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Loss of usb device connection while running an OpMode

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  • Philbot
    replied
    Originally posted by sethmo View Post
    Thanks Tom. We are definitely going to clean up the wiring and strain relief all the cables. We are going to try some 90 degree mini u.s. cables as well to make things more compact.
    I've had a lot of success with the right-angle connectors from L-COM.com They come in all different directions.
    If you plan out your layout, you can get the connector directions that make the most compact layout.

    Phil.

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  • sethmo
    replied
    Thanks Tom. We are definitely going to clean up the wiring and strain relief all the cables. We are going to try some 90 degree mini u.s. cables as well to make things more compact.

    Leave a comment:


  • Tom Eng
    replied
    Originally posted by sethmo View Post
    We seem to have fixed our issue. We swapped out parts from our other team, started with motor controllers, then core power, but the issue still existed. We then moved on to cables, we swapped out a USB cable from the core power unit to a motor controller and the issue is now fixed! The "bad" USB cable looks fine, but it must have been giving a poor connection on one of the sides.

    We drove around for several minutes and made several attempts at bouncing up the mountain and we did not have a single disconnect. If your team is having disconnect issues, replace the USB cables between the Core Power Distribution Unit and the Motor Controllers!
    sethmo,

    I see another thing that you could improve... Your cables are not secured and strain relieved. They might vibrate (even if your robot is driving across the floor) and disconnect, particularly the cable that connects the phone to the POwer Distribution Module. You might want to see if you can secure your cables so that they are not floating in the air. Unlike the RJ-45 style connectors that the NXT used, the USB cables need to be secured (we like to use zip ties and zip tie the cables to the frame near the connection points into the phone or Core Modules).

    In general, what we have seen, if the robot stops with that type of comm error message, it's often a loose cable. The cables that you replaced might not necessarily be "bad" but they might have been loose. If you strain relieve them so the connection to the modules are secure, the might be OK to use.

    Tom

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  • sethmo
    replied
    We seem to have fixed our issue. We swapped out parts from our other team, started with motor controllers, then core power, but the issue still existed. We then moved on to cables, we swapped out a USB cable from the core power unit to a motor controller and the issue is now fixed! The "bad" USB cable looks fine, but it must have been giving a poor connection on one of the sides.

    We drove around for several minutes and made several attempts at bouncing up the mountain and we did not have a single disconnect. If your team is having disconnect issues, replace the USB cables between the Core Power Distribution Unit and the Motor Controllers!

    Leave a comment:


  • sethmo
    replied
    This is the issue that our team is facing:
    https://www.youtube.com/watch?v=UbDt6JMtpiQ

    It seems that any light vibration will kill the opmode and require a robot restart. We never had a single issue with vibrations with the NXT and old motor controllers. Any suggestions? I just sent out an email to Modern Robotics. We have a meet on Nov 7th, and I am afraid that we will not be able to compete unless this issue is resolved soon.

    Leave a comment:


  • Tom Eng
    replied
    Originally posted by hexafraction View Post
    Tom, I will post an image when I get a chance. I'm currently unable to physically access our robotics stuff until Tuesday due to timing and other factors. I'll contact MR then, since I need to get the part and serial numbers for the components we're having troubles with. My current hunch is catastrophic overcurrent or manufacturing error, but I would defer to your expertise once I can get the pics posted.
    Thanks hexafraction.

    Leave a comment:


  • hexafraction
    replied
    Originally posted by Tom Eng View Post
    hexafraction - could you post a pic of the gash? Have you contacted Modern Robotics?
    Tom, I will post an image when I get a chance. I'm currently unable to physically access our robotics stuff until Tuesday due to timing and other factors. I'll contact MR then, since I need to get the part and serial numbers for the components we're having troubles with. My current hunch is catastrophic overcurrent or manufacturing error, but I would defer to your expertise once I can get the pics posted.

    Leave a comment:


  • Tom Eng
    replied
    Originally posted by hexafraction View Post
    We're getting the same issue with our Legacy module. However, in our case it appears to be messing with the phone's USB chip as we need to disconnect the cable at the PHONE side (presumably to release the USB OTG sense pin and reset the USB chip). Happened at the same time when our PDM stopped providing USB. Opened it up and there was a large GASH through one of the ICs, straight to the leadframe. The PDM was never opened before then by us.
    hexafraction - could you post a pic of the gash? Have you contacted Modern Robotics?

    Leave a comment:


  • hexafraction
    replied
    Originally posted by btipton View Post
    We just had the same problem with the second motor controller we got when we originally purchased out set. Couldn't drive more than a couple of minutes without an error, then replaced the controller, and no problems so far.
    We're getting the same issue with our Legacy module. However, in our case it appears to be messing with the phone's USB chip as we need to disconnect the cable at the PHONE side (presumably to release the USB OTG sense pin and reset the USB chip). Happened at the same time when our PDM stopped providing USB. Opened it up and there was a large GASH through one of the ICs, straight to the leadframe. The PDM was never opened before then by us.

    Leave a comment:


  • btipton
    replied
    We just had the same problem with the second motor controller we got when we originally purchased out set. Couldn't drive more than a couple of minutes without an error, then replaced the controller, and no problems so far.

    Leave a comment:


  • Roborams
    replied
    Sudden Loss of Communication

    It looks like others have experienced this problem as well.

    We purchased a new motor controller, but that didn't solve the problem for us. It appears to be the USB connection in our case.

    Leave a comment:


  • mhaeberli
    replied
    blipton,
    We are seeing exactly the same problem. While we haven't confirmed down to the logcat level on all three, with all three of our PDMs. With each of our two motor controllers. In fact, logcat traces show the original failure attributed, on different occasions, to disconnects from different motor controllers.
    Thanks,
    Martin Haeberli
    Mentor, Team 7593 TigerBots

    Leave a comment:


  • btipton
    replied
    Yes, we haven't had any more disconnect issues while driving since replacing the motor controller. We're going to contact Modern Robotics this week about replacing the unit that seemed to be causing the problem.

    Leave a comment:


  • Roborams
    replied
    We started having the same problem last week. We have ordered a new motor controller? Did you get a chance to test further?

    Leave a comment:


  • btipton
    replied
    Problem solved! (probably?)

    Originally posted by Tom Eng View Post
    btipton,

    Good luck and let us know if you are able to resolve this issue.

    Tom
    The new motor controller worked today for about 4 hours without any issues, whereas before we would be lucky to go more than a minute or so without throwing an error. We're going to put the old (suspected bad) controller back in and test once more to make sure it really is the cause, but I'm 90% sure it was just a bad motor controller.

    Leave a comment:

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