Y-Cables on high strengths?

Im trying to use 4 of the high torque/speed motors with the new cortex and i cant figure out how to wire it. theres only 2 of the 2 wire ports on the new cortex and i tried to put a controller on the ends of 2 high strength motors and a y-cable off of that and it doesn’t seem to work. anyone know whats wrong?

Well, do you have you motor controller to y cable red to red/yellow and black to black? This may be the problem you are having.

However, our D team actually had their motor controller burn out and start smoking when they tried programming it.

When attempting a project involving the 393 motor, the motor controller was the same one our D team burnt out, making it impossible for me to program that type of motor at the time (didn’t have any extra controllers and was using a PIC microprocessor).

You can plug two of the 393 motors into the two two-wire ports. The other two must be plugged into three-wire ports using Motor Controller 29s.



You can not use Y-Cables on two-wire ports see Rule R12

<R11> Robots may use up to ten (10) VEX EDR motors or VEX Servos (Any combination, up to ten)
a. Of these ten (10) allowed motors, teams may use a maximum of four (4) “2-Wire Motor 393”
b. 2-Wire Motors must be controlled by a 2-Wire Motor Port, either directly on a VEX
Microcontroller, or on a “VEX Motor Controller 29” module.
c. Teams may NOT use multiple 2-wire Motor Ports, 3-wire PWM Motor Ports, or Motor Controller
29 modules on a single motor.
<R12> A maximum of one (1) VEX Y-cable can be used per Motor Port of the Microcontroller or Power
Expander. (You cannot “Y off a Y” to have more than two (2) motors controlled by the same Motor Port.)
a. Teams using the Cortex Microcontroller can only power one (1) 2-wire Motor per each of the
two 2-wire motor ports on the Microcontroller. It is illegal to “Y” off a 2-wire Motor Port.](http://www.vexrobotics.com/products/accessories/motion/276-1668.html)

Wait, port or motor? I never really looked at that rule in depth…

  • Does this mean that two 2 wire motors can be powered in the three wire ports?

As the rule reads now, yes.

Port, just like the words you quoted.

Looking at the rules in depth would be a good idea.

It seems clear that every 2-wire motor needs to have its own #29 motor controller, (or use Cortex ports 1,10).

It seems clear to me that you can use a Y cable to power exactly two #29 motor controllers, but if you don’t read it that way, you should ask in the Q&A.

By technicality, you can even bypass those rules by using digital out to send signals out to the motor controller

Nice catch; I haven’t thought of that recently. It seems like there was some downside… Maybe that digital outputs do not have a high current power rail?

This methodology might be useful for College teams that use a power expander, and have > 10 independent motor controls needed.

Maybe Dean will be inspired to write a motor controller digital output routine for us.