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VEX Robot Troubleshooting Flowcharts

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Is the

Game LED

flashing?

Do all

LEDs

flash Red in a

repeating

cycle?

Cortex

VEXnet LED

on?

Is the

Robot LED

blinking?

Fast

or slow

blink?

Is the

VEXnet LED

green?

Does

the Cortex

turn on?

Start

Single

or double

blink?

Do all

motors work

correctly?

Is the

robot lagging

or slow

to respond?

Is the

Robot LED on

the Cortex

consistently

red?

Check batteries and power connections. The battery connectors on the

Cortex can become bent open over time. If necessary, bend the connectors

back in to ensure a solid power connection.

Low or missing 9v backup battery. If in a

competition setting, install a fully charged

9v backup battery before continuing

Programming error. Try switching to the

Default Code which can be found within

your programming software. If this xes the

issue, return to your user code and attempt

to isolate the issue to a particular line of

code. The best way to do this is to comment

out various sections at a time and test after

each change.

If the units are still not correctly linked, refer to the

VEXnet Troubleshooting Flowchart in Section 3.

Robot battery is dead. Charge

or replace batteries before

continuing.

Fast

Single

Double

Slow

YES

Update the VEXnet Firmware (Master CPU Firmware

for ROBOTC users) on both the Cortex and the

Joystick using the Firmware Upgrade Utility included

with your programming software. If you do not have

programming software this utility is available on the

Downloads page at vexrobotics.com.

The Cortex is currently running an Autonomous Only user code.

If you want to use the VEXnet Joystick, download a VEXnet

Enabled project such as the Default Code using the USB A-A

Cable.

If your robot seems slow to respond while running user code, it is likely

that there is something in your program that is slowing down the loop time.

Check your code for any slow-to-execute commands (such as updating an

LCD screen or printing to a debugging window) that are set to run on every

cycle of a loop. A slow response time can also be the result of having too

many background tasks running at the same time. For further help with this

issue, we recommend posting a question on the VEX Forum (vexforum.com).

For questions regarding a competition robot, see the Competition Robot

Troubleshooting Flowchart in Section 2. If you need further assistance, you

can refer to the other guides or post a question on the VEX Forum (vexforum.

com). You can also contact VEX Technical Support by phone at +1-903-453-

0802 or email support@vexrobotics.com. Please note: for programming ques-

tions contact the developer of your programming software.

Wait 20 second…

Refer to the Motor

Troubleshooting

Flowchart in Section 4.

1. General Robot Troubleshooting Flowchart

08/11

Summary of content (4 pages)

PAGE 1
VEX Robot Troubleshooting Flowcharts 1. General Robot Troubleshooting Flowchart Start Does the Cortex turn on? Check batteries and power connections. The battery connectors on the Cortex can become bent open over time. If necessary, bend the connectors back in to ensure a solid power connection. NO YES Is the Robot LED on the Cortex consistently red? YES Is the Robot LED blinking? Fast or slow blink? YES NO NO Slow Robot battery is dead. Charge or replace batteries before continuing.
PAGE 2
VEX Robot Troubleshooting Flowcharts 2. Competition Robot Troubleshooting Flowchart Start Did your robot stop working during a match? When this happened, did all motors not connected to a Power Expander completely stop moving? YES YES Did the Robot LED on The Joystick turn red? NO The main battery on the robot was dead or had been disconnected from the Cortex. The Cortex was running on the 9V backup battery which is intended to only maintain the VEXnet link in case of main battery failure.
PAGE 3
VEX Robot Troubleshooting Flowcharts 3. VEXnet Troubleshooting Flowchart Start Do both units turn on? Check batteries and power connections. NO YES Is the Joystick LED red? Is the Joystick LED solid? YES NO Joystick batteries are dead. Replace batteries before continuing. YES NO Are both VEXnet LEDs on? Update the VEXnet Firmware (Master CPU Firmware for ROBOTC users) on both the Cortex and the Joystick using the Firmware Upgrade Utility included with your programming software.
PAGE 4
VEX Robot Troubleshooting Flowcharts 4. Motor Troubleshooting Flowchart Start Do the Motors spin at all? Are you using Motor Controller 29 Modules on all 2-wire motors plugged into ports 2-9 on the Cortex? NO YES NO In order to run a 2-Wire Motor off a 3-Wire PWM motor port you must use a Motor Controller 29 Module (276-2193) for each 2-wire motor. This motor controller acts as a converter between a 2-wire motor and a 3-wire motor port.