Short problem description: Is it legal to use the built-in limit switches of aftermarket linear actuators?
Longer, more detailed description:
We bought a linear actuator not realizing that the motor it had on it would be illegal for FRC use. We switched the motor with an AndyMark 9015, making it a viable power source, but we wired it through the body of the linear actuator, which contains circuitry for limiting the travel of the actuator. According to R55, “Custom circuits shall not directly alter the power pathways between the Robot battery, PDP, motor controllers, … or other elements of the Robot control system.” Does this mean that using the built-in limit switches of the actuator between the motor controller and the 9015 is illegal?
If anybody can provide any information/clarification on this issue it would be greatly appreciated!
I think I would consider that to be modifying the power pathways.
HOWEVER, there would also be a legal way to do this: Wire the limit switches to the RoboRIO (or speed controller limit switch ports) and the motor to the speed controller in question, then program the RIO to react appropriately when a limit switch is pressed.
The actuator that the OP asked about includes a motor. Since that motor is not among those listed in Table 4-1 of R29 (see the Manual, Section 4.8, page 20), it is not legal. The OP’s team replaced the motor with one that is legal, Andymark p/n am-0912.
We can’t just buy any motor or device with an incorporated motor that we want and use it on our robots.
The only legal motors are listed in Table 4-1: Legal Motors on page 20 of the Game Manual Robot section.
In general, for actuators that we purchase on the open market, the motor it comes with will not be on the Legal list and will have to be removed and replaced with a legal motor.