Is software Estop allowed

Hi guys. Since i've worked about this topic, i wanted to say something. First of all, Benb you are right. I also think software e-stop should be implemented in software side. I've integrated emergency stop button like yours to my machine some time. It was actually a circuit which cuts the power of motors, so when you pressed it the motor movements were being stopped but with a problem. The problem is that user was being able to open e-stop via gui(change the pins iocontrol.emc-enable-in and iocontrol.user-enable-out) while the emergency button is still pressed. And of course user was being able to move motors in software, without actual physical movement. I wanted to stop this action. As result, i've tried to add some logic in hal layer. But it didn't work as i want. The thing i really wanted was updating iocontrol.emc-enable-in and iocontrol.user-enable-out pins with extra control, which is emergency button is pressed or not. I've decided to examine the iocontrol component's source code because of this is the component which does the software e-stop. I've changed the source of iocontrol component in the way i described before, and it worked. I've left it as it is. The thing i did is:
1. Intervention to EMC_AUX_ESTOP_ON_TYPE and EMC_AUX_ESTOP_OFF_TYPE with checking extra pin which shows the button status. If button is pressed, iocontrol.emc-enable-in and iocontrol.user-enable-out are not gonna changed. If button is not pressed, it is okay to open e-stop in software.
2. Check the pin which shows emergency stop button is pressed in iocontrol's while loop, if it is pressed, update iocontrol.emc-enable-in and iocontrol.user-enable-out pins to do e-stop.

This solved my problem. User is no more able to change iocontrol.emc-enable-in and iocontrol.user-enable-out pins with a pressed emergency button and when the button is pressed, machine actually stops the movement and does e-stop.

This is my solution. I've changed the iocontrol component and integrated it in the way i described. The problem is that the way i check emergency stop button is pressed or not can be late. Because i am actually measuring the voltage which is given to motor drives. When it is lesser from some value, i am updating my hal pin as button is pressed. So the software receives the button status little bit late. But it is ok, if the button is pressed and there is no power, motors are not gonna be moved. I think it is safe.


I hope i didn't get your problem wrong. This is what i understand from the topic. If you guys have any questions, i can answer it in this context.

Thanks.

ok Benb, you are not from germany

We distinguish between emergency off and emergency stop.

Yes, you need a physical switch, but it can be handled by software. It even has to be in many cases, as a safe shutdown/braking of the machine must be ensured.

de.wikipedia.org/wiki/Notausschalter

in the english version are many more types:
en.wikipedia.org/wiki/Kill_switch

sorry, i was totally wrong, i should have just had a look at home

Example:
whwplastics.com/shop/amann-girrbach-ceramill-mikro-5x/

also none of my commercial 3d printers has an estop

As I mentioned in my original message, anything larger than coffee maker i.e., machines that can cause harm requires an estop; a small 3d printers would fall in the coffee maker category, the only harm a 3d printer can cause is burn to your pinky.Since you are from Germany before selling or letting some else use the machine you refurbished double check your country machine wiring regulation.

Many years ago, I was assigned the design of the electrical controls of a machine for export to Germany. My hair went white trying to decipher the German DIN Electrical standard. DIN is the most rigid standard in the world, it even tells you if toilet paper hung under or over) . 

In your case a simple Estop/reset might not be sufficient, you might need a CE certified safety relay, if bought new it will cost you more than 7i92+7i77.

Don’t let those macho cowboys tell you otherwise, liability can ruin you all the way to your grave. In law, ignorantia juris non excusat which means "Ignorance of the Law excuses not" is a legal term holding that  a person who is unaware of a law may not escape liability.

There have been reports of 3D printers catching fire.

i thought the question was whether an estop via software is generally permitted.

Apparently yes,
e.g. the Amann Girrbach milling machines, which are much bigger than a coffee machine, cost several tens of thousands of euros, come from Germany and don't have one.
I think they have thought this through well enough.

And as I said, not all machines can simply be de-energised without creating even greater risks, a controlled shutdown is necessary there