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Error: "Motors: Multiple Controllers Specified"

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Error: "Motors: Multiple Controllers Specified"

Our FTC team has had an issue come up which we did not encounter last year, and frankly I am stumped.  The issue is happening with an installation of last year's FTC LabVIEW (on Mac OS X 10.10 Yosemite) as well as two fresh installations of this year's FTC LabVIEW, both on Windows 8.

Here's the issue: When specifying multiple motors for a motor block, we get an error (see below) that we did not encounter last year:

Error using multiple motors in one block.jpg

Our workaround is to have separate motor blocks for each motor we need to control:

Using separate motor blocks.jpg

After a brief look at the forum here as well as FIRST's FTC forum, I didn't notice any other teams reporting this issue.  So, it could be that we've just forgotten something really basic since last year.

Any input is appreciated!

Thanks,

Julie

Mentor, FTC Team 7314

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Re: Error: "Motors: Multiple Controllers Specified"

I think I figured it out by remembering how the robot is set up. Last year we had both sides of the drivetrain on the same motor controller.  This year's robot currently has one side on one motor controller and the other side on another motor controller, and the motor controllers are not daisy-chained.

So, I might have answered my own question, but I will confirm (hopefully at tonight's meeting) and post again here.  However, if anyone has a definitive answer, that would be great!

Thanks again,

Julie

Mentor, FTC Team 7314

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‎11-10-2014 03:22 PM

Re: Error: "Motors: Multiple Controllers Specified"

Hi jcbc,

You are right that you cannot control motors on two different motor controllers with a single motor function, and you have the right idea by using two different Move Motors/Stop Motors instances.

If possible, I encourage you to change your design so motors that move in sync are on the same motor controller. It is twice as slow to communicate with two motor controllers every iteration of the loop.

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Re: Error: "Motors: Multiple Controllers Specified"

After spending time with a student re-wiring the robot (still the prototype), we saw that code with two motors in one move motors block is fine when the motors are on the same motor controller.  Thanks for confirming, Garrett!  It is an important piece of information to have before finalizing the robot design.

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