View Single Post
  #1   Spotlight this post!  
Unread 30-01-2010, 23:49
technowizard12's Avatar
technowizard12 technowizard12 is offline
Programmer
AKA: Simon Orr
FRC #1072
Team Role: Programmer
 
Join Date: Jan 2010
Rookie Year: 2009
Location: San Jose, CA
Posts: 3
technowizard12 is an unknown quantity at this point
Exclamation Output signal failing problem fixed!

My team's been trying to solve a problem with the output signals switching rapidly on and off many times per second. We tested every component that we thought could possibly be causing this problem, replacing some of it which was faulty. Even after replacing our faulty bridge with a new one (for testing, unless FIRST deigns to let us use it for competition), switching between wired and wireless connections, disabling most every bit of the code going on the robot (to make sure that the cRIO wasn't being overtaxed, and thereby freaking out), checking the priorities of the VIs we were running (to see if any of them were hogging the processor), making sure that the watchdog wasn't malfunctioning, and was being properly fed (assuming proper operation), and checking to make sure that the issue wasn't caused by power supply, our eyes landed on the one thing left which could have gone wrong: the Classmate PC. We think that the problem was (well, still is. it just happens less often) caused by the low amount of RAM on the Classmate PC. The signal to the outputs failing, henceforth known as "flickering", was caused by the Classmate PC having senior moments, not being able to keep up with the data stream, and therefore placing farting in our data. Occasionally we get an error about the watchdog not being fed, which is still caused by the same thing. Attached is a graph of the current going to a single spike's signal wire. You'll see that the current drops to about once every twenty seconds. usually, this only lasts a couple milliseconds, although one burst of three events lasted three seconds.
Attached Files
File Type: pdf Spike Signal Graph.pdf (57.2 KB, 42 views)
Reply With Quote