Thread: VEX inputs
View Single Post
  #19   Spotlight this post!  
Unread 20-05-2006, 10:34
skimoose's Avatar
skimoose skimoose is offline
Parent/Mentor/Engineer
AKA: Arthur Dutra
FRC #0228 (GUS)
Team Role: Electrical
 
Join Date: Jan 2005
Rookie Year: 2003
Location: Meriden, Connecticut
Posts: 568
skimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond reputeskimoose has a reputation beyond repute
Re: VEX inputs

Quote:
Originally Posted by Damien1247
I am attempting to play with pots but for some reason the pot reads a constant value even when it isnt plugged it. Im going to play with it today during class and ill post a result here before i leave today.
If you're getting a constant value even when the pot isn't "plugged in", you're reading the value across the coil. The analog value should be taken, and read across one side of the coil and the wiper terminal. The pot should be wired to the vex controller like this:

pot coil
+5V ____/\/\/\/\/\/\/\______ GND
|
wiper
|
SIGNAL

The pot coil leads are almost always the outside two terminals and should always read 100K ohms, or 5 volts if energized, across them. The wiper terminal is almost always the center terminal. If you measure resistance across the +5V and Signal the value will change as the pot is turned. If the pot is energized, you should be measuring a variable voltage across +5V and Signal. If you are wired correctly, and you are not getting the correct values, then the pot is failed, or you're not using a 100K pot. Correct wiring is +5V red PWM wire, signal white PWM wire, and GND black PWM wire. as the cable comes off the Vex controller's analog input.

Hope this helps.
__________________

2009 CT Regional Motorola Quality Award
2010 VRC Connecticut Championship Winners & Amaze Award
2010 VRC Championship Divisional Energy Award
2010 WPI Regional Winner
2010 WPI Regional Engineering Inspiration Award
2011 WPI Regional Chairman's Award
2012 WPI Regional Finalists
Reply With Quote