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Unread 19-02-2015, 16:29
MattRain MattRain is offline
AZ FTC AF, FTC #2844 and FTC #8640
FRC #1492 (Team Caution)
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Re: [FTC]: Static issues. Solutions?

Quote:
Originally Posted by maths222 View Post
If I understand correctly, your symtoms are different from any I have observed when working with Tetrix robots. That said, would you be able to post any pictures of the affected encoders. Also, when this occurs, I assume you are moving forward using the encoders to measure distance. Does it behave as if the encoders were suddently reset to 0, and it therefore needs to move the whole distance again? I have noticed that the Tetrix motor controllers are relatively sensative to ESD, although in my experience, the whole controller tends to lock up, rather than the encoder counter simply reseting. I assume that the ESD passes through the encoder cable, into the motor controller, and causes the motor controller to reset itself. Due to the way the motor controller is designed, the controller keeps the count since the last reset, and then the NXT just reads that. Therefore, if it resets in the middle of the action, the encoder is set to 0. If there is a pause, it is probably because the controller needs to intitialize and recieve the command to set the motor power from the NXT.
Alright, interesting. Click on the link below in my sig, to the Trojan Robotics Twitter, it is currently the third picture on the page of the affected encoders. It is only during autonomous that this really applies. It just seems to reset the encoder, wether it be in the encoder itself, or the shock moving up through the wiring to the box. Our Autonomous is built on cases, which tell it to go a set amount of inches, until going onto the next case. Just seems to repeat the case when the shock happens. It only seems to happen while coming down the ramp or right off the ramp. The rest of the field, the robot seems fine.

Our next step is to rip out the tetrix motors, and replace with Andymark Motors, as the brother team, 2844, has them, and is shocking as well when coming down the ramp (2- or 3 shocks each time), but not being affected.
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Last edited by MattRain : 19-02-2015 at 16:32.
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