Emergency Stop button

My project is detecting defects on fabric sheet by image processing technology. I'm using AC motor to roll the fabric. Now I want to add an emergency stop button to a machine. By this button should be stop everything.(motor, running program)
Can I use Arduino for that task? And I want to know how to do that?
Please help me.

Can do but not recommended...

An eStop is a kill switch... to best to implement by hardware ie relays or supplies that the eStop can disable...

had a project where I had to implement a eStop as part of the system.

the eStop when triggered would kill power to everything

on the electronic side I had my arduino outputs go thru a tri-state buffer that would be diabled if the eStop was triggered.

I also had the eStop signal as an input to the arduino.

That way any output from the arduino would be stopped by the tri-state buffer as soon as the eStop is trigerred while the arduino would then detect it (which maybe a little later ) and safely end its program.

but then again if you are killing power to everything... are you not killing the power to the arduino as well?

in my case that did not happen as it was powered/connected to my laptop an acting as and interface to my motor drive

If the purpose of the EmergencyStop is to prevent damage or injury then you should not rely on a computer program - because computer programs can (and do) go wrong.

...R

In your case indeed an emergency stop would kill the power so everything switches off there and then. You may also want to add brakes on heavy rolls to stop them from moving (of a type where the loss of power engages the brakes).

Also, instead of a button, you may better implement a kick wire around the bottom of the machine. After all, if your hands are caught, how are you going to hit that button?

DinuR:
My project is detecting defects on fabric sheet by image processing technology. I'm using AC motor to roll the fabric. Now I want to add an emergency stop button to a machine. By this button should be stop everything.(motor, running program)
Can I use Arduino for that task? And I want to know how to do that?
Please help me.

By no means. It is explicitly forbbiden.

Regards.

vffgaston:
By no means. It is explicitly forbbiden.

Really? It's not life support or automotive. That's what AVR tells you not to use it for in their data sheet:

Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in,
automotive applications. Atmel products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life.

Also it doesn't sound exactly forbidden, but if you do it and it goes wrong, Atmel can point to this line to avoid liability claims.

Kill the motion causing stuff with hard wired stuff - relays are usually used with multiple E-Stop stations, leave the power to the Arduino up and also then have it reset the program for a controlled start

Software goes bad from time to time and processors can hang up - industrial PLC's also have a watchdog timer built in so if the program does not come around to the start after a certain amount of time (typically a few milliseconds and in the AB stuff it can be adjusted if your program has a slow scan time )

Sorry but doing E-Stops in software is not safe and the systems I worked on was not allowed by code

NFPA 79 - The Authority

NFPA E-stop requirements

E-stop white paper

Bottom line, as already pointed out, no Arduino controlling an E-stop. Annunciating, OK. Even industrial rated PLCs use relays and hard contacts for this.

If you're not in the U.S. YMMV.

dougp:
If you're not in the U.S. YMMV.

What does this mean?
Regards.

vffgaston:

dougp:
If you're not in the U.S. YMMV.

What does this mean?

Well, first of all that you're most likely not in the US :slight_smile: That's a very American expression.

YMMV = Your Mileage May Vary. Commonly used in automotive advertisements where fuel economy claims were made. Nowadays often used as "it could be a different situation/circumstance/... for you". In this case: different safety regulations.

wvmarle:
Well, first of all that you're most likely not in the US :slight_smile: That's a very American expression.

Thanks! I didn't consider that this might not be a universal thing.

wvmarle:
What does this mean?

Well, first of all that you're most likely not in the US :slight_smile: That's a very American expression.

YMMV = Your Mileage May Vary. Commonly used in automotive advertisements where fuel economy claims were made. Nowadays often used as "it could be a different situation/circumstance/... for you". In this case: different safety regulations.

Thanks. Is it used commonly in engineering or is it colloquial?

Regards

Highly colloquial. Never seen it in any serious engineering texts.
By the way, I also only know it from hanging out in too many US-dominated forums. Never even actually set foot in that country.

We seem to have been successful in "emergency stopping" the OP :frowning:

...R

Robin2:
We seem to have been successful in "emergency stopping" the OP (:

Hey, what's new? :slight_smile: