blog; Motor Controller Options for 2015

[FrankJ]

Motor Controller Options for 2015
Blog Date:
Wednesday, August 20, 2014 - 08:50

Link to Blog

Please see the note below from FRC Kit of Parts Manager, Kate Pilotte, regarding motor controllers for 2015.

Hi all,

The Motor Controller landscape for the 2015 FRC season is going to be changing, and we’d like to share a few details in advance of Kickoff to give you a heads up. We normally only provide advance information on the upcoming season when necessary, but we think these details fall into that category.

Victor, Talon, and Jaguar Motor Controllers will be legal for the 2015 season and compatible with the new control system. A selection of these controllers will be available in the 2015 Kickoff Kits and/or through FIRST Choice.

The manufacturers of these motor controllers are, however, discontinuing them, and our understanding is the only ones available for purchase are those already in distribution.

Cross the Road Electronics and Innovation First International (IFI) have been working together on new motor controllers. They’ve published a joint press release about this collaboration and are sharing more information about the new products here.

We are sending new motor controllers to the Beta Teams for evaluation for legality in the 2015 season. While these two new controllers will not be in teams’ 2015 Kickoff Kits, we want to use the beta program to collect feedback on the new motor controllers that will enable us to decide if the new motor controllers will be listed as legal motor controllers for the 2015 FRC season. Based on initial testing results, we don’t believe there will be an issue with approving them for use in 2015, but teams should know the final decision has not yet been made.

The first controller is the Victor SP, a PWM motor controller. The second controller, the Talon SRX, is a CAN enabled motor controller with additional communication protocols and PID control. It is in development now, and will be shared with beta teams upon completion. Technical information for both devices is posted here.

Beta test tasks will be updated as needed to accommodate testing and evaluation of these devices. Meanwhile, questions about these devices can be posted to FIRST’s 2015 FRC Beta Test Forum, or emailed to CTRE or VEX.

[Steven Donow]

Here's a document with more info about the controllers. And WOW I like the size

And here's the VEX product page with some other specifics. And the product page for the Talon SRX

And one that sums up pretty much everything...

[Boe]

Wow I really love how much smaller these are, hopefully everything works out and they're available this year.

[NWChen]

Stupid question. I don't see any screw terminals on the info sheet, how do leads connect to the motor controllers?

[Bryan Herbst]

Originally Posted by NWChen

Stupid question. I don't see any screw terminals on the info sheet, how do leads connect to the motor controllers?

One of the listed features is:

Robust embedded power & output cables will never shake loose during a match

So the cables are embedded, similar to CIMs.

Not sure how I feel about this yet. On one hand, it will ensure that the cables don't come out of these controllers. On the other hand, it means we either have less reusability by permanently splicing the cables, or the same problem we currently have by using an intermediate connector.

I also have never had a big problem with cables getting jiggled loose from the existing controllers with a proper crimp.

[D.Allred]

This is an interesting announcement. The old controllers are no longer made and the new controllers are not legal yet. Did I read that correctly?

David

[Steven Donow]

Originally Posted by D.Allred

This is an interesting announcement. The old controllers are no longer made and the new controllers are not legal yet. Did I read that correctly?

David

The new controllers probably will be available, but it's not offical and will depend on results of beta testing (though it seems they most likely will end up being legal)

[ttldomination]

Originally Posted by D.Allred

This is an interesting announcement. The old controllers are no longer made and the new controllers are not legal yet. Did I read that correctly?

Yeah, that struck me as weird, too. However, with FIRST opting to go into somewhat of a limbo, I think the fact that is not "approved" is only a formality at this point.

- Sunny G.

[timytamy]

Wow, those things are bloody tiny!!!

I'm still skeptical about having permanent cables, but I can see the benefits. Namely the PWM cable will never fall out again, and it will require significant talent to cross make the wrong connections between M+, M-, +12v, and GND.

I'm curious as to how AndyMark fits in with all this. With the Talon being discontinued and it seems like both the Victor SP and Talon SRX being distributed by VEX, will AndyMark find another controller? Or will the be able to distribute them as well?

Can't wait to hear more from the beta teams!

[ebmonon36]

I am curious to see what kind of connectors are on the CAN leads.

I hope it would be within the relaxed rules about repairing speed controllers to replace the cables if necessary. Many teams still have PWM cables getting eaten by drivetrains.

[dmaki]

Originally Posted by ebmonon36

I am curious to see what kind of connectors are on the CAN leads.

I talked to CTRE at CMP and he said he was considering using a 2 row 20 pin 2mm pitch connector for CAN, limit switch, and encoder inputs in order to fit on the small body of the motor controller. The same type of connector commonly used for JTAG debugging on ARM microcontrollers. Based on the drawing, 2mm pitch looks about right, but went down to 10 pins for limit switches and encoders and moved CAN to dedicated pigtails.

Also, I've just mounted 2 prototype Victor SP on a testbot. The wires are very supple and flexible. "Noodley", good stuff.

[FrankJ]

Since I don't speak for the Cross the Road people, this is based on what I know about CAN. CAN is a two wire bus. It is intended to be daisy chained. That would be the reason for two pairs. One in & one out. The legs of the pairs would be connected together in the Talon. I know some people use the star configuration for CAN & get away with it. It is not to the standard & it in not a best practice.

[Jared Russell]

I have lost count of the number of times I have helped teams debug their robots and found issues with how they had attached to their screw terminals, or had totally removed a screw and let debris fall in. The integrated pigtails are a great solution to this problem and will let teams find a connector that works for them while leaving all internal circuitry of the controller hermetically sealed.

Sure, some small percentage of speed controllers may have their leads compromised by being eaten by a mechanism (or being clipped by an overzealous freshman), but the cost reduction more than compensates for this.

[s1900ahon]

Originally Posted by Jared Russell

...or had totally removed a screw and let debris fall in...

Removing the screws on most motor controllers creates debris within the motor controller as a consequence (i.e. it doesn't have to fall in, it is already there). If I recall correctly, both Jaguar and Victor (at least 884) use captive screw terminals. When the screws are removed, little bits of the removed screw are left behind. This was a bigger problem for Jaguar due to the lack of conformal coating (before VEX manufacture).

[nuclearnerd]

I wonder if FRC would consider brushless motors & controllers in the future. Since the popularity of quadcopters exploded, there are tons of cheap options available