New Talon Speed Controller

[s1900ahon]

Originally Posted by flameout

The way I'm interpreting this is that, after the main breaker is switched off, dynamic braking still occurs.

I would not have interpreted it they way you have. I would have interpreted it as that when the PWM signal is disabled (flatlined) the Talon continues to apply brake mode if the brake/coast jumper is set to brake.

When the main breaker is switched off, power is cut to everything, including all Talons, Victors, and Jaguars. At that point, the MOSFETs in the H-Bridge turn off and the only conduction possible is through the reverse body diodes.

[flameout]

Originally Posted by s1900ahon

I would not have interpreted it they way you have. I would have interpreted it as that when the PWM signal is disabled (flatlined) the Talon continues to apply brake mode if the brake/coast jumper is set to brake.

That makes sense, and matches the behavior of every other FRC-legal motor controller.

When the main breaker is switched off, power is cut to everything, including all Talons, Victors, and Jaguars. At that point, the MOSFETs in the H-Bridge turn off and the only conduction possible is through the reverse body diodes.

This is why I'm skeptical -- and why I was curious to know how my interpretation is possible.

I'll assume your interpretation is correct, then, unless someone comes in and confirms that mine was correct.

Thanks for clearing that up.

[Mike Copioli]

Originally Posted by s1900ahon

I would not have interpreted it they way you have. I would have interpreted it as that when the PWM signal is disabled (flatlined) the Talon continues to apply brake mode if the brake/coast jumper is set to brake.

When the main breaker is switched off, power is cut to everything, including all Talons, Victors, and Jaguars. At that point, the MOSFETs in the H-Bridge turn off and the only conduction possible is through the reverse body diodes.

Scott, you are correct.

[Tom Bottiglieri]

Has anyone with a Talon trying to control it with a cRIO/WPILib found a set of PWM signal timings that work well? The source for the Victor notes that signal acceptance between units was a bit off and I was wondering if this can be attributed to the signal generator or consumer side. I have a feeling this can be chalked up to poor calibration on the Victor as the cRIO generating sloppy signals seems less likely.

If no one responds we will run a test across 4 Talons to find timings that work, then post the results here and to WPILib.

From Victor.cpp:

/*
* Note that the Victor uses the following bounds for PWM values.  These values were determined
 * empirically through experimentation during the 2008 beta testing of the new control system.
 * Testing during the beta period revealed a significant amount of variation between Victors.
 * The values below are chosen to ensure that teams using the default values should be able to
 * get "full power" with the maximum and minimum values.  For better performance, teams may wish
 * to measure these values on their own Victors and set the bounds to the particular values
 * measured for the actual Victors they were be using. 
 *   - 210 = full "forward"
 *   - 138 = the "high end" of the deadband range
 *   - 132 = center of the deadband range (off)
 *   - 126 = the "low end" of the deadband range
 *   - 56 = full "reverse"
 */

[Ether]

Using a custom PWM signal generator, I have run the Vic888 with periods from 5ms to 20ms, and with pulse widths from .5ms to 2.5ms with no problems. I believe I did the same with the Talon, also with no problems.

[edit] I have not tested whether the motor controllers would calibrate properly to this pulse width range [/edit]

[Joe Ross]

Originally Posted by Ether

Using a custom PWM signal generator, I have run the Vic888 with periods from 5ms to 20ms, and with pulse widths from .5ms to 2.5ms with no problems. I believe I did the same with the Talon, also with no problems.

[edit]
Just calibrated an 888 driving a 500 ohm resistive load. Calibrated to 2.000 ms max, 1.000 ms min, and 1.500 ms neutral. Then measured, and got 1.990 ms max, 1.021 ms min, and deadband from 1.482 ms to 1.523 ms
[/edit]

The problem that the comment that Tom is referring to was finding what values work best with factory default calibration, and with the Victor 884, it varied unit to unit.

[Ether]

FWIW. Vic888 calibration using 500 ohm resistive load.

[Ether]

Here's another calibration chart for the 888, this time with reduced range and asymmetric calibrations. The 1.625 is not a typo.

[Jon Stratis]

Ether - In practical terms (aka what a team would see from the Victor on the field), what all do those charts tell us about how we should be calibrating the Victors? I understand what the values mean, I'm just not sure how to best apply them.

[Ether]

The primary intent of the charts was to give a peek under the hood of what actually happens when a motor controller is calibrated.

A practical application is that the charts suggest that the 888 seems to have an adequately large range of calibration to handle expected min/max/neutral variations in joysticks and other UI devices, and provides some overtravel at each end to prevent any throttle clipping.

[IndySam]

FRC Blogged


It's official

2013 Control System

First, the list of approved motor controllers will be expanded. Specifically, Cross the Road Electronics’ Talon and Innovation First’s Victor 888 motor controllers will be legal.

[nuggetsyl]

We drove 2 side comps with no fans on our drives. Temp never went above 83 degrees and only took 10 mins to drop back to room temp. Our team is sold and we just bought 12 more for this upcoming season.

[sanddrag]

This is a lengthy thread I haven't been able to keep up with. I know Ether has done a lot of testing. Can someone give me the cliffs notes of the motor performance differences between the Victor 888, Talon, and Black Jaguar ?