Are all E-stop switches created equal?
Greetings all,
So I'm shopping for an E-stop switch and from the pictures they all look about the same. But the price will be from $10 to $20. Are you really getting twice the switch for the $20 version?
Thanks
Rick
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Personally an E-stop switch is something I don't want to cheap out on... One day it might save one of my limbs or my machine from total obliteration.Originally Posted by RicknBeachcrest
I think some of the more expensive ones are more configurable, the one I bought can have extra contacts added to it for switching off extra circuits simultaneously. Not sure that I'll ever need that, but it also seems well built...
There is basically two types of action, push-on twist-release, and simple momentary P.B.
Many manufacturers such as Telemecanique use their common switch block and just select the red mushroom head actuator.
Both have at least one N.C. type switch section, other sections can be added for auxiliary function if required.
The momentary type is customarily used with stop reset P.B. combination, and is the choice I prefer for the principle stop.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Ah, good point... I had forgotten about the momentary ones as I've never had reason to use one...
Strictly speaking the E-Stop should have a yellow background according to code, I usually build this into my panels using reverse engraved Lamacoid.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
i've purchased one e-stop from cncrp...
i've purchased one from automation technologies...
cncrp's grey switch (one made from korea) feels much sturdier, smoother than the one from automationtech site (from china)
[SIZE="1"]my first..."[B][COLOR="Red"]Big Ape[/COLOR][/B]" CNCRP 2448 [URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/151447-big_apes_crp-2448_build.html"]Build Log[/URL][/SIZE]
Lots of Telemecanique on ebay, but I am suspicious of the ones that are listed from China 260795011705?
I tried one of the Telemecanique joy sticks, but it did not quite appear to be the same quality, otherwise identical, right down to the markings!
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Doesn't an e-stop need to be maintained to meet code? In other words, a momentary pushbutton is not okay for an e-stop, you should have to pull it back out or twist to release. When you do, no motion should be possible without pressing a reset button.
Not according to NFPA79, if any momentary type is used in the string, it breaks the circuit of a device that maintained the circuit.
See top centre diagram of the pdf, note the function of the M contact.
http://static.schneider-electric.us/...0140CT9201.pdf
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
New rules require a latching estop button. Pull or twist to release only. Momentary is no longer allowed per NFPA 70e.
Don't skimp on E-Stop buttons.
Being that E-Stop buttons get hit in emergencies they need to be rather rugged. To that end I'd suggest purchasing a more rugged 22 mm or larger version. Note that not all industrial E-Stop buttons are created equal either. To that end I wouldn't skimp.
As far as type, look for twist to release with positive contact actuation. However I wouldn't be shy about allocating panel space for it, you really want the switch to be obvious.
I bought a cheap one for ten bucks, and if I hit it too hard, it falls apart and doesn't break the contact. I bought a very nice new one from Digi-Key, and am much happier.
Gabriel
I have purchased several different Estop switches form several popular sources. The funny thing is only the most expensive ones have failed me.
That said, what I do is use them in normaly closed position then wire two up in series. This way if one fails the other can be hit. Also in this configuration a failed switch wont mess up the other switch.
I have had to use my estops a couple times.
FYI, most failures have been once the switch opens It will no longer close again when returned to normal operation mode.
Last edited by msimpson99; 11-18-2012 at 04:54 PM.
Author of: The CNC Construction Set Books, the KRMx01, KRMx02, KRmc01, and KRmf70 CNC Books, the HANS Electric gear clock book. All available at www.kronosrobotics.com.
Some of the E-Stop buttons aren't worth your time.
We had a machine built with German controls that had terrible E-Stops. A couple of them fell apart when gently used by a older lady. So even big brand names can be questionable.
Reliability is important because almost everybody runs into a situation where they will need to hit the E-Stop very quickly. Having the switch fall apart isn't a very rewarding experience. This is why I suggest making sure that the E-Stop is of good quality even if you skimp on all other parts.
I have never had any problems with the (genuine) Telemecanique 16mm P.B.'s.
Been using them for several years now, and are plentiful on ebay.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
I use one of the e-stops from CNCRouterParts.com, and I'm very happy with it.
I actually trip/release it all the time because my router is in a shared workshop and triggering the e-stop is part of my system for making sure that unauthorized people are not able to use the router...
No problems yet, and I'm not exactly gentle with it.
Thanks for all the replies.
I just ordered one from CNC router parts.
Rick
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