Is software Estop allowed

Software Estop in the form of UI/HMI touchscreen, flat panel display driven by mouse/keyboard, software commands (G code …) and membrane switches are NOT ALLOWED.

Control regulation rules (common sense) calls for external hardwired red mushroom push button.
Emergency stop push button must be designed to fulfill the following requirements:

• Mushroom-head shape to make it easy to push
• Coloured red and mounted on a bright yellow background
• Push button must remain in latched position after it has been pushed
• Resetting of the Estop by pulling or twisting alone shall not resume operation. A second deliberate action is needed, such as the pressing of a reset button
• Must be located at each operator control station and at any other location where an emergency stop would be required

Now, Linuxcnc has built-in software estops (halui) and estop latch (iocontrol) these components should only used for testing and simulation. Any machine larger than coffee maker that can cause harm must be equipped with an external hardwired Estop push button and a reset button.Linuxcnc ‘gate keepers’ should warn users that - software estops are not allowed - for safety sake.The only OEM that I know uses Linuxcnc software is ‘Tormach’. If you take look at their machines, they equipped their  machines with an external hardwired Estop and reset/start push buttons, the reason liability.I am only trying to raise awareness about software estop, I am not trying to spread fear or trash Linuxcnc, to the contrary Linuxcnc is an excellent piece of software. However, Estops, safety devices and watchdogs must be built external to any controller including PLC, DCS, redundant controller …

There is a lot more to safety circuits than just the estop. Safety relays, redundant circuits, timers, force guided relays to name a few. Most readilly available estop buttons are not compliant to start with.  The added cost of compliancy is a few hundred dollars and few DIYers are willing to spend the money,

So yes, safety is in the hnads of the integrator.

Let me be clear ,I am only trying to raise awareness that screen estops are not allowed.

This discussion is not about machine safety relays, devices, … etc. So, let’s not mix-up things and muddy the discussion.

This awareness message is strictly about machine estop/reset only, which require very simple relay circuit. If you cannot read electrical diagrams just google start/stop circuit and you will find several examples showing realistic picture and wiring diagram for non electrical inclined. 

To build an estop/reset circuit you need: red mushroom shaped push button, a push button and a relay wired as follows:
 

Not really good enough. Everything needs dual redundancy.
 
Note that the estop button has two redunant circuits
The main contactor needs both K1 & K2 to be triggered
K3 & K4 are seperate force guided relays. Linuxcnc is not updated with a sucessful power on unless both K3 & K4 are triggered.
Force guided relays have a non conductive pin forced between the contacts to ensure contacts cannot be welded together.
Additional safety switches eg. door switches, guards etc are placed in the S33/S34 loop with the reset button.

With such a wiring layout, it is permissable to use  linuxcnc's software power button as a reset latch. In this case, use iocontrol.0.user-request-enable as it receives a pulse to repliciate the external reset button.

BUt the safety relay cost me $250 AUD and another $100 or so for the force guided relays.
 

Tommy what you saying in your rant is wrong “software estop is not allowed “.   So, do yourself a favor and add an external estop to your 50 kg bench drill press and your 16-ton machine.I also hope you don’t let anyone else uses your software estop equipped machines, they are unsafe and you will not forgive yourself if someone else using them gets hurt.

And yes, no one asked me for advice but since Linuxcnc documentation does not address this subject I felt obligated to make hobbits and new Linuxcnc users aware of the use of Estop.

Tommy as Linuxcnc gate keeper do us (Linuxcnc users) favor and add a warning in the Linuxcnc documentation “software estop is not allowed.  here is no substitute for an external standalone Estop/reset”.

Gatekeeper ?
Full of good solid advice would be the better description.

Man you are so out of line with that comment.
Up til then it's been a decent discussion.

I'm just hoping there was a bit of confusion into the term "e-stop latch".

Just a little aside.
I've worked a lot of casual labour hire, disposable workers is what we really are, I was at a recycling plant, pulling steel that was missed during separation and wasn't supposed to go into the crusher. The plant wasn't the best safety wise. Anyways they had this dodgy estop setup, was like 2 step away from where you had to work. So after being there for a bit I realised the issue, spoke to the guy on site, no reaction, spoke to my contact at the labour hire mob, all they hid was ring the plant up and were assured yes there is an estop on the machine, tho access wasn't never discussed. So I said "Fuck it" and walked out. Got a call from from the labour hire mob, told them never to call again as their "safety officer was useless". Yeah and they are a major player in concrete recycling in Sydney.
So yeah machine safety is fucking important.
I fully agree a software estop is not the ideal way to go. Ah fuck I've lost my train of thought.