Re: E-STOP SWITCH

Hello,
A 'momentary' switch is like a door bell switch. When you press
it, it makes contact. When you let go, the circuit opens up. The
important thing about an E-stop is that is 'latch' the event. If
your motors were to be just shut down WHILE you were pressing E-STOP,
they could come back ON when you let go of the button. For safety,
what you want, is to hit the button once, and have everything shut
down until you specifically remove the E-STOP input condition. There
are two ways to handle this. 1) Mechanical: Once you press the E-STOP
button, you must twist the button to release it from E-STOP
condition. 2) Logic/electrical The First press of the E-STOP sets a
latch that will hold the E-STOP state until you press another button
to release the system from the E-STOP condition.
Normally E-STOP circuits should be wired with a NORMALY CLOSED
(NC) switch. Thus, if the E-STOP wire breaks(or gets cut), the
circuit goes to an 'open' state, and the E-STOP condition is entered.

Jeff
www.xylotex.com


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "res0clvs" <rob.will@v...>
wrote:

> I think I understand what normally open and normally closed means,

but can't guess what momentary means, will someone please
explain "momentary"?

>
> Robert Williams
>
> [Non-text portions of this message have been removed]