Driver won't communicate with robot

[Potatonator]

Our driver station won't communicate properly with our D-Link. Initially it'll connect just fine, but then the connection will start going in and out. We'll be driving the robot and it will lose and regain connection every 2 seconds. Then, after about 30 or so seconds, it loses connection entirely.

Obviously, it's a bit of an issue that we really can't drive our robot. Any idea what could be causing this? We've tried changing several things, but nothing we did fixed it.

Thanks!

[randalcr]

check to see if there are any wifi networks that could be interfering with your signal, if there is, change it to something that isnt being used. If that doesn't work, check the diag tab of the driverstation and see if you are getting watchdog errors, if you are then look at your code and see if there are any functions that are taking a ton of cpu and slowing down the rest of the program.

if all else fails, reconfigure the bridge and the router from defaults .

[Chris_Ely]

How is you radio wired?
Be sure it is wired according to this diagram.

[Greg McKaskle]

You may also want to see if other computers are using the same IP address. You would normally see a nice message telling you such, but this weekend at a scrimmage, I saw it simply act squirrelly and drop the connection. Of course the router would also lose power because the battery was low and radio wasn't boosted, so it was hard to tell what was causing what.

Greg McKaskle

[Potatonator]

Thanks for the suggestions--we have triple-checked the radio wiring, no luck. There are also no other computers with the IP address we are using.

We get many dropped packets (typically ~25) and repeated warning messages in the diagnostics:

Warning 44004 Error on Driver Station [paraphrased, but the error code is right]
Warning 44002

and the status of the connection to the robot keeps changing from good to bad and back.

We do not have that problem when using the wired connection.

We are trying to connect wirelessly, but the complete network settings on the classmate are:

wired connection:
IP: 10.43.60.5
subnet mask: 255.0.0.0

wireless connection:
IP: 10.43.60.9
subnet mask: 255.0.0.0

[Tom Line]

This would initially appear to be one of three cases:

Network congestion. Are your robot and driverstation the ONLY two computers on the network?

Wifi congestion. Are there other networks in close proximity that utilize the same channel that might be interfering?

Gaming adapter placement. Is your adapter away from the drive motors, battery cable, and also not surrounded by metal?

Also, you should check the CPU usage of the cRIO. You can check it from the driver station. If it is at 100%, your code is likely the culprit.

Do the symptoms disappear when you tether? Do they happen when your robot is stationary, or only when it is trying to move (under electrical load)?

[Alan Anderson]

Have you accidentally started the Driver Station program under two users simultaneously?

[Potatonator]

Originally Posted by Tom Line

This would initially appear to be one of three cases:

Network congestion. Are your robot and driverstation the ONLY two computers on the network?

Yes

Wifi congestion. Are there other networks in close proximity that utilize the same channel that might be interfering?

We aren't sure how to check on that

Gaming adapter placement. Is your adapter away from the drive motors, battery cable, and also not surrounded by metal?

Yes

Also, you should check the CPU usage of the cRIO. You can check it from the driver station. If it is at 100%, your code is likely the culprit.

CPU usage is just fine

Do the symptoms disappear when you tether? Do they happen when your robot is stationary, or only when it is trying to move (under electrical load)?

Problems go away when we tether, but they do happen even if it's not moving.

@Alan: We checked, we aren't running it twice.

We're thinking it might be a bad router, but not sure yet.

[icecube45]

Potatonator,

We had the same problem, and unfortunately lost about 3 days of build time trying to solve it.

I believe it is simply wifi congestion for you,
at our workspace (school), we get the same error, but at nasa yesterday for driver practice (thanks 254), we had no problem, as there were only two wifi networks there, compared to the ~10 here.

If you can, try to go somewhere with less wifi, and check if you still have the problem.

We're kind of stuck with driver practice until we can find a spot at the school to practice (put your robot on the cart, and go travel around to different areas, looking for a less congested space)


Hope you resolve this,
icecube45

[Potatonator]

I just checked the wifi channels at our school. As far as I can tell, our router is channel 1, and all the school's networks are 11. So I doubt interference is the issue.

[Chris_Ely]

I have seen this happen at demos when there are many WiFi networks , and devices around. Other devices like smart phones will try to connect automatically to the network. We solved this problem by making the robot network an encrypted hidden network by selecting enable hidden wireless in the radio's wireless settings.

[Potatonator]

How would we access the radio's settings? We can't seem to find it.