Hi! Our team has been debating about whether we should use Talon SRXs or Spark motor controllers. Are there any major electrical and programming advantages in using one over the other? Is one typically more reliable? In past years we have used a mix of both and been successful, but the question has risen to switch to a full talon SRX controlled board. Any help would be appreciated!
The SRXs have the benefit of your team having full PID control integrated into the motor controllers, if your team isn’t using PID (you might want to) then you would be fine by just using Sparks.
Talon SRXes include numerous “smart” features such as current limiting, voltage ramping, built-in PID loops and motion profiling, and more. Sparks are “dumb” as in they take a percent output only. Sparks are not inherently worse, do not fall prey to using the shiny new toy that you won’t use the full extent of versus the one that costs half as much.
Do not buy talons if you are not planning to make use of the features that cause it to cost an extra $50. If are asking this question right now, you have probably no idea about the extra features and no plan, code, or experience to make use of them. In Week 4 I would tell almost any team to stick with the “dumb” controller and save their money.
(Not that Talons aren’t a great tool, but they take even a fairly competent controls team some time to figure out.)
I like the Talon SRX and the Victor SPX because having current limiting is just a really nice safety measure. Need to zero your elevator? Set a 30A current limit and run it to the bottom until you see a current spike. Intakes get a 20A or 15A limit to make sure they don’t jam on things and tear themselves apart. And the CAN bus, when soldered together or well-crimped/ lever nutted is very easy to work with over PWM connections (IMO, anyway).
Also, the data port input on the Talon when paired with the Mag Encoder makes positive cable retention which is a big plus for me.
This late in the season, use what you got. If you own Sparks and can’t afford to buy a full set of SPX and SRX motor controllers, just use PWM for now and upgrade to CAN later if you so choose.
Thank you for all of the information! We have used a mixture of both controllers over the past couple of seasons, and have used some of the features and code predominately for the drive train. We haven’t used it as much other than that and many of the more experienced members and mentors have been discussing this over the past week and haven’t reached a decision so I turned here.
And also just to make sure, both are just as reliable? I’m sorry if this is a dumb question.
We havent had a failure of a Spark motor controller yet in the years since they launched. We probably have ~15 of them in house. We have yet to run them in a competition robot on the drivetrain, but have fielded them in season, without issue on shooters, intakes, etc. Generally on our lighter current components.
Off-season and prototypes have used Sparks everywhere, again without issue.
We have had one Talon SRX failure, but honestly I don’t know the particulars of how the failure occurred and I wouldn’t consider them an unreliable motor controller. Tons of teams use the Talon SRX and Victor SPs with great success every year.
I’d consider them both to be reliable products.
Yes they are all durable. We have intentionally abused FRC motor controllers - we’ve locked drivetrains in place and routed multiple motors through a single controller to test them at high amperage (100+ amps continuous).
I would have no problem putting any of the current batch of speed controllers on one of our bots, though I always lean toward the CTRE option due to their high rate of innovation over the last several years. Here’s to hoping that built-in closed-loop heading control is on the horizon =).
Really 100 Amps continuous?
One more question. If we were to connect limit switches directly to the motor controllers is there a way to do it with talons? I know how to do it with sparks, but I have not seen it done with talons.
An SRX breakout board like one of these would be the easiest.
Would it be easy to figure out how to use these in the time we have left?
Yep. Used a clamp-on fluke ammeter to verify. The talon with fan survived for quite a while. The non-fan talon desoldered it’s internal components after a couple minutes. Water dropped on the external casing boiled off
There isn’t much learning involved. Plug them in, and wire as directed.
I can follow up this with a warning - Do NOT use VHB tape to secure these MCs. If you do, the backing may tear off (breaks the plastic where hardware secures the back) when you try to remove them. Only use the appropriate/provided screws/bolts! For some reason my previous Electrical team used VHB to no end and we lost a lot more than just Sparks.
In other words, try to use just the correct hardware. VHB has its uses (see duct tape), but it is not in the securing/insulation of electrical components!
I will echo nickbrickmaster - if you have not already coded for PID loops, it may be too late for your team. It takes considerable understanding and practice to run PID’s. Look to advance your programming in the off-season to run a premium product such as Talon SRX MCs.
Not to pester you, but this is interesting to me. What other motor controllers did you test at 100 amps continuous and what results did you get (or did you guys publish a whitepaper that I missed?)
Major Edit: I mixed up Victors and Sparks, as pointed out by pkrishna3028, so I have fixed the error.
Go for Victors. They aren’t much more expensive, and they have much more control and many more features.
For team that want to use Talon SRXs for Motion Control and their other many features, without needed to spend a ridiculous amount of money, I recommend this;
For every set of motors that needs Motion Control (one side of the DT, the lift motors, etc), use ONE Talon, and then use x number of Victors to communicate directly with the motors. Set the Victors as direct followers of the single “Master” Talon in code, and then program and tune your mechanism based on the Talon. Your Talon will be the motor controller that handles information and calculation, and works directly with the input/RIO Handers, and the Victors will be what actually drives the motors. This allows you to plug sensors into the TalonSRX for feedback control (PIDs, Position Setting, etc), use the current limiters (assuming you feedback wire the Victors to the Talons), and use the glorious Motion Magic/Profiling systems integrated into your Talon SRXs without needing to buy x number of Talons.
It’s a much more affordable way to use the glorious Talon SRXs without spending your annual budget on Motor Controllers
I don’t believe this is possible with SPARKs. You would probably want to use Victor SPX as those have support for following Talon SRXs. They are only $10 more than SPARKs as well ($50 vs $40).
It is possible in software, not directly over CAN. Read the %, then set the PWM. Max, have you experimented with this and found good results?
If you are asking this question with 20 days to go, you should probably use whatever came in your kit (2 Sparks) and probably just have the rest also be Sparks or SPXs.