View Single Post
  #2   Spotlight this post!  
Unread 19-02-2012, 22:21
Kevin Sevcik's Avatar
Kevin Sevcik Kevin Sevcik is offline
(Insert witty comment here)
FRC #0057 (The Leopards)
Team Role: Mentor
 
Join Date: Jun 2001
Rookie Year: 1998
Location: Houston, Texas
Posts: 3,717
Kevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond reputeKevin Sevcik has a reputation beyond repute
Send a message via AIM to Kevin Sevcik Send a message via Yahoo to Kevin Sevcik
Re: Robot lose power when reverse directions?

First off, you HAVE to use the 12V to 5V converter on the special radio 12V output of the PDB. That's for legal and practical reasons. You won't pass inspection if you don't, and the 12V output is a boost power supply that will maintain 12V even if the battery voltage drops considerably.

Secondly, there's ways to check if it's a cRIO reset or a radio reset. The radio has status lights on the front that indicate whether it's connected, etc. These go through a pretty recognizable startup sequence which takes about 30 seconds. If you're losing control of the robot for 30 seconds, then you've reset your radio.

If you're losing control of the robot for about 10-15 seconds, you've reset your cRIO.

If you're losing driving control for about 2-3 seconds, then you've actually just tripped the over-current protection on your Jaguars.

Whichever of these it turns out to be, your problem is that you're drawing too much current from your batteries by rapidly switching from forward to reverse. You know that 133 amp stall current of the CIMs? If you're switching from full forward to full reserve, you're trying to draw DOUBLE of that. You won't be able to since that will draw your battery down to a ridiculously low level, but that's what you're attempting.

I'd suggest either modifying your program to ramp the speed down slowly, or engage the ramping function on your Jaguars. If you have new Black Jaguars (new as in you got them this year) then you can put them in ramping mode by turning the limit switch jumpers sideways. That will force the Jaguar to gradually ramp the voltage between commands, which should reduce or eliminate your problem.
__________________
The difficult we do today; the impossible we do tomorrow. Miracles by appointment only.

Lone Star Regional Troubleshooter