Victor Disconnection Problem

[mattiej]

We have been having problems with our victor motor controllers. Whenever we try to run our robot, most of the time it runs just fine. Sometimes, the victors lose connection and either continue at their previous speed or stop. After a couple of seconds, it will sometime reconnect. We get the error codes 44004 (no negative sign): Driver station has lost communication with the robot. We have tried connecting with both an Ethernet and a crossover to the cRIO. We also get error code -44061 at Four Motors in the Vi path Robot Main.vi, but we haven't changed the basic mecanum code at all. We also get error codes 44007 and 44008 (while connected via Ethernet). We also get an error code 44003: no robot code is currently running when we definitely have code in the robot.  Help?

[matthewgkerr]

Is this new robot code that has been developed with FRC LabVIEW 2013? Or have you updated your development machine to FRC LabVIEW 2013 and deployed robot code that was developed using a previous version of LabVIEW? I ask because our team did the latter and we were finding some very strange behaviour with our robot. The robot was previously driving (using jaguar motor controllers) as expected, then after the update, one of the jaguars was not responding as expected (I'm not sure what the specifics were). Since we are fairly new to LabVIEW, we didn't know how to find the exact problem but we were confident that it was something to do with the software. So we created a new project from 2013 and re-wrote our robot. There is a chance that the re-write removed a bug we introduced but I have a sneaking suspicion that the problem was a compatability issue with the underlying code. This might not be very useful, but I would recommend creating a new project and put in the required code to talk to the victors and see if the problem still exists.

[KHartley]

Mattiej,

Make sure you don't have multiple wireless access points/router near each other. If multiple routers are too close together (even if they are on different wireless channels) the signals will smear (conflict with each other) and the signal quality will become very low. This can cause the robot to become uncontrollable for several seconds until the signal quality picks up or the robot runs into a wall.

Are you using the 12V to 5V transformer to power your access point? If the motors pull too much current it may power down or kill the antenna on the access point.  The transformer will prevent temporary spikes and drops in current from affecting the wireless too greatly.

Are you reusing code like Matthew suggests or creating a from scratch project in FRC 2013 software?

Make sure your battery if fully charged or better yet try a new battery. They can die very quickly especially if you haven't used them since last year.

Are you driving the robot behind walls or barriers? Make sure the router is in clear line of sight so the signal strength will be as great as possible. You may even want to change the access point to bridge mode and use a off the shelf router as these can provide greater range. External antennas usually provide the greatest range.

Is the router mounted too close to a motor? Try mounting the dlink access point as far away from the motors as possible. Sudden movements could create larger magnetic fields that could mess with the router. Also make sure the router is mounted securely.

I've been testing the mechanum code at NI on a robot and I've not noticed the errors you reported but I have seen similar issues that were caused by some of the mentioned scenarios.

Thanks,
Kyle Hartley

FRC - Application Engineer

National Instruments