Go to Post You never really graduate out of FIRST.... - Gnomegirl [more]
Home
Go Back   Chief Delphi > Technical > Programming
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
 
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 03-02-2012, 07:11
JohnFogarty's Avatar
JohnFogarty JohnFogarty is offline
Trapped under a pile of MECANUMS :P
AKA: @doctorfogarty
FTC #11444 (Garnet Squadron) & FRC#1102 (M'Aiken Magic)
Team Role: Mentor
 
Join Date: Aug 2009
Rookie Year: 2006
Location: Aiken, SC
Posts: 1,582
JohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond repute
Quote:
Originally Posted by wireties View Post
Why not use the encoder classes? They use the FPGA to process the encoder data.

HTH
By horrible I mean. There something seriously wrong with them. I've had other teams test it and they came back with the same results as me.
__________________
John Fogarty
2010 FTC World Championship Winner & 2013-2014 FRC Orlando Regional Winner
Mentor FRC Team 1102 M'Aiken Magic
"Head Bot Coach" FTC Team 11444 Garnet Squadron
Former Student & Mentor FLL 1102, FTC 1102 & FTC 3864, FRC 1772, FRC 5632, FRC 4901
2013 FTC World Championship Guest Speaker
  #2   Spotlight this post!  
Unread 03-02-2012, 08:02
Greg McKaskle Greg McKaskle is offline
Registered User
FRC #2468 (Team NI & Appreciate)
 
Join Date: Apr 2008
Rookie Year: 2008
Location: Austin, TX
Posts: 4,756
Greg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond reputeGreg McKaskle has a reputation beyond repute
Re: I woke up...and discovered CAN

Absolutely horrible is a pretty strong sentiment to place on something. This is a good opportunity to practice troubleshooting the elements you are using and tracking down the issue.

If you were reading them as digital inputs and doing your own logic for advancing or reversing the position, that should work if done properly, but it will only work for a slow progression. I suspect you are reading the pulses every few ms at best, and probably more like every 20ms +/- 5. If you have a 1024 pulse encoder, the 20ms sampling rate would start to fail at something like 1/80 rpm I think -- not very fast. By comparison, the fpga reads the digital inputs at a rock steady 6.xxx microseconds. I don't remember the number, but that is actually limited by the bus access time for the module. With a faster module, it could go far higher.

My initial advice would be to make a small test project using just an encoder example. spin the encoder by hand. If it is flaky, make sure that the issue isn't with the wiring, the digital breakout, or the sensor. Being the programmer, you are often the first to see that the system doesn't work, and since the system is complex, the issue could be any number of places. Being able to isolate parts of the system and determine if they are at fault is a valuable technique, and is actually fun once you become good at it.

Greg McKaskle
  #3   Spotlight this post!  
Unread 03-02-2012, 15:11
techhelpbb's Avatar
techhelpbb techhelpbb is offline
Registered User
FRC #0011 (MORT - Team 11)
Team Role: Mentor
 
Join Date: Nov 2010
Rookie Year: 1997
Location: New Jersey
Posts: 1,624
techhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond repute
Re: I woke up...and discovered CAN

The CAN bus and the Jaguars are a unique challenge. Many of the problems you'll see can be overcome fairly easily (once you find them)...but not if you're in a hurry. I don't encourage anyone with limits to their patience or available time to try them casually. You'll end up REALLY disliking them if you plan poorly for this and possibly a bit unfairly to them in general.

That being said...I don't advise people to fall asleep in: datasheets, on robots or in the box of the KOP. These would seem to be the places you'll most likely wake up and discover CAN. Safety first you know.

Last edited by techhelpbb : 03-02-2012 at 15:13.
  #4   Spotlight this post!  
Unread 03-02-2012, 19:18
sjspry sjspry is offline
Registered User
FRC #1984
Team Role: Programmer
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Kansas
Posts: 125
sjspry has a spectacular aura aboutsjspry has a spectacular aura aboutsjspry has a spectacular aura about
Re: I woke up...and discovered CAN

The only error I had been having is lack of connection to the cRIO. I can talk to it from the computer fine, but the cRIO Java implementation gives me an error message about the CAN interface not connecting. Otherwise, it seemed pretty self explanatory. (No, still haven't fixed it, nothing on the error message around).
Closed Thread


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 01:33.

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