For this season we began inventorying the electronics we have in our room that was left from the previous season. We found that we have 4 victor SPX’s, 10 victors 888’s, 8 victor 884’s, and 9 grey jaguars. Should we use a mixture of the 4 new ones and the rest be old or should we stick to one type of motor controller?
While I have never used any of these specific models and so cannot compare them, I would not expect any issues if you were to choose your controller for each motor based on what features you will need. For example, if any of the controllers have a built-in limit switch port, and you are planning to use a limit switch, it would make sense to use that motor controller for that motor, even if your other motors use different controllers.
If, however, you are not planning on using any of the special features offered by any of the motor controllers, or if you are planning to only use special features on a type of controller you have enough of for all of your motors, then to reduce potential issues with your programming I wiuld say to stick with one kind.
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You might want to consider what the different motors will be doing, and how you want to control them (CAN or PWM). What are your plans for the robot? Will it use conveyors, rollers, and perhaps a spinning shooter? A winch? An arm? An elevator?
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If you specifically have a desire to use CAN for control of your motors, only the newest motor controllers (Victor SPX) wills support that. The Victor 888 and 884 do not have CAN capability and Jaguars are no longer legal to control via CAN bus.
Given your team number you are also likely to have some Victor SP (not SPX), Spark, and Talon SR (not SRX) motor controllers from past Kit of Parts. I would look for these and utilize them as well as the 4 new Victor SPX controllers if you are looking to not buy additional motor controllers.
The old motor controllers you have found are usable and can drive a motor, but with the other options you should have available I wouldn’t recommend them for a few reasons:
- The Victor 884 and 888 have exposed circuit components that will short and release magic smoke in the event metal shavings or small parts like washers fall inside the controller case (I think some models of the Jaguar are susceptible to this as well but my memory isn’t great on them)
- The Jaguars have an internal thermal limiter on some (maybe all?) models that can cut power to your motors if you run them too hard in a match (when I was with 167 we kept having our drivetrain die in matches at our first Regional in 2014 from this)
- You’ll have trouble finding any resources for the Jaguar software anymore since they have been discontinued for a while. Similarly you won’t be able to get a spare for any of these, though you have a lot so that isn’t as much of a concern
If you can find some of the other motor controllers I listed they all have sealed cases that are less likely to short out during a competition.
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Jaguar PWM support is built into WPILib. Software support for Jaguar would only be an issue if CAN was still legal for them.
so we had some sparks motor controllers but they broke so sadly those are not a option but i will start looking for the talon SR’s and thank you for all of your advice.
I was thinking of support to update firmware and directly run closed loop control on the Jaguar through BDC-COMM, but I did find a getting started guide that mentioned none of these are possible when running in PWM mode - in which case the lack of support wouldn’t matter.
Good to know WPILib still supports it though, hadn’t realized that since I haven’t touched one in 6 years!
The physical PWM signal for all the controllers are basically the same. Programmatically, you could use a servo object to control all of them. If I had a choice, I would not use a Jaguar on a robot. They are big, don’t like metal shavings in them and have an aggressive over current strategy. We do have a few used in prototype testing though. The 888 & 884s are some what better but also don’t like metal shavings. (Begs the question of why not just don’t put metal shavings in your electronics.) If you use either the 888 or 884 be sure to use a little computer fan to keep them cool. The modern era motor controllers have better packaging
yeah all of our 884 and 888’s little fans. in fact when we where looking for motor controllers we found a box with about 50 little computer fans so we have plenty extra.
Victor 888s are actually very capable and reliable PWM controllers.
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