Skr pro v1.2 board plugin location for emergency stop button

LowRider CNC Advice
1

for my lr3 i need to know if the skr pro v1.2 board location to plug in an emergency stop im not talking about wiring to ac im talking about same ting in btt 3 e3 tft firmware feature of touch screen emergency stop a mechanical stop is more quicker than fumbling with touchscreen
is the v1 lr3 dual compiled for wired emergency stop?

IMG_20250221_065912
IMG_20250221_0659121800×4000 266 KB

2

IMO you are much better off using an AC switch to power down both the router and the controller, rather than trying to use DC to stop only the controller. In an emergency, you want the router to stop spinning, not just stopping the core from moving.

Something as simple as a power bar with an ON/OFF switch is effective

3

its about the same function as the software emerency stop on tft screen its quicker than cutting power off it takes 5 secs for the mainboard to power off which is not quick enough to stop the x y movement

so ac method power off is out of question

4

Am using multi switch power outlet, am able to plug and separately switch Vac, Compressor and other stuff… Has a master oh crap switch, it’s slightly slower to trigger than a push emergency stop though.

17410545509338485891247420744062
174105455093384858912474207440621920×3950 302 KB

5

In configuration_adv.h, I spotted some code that may provide you the functionality you are looking for.

/**
 * Instant freeze / unfreeze functionality
 * Potentially useful for emergency stop that allows being resumed.
 * @section interface
 */
//#define FREEZE_FEATURE
#if ENABLED(FREEZE_FEATURE)
  //#define FREEZE_PIN 41   // Override the default (KILL) pin here
  #define FREEZE_STATE LOW  // State of pin indicating freeze
#endif

I’ve never seen it mentioned on this forum, and I’ve never tried it, so it make take some experimentation to get it working. You will have to uncomment the feature to enable it, then you will need to define FREEZE_PIN to a free pin named on the SKR Pro board. The firmware will need to be compile and flashed to the board. The emergency stop will need to be wired normally open an connect to the freeze pin and the a ground pin.

Your 5 seconds of the control board and steppers running after AC power is removed is not my experience. I get an immediate stop, which makes me thing this is an artifact of your power supply.

I also question your focus on the control board for your stop switch. There is always the potential of fire with these machines, and stopping the control board while leaving the router running would increase the fire risk. Note having the machine stuck makes an ugly noise, but is nondestructive.

2 Likes
6

It’s not about the fire there a separate ac estop for that I’m talking about main board estop for stopping when routing goes wrong saving the wood project from getting ruined by miss routing or wood piece flyby

1 Like
7

Does this help?

ChatGPT:
James is trying to set up a hardware emergency stop switch on his SKR Pro v1.2 board for his LowRider 3 (LR3) CNC machine. He specifically wants a wired emergency stop button that functions like the software emergency stop on the BTT TFT touchscreen, but with faster activation than fumbling with the touchscreen.

Key Points:

  • He does not want an AC power cutoff since it takes 5 seconds for the mainboard to power down, which is too slow to stop the CNC movement.
  • His goal is to quickly stop X and Y movement when something goes wrong (e.g., bad routing) without completely cutting power to the whole machine.
  • He acknowledges that he has a separate AC emergency stop for fire safety, so this is purely about stopping motion without shutting everything down.
  • Robert Bunney suggested using the FREEZE_FEATURE in Marlin firmware (configuration_adv.h) and assigning a free GPIO pin on the SKR Pro v1.2 as a freeze pin for a normally open switch.

Possible Solution:

  • Enable FREEZE_FEATURE in Marlin’s configuration_adv.h.
  • Assign a FREEZE_PIN to a free pin on the SKR Pro v1.2.
  • Wire a mechanical emergency stop switch to that pin and GND.
  • Recompile and flash Marlin to include the new functionality.
  • Pressing the button should instantly halt motion, similar to the software emergency stop on the touchscreen.

If you need help modifying the firmware, I can guide you through the process. :rocket:

ME: How do you implement a similar instant freeze or halt behavior for a V1 Engineering JackPot CNC controller running FluidNC firmware?

ChatGPT:

For a V1 Engineering JackPot CNC controller running FluidNC, implementing an instant freeze/halt emergency stop requires configuring an input pin as an emergency stop (E-Stop) or feed hold switch. Unlike Marlin, FluidNC provides configurable GPIO inputs that can trigger emergency stop behaviors.

Steps to Implement an Emergency Stop on FluidNC (JackPot Controller)

1. Identify a Free Input Pin on the JackPot Board

  • The V1 Engineering JackPot board is an ESP32-based controller, meaning it has multiple GPIO pins available.
  • You’ll need to choose a free GPIO pin that can be used as an E-Stop trigger.
  • Common options include GPIO36, GPIO39, or other free input-capable pins.

2. Configure the Emergency Stop in config.yaml

FluidNC uses a configuration file (config.yaml) to define all hardware connections.

  • Open your config.yaml file and locate the switches section.
  • Add a new switch definition for an emergency stop button.

Example configuration:

EDIT: Striked through the following AI generated content because I don’t see any reference to a emergency_stop setting in the related Control section within FluidNC wiki docs.
emergency_stop: pin: gpio.36 # Replace with a free pin on JackPot

  • If your switch is normally open (NO), it will activate when pressed.
  • If your switch is normally closed (NC), set type: normally_closed instead.

3. Optional: Implement a “Feed Hold” Instead of Full Stop

If you want a softer halt (pausing motion without full estop), use:

EDIT: Again… Striked through the following AI generated content because I don’t see any reference to a emergency_stop setting in the related Control section within FluidNC wiki docs.
switches: feed_hold: pin: gpio.36 # Replace with your actual pin type: normally_open action: feedhold

  • feedhold will pause the motion instead of stopping the machine completely.
  • This can be useful if you want to resume the job later.

4. Save and Restart FluidNC

  • After editing config.yaml, restart FluidNC for the changes to take effect.

5. Test the Emergency Stop

  • Power on the CNC and start a small test job.
  • Press the emergency stop button.
  • The CNC should immediately halt movement.

Alternative: Use a Hardwired Kill Switch

If you want absolute instant stopping, consider:

  • Wiring a physical kill switch to cut power to the stepper drivers while keeping the ESP32 powered.
  • Using a relay module to disconnect the stepper driver enable pins.

Would you like a more advanced setup, such as triggering an on-screen notification when the estop is pressed?

8

+1

Wiring the switch to the 24v input to the drivers is a kill switch not an EPO. This is what I use in addition to a full system power switch and recommend this for quick instant movement stop. It doesnt kill power to the raspberry pi or the router like the main power switch will.

9

Wow great ai generated info …about right but does precomputed v1 engineering skr pro firmware have that feature compiled in ?

10

No, looks commented to me. I looked at SKR Doc https://docs.v1e.com/electronics/skrpro/#skr-bin to find firmware releases https://github.com/V1EngineeringInc/MarlinBuilder/releases which contains firmware for various controller and machine configs including SkrPro LR Dual endstop https://github.com/V1EngineeringInc/MarlinBuilder/releases/download/515/V1CNC_SkrPro_DualLR_2209-2.1.1.zip, fortunately the zip contains source used to compile, so we can see that build has freeze feature commented.

From Configuration_adv.h within the .zip

/**
 * Instant freeze / unfreeze functionality
 * Potentially useful for emergency stop that allows being resumed.
 * @section interface
 */
//#define FREEZE_FEATURE
#if ENABLED(FREEZE_FEATURE)
  //#define FREEZE_PIN 41   // Override the default (KILL) pin here
  #define FREEZE_STATE LOW  // State of pin indicating freeze
#endif
11

Ah I see … Documentation wasn’t quite clear on that hmmmm so pin 41 refers to what pin on skr pro v1.2 board?

12

You will have to pick a free pin and replace the 41 with that pin. You can find a pinout diagram for the SKR Pro here.

Most of the pins on Extension-1 and Extension-2 are free.

image
image315×153 31.4 KB

Pin PC9 is the designated pin for a laser. I believe all the rest are free. For example you can use PF9.

#define FREEZE_PIN PF9
1 Like
13

thanks a million!

1 Like
14

I don’t think it does.

2 Likes
15

that which is high or low?

16

I assume you will connect your switch between your chosen pin (PF9 in my example above), and ground. You can use any ground pin on your board for the ground connection including the one next to PC9. There is no polarity, so it doesn’t matter which end of the switch is connected to what pin.

The “#define FREEZE_STATE LOW” indicates the freeze will fire when the pin goes low. I haven’t looked at the code specifically, but typically the designated pin will be pulled high by the firmware. Then the firmware monitors the pin looking for it to go low. You make it go low by connecting that pin to a ground pin.

17

ran into issue build code in vscode using platformio
it says"Marlin\src\inc/…/…/Configuration_adv.h:4079:22: error: ‘PF91’ was not declared in this scope; did you mean ‘PF_1’?
4079 | #define FREEZE_PIN PF91 // Override the default (KILL) pin here"
i goes duh

18

The pin is PF9, not PF91.