Pololu Simple - Manual (Page 20)

The Errors box in the Status tab of the Pololu Simple
Motor Control Center reveals problems that are stopping
your motor.
3.4. Errors
The Simple Motor Controller has several features
that stop the motor when something is going
wrong. These are called errors, and they can help
protect your project from damaging itself.
Whenever you are having an issue with the
controller, you should first check to see what (if
any) errors are occurring. You can get information
about the errors by:
• Checking the Errors box in the Status tab of
the Simple Motor Control Center. This is
recommended because it gives you the most
information, including a running count of how
many times the error has been reported.
• Running the command-line utility (just type
SmcCmd -s
at the command line).
• Looking at the red LED on the device. It will
be lit if there are any errors stopping your
motor.
• Writing PC software or using a
microcontroller to send the Get Errors serial
command.
• Using a microcontroller to measure the
voltage on ERR pin. This pin is linked to the
red LED so it should go high (3.3 V) when
there is an error stopping your motor and low
(0 V) otherwise.
All the errors are explained below:
• Safe start violation: Safe Start is a feature that helps prevent the motor from starting up unexpectedly. This
feature is enabled by default, but can be disabled in the Advanced Settings tab. The behavior of Safe Start
depends on what Input Mode you are using.
In Serial/USB input mode, the Safe start violation error occurs whenever any other error is stopping the motor.
After all the other errors have been fixed, you can clear the Safe start violation error by pressing the Resume
button (which issues a native USB command) or using a serial command.
In Analog or RC input mode, the Safe start violation error occurs whenever the motor is stopped because of an
error AND the inputs that control the speed of the motor are not near their neutral positions. This helps prevent
the situation where there might be an error stopping your motor (such as a disconnected battery), and the motor
starts running at a high speed when you fix the error. To clear the Safe start violation error, move all the inputs
that control the speed of the motor to their neutral positions (the sum of the absolute values of their scaled values
must be less than 8 %).
• Required channel invalid: This error occurs whenever any required RC or Analog channel is invalid. This
error helps ensure that your motor will stop if you accidentally disconnect your joystick, potentiometer or RC
receiver. A channel is invalid if it is disconnected, or has a value that is out of range. A channel is required if it
controls the speed of the motor or it is configured as a limit switch or kill switch. By default, there are no required
channels because the input mode is serial and no limit or kill switches have been configured. You can check the
Pololu Simple Motor Controller User's Guide © 2001–2014 Pololu Corporation
3. Getting Started Page 20 of 101