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Unread 24-04-2011, 13:49
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Re: Robot losing and regaining drive power

Quote:
Originally Posted by Al Skierkiewicz View Post
3.5 second with power is Jag reset from over current/under voltage fault
Sounds like the issue is over current faults when trying to drive forward with 2 motor drive. I have a few more notes to add on the Jag fault logic. 3 sec is the default wait time on a fault (over current/under voltage/over temp). The Jag doesn't actually reset it just waits (with flashing light indicator red on Black Jag, multicolor flashing on Grey Jag) hoping that the issue (motor stall) will resolve and it can continue normal operation.

If you happen to be using CAN, you can set the wait down to half a sec using ConfigFaultTime() (thats C++, I assume there is a LV equivalent). Also with CAN you can monitor your current in the code. Unfortunately, it doesn't sound like you are using CAN. Reducing the wait time probably wouldn't solve the problem any faster since it sounds like you are having multiple faults in a row (2 - 8sec as you said).

Does it go forward fine under no load (on the cart or blocks)? If it doesn't then it is probably an over current fault. As Al & Kevin said the it is likely that some mechanical issue the drive has more resistance going forward. It is unlikely, but also possible, that one Jag has something wrong with the circuitry in one direction (such as the Gray Jags that would only run one direction because the U6 gate driver failed). You could swap the output wires and see if it has a problem going backwards to test for this.
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