which is connected to the potentiometer until I get in the correct range. And then once I do that, I can put the shaft back into the base because everything is now back into master and then tighten the shaft collar that is associated again with that shaft.

So that is how I actually go through and fix joint one if it is out of master.

If joint one is failing, you do not need to take the top of the arm off because the only thing I'm concerned with is the potentiometer that's actually connected to the base of the Workcell there.

All right. Now, what happens if joints two through four are out of master? If joints two through four are out of master, they deal with these motors, these potentiometers, and the shafts associated with them on the top here of the base of the arm. If any of joints two through four are failing, then I do actually need to take the arm off.

So let's actually see what happens when I take the arm off and I mess with the whole, the Target, and all of the different options that I have here on the arm install project. All right, so what I did here was I actually took the shaft out that keeps the arm attached. That shaft goes through all of the different red gears here associated with the top part of the arm. It also aligns them to the gears in the actual base of the arm there. So I took that shaft out.

Again, that's the shaft that's going to hold everything together. Now, when you do that, notice that you do have a rubber band attached. You can either take that rubber band off if you want to take the arm off completely, or you can just set it here like I did. The only thing that you want to make sure of is that nothing is connected to these three gears here associated with joints two, three, and four. As long as these gears are still not attached to that, that's okay, you're good to go. So again, if you want to rest it next to it, that's perfectly fine, as long as nothing is touching these three gears here.

All right, so let's turn this back on. Now, I do recommend that when you are taking this off, you power everything down. You have to take the mastering jig out. And again, just be really careful if you need to unplug some motors or again, take this rubber band off, you absolutely can do that.

Now I'm going to get into the arm install project. I'm going to run that. I can see that everything is actually passing. Now let's talk about the three at the bottom here. I have some different options: Coast, Hold, and Target. Coast is going to allow me to freely move everything so I can actually spin these if I want to, I can actually spin those manually. Hold is going to lock all of these motors in place.

Hold is really helpful when I put the arm back on because if you can imagine, if I have everything set and mastered, if I put the arm back on and everything is free spinning, I can potentially knock something out of master by accident. So you want to put things in Hold when you're reattaching the arm back on. Finally, the third is Target. Target is going to actually spin these to put them into their correct master.

So I'm going to push a couple of these out of master right now. I pushed three and four out of master currently. Put these in Coast. All right, I knocked three and four and two. I knocked all three of them out of master. I basically just spun them until they're no longer in master. And when I hit Target, these are going to actually move and put themselves back into mastering range.

So when I hit Target, what's happening right now is that on the left, it says, pass. This yes or no means is it still currently moving? So as you can see here a little bit bigger. Again, Coast, Hold, and Target, is it passing or failing? That Y or N on the right side means is it still moving? You know, is it still turning those shafts, which is again associated with the potentiometer, the motor, and the associated gears that are on that shaft.

Once everything is completely done, you can see here on my brain screen, it's a little small, however, everything is passing now and everything is Y, which means that everything is done moving. So these actually moved.

Again, these shafts and the motors actually moved the shafts so that the potentiometer were in range. Now I'm going to put everything back in Hold. And then what I would do is I would put that arm back on. I would put the shaft back through and then everything would be back into master.

So one thing to note is that again, joints two through four, if those are out of master, there are a lot of things that you can check before you actually have to take the arm off. Use the arm install example project, and actually use Target to put them back into range.

So again, going through what are the steps that I need to check, what are the different troubleshooting steps that I should look for, and what is the process that I should go through to check to make sure if everything is mastered. And if something is out of master, what should I actually do in order to put it back into master?

I hope that all of this was helpful and I will see you in another video.

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