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 Robotics / RCX / 2693
  different output power at different ports?
 
I just confirmed that some RCX happens to allow various output power to different output ports. In my case, the port A tends to produce more power thru motor and the port C does. I then switched the two motors. The condition stays the same. (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
(...) This might be a dumb question, but are we talking actual different voltage levels, or different PWM duty ratios? Have you ensured that you have set (from code) the power levels of all the ports to be the same? How have you observed the (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  RE: different output power at different ports?
 
(...) Without any precious hardware verification, this is what I did: - symptom: motor C was not able to make turn as well as motor A can - troubleshooting steps: a) to ensure even load on both motor ports, I removed all other attachments, and left (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  RE: different output power at different ports?
 
Sorry... I meant "precise hardware verification" not precious. I do not the equipment to measure them. Any suggestion, other than getting extra hardware like a power analyzer, for trouble shooting? Trouble shooting is always (well, almost always) (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
(...) Okay - did you try a simple program going in a straight line, and check how much it veered after a few meters? Unfortunately - it does not sound an entirely unlikely problem - if there are variations between the h-bridges (general (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  RE: different output power at different ports?
 
On Thu, July 14, 2005 10:12 am, Elizabeth Mabrey said: (...) well, I'm not a precious hardware guru, :) but I find it hard to believe the small difference in the electronics would make a noticeable difference in the output of the motors. If you're (...) (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
(...) This sounds to me like a good tactic. Your program might have some issue with turning in one direction vs another. (...) I also have trouble believing variations in parts (except the motors themselves) will cause this much difference. Ralph (19 years ago, 14-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
You're absolutely sure it's not a sticky wheel? Thomas (...) (19 years ago, 15-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
(...) Sounds like more friction in the drive mechanism to one wheel than the other. I've had the same problem with tank-driven robots. I was using the fast 9V motors geared down, but they were under-powered for the application. The friction in the (...) (19 years ago, 15-Jul-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)
 
  Re: different output power at different ports?
 
(...) I've discovered a thread in legofan (URL) that talks about new features of a possible RCX 3.0. Is there more information that can be handed out? - Dave (19 years ago, 22-Aug-05, to lugnet.robotics.rcx, lugnet.robotics.rcx.robolab)

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