New Talon Speed Controller

[theprgramerdude]

It seems like the Talon is essentially just a different version of the same thing that the new 888 and Jaguar provide. There's really no appreciable difference between them, except that the Talon provides passive cooling. As a side note, based on the dynamometer tests, it seems like the new models (not the 884) have a much better high-side driver for full power and lower resistance than the older 884.

[Mike Copioli]

Originally Posted by theprgramerdude

It seems like the Talon is essentially just a different version of the same thing that the new 888 and Jaguar provide. There's really no appreciable difference between them, except that the Talon provides passive cooling. As a side note, based on the dynamometer tests, it seems like the new models (not the 884) have a much better high-side driver for full power and lower resistance than the older 884.

There are some other differences:

- Smaller footprint
- Lower mass
- Improved ingress protection
- Secure PWM connection
- Brake is maintained during disable
- PWM input can be split (2 Talons on one PWM channel)
- Higher switching frequency
- Lower on-state resistance
- Locked anti-phase rectification
- Clear polarity indicators
- Smart LED

[Ether]

Originally Posted by theprgramerdude

As a side note, based on the dynamometer tests, it seems like the new models (not the 884) have a much better high-side driver for full power and lower resistance than the older 884.

What test data are you looking at as a basis for that conclusion?

[Ether]

Originally Posted by Mike Copioli

There are some other differences:
...
- PWM input can be split (2 Talons on one PWM channel)
...

Mike, can you please tell us what is the rated maximum forward current the LED in the Talon's optocoupler can sustain without damage? Also, what is the minimum current required to guarantee pulse detection? One more: what is the rated maximum reverse voltage it can sustain? I ask because I want to make sure I use a properly designed cable with the custom PWM signal generator I use for testing.

[Tom Bottiglieri]

The Talon looks great, but it is going to have to compete on price with the 888 to make it on to our robot for 2013. We will probably wait until January to purchase speed controllers.

[billbo911]

Originally Posted by Tom Bottiglieri

The Talon looks great, but it is going to have to compete on price with the 888 to make it on to our robot for 2013. We will probably wait until January to purchase speed controllers.

Maybe I missed something, which is highly possible, but from what I've read, the 888 is approved for 2013, but I haven't seen the same for the Talon.
I HOPE I'M WRONG!!

[Jon Stratis]

Originally Posted by billbo911

Maybe I missed something, which is highly possible, but from what I've read, the 888 is approved for 2013, but I haven't seen the same for the Talon.
I HOPE I'M WRONG!!

Yes, you are wrong... There has been NO official communication that the Victor 888 is legal this year. Personally, I believe we'll be told which speed controllers are legal prior to FIRST Choice going live, as that could directly influence how we spend our PDV's.

[billbo911]

Originally Posted by Jon Stratis

Yes, you are wrong... There has been NO official communication that the Victor 888 is legal this year. Personally, I believe we'll be told which speed controllers are legal prior to FIRST Choice going live, as that could directly influence how we spend our PDV's.

This is one time when I don't mind being wrong.

The reason I believed, and still do, that the 888 will be legal is based on the announcement of the price they will be available for during Dec. 5th -April 20th.
I know I'm reading the tea leaves here, but this reading seems fairly clear, IMHO.
Now, if the Talons go for a similar price, the decision might be a bit more difficult, but for now, the 888's seem to be an "obvious" choice......once officially approved.

[Bob Steele]

While I think it is certainly great that IFI is putting the new 888 controller on sale at $50 I find the timing interesting... pretty much pushing the Talon speed controller sales right down the toilet.

i have some and I think they are really nice in form factor and performance but how can a team reasonably want to use them if they are twice as much as the new 888?

[maddoctor90]

Originally Posted by Jon Stratis

Personally, I believe we'll be told which speed controllers are legal prior to FIRST Choice going live, as that could directly influence how we spend our PDV's.

From the FRCBlog post, the only motor controllers that can be bought with the PDVs are the Jaguar or Victor (not sure which one) from IFI. The AndyMark PDV excludes items that AndyMark carries from other suppliers (Talon - Cross The Road Electronics).

Because of this, it is a real possibility that FIRST won't officially tell us if the Talon or Victor 888 (if the 884 is the only one offered with the IFI voucher) will be legal till kickoff. I would really like FIRST to come out and clear up some of this confusion though as soon as possible. If IFI is selling the Victor 888 on December 5th at $50 for FIRST Teams then I think we are all going to assume that they are legal. I don't think it is fair for the Talon by Cross the Road Electronics if we don't know it's legality by then. I would doubt many teams will plan on using the Talon when they already assume the $50 Victor 888 will be legal.

The Talon does offer some advantages over the Victor 888. It does have a lower R_DSN or "on resistance" then the Victor 888 and this would equate to power savings and allow more power delivered to the motor when near stall or highly loaded. Ether's tests support this showing the spike current to be near 130 amps for the Talon and only 120 amps for the Victor 888. It also has a few handy features already mentioned. Whether these differences will be worth and extra $50 per controller and the wait to know if they are legal is going to be decision teams will have to evaluate for themselves.

[Ether]

Originally Posted by maddoctor90

[The Talon has] a lower R_DSN or "on resistance" then the Victor 888

May I ask: how do you know this?

... this would equate to power savings and allow more power delivered to the motor when near stall or highly loaded. Ether's tests support this showing the spike current to be near 130 amps for the Talon and only 120 amps for the Victor 888.

I wouldn't recommend using the transient inrush current test to draw that conclusion.

Look at the curves in the speed vs torque report. The Victor888 and the Talon create virtually identical power output from the CIM at max PWM. See attached graph showing the max PWM traces from the report overlaid for Talon and Vic888.

[Mike Copioli]

Originally Posted by Ether

Mike, can you please tell us what is the rated maximum forward current the LED in the Talon's optocoupler can sustain without damage?

I forward MAX continuous = 60mA
I forward Peak = 3 amps

Originally Posted by Ether

Also, what is the minimum current required to guarantee pulse detection?

I turn-on MAX= 1.6mA

Originally Posted by Ether

what is the rated maximum reverse voltage it can sustain?

Vrev MAX = 6 volts.

[Ether]

Originally Posted by Mike Copioli

I forward MAX continuous = 60mA

I forward Peak = 3 amps

I turn-on MAX= 1.6mA

Vrev MAX = 6 volts.

OK great. My existing cables will work fine. Thanks.

[maddoctor90]

Originally Posted by Ether

Look at the curves in the speed vs torque report. The Victor888 and the Talon create virtually identical power output from the CIM at max PWM. See attached graph showing the max PWM traces from the report overlaid for Talon and Vic888.

I was looking at Mike's post which states "lower on resistance" as difference between the Victor 888 and the Talon. Thanks for plotting both the Victor 888 and Talon together. I would agree, if the Talon does have a lower on resistance, it does not show when plotting the test data together.

[theprgramerdude]

Originally Posted by Mike Copioli

There are some other differences:

- Smaller footprint
- Lower mass
- Improved ingress protection
- Secure PWM connection
- Brake is maintained during disable
- PWM input can be split (2 Talons on one PWM channel)
- Higher switching frequency
- Lower on-state resistance
- Locked anti-phase rectification
- Clear polarity indicators
- Smart LED

What are these differences in respect to? The Jaguar? The Victor?
Also, what is locked anti-phase rectification? I've never heard that used before. Most of the other features are already available in some form on either the Jaguar or Victor, with the exception that they don't occur on both at the same time.