Go to Post The first law of programming is that there are always ways of doing things quicker and in less space than you already are. - jgannon [more]
Home
Go Back   Chief Delphi > Technical > Programming > NI LabVIEW
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
  #1   Spotlight this post!  
Unread 09-02-2014, 01:23
popnbrown's Avatar
popnbrown popnbrown is offline
FIRST 5125 HOTH Lead Mentor
AKA: Sravan S
FRC #5125 (Hawks on the Horizon)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2007
Location: Illinois
Posts: 367
popnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond reputepopnbrown has a reputation beyond repute
First Programming - Victor/PWM help

So as a mentor this is my first step back into working on the control system. Unfortunately, I've been very out of touch with common issues and am having a difficult time diagnosing the issue that my team is having.

We've got a 4-motor powered 6WD, with each of the motors running off of Victor 888s.

Programming-wise we're using the Open 4 Motor vi in Begin to open up 4 motors and we are using the Tank Drive vi that's provided in the library. I should have gotten some screenshots in hindsight but it's a pretty straight-forward program.

By not-working below I mean blinking orange (like a no signal) and working meaning fully responding to the joystick for which it was correctly programmed.

So for a while our issue was that when the PWMs were set to 1,2,3,4 only PWM Channel 3 would work. So I switched the left motors (PWM 1 and PWM 3) and the right front victor (originally PWM 3) worked. However, I was unable to replicate this working with both PWM 1 and PWM 3.

I couldn't get that victor working on PWM 3 or PWM 1 again, so I flipped the PWMs for the right and left side. Then, PWM 3 (which was now on the front right motor) now started to work.

So I changed the PWMs to use 3,4,5,6 to see if it was a PWM Channel issue, but then none of them worked (and they still don't).

I decided to dig deeper into some of the WPI library. Clearly the joysticks were working and that was definitely indicated, and it also looked like the RobotDriveRef set up the 4 motors for the correct PWM Channels. However I was unable to Probe the Set Output vi to see if the value was actually accurately getting set to the right PWM Channel.

One of my leading theories was cables are not set in enough, but I've probably quadrupled checked them, and had two different students also put them in. The fact that two different victors worked and weren't consistent leads me to believe the issue is beyond just fitting wires. I'm semi ruling out bad PWM cables because of the fact that none of them work currently but did before. We also switched out one of the wires and it did not fix anything.

Any tips on how I can debug this or on what may be the problem?

I know this is hard to debug without being present or seeing things so please ask questions, I'll respond as quickly as I can.

My next experiment is going to be to image the cRIO and try this game all over again.

I'm going to have an orange light nightmare tonight.
__________________
I am an employee of FIRST. However, the postings on this site are of my own perspective as a FIRST mentor and volunteer and do not necessarily reflect the views of FIRST.

FIRST Team 5125 Hawks on the Horizon Lead Mentor
FRC Team 4096 Ctrl-Z Former Mentor
FTC Team 5203 #19@! Former Mentor
FRC Team 1403 Cougar Robotics Alumni
Reply With Quote
 


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


All times are GMT -5. The time now is 09:55.

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