E Stop Buttons

Grbl_ESP32 does not directly support e-stop buttons. This is intentional. An e-stop button should cut the primary power. Relying on firmware defeats one of the primary purposes of having an e-stop.

Less Urgent Stops

If you want to stop quickly, but it is not a true emergency and the firmware is still running, you can use these alternatives. All of these can be sent via a gcode sender, the WebUI or a hardware button.

• Feed Hold. This very quickly stops the machine without loss of position. It can be resumed with the cycle start. The feed hold command is the "!" character. The hardware pin is CONTROL_FEED_HOLD_PIN.
• Reset. This immediately stops the machine, but position is lost and you will need to re-home. The command is CTRL-X (0x18). The hardware pin is CONTROL_RESET_PIN. This could be used in parallel with a true e-stop. The power will be cut and Grbl_ESP32 will reset.
• Door/Parking. This feature is used for an enclosure door. If the door is opened during a job, the motion will quickly stop, the bit will retract, the spindle will stop and retract further from the work. The command is character 0x84. The hardware pin is CONTROL_SAFETY_DOOR.