Educate me about estop chains and latches

I've looked and can't find an example of using estop_latch with multiple estop circuits? They all seem to have a single estop switch. But now I have 3 of them and I need to clean up my hal file.

The first mushroom button, I wired up so it dropped mains power to the 48 volt power supply that drives my stepper motors and enables a pin on my 7i76e.

The next one is a plasma torch breakaway switch which is connected to its own input. So I ored that with the estop signal to iocontrol.

So now I've added a remote pendant that controls a dedicated normally closed estop relay in the control box. This would be ideal if all I had was one pin with a chain of switches for estop but I don't.

It looks like I can create a software estop_latch chain where the outputs feed into the inputs of the next.

So is that how it is meant to work?
Does anyone have an example of multiple estop circuits they can share?

E-Stop for me is always to shut off power to the whole machine.

All *mushrooms* always in series NC configuration.

Cheers
Bengt

Thats all very well if all they are are estop buttons but a plasma torch falling off a magnetic mount is not really a mushroom button but certainly worthy of stopping everything. Plus I want to know what happened so it needs to light an indicator.

There has to be a software solution.

Simple inductive sensor for the torch head with indicator light = no need for software solution other than series with Enable to shut down ongoing operation.

Rod, you should wire the torch and the pendant e-stop to just stop motion and disable drives, e-stops on the machine should cut the power as they are to be used only if something is teribly wrong.

Tommy , thanks. Thats what I have got. One estop on machine drops AC mains power to anything that moves was how I was advised. Initially, the PC was to have been powered from the cabinet so I wanted to keep it alive. but that is not the case anymore so all power could be dropped to the cabinet.

As the build progresses, its got more complicated. So if I tie the torch breakaway and the pendant estop together, what signals do I trigger in LCNC to disable motion and drives? I still have not connected my stepper enable lines but they are 5 volts so I'd need a relay to trigger them.

Pendant e-stop is E-STOP and must be in series with the big mushroom!

tecno wrote:

Pendant e-stop is E-STOP and must be in series with the big mushroom!

I think I need to buy a better estop switch so I can add an additional NC mechanism instead of using the cheap one I had in my box of tricks then. I was trying to avoid that as it will just take time to get in.

I always thought E-Stops should stop all hazardous mechanical motion, but not shut off associated equipment.
Merely shutting power to equipment would cause devices to roll to a stop.

LinuxCNC when estop is triggered the drives get disabled and therefore stopping most mechanical motion including spindle rotation. Removing power from an inverter that is driving a spindle would take a few minutes for the spindle to stop instead of using breaking.

When you have requirements for inputs to be in the e-stop chain, energize a relay and place the contacts in series with the e-stop chain. I do this when it is not a safety issue but for mechanical protection like the plasma head falling off.

I never remove power from equipment on an e-stop.

Just my thoughts.