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View Full Version : D-Link Randomly Dropped Wireless Link


de_
02-20-2011, 04:04 PM
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
02-20-2011, 04:29 PM
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
02-20-2011, 04:30 PM
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_
02-20-2011, 06:28 PM
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
02-20-2011, 07:00 PM
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
02-20-2011, 08:00 PM
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
02-20-2011, 08:12 PM
Congrats on the troubleshooting.

Greg McKaskle

Joe Ross
02-20-2011, 08:24 PM
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
02-20-2011, 10:00 PM
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
02-20-2011, 10:08 PM
Is this allowed?
It is actually required.

mtndurbin
02-21-2011, 07:45 AM
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
02-23-2011, 03:05 PM
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: