Motor Controllers

[PJRice]

Hi Guys-

This is getting pretty last minute but our rookie team is a little lost on the "one motor controller per motor" requirement. It seems the choices are the Vex
Spike Relay H, the Vex Victor controller and the Motor Controller 29, of which we only have one each. Meanwhile Vex is out of the Spike Relay and BESIDES
We have no idea how to use these or which one might be advantageous for our 6-7 motors. Any suggestions??!!

[MagiChau]

You should have also received black jaguars in your Kit of Parts. These are also speed controllers that you can use. If I am correct you should have 4 MDL-BDC24 Black Jaguars. You should be using the Victor & Jaguars for motors that need to have different speeds due to their ability to adjust voltage delivered to the motor. The Spike Relay can only go the full 12 volts in either direction.

[Kevin Sevcik]

You can also use the TI Jaguar speed controller. Also, the Vex motor Controller 29 would only be legal for vex motors.

Regardless, that's a very important limit. You can't drive two motors off one controller, nor can you drive one motor with two controllers. Either one is asking for trouble anyways, besides being illegal.

Speed controllers (Victor, Jaguar) let you smoothly vary the speed/power of a motor. Spikes are either full forward, off, or full reverse. In addition, the Spikes are limited to 20A max. You'll only want to use spikes with small, low power motors that you only want to be on or off.

[Sconrad]

Another option that I didn't see in your post is the Jaguar motor controllers. As far as I know, very few teams use Motor Controller 29s on their robots, mainly because it is designed almost solely for the 2-wire VEX motors. As far as which ones are best for which situation, The relays are a good choice if you only want to go one speed (Max speed). The relays will not give you control over speed, just direction. The Victors and Jaguars are extremely similar and are almost interchangeable as far as their purpose. I believe the main difference between the two is at what point their amperage cutoff (feel free to correct me on this one). That is, unless you choose to use the Jaguars CAN capabilities, but IMHO it's probably best to stick with the simpler PWM system at this point. Our team prefers Jaguars because we find them to be more durable, but I'm sure there are teams that will argue this point. Generally, the Victors or the Jaguars will give you more control, but weigh more, cost more, and take up more space (especially the Jags).

Good luck at the competitions!

[PJRice]

Thanks SO MUCH for the helpful posts this late in the game!

So in our sitch, we are using all the jaguars (4) for the drive motors. That leaves us with three motors to have relays or speed controllers for-

the elevator motor which is a banebot 550 or 775
the shooter motor which is a banebots 550 or 775
the ramp pusher downer motor which is a window motor

We have (1) victor speed controller and (2) Spike relays to use.

It seems to me from what my helpful comrades are saying is that the spike relays could be a problem with powerful motors bcs of the 20 Amp limit?

So we might want to put those where we need the least power?

And Ive not yet been able to figure out for sure- do the PWM terminals on the digital side car act or count as a motor controller? Or do they just control the motor controllers? If so- we must work around our two spikes and a victor it seems like UNLESS ANYONE OUT THERE might have a spare jag or victor we could borrow/buy?

Thanks for any more input at all!

PJ and Banning HS Team 4345

Also,

[EricH]

Or you could buy more controllers, given that you have the budget.

Spikes are on/off. They'd work best for something like the bridge pusher. You could also use them on the elevator.

Victors are variable speed, similar to the Jaguars. That's what I'd probably be using on the shooter.

PWMs control the motor controllers.

[DonRotolo]

Originally Posted by PJRice

We have (1) victor speed controller and (2) Spike relays to use.


And Ive not yet been able to figure out for sure- do the PWM terminals on the digital side car act or count as a motor controller? Or do they just control the motor controllers?

I recommend using the 1 Victor to control the shooter, since you may want to vary its speed.

Use one spike for the elevator - but be aware that you may blow the 20A fuse, the RS550/750 is a bit powerful for the spike but not overly so.

Use one spike for the pusher downer motor, that is well within a spike's capability. Just be aware that MANY teams have found that a window motor doesn't have enough power to push the ramp down.

You should be able to buy or borrow a Victor or Jaguar (for the elevator) at your competition - just ask Pit Admin to make an announcement as soon as you unbag your robot. Or order a Jaguar from DigiKey, you can have it Thursday if you order it Wednesday. (Unless you live near Thief River Falls MN, then you can pick it up same day

The PWM outputs from the sidecar are extremely low power, and are control signals only, they definitely will not drive even a very tiny motor.See Als' comment below - I forgot about servos and their motor-like brothers...

[Al Skierkiewicz]

PJ,
The PWM outputs can drive the VEX motor or servos. The VEX motor came with (or should have come with) a three wire to two wire VEX motor speed controller. (the controller is available from VEX outlets) It is pretty powerful for small applications that might fit your needs. When using the PWM outputs for VEX and servo you need to add the jumper on the DSC to put +6 volts on the center wire of the PWM cable.

As a reminder to everyone, the Spike fuse can be changed to a breaker for the compressor only. All other uses of the Spike must use the 20 amp fuse or equivalent that came with the Spike.

[Cal578]

Using the Jags for the drive motors was a very good idea. For your bridge manipulation window motor, I recommend the Victor. Although we mostly prefer jags, our experience has been that window motors and jags don't play nice together, and we've never had trouble with a victor controlling a window motor.

Victors are not difficult to get (Jaguars have been sold out for much of this build season). If you can get some victors, either in advance or at your regional competition, they should do well for your remaining motors.

Best of luck to you!