Originally posted by hexafraction
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Loss of usb device connection while running an OpMode
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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.
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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!
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Originally posted by sethmo View PostWe 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!
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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Originally posted by sethmo View PostThanks 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.
If you plan out your layout, you can get the connector directions that make the most compact layout.
Phil.
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