New Talon Speed Controller

[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 ?

[Richard Wallace]

Originally Posted by 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 ?

Short version:

Talon linearity is nearly as good as a Jaguar. Talon is less susceptibile to shorting due to swarf.

Victor 888 linearity is much better than Victor 884, but not as good as Talon or Jag.

Jags have CAN now. Talons will have it later.

Competition has provided customers with better performance and prices.

[nuggetsyl]

Number one reason to buy the talons. Not jumping back 4 feet when you brush you finger against a fan and you think you just lost your knuckle lol. I think i did more injury to myself jumping from fans then everything else combinded.

[sanddrag]

Maybe I missed it somewhere, but how does the width of the terminal space compare to the Victors? On the Victors (at least the 884s) I've found some terminals to be too wide to fit.

[Richard Wallace]

Originally Posted by sanddrag

Maybe I missed it somewhere, but how does the width of the terminal space compare to the Victors? On the Victors (at least the 884s) I've found some terminals to be too wide to fit.

Yeah, I've seen that problem also. When I found the right terminals, I bought a big bag of them. That was about six years ago, and now my supply is running low -- time to figure it out again.

Based on the day we spent testing Victors, Talons, and Jaguars in my lab, I recall that our terminals fit Talons and Victors the same way. I think Victor and Talon footprints are the same, and their terminal layouts also match. Mike and Paul should be able to confirm or counter.

[Tom Line]

I wanted to follow up on our promise to toast the Talon. We didn't really accomplish it the way we meant to. First, we ran the Talon without a fan. We connected 2 cims to the output, and 4 inputs from the PD board. We locked the drivetrain in place, and then started ramping up the voltage.

Initially, we thought we had an infant mortality when the Talon dropped out at around 60 amps. The truth of the matter (after disassembly and testing back at the manufacturer) was that the Talon got SO hot that it desoldered components from the board. That's what happens when you run 60 amps through an uncooled speed controller for an extended period. It still didn't actually smoke for us, though I understand it did when it had cooled and resoldered some of the joints at the manufacturer.

Today we retested the Talon with a fan on it. We hooked it up to 1 cim, 2 inputs, and ramped the amperage up. In this case, we had a borrowed Cross The Road engineer with a datalogger in-line with the input to the Talon, so we know exactly how much amperage we were running. We couldn't kill it. We ramped up to 74 amps continous (for an extended period). The silly thing just wouldn't die.

The Victor provided equally good results in both cases. The bottom line is that there is NO way an FRC team should be able to fry either one of these with a fan on.

We have one more 'test' we'd like to try: we're going to bolt a talon to an aluminum bar (simulating a chassis bar) and see if it sinks enough heat to keep the Talon happy over extended periods at high amperage. I think that will wrap up our Beta season this year.

[sanddrag]

Originally Posted by Tom Line

Today we retested the Talon with a fan on it. We hooked it up to 1 cim, 2 inputs, and ramped the amperage up. In this case, we had a borrowed Cross The Road engineer with a datalogger in-line with the input to the Talon, so we know exactly how much amperage we were running. We couldn't kill it. We ramped up to 74 amps continous (for an extended period). The silly thing just wouldn't die.

I'd be curious about this same test but with no fan. Did you happen to perform that at any point?

[Tom Line]

Originally Posted by sanddrag

I'd be curious about this same test but with no fan. Did you happen to perform that at any point?

No, we didn't. I'm not sure how much additional practical data we'd get from that. Here's my take on it. We found that a Talon without a fan can be killed by a very high (by FIRST standards) amount of current for an extended time period. In fact, you can't generate that much in FIRST because of the 40 amp breakers.

I think the data in the user manual really covers the rest of the questions with regards to FIRST applications. For instance, look at the 30 amp data in the user manual. Keep in mind that a single cim pulling 30 amps through an entire match is fairly unlikely.

The graphs show data for a 3 minute match and a 7 minute cool down. Using that data you'll be wandering into a temperature zone you probably don't want to stay in after four consecutive back-to-back matches. So, it appears that unless you find a novel way to keep them cool without a fan, you may want a fan on a drive train application.

Of course, we could attempt to quantify this further with more scientific tests, but I think it would be a waste of time. If teams choose to go without fans in high-current applications, they should grab an infrared thermometer and check the Talon after practice matches to see how much your temps are changing. Or measure the current you're drawing, and extrapolate from there using the User Manual charts. Or get really fancy and wire a thermistor back to the cRio and log the data.

If only we had endless time to play

[Gary Dillard]

Originally Posted by Tom Line

The bottom line is that there is NO way an FRC team should be able to fry either one of these with a fan on.

Key word in this quote is "should". So I don't need to cover my speed controllers when I'm grinding aluminum now? Excellent.

[Gdeaver]

Tom,
That is a static resistive test. You are most likely testing the current carrying capacity of the FET bond wire. The thin wire that connects the FET leads to the chip die. Most recent heavy duty FETs are current limited by the bond wire. The die can carry more current than the bond wire. It's a one shot thermal fuse. Hook a FET up to a direct short and watch the case pop. The bond wire vaporizes and blows the case. To really test the Talon you need a dynamic test to stress the die. You need to have the H-bridge coping with switching transients. A good test would be to but a cim into a gear box with a fly wheel attached. Say like a AM pneumatic wheel or a little heavier. Test by applying full power till it is up to speed and then reverse the direction. Wait till it gets up to speed reverse direction. This will stress the FET die in addition to the bond wire. Again with modern power FETs This repetitive avalanche condition affects the FET thermally. It's more like a real world FRC condition. My robot goes forward my robot goes backwards. Especially in this years game. If a Fet is allowed to heat beyond Tj max they fail fast. However if they are subjected to high temps close to Tj max they will have a shortened life. High energy switching transients tend to damage the structures around the gate. For these reasons teams should monitor the talons heat sink temp and a small fan would be a good idea in most drive train applications. Drive teams tend to go hard on the robot way beyond the 2 minute match time. Andy Mark has a IR thermometer on First Choice. A wise purchase for Talon running teams.