Why are Limit Switches outlawed with PWM, but not CAN?

[PhilBot]

One reason that I haven't asked GDC yet is that I don't think they usually like "why" questions... If they opened the gates for these they would be flooded with questions.

For me... Limit switches have three usefull purposes:

1) To tell you when a motion is complete in autonomous:
2) To stop a heavy handed student from braking something because they couldn't tell what was hapenning on the robot in teleop.
3) They protect the hardware while still developing the software.

Your thoughts make perfect sense for 1), but if all we want to do is prevent accidents on manual motions (like in 2), or during S/W development (like in 3) being able to wire the limit switches directly into the Jaguar even when using PWM provides the best protection.

Since you have verified that the limts do work automatically in both control modes if makes me feel more justified in asking GDC the question.

Thanks
Phil.

Originally Posted by dyanoshak

When using Servo PWM or CAN to control a Jaguar, the Limit Switch inputs always stop their corresponding direction when the circuit it open.

It is my understanding* that the reasoning for this rule is that you cannot read the state of the limit switch inputs with the cRIO when using PWM. Not having the ability to know the state of the limit switches could potentially lead to undesired behavior.

When using CAN, the cRIO can request the state of the limit switches so it knows what is going on with a particular Jaguar.

*My understanding does not represent the intent of the GDC. So to get an official answer to this question, you should ask the GDC on the Q&A.