Runaway CIM motors

[BullBot Mentor]

Originally Posted by slijin

Immediately check your robot for a chassis short.

Although Jaguars are a point of failure, applying 12V across drive motors will spin them, no matter where the source. Albeit unlikely, make sure that this is not the case.

Thank you for the tip. We did stop and check all connections to make sure we were not shorting anywhere and everything looked good. We will check again when we meet up this evening.

[Al Skierkiewicz]

If you could check the jumpers, reinstall the PWM cable and let us know what happens when you power the robot, when you enable and then what you see on the Jaguar during each condition. With the PWM installed, does the motor spin immediately when power on the robot?

[shuhao]

See if you flipped the input with the output on the jags. We (i) did that and fried 2 jagur

[StevenB]

Originally Posted by Al Skierkiewicz

Did a limit switch jumper on the Jaguar fall out? It is possible that the Jag is trying to get back from a limit condition.

I've never used a Jaguar with limit switches, but I'm confused how this could happen. The switches are supposed to be wired normally-closed, so if a jumper came out the Jaguar would act as if the switch had been pressed. The Jaguar datasheet specifically says that the motor stops when a switch is pressed. Am I missing something?

Originally Posted by Jaguar datasheet

Two limit switch inputs provide a method for immediate shut-down of the motor. The inputs expect typically-closed contacts - one for each direction of rotation.
http://www.ti.com/litv/pdf/spmu064c

[Al Skierkiewicz]

Steven,
If limit switches are not used, there must be jumpers in place on the Jag.