I realize that I'm jumping into a thread here, but I really want to say one
thing.
An E-stop should be as fail-safe as physically possible. If there is any
scenario in which the driver could fail in a way that would prevent an
immediate (but controlled) stop, then the E-stop isn't placed/designed
properly. That's the difference between the Stop button and the E-stop.
You don't use the E-stop under normal circumstances, but under ABnormal
ones, when the Stop control is either non-functional, or would be too slow
to decelerate.
In other words, preventing someone from being injured by a runaway machine
is worth the possible sacrifice of the driver, unless there is a way to
GUARANTEE that the machine stops without damaging it. If the operators of
the machine routinely use the E-stop to stop the machine, they haven't been
properly trained.
<./rant>
-DM
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----- Original Message -----
From: "ghidera2000" <ghidera2000@...>
To: <Electronics_101@...>
Sent: Monday, April 12, 2004 11:31 AM
Subject: [Electronics_101] Re: A3977 Stepper driver (finally) updated.
Actually, I just realized. Using E-Stop to cut ALL power to the
driver is probably a bad idea. The A3977 needs power to handle the
stepper motor deceleration (Back EMF). If I just cut all power I'll
likely force an overvoltage back to the A3977 and possibly damage
things.
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