Signal Wire Length

[Al Skierkiewicz]

Eric,
This is the rule in question...
<R68> A signal filter may be wired across motor leads or PWM leads. For the purposes of
inspection and rules compliance, such filters will not be considered custom circuits, and will
not be considered a violation of Rule <R53> or Rule <R67>. Acceptable signal filters are:
A. A one microfarad (1 μF) non-polarized capacitor may be applied across the power leads of
any motor on your ROBOT (as close to the actual motor leads as reasonably possible)
B. A ten kilo-ohm (10 kΩ) or larger resistor may be used as a shunt resistor in-line with the
PWM control signal feeding a servo.

In most cases you should not have an issue with a 7 foot PWM cable. Some teams have reported erratic camera behavior under certain conditions when running camera servo PWM cables next to/in parallel with high current motor wiring. The use of the above allowed filter methods have cured these issues in the past. Please be sure to insulate well if you use these methods. With the source impedance of the DSC the impedance on the PWM is fairly low and should not be a problem. Sensors in general, do not draw a lot of current unless there is a wiring error. However, there are some non-KOP sensors that can be found that use more current than allowed by simple #24 gage wiring. Those devices may need to be fed via #18 gage from a dedicated breaker on the PD. Know your sensors.