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Unread 16-10-2014, 14:50
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Ether Ether is offline
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Re: Mechanical limit switches - acceptable practice?

Quote:
Originally Posted by bmammen View Post
We were wondering if it’s an acceptable practice to have a second normally closed limit switch wired in line with a motor and sitting just a little longer in the throw, past the electrically monitored limit switch as a safety precaution?

The reason that I ask is that last season we had two instances where our software controlled limit switch either didn’t work or was physically knocked off center causing a very strong bag motor with planetary gearbox to bend and break our launching mechanism as it didn’t shutoff the motor at the end of the throw.

Any suggestions?
FRC legality aside, a few technical questions:

What motor controller were you using?

About the software you were using to detect the switch state: Was this an interrupt service routine or a polled task? If polled, at what frequency?

About the software you were using to react to the limit switch state: Was this an interrupt service routine or a polled task? If polled, at what frequency?

About the limit switch actuating lever: did you add a flexible extension to prevent permanent bending of the lever?

and finally:

What's the current rating on the limit switch you plan to put in the power line going to the motor?