Pololu Simple - Manual (Page 46)

The primary use of mixing is for controlling a motor on a differential drive robot. You can use one Simple Motor
Controller for each motor on the robot, and feed the same inputs in to both of them. We recommend connecting the
throttle (forward/reverse) input to channel 1, and the steering (left/right) input to channel 2.
• None: In this mixing mode, the Target Speed is calculated as a function of the Scaled Value of the first channel
only (Analog Channel 1 or RC Channel 1).
• Left (+): In this mixing mode, the Target Speed is calculated as a function of the sum of the Scaled Value of
both channels.
• Right (-): In this mixing mode, the Target Speed is calculated as a function of the difference of the Scaled
Value of both channels (channel 1 minus channel 2).
Note that in RC and Analog mode, the Target Speed depends not only on the Scaled Values of the channels, but also
on the Starting Speed and Max Speed parameters, as explained in
Section 5.2 .
The table below summarizes all the input and mixing modes you can choose:
Input
Mode Mixing
Mode
Motor speed is calculated from… Example Applications
Serial/
USB
N/A Serial and/or USB commands
Motor controlled by microcontroller or
PC.
Analog None Analog Channel 1 Motor controlled by joystick.
Analog Left (+)
Analog Channel 1 plus Analog
Channel 2 Differential drive vehicle controlled by
joystick.
Analog Right (-)
Analog Channel 1 minus Analog
Channel 2 Differential drive vehicle controlled by
joystick.
RC None RC Channel 1 Electronic Speed Controller (ESC).
RC Left (+) RC Channel 1 plus RC Channel 2 Differential drive RC vehicle.
RC Right (-) RC Channel 1 minus RC Channel 2 Differential drive RC vehicle.
The settings on the bottom half of the Input Settings tab are all channel-specific settings. To view or edit them, you
must first select the desired channel using the list box in the bottom left corner.
Alternate Use
The Alternate Use setting allows you to configure any channel that is not used to control the speed of the motor as a
limit or kill switch. The available options are:
• None: This channel will not be used for anything special, but its Raw and Scaled values can be read using
serial or USB.
• Forward limit switch: When the scaled value of the channel is above 1600 (50%), the limit switch will be
considered active and the motor will not be allowed to move forward. If the target speed is positive, a “Limit/kill
switch” error will occur.
• Reverse limit switch: When the scaled value of the channel is above 1600 (50%), the limit switch will be
considered active and the motor will not be allowed to move in reverse. If the target speed is negative, a “Limit/
kill switch” error will occur.
• Kill switch: When the scaled value of the channel is above 1600 (50%), the kill switch will be considered
active and the “Limit/kill switch” error will occur, preventing the motor from moving. For example, you
Pololu Simple Motor Controller User's Guide © 2001–2014 Pololu Corporation
5. Configuring Your Motor Controller Page 46 of 101