Constant DAP-1522 Resets

[thepcphysician]

Hello everyone,

Our D-Link AP has an unusual problem. On a fully charged battery, it works fine when the robot is disabled. Once the robot is enabled, it works fine in teleop for a few minutes. Then, the AP resets. Once this occurs, we have to wait for the AP to boot back up before we can connect again. Usually, after the battery has been used for more than 3 minutes or so and the first reset has occurred, the small voltage dip caused as the speed controllers initialize causes the AP to reset, making it pretty much undrivable, even though the battery is fresh off the charger and delivers 12.1+ volts.

We were considering placing a capacitor in line with the router (AP) to compensate for the voltage dip. Is this a good idea? We have 4.7 and 10 microfarad capacitors, but we can get other caps if we need to. I have tried unsuccessfully to boot the AP with a capacitor in line, and I'm worried I'm going to kill it if I keep on experimenting. How should I go about wiring this?

Thanks for your help.

[Vikesrock]

Is the converter for the D-Link device wired to the regulated 12V output on the end of the PD previously used for the Wireless Bridge? That voltage should be stable to a very low battery voltage (3 or 4 volts I think).

[thepcphysician]

We tried the 12v regulator first, and that gave us constant resets. It was actually more stable on the 5v bus direct from the PDB (where the camera used to connect).

[Vikesrock]

Originally Posted by thepcphysician

We tried the 12v regulator first, and that gave us constant resets. It was actually more stable on the 5v bus direct from the PDB (where the camera used to connect).

That configuration is not legal and will not pass inspection so I wouldn't put too much time into debugging it.

The relevant rule is <R38-B>

B. The radio power feed must be connected via the 5V converter (model # TBJ12DK025Z) to the marked 12 Vdc supply terminals located at the end of the PD Board (i.e. the terminals located between the indicator LEDs, and not the main WAGO connectors along the sides of the PD Board). No other electrical load can be connected to these terminals (please see the 2011 Robot Power Distribution Diagram posted online at www.usfirst.org/frc/kitofparts for wiring information).

As described in the rule you must use the 12V-5V provided in the Kit of Parts and you must wire it to the 12V supply terminals on the end of the PDB. If you have trouble with that configuration, that is what I would look to troubleshoot.

[thepcphysician]

Ok, thanks for the heads-up. Now that you bring it up, it makes sense to me that the regulator should be able to easily compensate for voltage dips, since it's stepping 12v down to 5v. That said, do you think we should be investigating an issue with the regulator or the bridge itself? I'm thinking the regulator...

[Vikesrock]

Originally Posted by thepcphysician

Ok, thanks for the heads-up. Now that you bring it up, it makes sense to me that the regulator should be able to easily compensate for voltage dips, since it's stepping 12v down to 5v. That said, do you think we should be investigating an issue with the regulator or the bridge itself? I'm thinking the regulator...

The 12V regulator on the end of your Power Distribution board (not the Wago connectors along the long edges) should be providing a fairly stable 12V. If it isn't that is where I would start, probably by trying another PDB. If it is providing a stable 12V and your 5V is dipping then I would think the problem is likely with the 12V-5V regulator.

[thepcphysician]

Oh, that makes sense. Before, we were wiring it to one of the Wagos with a 20 amp fuse. I'll wire it to the 12V on the end and post back. Thanks for your help!

[Al Skierkiewicz]

Originally Posted by thepcphysician

Oh, that makes sense. Before, we were wiring it to one of the Wagos with a 20 amp fuse. I'll wire it to the 12V on the end and post back. Thanks for your help!

The 12 volt output at the end of the PD is specifically designed to provide 12 volts out even if the input from the battery should fall to 4.5 volts. It is for this reason you must use the 12 volt output connector intended for radio wired to the power convertor provided in the KOP to feed the Dlink.

[thepcphysician]

Thank you so much! That took care of the problem. Now on to line tracking...