Guidance; Best Practices - Kauai Labs navX-MXP User Manual

Guidance

Best Practices

This page summarizes the recommended best practices when integrating navX-MXP with the
National Instruments RoboRIO™. Following these best practices will help ensure high reliability
and consistent operation.
1) Secure the navX-MXP circuit board to the Robot Chassis
Excessive vibration will reduce the quality of navX-MXP sensor measurements. The navX-MXP
circuit board should be
2) Plan for RoboRIO Brownouts
The RoboRIO contains circuitry to remove power from the MXP connector when it detects an
input voltage drop below a certain voltage level; this is known as a Stage 2 brownout. While
brownouts do not typically occur during a FRC match (since fresh batteries are typically used at
these times), during practice matches brownouts are common. If the robot drive chain draws
large amounts of current, even for a short time, brownouts could potentially occur even with a
FRC match.
navX-MXP maintains state information that will be reset when the navX-MXP circuit board is
restarted. Avoiding navX-MXP restarts is very important if your robot software uses the "yaw"
angle.
To avoid a navX-MXP restart when stage 2 brownouts occur, a secondary power supply for the
navX-MXP circuit board should be provided. Fortunately, the RoboRIO provides just such a
power supply, since its onboard USB interface is powered by a boost regulator which will
provide 5V of power even when the RoboRIO input voltage (VIN) drops as low as 4.4 volts
(once the RoboRIO VIN drops lower than this, the RoboRIO itself will restart).
To address this situation, simply connect a
RoboRIO; if a brownout does occur, the navX-MXP circuit board will automatically switch to use
power from the RoboRIO's USB port.
3) Understand and Plan for Calibration
Gyro/Accelerometer Calibration
understand this process, and ensure that it completes successfully each time you use the robot.
If your robot moves during calibration, or if noticeable temperature changes occur during
calibration, the calibration process may take longer than normal.
Guidance
Best Practices
mounted in such a way that it as firmly attached to the robot chassis.
USB cable
is vital to achieving high-quality navX-MXP readings. Be sure to
from the navX-MXP circuit board to the
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