Go to Post You can build bridges, or you can burn them. The choice is yours. - dlavery [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 Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 17-02-2013, 15:30
Hoogyme Hoogyme is offline
Registered User
FRC #2852
 
Join Date: Feb 2013
Location: St. Catharines, ON
Posts: 1
Hoogyme is an unknown quantity at this point
How many servos can be powered off a single PWM terminal on the Sidecar?

I found this answer from 2009: http://forums.usfirst.org/showthread.php?t=11822

I'm wondering if this is still the case.
  #2   Spotlight this post!  
Unread 18-02-2013, 13:53
toastnbacon toastnbacon is offline
Registered User
AKA: James
FRC #3169 (Saintborgs)
Team Role: College Student
 
Join Date: Jan 2010
Rookie Year: 2010
Location: Edmond
Posts: 97
toastnbacon is a jewel in the roughtoastnbacon is a jewel in the roughtoastnbacon is a jewel in the roughtoastnbacon is a jewel in the rough
Re: How many servos can be powered off a single PWM terminal on the Sidecar?

As far as I'm aware. One device per port tends to be the standard.
__________________
"This must be what going insane feels like."-Simon Tam, Firefly
  #3   Spotlight this post!  
Unread 18-02-2013, 14:07
EricVanWyk EricVanWyk is offline
Registered User
no team
 
Join Date: Jan 2007
Rookie Year: 2000
Location: Boston
Posts: 1,597
EricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond repute
Send a message via AIM to EricVanWyk
Re: How many servos can be powered off a single PWM terminal on the Sidecar?

I couldn't find a rule that explicitly ruled in one direction or the other.

R54 was the closest I could find:
Quote:
Servos must be directly connected to the PWM ports on the Digital Sidecar. They must not be connected to motor controllers or relay modules.
  #4   Spotlight this post!  
Unread 18-02-2013, 15:01
Andy A. Andy A. is offline
Getting old
FRC #0095
Team Role: Coach
 
Join Date: Jun 2001
Rookie Year: 2001
Location: New Hampshire
Posts: 1,017
Andy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond reputeAndy A. has a reputation beyond repute
Re: How many servos can be powered off a single PWM terminal on the Sidecar?

Quote:
Originally Posted by EricVanWyk View Post
I couldn't find a rule that explicitly ruled in one direction or the other.

R54 was the closest I could find:
Eric- is it correct to assume that the DC power pins on the PWM ports are all supplied by the same source? In other words, is there any performance difference between using a Y cable or separate ports for each servo (possible signal issues aside)?
  #5   Spotlight this post!  
Unread 18-02-2013, 15:11
EricVanWyk EricVanWyk is offline
Registered User
no team
 
Join Date: Jan 2007
Rookie Year: 2000
Location: Boston
Posts: 1,597
EricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond repute
Send a message via AIM to EricVanWyk
Re: How many servos can be powered off a single PWM terminal on the Sidecar?

Quote:
Originally Posted by Andy A. View Post
Eric- is it correct to assume that the DC power pins on the PWM ports are all supplied by the same source? In other words, is there any performance difference between using a Y cable or separate ports for each servo (possible signal issues aside)?
Your assumption is correct. All of the 6V power pins are directly tied together with nothing separating them. Power wise, a Y-cable really shouldn't have a measurable* effect.

I haven't tested signal effects, but most servos are not opto-isolated and therefore don't consume measurable signal current.


* Assuming that extra cable length is 50mOhms and 800mA draw at stall, you losing 40mV above what you would with separate power pins, which amounts to less than a 1% performance difference - and this is an extremely conservative estimate. I would imagine that it would be swamped by measurement accuracy and part-to-part variability.
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 20:07.

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