Go to Post Actually, FIRST Is hoping the reverse, that your bot will be "Ball damage proof" - Rombus [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

 
Closed Thread
Thread Tools Rating: Thread Rating: 2 votes, 5.00 average. Display Modes
  #1   Spotlight this post!  
Unread 12-01-2014, 11:51
idooriane idooriane is offline
Electrical Head Team
FRC #1943 (NeatTeam)
Team Role: Electrical
 
Join Date: Jan 2013
Rookie Year: 2012
Location: Israel
Posts: 6
idooriane is an unknown quantity at this point
3 Jaguar to one input at the sidecar?

It's ok to connect 3 Jaguar to one input at the sidecar (With PWM-Y)?
__________________
Ido Oriane

FRC #1943 NeatTeam (2012 - Present)
Electrical Head Team #1943 (2013 - Present)
Programming Team C++ #1943 (2012 - Present)
Media Head Team (2012 - Present)
  #2   Spotlight this post!  
Unread 12-01-2014, 12:51
ohrly?'s Avatar
ohrly? ohrly? is offline
Griffin Alum
AKA: Colin Poler
FRC #1884 (The Griffins)
Team Role: Alumni
 
Join Date: Jan 2013
Rookie Year: 2011
Location: London
Posts: 58
ohrly? is an unknown quantity at this point
Re: 3 Jaguar to one input at the sidecar?

R67B expressly forbids controlling multiple Jaguars from a single PWM port on the digital sidecar.

Interestingly, I can't find anything that forbids multiple Victors or Talons from being controlled by the same PWM port [depending on whether "corresponding", in R66 implies "unique"]
  #3   Spotlight this post!  
Unread 12-01-2014, 13:01
CalTran's Avatar
CalTran CalTran is offline
MST Rolla Senior
FRC #2410 (BV CAPS Metal Mustang Robotics)
Team Role: College Student
 
Join Date: Apr 2010
Rookie Year: 2010
Location: Overland Park, Kansas
Posts: 2,418
CalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond reputeCalTran has a reputation beyond repute
Re: 3 Jaguar to one input at the sidecar?

Quote:
Originally Posted by ohrly? View Post
R67B expressly forbids controlling multiple Jaguars from a single PWM port on the digital sidecar.

Interestingly, I can't find anything that forbids multiple Victors or Talons from being controlled by the same PWM port [depending on whether "corresponding", in R66 implies "unique"]
Quote:
Originally Posted by R67 B.
PWM configuration: If the Jaguar motor controller is controlled via PWM communications, the PWM port on the
Jaguar motor controller must be connected directly to a PWM port on the Digital Sidecar with a PWM cable.
No other device may be connected to these PWM ports. No other device may be connected to any other port
on the Jaguar motor controller with the exception of connection to the coast/brake port or the limit switch ports.
Where in that does it "expressly" forbid using a Jaguar with a PWM-Y cable?
__________________
Team 2410 thinks KISSing is amazing! Keep It Super Safe!
  • "You know you've been in robotics too long when you start talking to your tools." "Well, you've been in robotics CLEARLY too long when they start talking back"
  • Theory is when you know everything but nothing works. Practice is when everything works but you don't know why. On our team, theory and practice comes together - nothing works and nobody knows why.
MMR 2410 Student (2010 - 2013) | MMR 2410 Mentor (2013 - Present)
FTC Game Announcer / EmCee (2014 - Present) | FRC EmCee (2015 - Present) | FRC Referee (2016) | FTC Referee (2017)
Academic Student (Forever)
  #4   Spotlight this post!  
Unread 12-01-2014, 13:07
otherguy's Avatar
otherguy otherguy is offline
sparkE
AKA: James
FRC #2168 (The Aluminum Falcons)
Team Role: Mentor
 
Join Date: Feb 2010
Rookie Year: 2009
Location: CT
Posts: 443
otherguy is a splendid one to beholdotherguy is a splendid one to beholdotherguy is a splendid one to beholdotherguy is a splendid one to beholdotherguy is a splendid one to beholdotherguy is a splendid one to beholdotherguy is a splendid one to behold
Re: 3 Jaguar to one input at the sidecar?

While I'm inclined to say this this is allowed, my only reservation is with R67. It's specific to Jaguars. Item B states:
Quote:
PWM configuration: If the Jaguar motor controller is controlled via PWM communications, the PWM port on the Jaguar motor controller must be connected directly to a PWM port on the Digital Sidecar with a PWM cable. No other device may be connected to these PWM ports. No other device may be connected to any other port on the Jaguar motor controller with the exception of connection to the coast/brake port or the limit switch ports.
The "directly" bit has me confused. I'm not sure what they are trying to prevent from happening here. Further, this rule only applies to Jaguars, so it would seem there's a specific concern with them. I would be surprised if they were actually trying to prevent PWM Y cables from being used as you have described.

It might be worth asking a question on the Q&A, as I wouldn't expect the use of PWM Y cables to be prohibited with any of the motor controllers.

FWIW Section 4 of wpilib screensteps live shows them being used with Jags...
__________________
http://team2168.org
  #5   Spotlight this post!  
Unread 12-01-2014, 13:08
EricH's Avatar
EricH EricH is online now
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 19,824
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: 3 Jaguar to one input at the sidecar?

Quote:
Originally Posted by ohrly? View Post
R67B expressly forbids controlling multiple Jaguars from a single PWM port on the digital sidecar.
I don't read R67B that way, necessarily, though I do see how you could draw that conclusion.

Quote:
B. PWM configuration: If the Jaguar motor controller is controlled via PWM communications, the PWM port on the Jaguar motor controller must be connected directly to a PWM port on the Digital Sidecar with a PWM cable.
Translation: Jaguar connected to PWM port--theoretically, using the Y-cable would be legal here, especially if the other end of the Y wasn't connected.
Quote:
No other device may be connected to these PWM ports.
Can't connect anything else--including another Jaguar that's powering a motor in the same gearbox? That's a ruling that would be pretty dumb, at least on the surface. I can see not having a Victor or Talon on the Jag ports, but not having two Jags? Also, having the Talons and Victors allowed to Y-cable but not the Jags doesn't make sense.

I'd say to ask Q&A whether R67B prohibits connecting Jags to the same PWM port via Y-cable, and if it does, what the reasoning is behind that, given that R66 seems to allow Talons, Victors, and Spikes to share PWM ports via Y-cable.


Of course, if you wanted to use CAN capability, you'd have no trouble connecting all the Jags you wanted in line...
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk

  #6   Spotlight this post!  
Unread 12-01-2014, 14:11
ohrly?'s Avatar
ohrly? ohrly? is offline
Griffin Alum
AKA: Colin Poler
FRC #1884 (The Griffins)
Team Role: Alumni
 
Join Date: Jan 2013
Rookie Year: 2011
Location: London
Posts: 58
ohrly? is an unknown quantity at this point
Re: 3 Jaguar to one input at the sidecar?

Quote:
Originally Posted by CalTran View Post
Where in that does it "expressly" forbid using a Jaguar with a PWM-Y cable?
Quote:
Originally Posted by R67B
B) PWM configuration: If the Jaguar motor controller is controlled via PWM communications, the PWM port on the Jaguar motor controller must be connected directly to a PWM port on the Digital Sidecar with a PWM cable. No other device may be connected to these PWM ports. No other device may be connected to any other port on the Jaguar motor controller with the exception of connection to the coast/brake port or the limit switch ports.
It is saying that if there is one jaguar connected to a PWM port, then nothing else (including a second jaguar) can be connected to the same PWM port. You are right, you can use a PWM Y-cable, if there is only one jaguar attached.

Quote:
Originally Posted by EricH
Also, having the Talons and Victors allowed to Y-cable but not the Jags doesn't make sense.
I agree. I would also like to know what their intentions are, and if indeed, we can use a single PWM port for multiple talons, spikes or victors.
  #7   Spotlight this post!  
Unread 12-01-2014, 15:34
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,125
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: 3 Jaguar to one input at the sidecar?

Quote:
Originally Posted by ohrly? View Post
Originally Posted by R67B
B) PWM configuration: If the Jaguar motor controller is controlled via PWM communications, the PWM port on the Jaguar motor controller must be connected directly to a PWM port on the Digital Sidecar with a PWM cable. No other device may be connected to these PWM ports. No other device may be connected to any other port on the Jaguar motor controller with the exception of connection to the coast/brake port or the limit switch ports.
Here's a possible interpretation which makes more sense: Perhaps the pronoun "these" in the sentence "No other device may be connected to these PWM ports" refers to the Jaguar PWM port, so the rule is intended to mean:
"No other device, such as an arduino, may be connected to the Jaguar's PWM input port".

  #8   Spotlight this post!  
Unread 12-01-2014, 16:19
nuttle nuttle is offline
Registered User
AKA: Allen Nuttle
FRC #4080
Team Role: Mentor
 
Join Date: Mar 2010
Rookie Year: 2009
Location: United States
Posts: 104
nuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud ofnuttle has much to be proud of
Re: 3 Jaguar to one input at the sidecar?

In the event this is determined to be within the rules, the question becomes one of the DSC PWM output being able to drive enough current to power the optoisolators on three Jags. The spec on the DSC says 15mA, so up to 5mA for each of the three Jags.

The spec for the Jag says 5mA typical current, but up to 25mA maximum current. Note that 25mA is over 15mA, so this maximum is a theoretical issue in any case.

Bottom line is that this should work electrically, but if you have the extra PWM outputs, just using these avoids any question, so long as you couple them in S/W.
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 19:19.

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