RoboRIO Occasional Comm Issue

[agapedad]

Good morning - we are FRC team #5413. We have been practicing with our robot for about 2 weeks now.

We began having temporary comm loss issues when the robot would hit something hard or jostle. It was not every practice match, or every time we jostled.

Last week we put a piece of foam under the RoboRIO and the problem went away. We practiced every night last week beginning Monday, and all day Saturday with no issues. This week we started practicing on Monday, and we started having the problem again.

We have checked and rechecked all our wires. Nothing is loose. We do not lose any lights on the radio, and comm is only gone for about 20 seconds. Within 30 seconds we are able to re-enable driver station and start driving again without touching anything on the robot.

It appears that it is something in the RoboRIO that is acting like the reset button is getting pressed. If we simply do a quick press of the reset, it acts exactly the same way with the same timing.

Is there something in the accelerometer that would cause this, or is there something in the RoboRIO that would cause it to act like a reset button press?

Thank you!

Randy Allen

FRC Team #5413

[DAQjr]

I know you said that you checked the wires, but these sound exactly like a roboRIO power wiring issue.  Check for stray strands of wire that may be shorting.

[agapedad]

Thanks DAQjr...we checked the wires over last week. Last night when it started again, we went over our wires with a fine tooth comb. I was specifically looking for stray wires on the RoboRIO power. Everything looks perfect. None of our electronics mentors were able to find any wiring issues at all. This really has us puzzled.

[DAQjr]

The accelerometer just measures bumps, it does not have any affect on any behavior unless your code reads it and does something with the data.

You can check out the reset source after one of these events to verify that it is a power issue.  Run this from a shell (such as SSH or serial console): cat /sys/bus/i2c/devices/0-0040/reset_source

This will tell you what caused the most recent reset of the roboRIO.

Make sure that the power connector on the roboRIO is securely screwed down.

[agapedad]

Great...we'll do that tonight if we get a reset.

[agapedad]

DAQjr - we lost comm and ran that line from shell, but it said no such file or directory.

I am using putty and connected via ethernet...would you recommend another way of accessing? Am I missing something on the shell command?

[DAQjr]

Really? Where along the path do you lose the hierachy?

[agapedad]

Well - I have only messed with Linux a little...first time I tried just typing the 'cat' to work from there. It just sat there. I tried typing the complete command line and got the error...so it might have been operator error?

[jinlem]

Do this... http://www.ni.com/download/first-robotics-software-2015/5112/en/