FRC Blog - 2016 Motor Controllers

[Doug Frisk]

Originally Posted by Knufire

Also listed here in the WPILib Docs

In theory it should work like that, but in practice more often than not the voltage drops so fast that none of the brownout stages really take effect and the radio just reboots.

[IKE]

Originally Posted by marshall

I love this thread. Three responses with answers for the question in a row but all in different forms.

For Most drive teams:
12-7.3V =
7.3-4.5V =
4.5-0V =

For some:
12-7.3V =
7.3-0V =

I did not see this much last year (compared to previous years of CRIO or radio resets), but of course last year was a very different type of game.
Primary times I saw it occur were due to teams gearing robots too fast (say 40 FPS) or poor battery management/connections.
Most teams started angry with the field, and then once explaining/showing root cause were less upset.

[mman1506]

Are there any data sheets available for the SD540 controller? With all those pins it must have more than just pwm communication. Some dimensional info would be great too.

[Monochron]

Originally Posted by mman1506

Are there any data sheets available for the SD540 controller? With all those pins it must have more than just pwm communication. Some dimensional info would be great too.

Those are heatsinks actually. And I'm a bit worried by their proximity to that 3D printed mount though.

[mman1506]

Originally Posted by Monochron

Those are heatsinks actually. And I'm a bit worried by their proximity to that 3D printed mount though.

Are you sure those pins on the front of the case are heatsinks? They look like header pins to me.

[Monochron]

Originally Posted by mman1506

Are you sure those pins on the front of the case are heatsinks? They look like header pins to me.

Oh my bad
I believe that is a port for a ribbon cable, which they also sell. Not sure about the protocol used though, so I can't tell if more than PWM is possible.

[Lil' Lavery]

"Power gap" or not, there is still an embarrassment of riches when it comes to motor selection in FRC.

[Foster]

Originally Posted by Lil' Lavery

"Power gap" or not, there is still an embarrassment of riches when it comes to motor selection in FRC.

Please say that again, I remember the days of window seat, window glass and FP motors...

[DaveL]

We are not a rich team and have invested in a variety of Banebots transmissions. It would be a huge waste of our funds and I imagine other teams funds to have to replace these transmissions.

Does anyone know how to interface an AndyMark 9015 motor with a P60 transmission?

[Knufire]

Originally Posted by DaveL

We are not a rich team and have invested in a variety of Banebots transmissions. It would be a huge waste of our funds and I imagine other teams funds to have to replace these transmissions.

Does anyone know how to interface an AndyMark 9015 motor with a P60 transmission?

Yup! Here you go: http://www.andymark.com/product-p/am-2890.htm

Both the AM 9015 and the BB 550 are RS-500 style motors so they should have the same mounting features and shaft size. As long as you can get the correct pinion gear on the 9015 it should work.

[MrRoboSteve]

Per this post by NI, the brownout info in the NI RoboRio User Manual is incorrect, and the WPILib documentation should be considered authoritative.

[Richard Wallace]

Originally Posted by Knufire

Yup! Here you go: http://www.andymark.com/product-p/am-2890.htm

Both the AM 9015 and the BB 550 are RS-500 style motors so they should have the same mounting features and shaft size. As long as you can get the correct pinion gear on the 9015 it should work.

Using this kit with an AndyMark 9015 motor requires some care, because that motor has a knurled shaft. Refer to the layout drawing provided on the AM site; measurement over the knurls is larger than the pinion bore by 0.002 inch at the tolerance limits. Be careful to keep the shaft square to the pinion and to the tool you are using to press.

Also, the AM 9015 has a longer shaft than BB500. Not sure if there is enough clearance inside the P60 to accept that shaft without trimming; in any case the pinion will have to be pressed further so that the AM 9015 shaft protrudes, not simply flush with shaft as you would for the BB500.

[Doug Frisk]

Originally Posted by EricH

I agree with Knufire. WARNING: You just woke up a geezer!

[geezer]Back in my day, we didn't have no stinkin' 775 motors! Didn't have more'n TWO, count 'em, TWO, CIMs! Unlimited motors? HAH! We was lucky ta get more'n two of any one motor! And we didn't have all this selection of controllers either--all we had were Victor 884s! And Spikes! And don't get me started on the gearboxes! You think more restrictions means harder challenge, you're darn right, maybe it's ACTUALLY a challenge now! You young whippersnappers these days...[/geezer]

All right, back to seriousness... You get two drill motors, two CIM motors, two Fischer-Price motors, two Globe motors with attached gearbox, two window motors, and one van door motor. Build a robot that can play Recycle Rush. I can do it with two drills, one CIM, and one van door motor (and a couple of pneumatic cylinders). Won't be very fast, but I'm pretty sure that it'd be a second-rounder for consistency. (Hint: I've done it--2003.) By the way, that's the actual motor list from around '03-04 timeframe--we didn't get the second pair of CIMs until '05 and lost the drill motors to get it. And somehow, everybody showed up with a robot that--at least in general--ran, and most of them actually ran pretty well.

This whole "unlimited high-power motor" thing has been kind of... well, I don't know. It is what it is, but I'm thinking that it was about time for it to end. Maybe we'll get some contact back next year with the power dialed down...

I don't see any reason to limit motors at all. The battery and robot weight limits enforce a practical limit on motors. If someone want's to build a robot with 28 CIMs, I say more power to them. Or rather exactly the same amount of power as the team that uses 2 CIMs. Good luck operating more than 6 to 8 of them simultaneously.

[EricH]

Originally Posted by DareDad

I don't see any reason to limit motors at all. The battery and robot weight limits enforce a practical limit on motors. If someone want's to build a robot with 28 CIMs, I say more power to them. Or rather exactly the same amount of power as the team that uses 2 CIMs. Good luck operating more than 6 to 8 of them simultaneously.

The problem is that then somebody is bound to try to ignore those limits and complain all over the Internet that the battery/power distribution/control/whatever system isn't good enough and needs to be fixed. (Just like the limits on pit setup during load-in!) It's not that the system is lousy, it's that you don't know how to use it properly!

Sometimes, you just have to have easy-to-enforce limits in place to keep someone from hurting themselves.

[DaveL]

Rahul and Richard:
Thanks for your comments!