"No Comms"

[pitzoid]

Originally Posted by squirrel

Should the WGA be at least 6" away from the Jaguar(s)?

At least 6" and as free of metal structure as possible.

[MrForbes]

Thanks, that's what I wanted to hear! We have the WGA on top of the wood electronics box now, not sure if it's 6" away from the nearest Jaguar, but we can make that happen if we still have problems.

[GBIT]

Originally Posted by squirrel

Alan--

Trying to get a better understanding of this, what distances are you talking about? Should the WGA be at least 6" away from the Jaguar(s)? a foot? more?

thanks

Originally Posted by pitzoid

At least 6" and as free of metal structure as possible.

once we moved ours away from our control system and out of the frame of our robot we had no problems with lost comms again....

[Alan Anderson]

Originally Posted by Alan Anderson

Two teams at the DC Regional had issues where they'd lose communication when driving. Both of them had the WGA mounted adjacent to a Jaguar...

Originally Posted by squirrel

Trying to get a better understanding of this, what distances are you talking about?

A half inch is definitely too close. The team I assisted directly had put a Jaguar on the top side of a piece of lexan, and the WGA was mounted to the bottom side directly underneath it.

I only heard about the other team second-hand, so I don't actually know how near the parts were to each other, but I got the impression it was less than a couple of inches. I'll try to find out details from the Spare Parts volunteer who helped them correct the problem when they requested a replacement WGA.

[MrForbes]

Ok, thanks! This is how we had our WGA when we had some occasional no comm problems, it's now on top of the box, sitting flat.

[Al Skierkiewicz]

Let us not forget that any time the gaming adapter is trying to connect or is rebooting or has lost a security packet, you will see "No comm".

[pitzoid]

Still investigating the "no comms" dropout during match issue, but it does appear its the network switch chip reset in the DS being susceptable to EMP. I can repeat the drop of multiple DSes connected to different SCCEs while a match is running with an EMP event. Logs show the reset takes ~31 seconds for the DS to reconnect with FMS after such an event. No FMS issues that I can find when the event happens. Why the reset trips is still undetermined and I don't know if we can come up with a quick fix for it. Will relay more as I know.

[rrossbach]

Thanks for the update!

[484-ben]

During our competition on Saturday at NJ our robot failed completely to operate during autonomous. During teleop motors connected to spikes worked well, motors connected to Jaguar speed controllers did not operate. Everything worked perfectly on Friday. Any suggestions?

[484-ben]

During our competition on Saturday at NJ our robot failed completely to operate during autonomous. During teleop motors connected to spikes worked well, motors connected to Jaguar speed controllers did not operate. Everything worked perfectly on Friday. Any suggestions?

[pitzoid]

Update:

Sent a bunch of test data to FIRST and DEKA yesterday confirming the DS Network chip susceptability to EMP. Today they were able to repeat my results, so it seems confirmed. We can't fix the DS easily, but we're working on a bunch of "workarounds". FIRST is looking into ways to eliminate static generation, which if they can will fix the source of the issue and I've been testing some FMS network mods today that enable the DS to do a minimal association with the the FMS network. I.e. now when the DS network chip resets on an EMP event, I can have it talking with both FMS and the robot in under 2 seconds. If the DS completely reboots its a few more seconds but it still comes back fast. Not the ideal situation, but it should help. Hopefully we won't have any static issues this weekend.

Oh, and the added extra benefit of the network mods? Looks like we dropped about 20 seconds off the initial DS/robot/fms linkup before a match starts

Real engineering: see a problem, analyze the data, if you can't "fix it", find the work around

[NickE]

Originally Posted by Daniel_LaFleur

Orientation does not seem to be an issue but location is important

Actually, we found that orientation can be a huge issue. When we had teams in for our pre-ship practice day and scrimmage, one team had mounted their WGA sideways. Midway through a practice match, they lost comms and did not regain comms for the remainder of the match. Upon later troubleshooting, it was found that rotating the WGA 90° while keeping it in the same position allowed the WGA to connect to the field network again.

It seems that in very close proximity to the router, the orientation does not matter much. However, as the robots get farther away (it was still less than 30 feet, unobstructed, from the router), the orientation matters. We found that it is best to place the WGA on a flat plane (bottom of WGA parallel to ground)

[petek]

Originally Posted by NickE

Actually, we found that orientation can be a huge issue. When we had teams in for our pre-ship practice day and scrimmage, one team had mounted their WGA sideways. Midway through a practice match, they lost comms and did not regain comms for the remainder of the match. Upon later troubleshooting, it was found that rotating the WGA 90° while keeping it in the same position allowed the WGA to connect to the field network again.

It seems that in very close proximity to the router, the orientation does not matter much. However, as the robots get farther away (it was still less than 30 feet, unobstructed, from the router), the orientation matters. We found that it is best to place the WGA on a flat plane (bottom of WGA parallel to ground)

I see that the Linksys documentation shows that you can see its signal strength in the setup Status page. This would allow you to see what orientation gives the best performance. I did a quick search online and saw several posts on DirectTV and gaming forums that suggested that orientation affects bit rate, but nothing that said if there was an optimum configuration.

[pitzoid]

For people interested in finding out more about ESD sensitivities and ways to mitigate. Do a google search on "triboelectric series"

[Team 135]

We had our Linksys wireless bridge go bad. We took it to Pit Admin to have it programed and they said that the setting were corrupted. They would correct them, and unplug the box, plug it back in and it would be corrupted again. We borrowed one from replacement parts and out bot worked fine during the rest of the competition. Luckily the problems were only during practice matches.