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  • Introduction
  • Getting Started with Control Hub
    • Connect to the Robot Controller Console
    • Updating Wi-Fi Settings
    • Connecting Driver Station to Control Hub
    • Wiring Diagram
    • Next Steps
  • Getting Started with Driver Hub
  • Adding More Motors
    • SPARKmini Motor Controller
    • Adding an Expansion Hub
  • Troubleshooting the Control System
    • General Troubleshooting
    • Control Hub Troubleshooting
    • Driver Hub Troubleshooting
      • Driver Hub Battery Troubleshooting
    • Expansion Hub Troubleshooting
    • Status LED Blink Codes
  • System Overview
    • Control Hub Specifications
    • Expansion Hub Specifications
    • Driver Hub Specifications
    • Port Pinouts
    • Protection Features
    • Cables and Connectors
      • XT-30 - Power Cable
      • JST VH - Motor Power
      • JST PH - Sensors and RS485
    • Integrated Sensors
    • Dimensions and Important Component Locations
  • Updating and Managing
    • Managing Wi-Fi on the Control Hub
    • REV Hardware Client
    • Updating Firmware
      • Firmware Changelog
    • Updating Operating System
      • Control Hub Operating System Changelog
    • Updating Robot Controller Application
      • Updating Robot Controller Application via Android Studio
    • Updating the Driver Hub
      • Driver Hub OS - Change Log
    • Accessing Log Files
    • Android Studio - Deploying Code Wirelessly
  • Hello Robot - Intro to Blocks Programming
    • Welcome to Hello Robot!
    • Where to Program - Client vs. Browser
      • What is an OpMode?
    • Setting up a Configuration
      • Common Errors in Configuration
    • Using a Gamepad
    • Part 1: Tackling the Basics
      • Tackling the Basics Directory - Blocks
      • Creating an OpMode - Blocks
      • Programming Essentials
      • Programming Servos
        • Programming Servo Basics
        • Using a Gamepad with a Servo
        • Programming Servo Telemetry
      • Programming Motors
        • Programming Motors Basics
        • Programming a Motor with a Gamepad
        • Programming Motor Telemetry
      • Programming Touch Sensors
      • Programming Color Sensors
        • Color Sensor Telemetry
        • Detecting Color
    • Part 2: Robot Control
      • Robot Control Blocks Directory
      • Programming Drivetrain Motors
      • Arcade Style TeleOp - Blocks
        • Establishing Variables in Blocks
        • Motor Power vs. Robot Movement
        • Programming Arcade Drive
      • Arm Control - Blocks
        • Adding a Limit Switch
      • Robot Control Full Program
    • Part 3: Autonomous and Encoders
      • ElapsedTime - Blocks
        • ElapsedTime Setup
        • ElapsedTime Logic
        • ElapsedTime - Multiple Movements
      • Encoder Basics
      • Drivetrain Encoders - Blocks
        • Converting Encoder Ticks to a Distance
        • Moving to a Target Distance
        • Setting Velocity
        • Turning the Drivetrain Using RUN_TO_POSITION
      • Arm Control with Encoders - Blocks
        • Estimating the Position of the Arm
        • Calculating Target Position
        • Using Limits to Control Range of Motion
    • Part 4: Going Beyond!
      • Exploring Functions
      • Programming Mecanum - Simplified
      • Programming Mecanum - Refined
  • Hello Robot - Intro to OnBot Java Programming
    • Welcome to Hello Robot!
    • Where to Program - Client vs. Browser
      • What is an OpMode?
    • Setting up a Configuration
      • Common Errors in Configuration
    • Using a Gamepad
    • Part 1: Tackling the Basics
      • Tackling the Basics Directory - OnBot
      • Creating an OpMode - OnBot
      • Programming Essentials
      • Programming Servos
        • Programming Servo Basics
        • Using a Gamepad with a Servo
        • Programming Servo Telemetry
      • Programming Motors
        • Programming Motor Basics
        • Programming a Motor with a Gamepad
        • Programming Motor Telemetry
      • Programming Touch Sensors
    • Part 2: Robot Control
      • Robot Control OnBot Java Directory
      • Programming Drivetrain Motors
      • Arcade Style TeleOp - OnBot Java
        • Establishing Variables in OnBot Java
        • Motor Power vs. Robot Movement
        • Programming Arcade Drive
      • Arm Control - OnBot Java
        • Adding a Limit Switch
      • Robot Control Full Program
    • Part 3: Autonomous and Encoders
      • ElapsedTime - OnBot Java
        • ElapsedTime Setup
        • ElapsedTime Logic
        • ElapsedTime - Multiple Movements
      • Encoder Basics
      • Drivetrain Encoders - OnBot Java
        • Converting Encoder Ticks to a Distance
        • Moving to a Target Distance
        • Setting Velocity
        • Turning the Drivetrain Using RUN_TO_POSITION
      • Arm Control with Encoders - OnBot Java
        • Estimating the Position of the Arm
        • Calculating Target Position
        • Using Limits to Control Range of Motion
  • Sensors
    • Introduction to Sensors
    • Digital
    • Analog
    • I2C
      • IMU
        • Orientating the IMU
      • Adding an External IMU to your Hub
    • Encoders
      • REV Motor Encoders
      • Through Bore Encoder
    • Using 3rd Party Sensors
      • Sensor Compatibility Chart
  • Useful Links
    • REV DUO Build System
  • Legacy Documentation
    • Configuring Your Android Devices
    • Expansion Hub with Android Device Robot Controller
      • Driver Station and Robot Controller Pairing
      • Wiring Diagram
      • Configuration
    • REV Hub Interface Software
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On this page
  • Common Indicators and their Solution Steps
  • Issues Connecting Control Hub to an Expansion Hub
  • XT30 Pins are Compressed
  • Firmware Update
  • USB Serial Converter Check
  • Expansion Hub Power Cycle
  • Still Need Assistance?

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  1. Troubleshooting the Control System

Expansion Hub Troubleshooting

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Last updated 11 months ago

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The following sections, "," provides common indicators of issues seen in the Expansion Hub. Think about what the potential indicators your Hub is currently exhibiting and consider the following questions:

  • Did you perform a firmware update before the Hub began to have issues?

  • What is the behavior of the Status LED on the Expansion Hub?

  • Is the Driver Station showing an error message 'Cant find the Expansion Hub Portal"?

  • Did the Robot Controller app open when you plugged in the RC phone and gave power to the Hub?

  • Are you experiencing issues with communication between a primary and secondary Hub?

If a path in this guide does not resolve the issue please contact REV Robotics Support at support@revrobotics.com

Common Indicators and their Solution Steps

  • The firmware update failed and the Hub is unresponsive

    • Try a

  • The LED on the Expansion Hub is not lighting up

    • Try a

  • The Hub is not being recognized or communicating with the phones

    • Try doing the

  • There are

Expansion Hubs purchased AFTER December 2021 no longer include an internal IMU

Issues Connecting Control Hub to an Expansion Hub

XT30 Pins are Compressed

The most common cause of a loose or wiggly XT30 port is compressed pins within the male XT30 connector on your Hub. Each pin of the male XT30 connector is made of 4 tines that should have a small amount of space between them. In the image below, the pin on the top has the correct amount of space and the bottom one is visibly compressed, however, an XT30 pin can still be too compressed even if there is visible space.

To help repair compressed XT30 pins, we recommend using an X-ACTO Knife or similar very thin blade to slightly separate the tines. Please use extreme caution when doing this repair as expanding the tines too far can cause the XT30 connector to not fit.

After slightly separating the tines, the male and female XT30 connectors should have a more secure connection.

Again, please remember that this repair needs to be done carefully, as overextending the tines of the XT30 connector can cause them to become weakened and hold their shape less. Because of the nature of this kind of damage or wear to your Hub, compressed or overextended pins are not covered under warranty.

Firmware Update

USB Serial Converter Check

  1. Plug your Expansion Hub into a Windows PC

  2. Open the Device Manager in Settings

  3. Click the arrow next to Universal Serial Bus Controllers

  4. Find USB Serial Converter under the menu

  5. If this is not present there maybe a larger issue with your hub. Email support@revrobotics.com with details of the steps you have taken so far and any order numbers for the Expansion Hub (if you have them)

If you are using a Mac you can use System Information in Lion or later (or System Profiler in Snow Leopard and earlier versions of Mac OS) in Spotlight (press ⌘ and Space ). The program is in /Applications/Utilities and is the tool to see the connected USB devices and other hardware details.

Expansion Hub Power Cycle

  1. Unplug the USB from your RC phone

  2. Power off the main robot switch (turn off 12V power from the Expansion Hub(s))

  3. Wait a few seconds

  4. Turn on the Main Robot Switch (supply 12V power to the Expansion Hub(s))

  5. On your RC phone, press the square button and the swipe to close the FTC RC app

  6. Plug your RC phone into the USB-- the FTC app should automatically open

    1. If the app doesn't automatically open, you do not have a good connection from the Expansion Hub to the Phone. Check your cables first, followed by the micro and mini USB connections.

Still Need Assistance?

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

The steps below utilize information provided in the article. Use this article to help you navigate as you run through the troubleshooting flowchart.

To update a Robot Controller check out the article on .

If you are attempting to connect two Expansion Hubs together please confirm that the first Expansion Hub is connected to the Robot Controller. From there change the Expansion Hub address. For information on how to change the Expansion Hub address check out the article.

Use the to .

Consider using some form of strain relief (like the or one of the many 3d printable options available on places like Thingiverse) to keep the USB-mini port from being damaged.

If the issues persist after applying the Retention Mount, try running through the procedure.

Need help getting the Log Files to send to REV Support? See for more information.

Adding an Expansion Hub
Updating the Robot Controller Application
FTC Wiki Using a Second Expansion Hub
REV Hardware Client
update the Expansion Hub
REV USB Retention Mount
Firmware Update
Firmware Update
The LED is still not lighting up
Hub Startup Procedure
issues seeing a secondary Expansion Hub
Downloading Log File
Common Indicators and their Solution Steps
Firmware Update
detail shot of the XT30 connector's tines. The top pin has tines that show the correct amount of space and the bottom pin shows a pin that's pins are compressed
close up of the Male XT30 port's tines being separated with an x-acto knife