Pololu Simple - Manual (Page 21)

Input Settings tab to see which channels are required. Channels that are required and invalid are highlighted in
red in the Input Channels box of the Status tab so you can quickly see which channel is causing this error.
• Command timeout: This error occurs if you are controlling your motor using a microcontroller or a
PC (Input Mode is Serial/USB) and the (configurable) time period has elapsed with no valid serial or USB
commands being received by the controller. The purpose of this error is to ensure that your motor will stop if
the software talking to the controller crashes or if the communications link is broken. All valid serial commands
clear this error. The native USB commands for setting the speed and exiting safe start also clear this error.
By default, this error is disabled, but it can be enabled from the Advanced Settings tab by setting a non-zero
Command Timeout value.
• Limit/kill switch: This error occurs when a limit or kill switch channel stops the motor. More specifically, it
occurs in three cases: when a kill switch is active, when a Forward Limit switch is active AND the Target Speed
is positive, or when a Reverse Limit switch is active AND the Target Speed is negative. A limit/kill switch is
considered active if its scaled value is above 50 %. If you are using a limit switch and your input mode is Serial/
USB, you will need to check the Count column in the Status tab to see this error because in Serial/USB mode
the Target Speed gets set to 0 whenever there is an error.
• Low VIN: This error occurs whenever your power supply’s voltage is too low or it is disconnected. If you
set the correct thresholds in the Advanced Settings tab, this error will prevent you from over-discharging your
battery.
• High VIN: This error occurs whenever your power supply’s voltage is too high. You can set the threshold
voltage in the Advanced Settings tab.
• Motor driver error: This error occurs whenever the motor driver chip reports an under-voltage or over-
temperature error (by driving its fault line low).
• Over temperature: This error occurs whenever the reading from the temperature sensor is too high. You can
see the temperature reading in the Conditions box of the Status tab. The behavior of this error and the threshold
temperatures can be configured in the Advanced tab.
• ERR line high: This error occurs whenever there are no other errors but the voltage on the ERR line is high
(2.3–5 V). This error allows you to connect the error lines of two Simple Motor Controllers together and have
both of them stop when either one experiences an error. This error can be disabled in the Advanced Settings tab.
• Serial errors: Serial errors are recorded whenever something goes wrong with the serial communication,
either on the RX/TX lines or on the USB virtual COM port. If the input mode is Serial/USB, then a serial error
will stop the motor from running until a valid serial command is received, or the Resume button is pressed, or the
native USB Set Speed or Exit Safe Start commands are sent. If you are using serial and have not disabled Safe
Start mode, you will need to send the Exit Safe-Start command, followed by a Set Speed command to recover
from an error and get the motor running again. If you are using serial and have disabled Safe Start, the motor
will start driving as soon when a valid Set Speed command is received. These are the types of serial errors that
are recorded:
◦ Frame: This is error occurs when a de-synchronization or excessive noise on the RX line is detected.
◦ Noise: This error occurs when noise is detected on the RX line.
◦ RX overrun: This error occurs when the buffer for storing bytes received on the RX line is full and data
was lost as a result. This should not occur during normal operation.
◦ Format: This error occurs if the serial bytes received on RX or the virtual COM port do not obey the
protocol specified in this guide. If you get this error, check the bytes you are sending carefully, and compare
them to the examples provided.
◦ CRC: This error occurs if you have enabled cyclic redundancy check (CRC) for serial commands, but
the CRC byte received was invalid. CRC helps prevent the motor controller from accidentally performing
unwanted actions when it is receiving commands over a noisy serial link. If you get this error, check your
algorithm for calculating CRCs and check the quality of your serial signal at the RX pin.
Pololu Simple Motor Controller User's Guide © 2001–2014 Pololu Corporation
3. Getting Started Page 21 of 101