Too many PWM's shorting out power?

[Alan Anderson]

When you say "disable the Victor", what do you mean?

Since you're asking about programming, it would help greatly if we could see your code. Show us at least the relevant sections of Begin and Teleop.

[WizenedEE]

Is your digital sidecar powered by wires coming from the PD board? ie, are the BAT, 5V, and 6V LEDs on? I've heard that could make one or two PWMs work but not all of them. That doesn't theoretically make much sense, since the sidecar circuitry is mostly pass through for PWM, but hey.

[EricVanWyk]

Originally Posted by WizenedEE

Is your digital sidecar powered by wires coming from the PD board? ie, are the BAT, 5V, and 6V LEDs on? I've heard that could make one or two PWMs work but not all of them. That doesn't theoretically make much sense, since the sidecar circuitry is mostly pass through for PWM, but hey.

Actually, the PWM signals are buffered on the DSC. It does make sense

[slijin]

Originally Posted by WizenedEE

Is your digital sidecar powered by wires coming from the PD board? ie, are the BAT, 5V, and 6V LEDs on? I've heard that could make one or two PWMs work but not all of them. That doesn't theoretically make much sense, since the sidecar circuitry is mostly pass through for PWM, but hey.

The reason it works is because the DS leeches power from the cRIO, which is generally enough to run a few of the outputs, but not all.

[Landonh12]

Originally Posted by Alan Anderson

When you say "disable the Victor", what do you mean?

Since you're asking about programming, it would help greatly if we could see your code. Show us at least the relevant sections of Begin and Teleop.

Disabling the Victor in the code.
I will post a picture later today, around 5 CST.

@WizendEE
Yes, the 5v and 6v lights are on.

[zaphodp.jensen]

Troubleshooting information and Ideas:

Do you have your Victor PWM cable plugged in the correct direction?

Does enabling both do anything different?

Does plugging a Jaguar into the victor's cable work? Does plugging the victor into a Jaguars cable work?

Does changing the PWM port to say, 8 make it work?

What the problem sounds like is a hardware problem and not a software problem.

[dyanoshak]

Originally Posted by zaphodp.jensen

Does plugging a Jaguar into the victor's cable work? Does plugging the victor into a Jaguars cable work?

A side note: Remember that you must configure your code to use either a Jaguar or a Victor (for each motor instance). Jaguar uses the full range of the Servo PWM signal coming out of the cRIO. If your code is configured for a Victor but you really have a Jaguar hooked up, the Jaguar will not swing to full forward or full reverse.

[Landonh12]

The problem is resolved.
Most of the problem was wiring, and some was programming.
We had the code using a Victor, which is what we were using. Thanks.

[Hawiian Cadder]

Could you specify the solution you found? We have a Crio that will only do 2 motors controlled at the same time and are utterly stumped.

[Landonh12]

Originally Posted by Hawiian Cadder

Could you specify the solution you found? We have a Crio that will only do 2 motors controlled at the same time and are utterly stumped.

Our cRIO was plugged into the power supply for a camera, so it wasn't getting enough power.
What are you programming in?

[el_pablo]

We are having the same problem.

When we try to control more than 2 motors with the PWMs, the system starts to have problem.

Scenario 1
With the Axis camera, when running the 2 step motor, one of them starts to skip. Adding a third motor, both of step motors jitters.

Scenario 2
Using 2 jags and 1 victor, one jag skips every few seconds.

So what could be the problem? Power?

Thanks for helping

[Alan Anderson]

Originally Posted by el_pablo

We are having the same problem...
So what could be the problem? Power?

The same symptoms suggest the same fix: make sure you are properly supplying 12 volts to the Digital Sidecar from a 20 amp breaker on the Power Distribution Board.

[slijin]

Originally Posted by el_pablo

Scenario 1
With the Axis camera, when running the 2 step motor, one of them starts to skip. Adding a third motor, both of step motors jitters.

To add to Alan's response, check to make sure that the frame of the Axis camera is isolated from the robot's, as the Axis camera is grounded to its frame.

[el_pablo]

Here is a video I made yesterday during the testing.

It's in french but I wrote in a previous post what is happening.


Youtube video here

As you can see, it jitters even when not running.

Here is a screen shot of our begin.vi


Here is the teleop code


Thanks for helping

[Alan Anderson]

el_pablo:

When you said "step motor" before, did you mean "servo"?

You're defining the camX and camY servos, but you never command them to move.

The nouveauMotor device reference is not defined in Begin. You should be seeing an error message on the Driver Station telling you about that.

I can't see YouTube videos from where I am, but I'm going to guess that you haven't installed the servo power jumpers next to the PWM pins on the Digital Sidecar for the camera servos. If they are indeed being powered, then a "twitch" is usually an indication that they're not getting a PWM signal, and are just picking up noise on the wires.