Support » Pololu TReX Jr User’s Guide » 4. RC/Analog in Detail »
4.b. Channel Calibration
As was covered in Section 3.e, you can automatically calibrate your TReX Jr for your RC or analog controller. If this doesn’t prove sufficient for your needs, you can manually calibrate your TReX Jr for your controller by specifying the minimum, neutral, maximum, and deadband values for each channel. The TReX Jr can simultaneously store both a set of RC and a set of analog calibration parameters. The calibration parameters are in the units of the raw channel values: 0.4 us for RC, 4.89 mV for analog. In general, these parameters affect how the TReX Jr interprets the channel input values.
Perhaps most noticeably, these parameters help determine how the channel inputs affect the motors. Motor speed is scaled linearly (or parabolically, if the channel is set as parabolic using the “parabolic channels” configuration parameter) from 0 at a channel input of neutral+deadband to max speed at a channel input of maximum. In the other direction, motor speed goes from 0 at neutral-deadband to max speed at minimum. Motor speed is 0 for channel inputs between neutral-deadband and neutral+deadband, and motor speed is at a maximum for channel inputs greater than maximum or less than minimum. Motor direction is determined by the side of neutral the channel input is on, and notions of forward and reverse can be switched on a channel by channel basis using the “reversed channels” configuration parameter.