Periodic connection loss to D-link

[TBots]

For the past few weeks that we've been testing our robot, we've been having some major difficulties keeping a connection to the D-link. Our dashboard will flicker between teleop disabled and teleop enabled, even while we are connected to the D-link. We've even tried hooking up a physical Ethernet cable to the D-link and to the laptop, but it doesn't help any.

The disconnections seem to be directly linked to when we use a lot of power. If we turn abruptly, or especially when we pull a heavy load, we'll lose connection. In fact, on the dashboard, the battery use will shift to critically low during these instances. Perhaps these disruptions are linked to us trying to use too much power in too short of a time frame?

Any ideas on how to fix this problem, would be GREATLY appreciated!

We are using LabVIEW.

[Chris_Ely]

Is your radio wired to the proper output of the VRM, as shown here?
Could you post your driver station logs?

[TBots]

Yes our D-link is connected in that fashion. How do we send you logs from our drivers station?

[Chris_Ely]

Originally Posted by TBots

Yes our D-link is connected in that fashion. How do we send you logs from our drivers station?

Look in the following file path for the log files:
C:\Users\Public\Documents\FRC\Log Files
You can then attach them in a zip file to a post.

You can also view the logs using the log viewer. More information about that here.

Unfortunately, I don't have access to a drivers station to view logs myself, so someone else will have to help with that.
In the mean time, look at your logs, and see if any of them resemble the ones shown in the Identifying Common Connection Failures with the Log Viewer section at the above link.

Also, what battery voltage does the driver station read when the robot is sitting idle, and when you lose connection?

[JacobD]

I had the same problem, just try using a fully charged battery. I'm not sure if it is a problem with the Control System or if it's a safety of some sort.

[Chris_Ely]

Originally Posted by JacobD

I had the same problem, just try using a fully charged battery. I'm not sure if it is a problem with the Control System or if it's a safety of some sort.

When the battery voltage drops too low, the boost power supplies for the control system can no longer supply the proper voltage. To preserve battery voltage, the RoboRIO uses a staged brownout scheme that shuts down motors and other outputs. You can learn more about this here.

As a general rule, when the battery voltage drops near or below 12V when the robot is idle, you should change the battery.

[JacobD]

Originally Posted by Chris_Ely

When the battery voltage drops too low, the boost power supplies for the control system can no longer supply the proper voltage. To preserve battery voltage, the RoboRIO uses a staged brownout scheme that shuts down motors and other outputs. You can learn more about this here.

As a general rule, when the battery voltage drops near or below 12V when the robot is idle, you should change the battery.

The funny thing is that my robot would do this at 12.5v idle. But thanks for the information. I'll look for the light indicators next time it happens. That's assuming it my robot isn't on the field during competition.

[Chris_Ely]

Originally Posted by JacobD

The funny thing is that my robot would do this at 12.5v idle

It would lose connection at 12.5V, or with a nominal battery voltage of 12.5V it would lose connection under load? If the latter, your battery might not be able to hold a charge very will anymore. Is this an old battery?

[JacobD]

Originally Posted by Chris_Ely

It would lose connection at 12.5V, or with a nominal battery voltage of 12.5V it would lose connection under load? If the latter, your battery might not be able to hold a charge very will anymore. Is this an old battery?

It has happened with 3 new batteries. So, I can say that the battery is not the problem. Don't stress over it. We can still drive for a solid 30 minutes without having any issues.

[Chris_Ely]

Originally Posted by JacobD

It has happened with 3 new batteries. So, I can say that the battery is not the problem. Don't stress over it. We can still drive for a solid 30 minutes without having any issues.

If you are driving 30 minutes on the same battery, you are most likely draining it down to the point where you can damage it. My team has lost several otherwise good batteries because of this.