Quote:
Originally Posted by controls weenie
Right....I would like to see the 6V signal when the servos is trying to move a high inertia mass. I am guessing the 6V signal will drop from 5.7 to below 5.0  when there is a load on the servo. Can some of you RoboRIO owners try that ? We are designing a PWM extender (for servos and motors) that needs the 6V supply to stay above 5.3V.
Thanks, |
Fear not. This is an artifact of the back-drive protection on this supply. The current path passes through a diode when the load is low. When the current is detected to be enough greater than 0, a FET is switched on and the diode is bypassed. This means that at no load the output looks low, but as soon as there is a load, the voltage climbs to 6V.
Please see the attached image. This is a graph created using the new Power palette in WPILib (that's right, you can monitor this directly in the controller without external connections). I plugged in a servo, enabled, and then twisted the output shaft with my hand, forcing it to fight me and increase load on the power supply. You can see that under load the voltage increases, not decreases.