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-   -   D-Link Randomly Dropped Wireless Link (http://www.chiefdelphi.com/forums/showthread.php?t=92471)

de_ 20-02-2011 17:04

D-Link Randomly Dropped Wireless Link
 
We have had an ongoing problem with the wireless link going down randomly. It would eventually recover without power cycling anything. It appears to be isolated to be the Dlink as the C-Rio would still be running and had not rebooted. So we swapped to last years Linksys bridge and did not get a single drop of the wireless link with an hour of testing when we had one every 3-5 minutes before.

Power and cabling to the Dlink appears solid and reliable physically and the robot was being very lightly used (no collisions etc). We did not see the Dlink reboot but might have missed it.

Anyone else with similar experiences ? Its near the CPU and sidecar and the converter is right under it. Could EMI be affecting it (but not the Linksys in the same location) ?

aaronhammond11 20-02-2011 17:29

Re: D-Link Randomly Dropped Wireless Link
 
Have you updated the cRIO to the latest image file (v28)? We are having the same problem after updating our cRIO during a pre-regional event yesterday. It's quite infuriating, especially given the proximity to ship and the inability to test robot functionality.

tomy 20-02-2011 17:30

Re: D-Link Randomly Dropped Wireless Link
 
when we hit the wall our dlink drops the wireless

also make sure you have a patch cable from your dlink to your crio

de_ 20-02-2011 19:28

Re: D-Link Randomly Dropped Wireless Link
 
I believe we updated to latest version yesterday night (before testing today) but I also sort of remember losing the link before the upgrade.

Is there something special about the ethernet cable that came with the DLink versus any other cable. We had substituted a short 1' cable.

re dropping link when hitting wall: Ouch. We will have to see how things work in the early regionals. Could be a lot of dead robots.

Greg McKaskle 20-02-2011 20:00

Re: D-Link Randomly Dropped Wireless Link
 
There is nothing special about the cable, though perhaps you should see if the link lights are on or swap out to a different cable to see if that changes things.

Greg McKaskle

mtndurbin 20-02-2011 21:00

Re: D-Link Randomly Dropped Wireless Link
 
It appears that this dropped connection is not random or a loose connection.
Our triage of this indicates that under heavy current draw, like when the
drive motors are running, the 12v power can drop to around 7 volts.

This low voltage condition causes temporary failure of the power converter
supplying power to the dlink. This results in the dlink performing a power on reset.

If you can safely, watch blue lights on the dlink while you drive the robot.
At the point of failure all of the DLINK blue indicators will blink simultaneously.
This will indicate a power on reset has occurred.

What I am now waiting for is the official fix for this.

Greg McKaskle 20-02-2011 21:12

Re: D-Link Randomly Dropped Wireless Link
 
Congrats on the troubleshooting.

Greg McKaskle

Joe Ross 20-02-2011 21:24

Re: D-Link Randomly Dropped Wireless Link
 
Quote:

Originally Posted by mtndurbin (Post 1027855)
Our triage of this indicates that under heavy current draw, like when the
drive motors are running, the 12v power can drop to around 7 volts.

This low voltage condition causes temporary failure of the power converter
supplying power to the dlink. This results in the dlink performing a power on reset.

What I am now waiting for is the official fix for this.

What is your wiring like? It sounds like you wired directly to the PDB through a breaker. You should have wired it to the dedicated 12v radio output on the PDB. This will output 12v until the battery gets to 3.5v or so.

wireties 20-02-2011 23:00

Re: D-Link Randomly Dropped Wireless Link
 
Quote:

Originally Posted by Joe Ross (Post 1027891)
What is your wiring like? It sounds like you wired directly to the PDB through a breaker. You should have wired it to the dedicated 12v radio output on the PDB. This will output 12v until the battery gets to 3.5v or so.

Is this allowed? Team 1296 had the same problem described here and we changed to using the 12V of the PDB but were not sure it is allowed.

Mark McLeod 20-02-2011 23:08

Re: D-Link Randomly Dropped Wireless Link
 
Quote:

Originally Posted by wireties (Post 1027994)
Is this allowed?

It is actually required.

mtndurbin 21-02-2011 08:45

Re: D-Link Randomly Dropped Wireless Link
 
Quote:

Originally Posted by Joe Ross (Post 1027891)
What is your wiring like? It sounds like you wired directly to the PDB through a breaker. You should have wired it to the dedicated 12v radio output on the PDB. This will output 12v until the battery gets to 3.5v or so.

Thx I wiil verify with our electical department

Blackphantom91 23-02-2011 16:05

Re: D-Link Randomly Dropped Wireless Link
 
Its new for this year so it gives the Dlink the right voltage. Other things that have been happening is the power cable is lose and it needs to be secure during play because you will get hit and it could knock it lose. Make sure the cables are not bad and the port on the router is still ok. (very easy to destroy the inside of that port and its connections). just some percautions that we have recently taken. Best of luck.:cool:


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