Controlling 6 motors

FIRST General Forum
1

Does anyone have success in controlling 6 motors on a robot? They are not all on at once…our code is simple and not the issue. We think it is either a defective sidecar or a restrictive glitch in one of the drive Vi’s

I can make 3 motors work perfect on any of the 10 PWM channels but when I try to initialize the 4th or more…the motors are erratic.

Another interesting quirk is that if I set the robotdrive VI to jaguar, 3 motors work perfect, BUT if I set the robotdrive VI to Victor, motors do not work…I am using Victor 888’s

Any ideas greatly appreciated
Brent Neudorf
4497

2

Did you try moving around and re addressing the PWMs/using different slots? This could determine whether the issue is the sidecar.

3

Sounds like a standard Sidecar power issue.

You have 12v piped in from the Power Distribution Panel to the Sidecar?
3 bright green power status lights on the Sidecar?

4

It sounds like you are using RobotDrive VI’s for all of your motors. Only use this VI for your drive motors. The rest of the motors in your system should use just Motor Set VI’s. This can be found under the RobotDrive Palette > Advanced > MotorControl.

I believe if you use more than one RobotDrive VI, the motor safety kicks in and stops the robot because of the conflict.

5

Good catch on the Drive VIs comment. Using single motor defs for non-drivetrain motors is the common practice.

But we can have multiple Drive Vi’s and the motor Safety won’t conflict.
The Motor Safety checks are based on unique device references.

6

Ah, thanks for clearing that up. I wasn’t quite sure, seem to be conflicting reports around.

7

The big clue here is that it works a little when telling the code to control Jaguars, but doesn’t work when telling the code to control Victors. That’s about as specific a symptom as one could ask for. I think the Jaguar PWM pulse happens twice as often as the Victor PWM pulse, giving just a little more phantom power to the sidecar.

Bottom line: make sure 12 volt power is getting from the Power Distribution Board to the Digital Sidecar.