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Unread 25-01-2016, 09:56
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Greg Needel Greg Needel is offline
REVving up for a new season
FRC #2848 (All-sparks)
Team Role: Engineer
 
Join Date: Jan 2002
Rookie Year: 2002
Location: Dallas, TX
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Re: 3-way PWM Splitter

Quote:
Originally Posted by philso View Post
We confirmed with the manufacturer that we should not have been paralleling the inputs of the two types of motor controllers we had and that the LED VF's were the problem. Once we had only controllers of one type connected together, they all worked properly. We had no defective motor controllers.

Perhaps some of the motor controllers have a current limiting resistor in series with the LED. If the one with the lowest VF does not have a current limiting resistor, it will still prevent the other ones from turning on.
The SPARK has a 150 ohm series resistor with the optocoupler's LED. If you are curious about anything else inside the spark our complete schematic is in the back of our users guide on our website. http://www.revrobotics.com/wp-conten...1200-UM-00.pdf
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Greg Needel│www.robogreg.com
Co-founder REV Robotics LLC www.REVrobotics.com
2014 FRC World Champions with 254, 469, & 74