Jaguar problems

[Otis22894]

We are running four CIM motors for our drive system, and the two motors on the left side of our robot work perfectly, but the two motors on the right side will start and cut out randomly, or barely work at all. While looking at the two jaguars they are attached to they start out with a blinking green light (as would be normal) and then they cut to slow flashing red lights. I have looked at all of the threads on flashing red lights and the jaguars, but I simply don't know where to start in troublshooting them. Any help would be greatly appreciated. Also, when we try to run any of the motors, the voltage drops significantly, how do we fix this?

[Kevin Sevcik]

Slow flashing red means there was a voltage, temperature, or limit switch problem. Slow flashing red and yellow means there was an over current problem.

Your problem sounds like the motors on the right side might be wired opposite of each other. Put your robot on blocks to get the wheels off the ground and then try driving it. If the right side motors still act funny, either one is wired backwards, or you have some serious mechanical binding on the right side of the robot.

To check for the first problem, simply unplug/disconnect one of the right side motors and run the right side. Things should work just fine. Then plug in the other motor and unplug the one you just checked. Run the right side again, and make sure it's turning in the same direction as with the first motor. If they run in opposite directions, you're just identified the problem.

If they run in the same direction, turn off the robot and start looking for places you might have binding. Any place that a moving/turning thing comes close to a stationary thing is a potential place of binding. Grab a wheel and spin it and look/listen for anywhere the chain, wheel, sprocket, etc. might rub against the frame of your robot or some other stationary object.

[Otis22894]

Originally Posted by Kevin Sevcik

Slow flashing red means there was a voltage, temperature, or limit switch problem. Slow flashing red and yellow means there was an over current problem.

Your problem sounds like the motors on the right side might be wired opposite of each other. Put your robot on blocks to get the wheels off the ground and then try driving it. If the right side motors still act funny, either one is wired backwards, or you have some serious mechanical binding on the right side of the robot.

To check for the first problem, simply unplug/disconnect one of the right side motors and run the right side. Things should work just fine. Then plug in the other motor and unplug the one you just checked. Run the right side again, and make sure it's turning in the same direction as with the first motor. If they run in opposite directions, you're just identified the problem.

If they run in the same direction, turn off the robot and start looking for places you might have binding. Any place that a moving/turning thing comes close to a stationary thing is a potential place of binding. Grab a wheel and spin it and look/listen for anywhere the chain, wheel, sprocket, etc. might rub against the frame of your robot or some other stationary object.

We put it on blocks and after testing both motors individually, they both run in the same direction, so that isn't the problem. I can't identify any places where it is binding. But, they only start blinking after a sudden start or change in direction, when we begin slowly, they seem to work fine.

[slijin]

Originally Posted by Otis22894

We put it on blocks and after testing both motors individually, they both run in the same direction, so that isn't the problem. I can't identify any places where it is binding. But, they only start blinking after a sudden start or change in direction, when we begin slowly, they seem to work fine.

Again, what colors are the LEDs of the Jaguars in question?

The symptoms you describe sound like you need to implement ramping. The reason is that a sudden start or change in direction induces a current spike well above 40A to overcome the moment of inertia, which trips the Jaguars' over current protection. Ramping will allow you to avoid this current spike and thereby avoid tripping said protection.

Refer to this thread to see some details on how to do this.