PWM Duty Cycle [Archive]

Bpk9p4

25-01-2015, 20:10

Does anyone know how to read a PWM duty cycle on the roborio?

Ether

25-01-2015, 20:16

Does anyone know how to read a PWM duty cycle on the roborio?

Some teams filter it to create an analog signal proportional to duty cycle, then run it into an analog input.

http://www.chiefdelphi.com/forums/showthread.php?p=1432868#post1432868

DonRotolo

26-01-2015, 17:09

Bear in mind that duty cycle is not the salient value in a PWM signal used for controlling motors in FRC. Instead, we use pulse width, varying from about 1.5 mSec to about 2.5 mSec, with varying amounts of time between pulses depending on which motor controller is being used.

I know you know this, but for others reading this thread in the future they should be aware of this detail.

Ether

26-01-2015, 17:20

Bear in mind that duty cycle is not the salient value in a PWM signal used for controlling motors in FRC. Instead, we use pulse width, varying from about 1.5 mSec to about 2.5 mSec, with varying amounts of time between pulses depending on which motor controller is being used.

I know you know this, but for others reading this thread in the future they should be aware of this detail.

Another detail to be aware of:

The US Digital MA3 and Austria Microsystems AS5145 encoder datasheets recommend duty cycle -- not pulse width -- decoding of their PWM signal outputs.