GUI for PlasmaC - QtPlasmac

robertspark wrote: latching circuit / latching enable?

Yeh, there are a few ways to wire it in that did my head in
I've got a contactor coming so will know more when I get it and experiment more.
The way I have it now more or less replicates how my press brake works, A momentary switch turns the hydraulic pump on and it trips out if you hit estop so if power is lost in a blackout, the motor is not enabled when power is restored without human intervention.

There is no GUI power button on that machine even though it is a touch screen device so I think the power on button in most linuxcnc GUIs is not required.

Something like a 1 shot timer is sometimes used for these sorts of things (or at least to be used when I still was a spark.

The one shot timer allowed everything to get powered up, and then for it to kick in the momentary pulse to allow for the latching circuit to be powered.

The estop (or another device [fire detector, current overload etc]) broke the latching circuit power supply and the oneshot would not fire again until power was reset.

Sorry, I know how to physically do / mark such a device with physical components and I can do it in software with a microcontroller, but not in linuxcnc / python (yet).

Thanks Robert.

robertspark wrote: Sorry, I know how to physically do / mark such a device with physical components and I can do it in software with a microcontroller, but not in linuxcnc / python (yet).

We'd probably use the oneshot component to do it from HAL
So we'd just need to find a pin to fire it.

(ASIDE: If you go to the bottom of the main documents page and click on the button "Expand Man Pages" all the components and their documentation will be revealed. I spent hours reading those docs! Just make sure you read the docs for the version you are using.)

I'd already decided the green button needs to be replaced by a relay so the green button (if used) could be remote from the contactor. The safety relay docs refers to ESC (external start conditions) which is what you describe.

This is still all a learning curve. I had some rather interesting discussions about the estop chain with some very qualified people. The long and the short of that was if you are using a number of estops around a large machine, unless you want to route mains power everywhere (which is in itself a safety issue), you need to use a safety relay to comply with ISO 13850,. This red one here cost me AUD $250

Anyway, thanks for the idea. Having never used a CNC machine before I built one, I don't have any reference point.

I just use a series of estop (mushroom) buttons that are wired in series and all are normally closed.

if I press any estop, then stuff stops in a controlled manor. (the servo and vfd loose their OKtoRUN signals and stop, the steppers loose their enable signals)

nothing looses it's power supply (not good practice)

no it's not iso13850 compliant.... but that is only for some specific (daft??) reasons, and nothing to do with the relay. (shrouded mushroom buttons, keyed mushroom buttons (ok not daft), mushroom buttons without text (daft))

www.google.com/url?sa=t&source=web&rct=j...72F7d4DzpoB4HsUnRdzv

but then I am in my own garage where no one else has access to, and it's not used for commercial purposes.

the worst practice I've seen is full modbus control of a vfd without an stop interlock.....

Yeh, its not a case of what you can do but what you have to do. I lost the argument. I think the risk assessment might set a lower bar for plasma machines than other machines.

it's difficult to rewrite the risk assessment with less fingers or no eyesight later....