Faulty Jaguars (CAN)

[dyanoshak]

Originally Posted by Kevin Wang

We have tested each of our faulty Jaguars, and have compiled our results into this spreadsheet:

http://dl.dropbox.com/u/16958628/Jaguar%20Testing.xlsx

Please take a look at it and let us know what you think.

Wow, 7-8 failures (does the crooked LED Jag work otherwise). Your team is a statistical anomaly.

First, let's address the ones that work individually. Since only the first one works on the network and the others fail, this points to bad CAN cabling. The first Jaguar connects to the cRIO over the serial port, but the rest following it use CAN. I have seen this issue on my own team's robot, all but the first Jag was slow blinking amber. We determined that the terminator at the end of the chain was shorting the CAN bus.

Another cause could be the CAN cables themselves. If they are crimped incorrectly, not pin 1 - pin 1, pin 2 - pin 2, and so on, they will prevent the CAN bus from operating correctly. To quickly verify correctly crimped cables, check that when held flat and stretched out, that the tabs on the modular plugs are opposite eachother.

Finally, check the continuity of your cables, maybe there is a loose or broken connection.

Did you assign each Jaguar a unique ID? If multiple Jags have the same ID, they will not operate correctly on the bus.

Your spreadsheet tells me that "Yes" there is something going on with the LED. I need more detail, what is the LED indicating?

As for the 3 Jaguars with DOA failures; you didn't answer my question. Did you power up and attempt to run these DOA Jags all at the same time or individually?

I have helped other teams that had their battery wired backwards, and when they powered their robot on the first time, they fried 4 Jaguars at the same time because of reverse polarity. It looked like a DOA failure at first, but we soon figured out the real issue.

-David