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--- equipment:cnc:mill:maintenance [2024/02/22 15:15] – Homing samp20
+++ equipment:cnc:mill:maintenance [2024/11/19 21:42] (current) – external edit 127.0.0.1
@@ Line 98: / Line 98: @@
 The touch probe signal ''probe-hw'' is connected to ''motion.probe-input'' through a oneshot pulse generator. This effectively pulse stretches the incoming signal to ensure a clean trigger.
+===== Emergency stop =====
+The emergency stop system is split into a hardware e-stop circuit and a software stop.
+The hardware e-stop circuit runs at 240V and provides power to the VFD contactor and 48V stepper power supply. This circuit is fed from the following chain:
+  - Main power NVR switch.
+  - E-stop button.
+The software e-stop has a few different sources:
+  * GPIO from the e-stop button (''estop-button-fault'').
+  * LinuxCNC internal faults.
+While the MESA card is configured with an ''estop-relay'' output that would link the software e-stop to the hardware, we have decided not to connect it. The main reason is to allow the VFD active braking to work correctly during a soft e-stop. We may revisit this later, perhaps with a time delay before cutting the relay.
 ===== Axis limits and homing =====
@@ Line 147: / Line 163: @@
 MIN_LIMIT = -(travel_z - (margin*2))
 MAX_LIMIT = 0
-HOME = MAX_LIMIT - 20
+HOME = MAX_LIMIT - 5
 </code>