Go to Post After this trip, a person might want to change their underpants. - Andy Baker [more]
Home
Go Back   Chief Delphi > Technical > Electrical
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #9   Spotlight this post!  
Unread 21-02-2003, 07:31
Lloyd Burns Lloyd Burns is offline
Registered User
FRC #1246 (Agincourt Robotics)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Toronto
Posts: 292
Lloyd Burns is an unknown quantity at this point
Don't do it directly from a PWM port !

rust;

In asking about PWM and Amps, you seem to indicate you want to vary a voltage for a HEAVY load.

The PWM outputs on the RC give little pulses every so often, NOT a continuous steady voltage. I haven't checked the timing since the 98 season, but they give an approx 1 ms pulse every, perhaps, 26 ms.

The way to achieve your end is to use a translator that will handle the current, and take the PWM signal and turn it into a voltage level. One such device is currently available to you : it comes from a company called Innovation First, in Texas. It is called a Victor 884. It gives square waves with a duty cycle from near zero to 100 % (not a square wave, just continuous 12 V). If your load can take 12 V with an average viltage of your choice (for instance a lamp, but not a portable radar-on-a-chip with a requirement for filtered 5 V dc)) then this is the way to do it. Current reportedly up to 40 amps.

Connect it, and in your program, limit the pwm signal to the maximum you want, and don't go to the other side of 127, if your load is polarity-sensitive.
 


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
pwm 13-15 wayne 05 Programming 2 04-10-2003 12:08
PWM and burning out motors patrickrd Technical Discussion 7 19-06-2003 15:30
Fried program slots? Jeff Waegelin Programming 18 19-03-2003 18:08
power of globe motor with gear box? Ken Leung Motors 5 21-11-2001 13:43
Max mechanical power of motors, how is it useful? Ken Leung Motors 1 09-11-2001 14:15


All times are GMT -5. The time now is 22:45.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi