User Manual

Safety Recommendations
34 Advanced Digital Motor Controller User Manual V2.0, July 8, 2019
• Errors or oversights in user MicroBasic scripts
• Controller hardware failure
Motor Deactivation in Normal Operation
In normal operation, the controller is always able to turn off the motor if it detects faults or
if instructed to do so from an external command.
In case of wiring problem, sensor malfunction, firmware failure or error in user Microbasic
scripts, the controller may be in a situation where the motors are turned on and kept on as
long as the controller is powered. A number of features discussed throughout this manual
are available to stop motor operation in case of an abnormal situation. These include:
• Watchdog on missing incoming serial/USB commands
• Loss detection of Radio Pulse
• Analog command outside the valid range
• Limit switches
• Stall detection
• Close Loop error detection
• Other …
Additional features can easily be added using MicroBasic scripting.
Ultimately, the controller can be simply turned off by grounding the Power Control pin. As-
suming there is no hardware damage in the power stage, the controller output will be off
(i.e. motor wires floating) when the controller is off.
Important Warning:
While cutting the power to the motors is generally the best thing to do in case of
major failure, it may not necessarily result in a safe situation.
Motor Deactivation in Case of Output Stage Hardware Failure
On brushed DC motor controllers, the power stage for each motor is composed of 4
MOSFETs (semiconductor switches). In some cases of MOSFET failures, it is possible
that one or both motors will remain permanently powered with no way to stop them
either via software or by turning the controller off.
On brushless motor controllers, shorted MOSFETs will not cause the motor to turn on its
own. Nevertheless, it is still advised to follow the recommendations included in this sec-
tion.