There are common errors that you may encounter when building and/or coding the VEX V5 Workcell. This article will address some common errors and questions about the VEX V5 Workcell and will outline the process to resolve each error. Use the navigation in the article to skip to the question that most accurately reflects your issues.

With every change that you make, be sure to test and see if the change resolved your problem. Frequent iterative testing can help you to identify exactly where the issue is and what single step is needed to resolve the issue. This can also help you and your students to master this troubleshooting process and potentially avoid issues in the future.

Note: This article assumes that the V5 Workcell Arm has been built correctly. Before beginning, compare your arm to the build instructions linked here. Check for details such as the size of spacers, and screws, etc.


V5 Workcell Arm Not Moving Accurately?

When completing activities in the STEM Labs, you may encounter issues with the arm not moving as expected. Follow the steps below to determine where the error may lie. These same steps apply when the arm is not moving at all.

Mastering Values

The first thing that always needs to be checked with the Workcell is the mastering values.

Values need to be collected every single day when you use the Workcell. These values may change if you pick up and move a Workcell from one location to another in the classroom and jostle the machine in the process.

With each change that you make in VEXcode V5, make sure that you download and run the project. This will help determine what change solved the issue and can help inform your next steps.

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First, gather your mastering values. Run the ‘Arm Mastering’ project in VEXcode V5. For steps on how to open, download, and run this project on your Workcell, see the Play section linked here.

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If any of your joints are out of master and listed as “Failing,” follow the steps in this article to remaster those joints.

If one of your joints will not move into passing, there may be an issue with your build. Continue to follow the steps below to determine the error.

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Once all of your joints are passing, record those values and ensure that these values are in your VEXcode V5 project.

Cables

Cables are a frequent cause of errors. Organized cables can make troubleshooting faster and prevent future errors. Consider using zip ties to create organized cable sections.

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Check that all Smart Cables are plugged into the correct port on the Brain and match the port in this table.

A 3-D model of the Workcell arm is also available on this page.

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You can ensure that a Smart Cable is plugged in and working correctly by turning on the Brain. When the Brain is on, the light in the Smart Port of the motor will glow red.

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All 3-Wire cables need to be checked as well. First, verify that the cables coming from the potentiometers are tightly fastened to the 3-Wire Extenders.

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Then, verify that the 3-Wire Extenders are plugged into the correct port on the Brain and match the ports in this diagram.

Trace each 3-Wire cable from the potentiometer directly to the port on the Brain to ensure the potentiometers and ports match.

Potentiometers

The V5 Workcell uses potentiometers to know the position of the joints at all times.
Failure of a potentiometer would prevent the arm from understanding its current physical location and may cause damage to the Workcell or the arm itself.

If your arm will not master and your motors and cables are correct, the problem likely lies within your potentiometers.

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Use the Devices Screen to check your potentiometers.

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First, open the Devices Screen and verify that ports A - D are showing values.

If any of these ports are not showing values above 0%, check the 3-Wire Extenders. They need to be firmly seated in the ports and connected to the 3-Wire cables coming from the potentiometers.

If ports A-D are showing values, look at the values being reported.

Manually move the arm slowly within its range of motion. Watch the values of each potentiometer change in real time on the Brain screen as the arm is moving. The values should change in a predictable and continuous pattern.

If the shaft is continuing to rotate while you are mastering the arm or the values are jumping wildly when moving the arm, the potentiometer may need to be replaced. Contact VEX Support: support.vex.com.

Screws

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Ensure the screws on your Workcell are not overtightened.

Overtightened screws located on any component necessary to arm movement adds extra resistance.

Use the video in this article for reference on how to secure nuts and screws when working with V5 pieces.

Rubber Bands

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If you notice that your V5 Workcell’s arm is not moving accurately, shaking, or generally not moving in a smooth manner, the rubber bands may not be installed correctly, or may be missing.

Follow the steps in this article for aid when installing the V5 Workcell rubber bands.

VEXcode V5

If the mastering values, hardware, and cables all seem to be correct, check your VEXcode V5 project.

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Be sure that your latest mastering values are in your VEXcode V5 project.

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If you have an Enable manual movement block in your project, it will override all other movement blocks. Remove this block from your project and try again.

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The Set end effector block should be set to the end effector you are using with the Workcell. This will change the location of the tool center point (TCP) for the arm and impact the z-coordinates reported.


V5 Workcell Arm Shaking?

Motors

If your robot appears to be shaking, you may have the incorrect motors installed on the arm.

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Ensure you are using the 11W Smart Motor, NOT the 5.5W smaller motor. This error will cause the arm to shake.

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After verifying that you have the correct motors on the arm, be sure to remaster your arm and use the new values in your VEXcode V5 project.

Screws

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Ensure the screws on your Workcell are not overtightened.

Overtightened screws located on any component necessary to arm movement adds extra resistance.

Use the video in this article for reference on how to secure nuts and screws when working with V5 pieces.

Rubber Bands

Screenshot 2024-03-18 at 11.52.00 AM.png

If you notice that your V5 Workcell’s arm is not moving accurately, shaking, or generally not moving in a smooth manner, the rubber bands may not be installed correctly, or may be missing. 

Follow the steps in this article for aid when installing the V5 Workcell rubber bands.


V5 Workcell Arm Having Trouble Moving Side to Side?

When looking for specific movements from the arm, you can start to determine which joint may be the problem. Moving side to side indicates that the issue may be with Joint 1, which is connected to the movement of the turntable.

Mastering Values

The first thing that always needs to be checked with the Workcell is the mastering values.

Values need to be collected every single day when you use the Workcell. Values may also change if you pick up and move a Workcell from one location to another in the classroom and jostle the machine in the process.

With each change that you make in VEXcode V5, make sure that you download and run the project. This will help determine what change solved the issue and can inform your next steps.

image8.png

First, gather your mastering values. Run the ‘Arm Mastering’ project in VEXcode V5. For steps on how to open, download, and run this project on your Workcell, see the Play section linked here.

image17.png

If any of your joints are out of master and listed as “Failing,” follow the steps in this article to remaster those joints.

If one of your joints will not move into passing, there may be an issue with your build. Review the Electronics section below.

image2.png

Once all of your joints are passing, record those values and ensure that these values are in your VEXcode V5 project.

Cables

Cables are a frequent cause of errors. Organized cables can help to make troubleshooting faster and prevent future errors. Consider using zip ties to create organized cable sections.

image11.png

image13.png

Check that all Smart Cables are plugged into the correct port on the Brain and match the port in this table.

A 3-D model of the Workcell arm is also available on this page.

image6.jpg

You can ensure that a Smart Cable is plugged in and working correctly by turning on the Brain. When the Brain is on, the light in the Smart Port of the motor will glow red.

image18.png

All 3-Wire cables need to be checked as well. First, verify that the cables coming from the potentiometers are tightly fastened to the 3-Wire Extenders.

image4.png

Then, verify that the 3-Wire Extenders are plugged into the correct port on the Brain and match the ports in this diagram.

Trace each 3-Wire cable from the potentiometer directly to the port on the Brain to ensure the potentiometers and ports match.

Turntable

If your robot still appears to have issues turning side to side, there is a possibility that something is incorrect in your turntable.

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Make sure the rubber band is attached and in the correct position. If it is not, there can be extra friction that makes the turntable movement more difficult.

Follow the steps in this article for aid when installing the V5 Workcell rubber bands.

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If your mastering values are within range, your Workcell may not be accurate and may shake because you need to lubricate your turntable.

An unlubricated turntable causes Joint 1 to account for extra resistance.

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If the four screws securing the turntable to the standoffs are too tight, there also may be more resistance.

Use the video in this article for reference on how to secure nuts and screws when working with V5 pieces.

Potentiometers

The V5 Workcell uses potentiometers to understand joint positions at all times.
Failure of a potentiometer would prevent the arm from understanding its current physical location and may cause damage to the Workcell or the arm itself.

If your arm will not master and your motors and cables are correct, the problem likely lies with your potentiometers.

image1.jpg

Use the Devices Screen to check your potentiometers.

image12.png

First, open the Devices Screen and verify that ports A - D are showing values.

If any of these ports are not showing values above 0%, check the 3-Wire Extenders. They need to be firmly seated in the ports and connected to the 3-Wire cables coming from the potentiometers.

If ports A-D are showing values, look at the values being reported.

Manually move the arm slowly within its range of motion. Watch the values of each potentiometer change in real time on the Brain screen as the arm is moving. The values should change in a predictable and continuous pattern.

If the shaft is continuing to rotate while you are mastering the arm or the values are jumping wildly when moving the arm, the potentiometer may need to be replaced. Contact VEX Support: support.vex.com.


V5 Workcell Arm Not Staying In Master?

The V5 Workcell uses potentiometers to understand joint positions at all times.
Failure of a potentiometer would prevent the arm from understanding its current physical location and may cause damage to the Workcell or the arm itself.

Values need to be collected every single day when you use the Workcell. Values may also change if you pick up and move a Workcell from one location to another in the classroom and jostle the machine in the process.

Mastering Values

Begin by mastering the arm and gathering the mastering values.

With each change that you make in VEXcode V5, make sure that you download and run the project. This will help determine what change solved the issue and can help inform your next steps.

image8.png

Run the ‘Arm Mastering’ project in VEXcode V5. For steps on how to open, download, and run this project on your Workcell, see the Play section linked here.

image17.png

If any of your joints are out of master and listed as “Failing,” follow the steps in this article to remaster those joints.

If one of your joints will not move into passing, there may be an issue with your build. Move to the Electronics section below.

image2.png

Once all of your joints are passing, record those values and ensure that these values are in your VEXcode V5 project.

Cables

Cables are a frequent cause of errors. Organized cables can help to make troubleshooting faster and prevent future errors. Consider using zip ties to create organized cable sections.

image11.png

image13.png

Check that all Smart Cables are plugged into the correct port on the Brain and match the port in this table.

A 3-D model of the Workcell arm is also available on this page.

image6.jpg

You can ensure that a Smart Cable is plugged in and working correctly by turning on the Brain. When the Brain is on, the light in the Smart Port of the motor will glow red.

image18.png

All 3-Wire cables need to be checked as well. First, verify that the cables coming from the potentiometers are tightly fastened to the 3-Wire Extenders.

image4.png

Then, verify that the 3-Wire Extenders are plugged into the correct port on the Brain and match the ports in this diagram.

Trace each 3-Wire cable from the potentiometer directly to the port on the Brain to ensure the potentiometers and ports match.

Potentiometers

If your arm will not master and your motors and cables are correct, the problem likely lies with your potentiometers.

image1.jpg

Use the Devices Screen to check your potentiometers.

image12.png

First, open the Devices Screen and verify that ports A - D are showing values.

If any of these ports are not showing values above 0%, check the 3-Wire Extenders. They need to be firmly seated in the ports and connected to the 3-Wire cables coming from the potentiometers.

If ports A-D are showing values, look at the values being reported.

Manually move the arm slowly within its range of motion. Watch the values of each potentiometer change in real time on the Brain screen as the arm is moving. The values should change in a predictable and continuous pattern.

If the shaft is continuing to rotate while you are mastering the arm or the values are jumping wildly when moving the arm, the potentiometer may need to be replaced. Contact VEX Support: support.vex.com.


If you still are unable to get your VEX V5 Workcell to work as intended after following all of the steps provided in this article, contact VEX Support: support.vex.com.

For more information, help, and tips, check out the many resources at VEX Professional Development Plus

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