GRBL Question: Will E-STOP also affect SPINDLE PWM?


(Reiner) #1

I am currently building a Emergency Stop / Router Control Box for my SO3. I will use a solid state relay (SSR) to switch the router on and off and have included an emergency stop switch where the normally-open portion connects E-STOP to GND if pressed. If I do an emergency stop that way, will GRBL also set SPINDLE PWM to 0 in such a situation or do I need to add the normally-closed switch of the emergency stop switch between SPINDLE PWM and the SSD?


(Daniel Story) #2

As others have recommended, the E-Stop should cut power to the Shapeoko and Spindle/Router in cause of an emergency. the E-Stop/Feed Hold pin depends on software and hardware cycles/interrupts, it may not immediately react and stop motion or the spindle.

There has been discussion on having the hard E-Stop (cutting power) along with a soft stop (Feed Hold) in those causes of not so dire emergency, if thats what you were aiming for. In which case I wouldn’t be able to answer how the PWM pin behaves, but someone will I’m sure momentarily :slight_smile:


(Luke) #3

Just cutting PWM isn’t great. If you can use the M5 command some how you can decelerate the spindle really really quickly


(Reiner) #4

I don’t think I have any way to interact with GRBL to inject a M5 G-Code command when the E-STOP button is pressed. That would have to be a function in GRBL itself I gues and I don’t want to mess with the firmware.

If I want to stop the router, I see only the options to cut the power to the router (which is not regulated by the PWM signal but just uses it to switch on/off - see S3 Spindle Control, final redux) on the mains side or on the trigger signal side of the SSR or hope for the firmware to stop PWM when E-STOP is engaged.


(Luke) #5

Ah if you just have a router you won’t get braking.

Your best bet is hook everything up to a bank of high power SSR relays keeping them on a single switch - thats what I have. One flick and everything killed.


(JT) #6

Luke,

Would you mind showing how you hooked/wired yours up? I am new to this however before I get cranking on my new XXL, I am building a full enclosure and wish to mount the control box externally and add an E-Stop switch killing everything. Please correct me if I’m wrong but you are referring to the IOT Power relay correct and hooking up the E-Stop switch to that? It would kill power to the Router and controller. It seems the easiest to assembly. It avoids having to install pins/ soldering or press fit connectors. Ideally I would love to be able to pause the motors and cut power to the router if I need to move a clamp or something then resume the work without having to reset the value. Is this possible?
Btw, looking forward to receiving my Beaver CNC Probe shortly. I plan on upgrading to the HDZ as well.


(system) closed #7

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.