Redundant PSU Control with EDM

Marlin/Configuration.h

@@ -401,9 +401,18 @@
   //#define PS_OFF_SOUND            // Beep 1s when power off
   #define PSU_ACTIVE_STATE LOW      // Set 'LOW' for ATX, 'HIGH' for X-Box
 
-  //#define PSU_DEFAULT_OFF               // Keep power off until enabled directly with M80
-  //#define PSU_POWERUP_DELAY      250    // (ms) Delay for the PSU to warm up to full power
-  //#define LED_POWEROFF_TIMEOUT 10000    // (ms) Turn off LEDs after power-off, with this amount of delay
+  //#define PSU_DEFAULT_OFF             // Keep power off until enabled directly with M80
+  //#define PSU_POWERUP_DELAY      250  // (ms) Delay for the PSU to warm up to full power
+  //#define LED_POWEROFF_TIMEOUT 10000  // (ms) Turn off LEDs after power-off, with this amount of delay
+
+  //#define PSU_OFF_REDUNDANT           // Second pin for redundant power control
+  //#define PSU_OFF_REDUNDANT_INVERTED  // Redundant pin state is the inverse of PSU_ACTIVE_STATE
+
+  //#define PS_ON1_PIN               6  // Redundant pin required to enable power in combination with PS_ON_PIN
+
+  //#define PS_ON_EDM_PIN            8  // External Device Monitoring pins for external power control relay feedback. Fault on mismatch.
+  //#define PS_ON1_EDM_PIN           9
+  #define PS_EDM_RESPONSE          250  // (ms) Time to allow for relay action
 
   //#define POWER_OFF_TIMER               // Enable M81 D<seconds> to power off after a delay
   //#define POWER_OFF_WAIT_FOR_COOLDOWN   // Enable M81 S to power off only after cooldown

Marlin/src/MarlinCore.cpp

@@ -671,6 +671,12 @@ inline void manage_inactivity(const bool no_stepper_sleep=false) {
 
   TERN_(HOTEND_IDLE_TIMEOUT, hotend_idle.check());
 
+  #if ANY(PSU_CONTROL, AUTO_POWER_CONTROL) && PIN_EXISTS(PS_ON_EDM)
+    if ( ELAPSED(ms, powerManager.last_state_change_ms + PS_EDM_RESPONSE)
+      && (READ(PS_ON_PIN) != READ(PS_ON_EDM_PIN) || TERN0(PSU_OFF_REDUNDANT, extDigitalRead(PS_ON1_PIN) != extDigitalRead(PS_ON1_EDM_PIN)))
+    ) kill(GET_TEXT_F(MSG_POWER_EDM_FAULT));
+  #endif
+
   #if ENABLED(EXTRUDER_RUNOUT_PREVENT)
     if (thermalManager.degHotend(active_extruder) > (EXTRUDER_RUNOUT_MINTEMP)
       && ELAPSED(ms, gcode.previous_move_ms + SEC_TO_MS(EXTRUDER_RUNOUT_SECONDS))

Marlin/src/feature/power.cpp

@@ -60,6 +60,10 @@ bool Power::psu_on;
   millis_t Power::lastPowerOn;
 #endif
 
+#if PSU_TRACK_STATE_MS
+  millis_t Power::last_state_change_ms = 0;
+#endif
+
 /**
  * Initialize pins & state for the power manager.
  *
@@ -87,8 +91,14 @@ void Power::power_on() {
   #endif
 
   OUT_WRITE(PS_ON_PIN, PSU_ACTIVE_STATE);
+  #if ENABLED(PSU_OFF_REDUNDANT)
+    OUT_WRITE(PS_ON1_PIN, TERN_(PSU_OFF_REDUNDANT_INVERTED, !)PSU_ACTIVE_STATE);
+  #endif
+  TERN_(PSU_TRACK_STATE_MS, last_state_change_ms = millis());
+
   psu_on = true;
   safe_delay(PSU_POWERUP_DELAY);
+
   restore_stepper_drivers();
   TERN_(HAS_TRINAMIC_CONFIG, safe_delay(PSU_POWERUP_DELAY));
 
@@ -117,6 +127,11 @@ void Power::power_off() {
   #endif
 
   OUT_WRITE(PS_ON_PIN, !PSU_ACTIVE_STATE);
+  #if ENABLED(PSU_OFF_REDUNDANT)
+    OUT_WRITE(PS_ON1_PIN, IF_DISABLED(PSU_OFF_REDUNDANT_INVERTED, !)PSU_ACTIVE_STATE);
+  #endif
+  TERN_(PSU_TRACK_STATE_MS, last_state_change_ms = millis());
+
   psu_on = false;
 
   #if ANY(POWER_OFF_TIMER, POWER_OFF_WAIT_FOR_COOLDOWN)

Marlin/src/feature/power.h

@@ -24,8 +24,11 @@
 /**
  * power.h - power control
  */
+#if PIN_EXISTS(PS_ON_EDM) || (PIN_EXISTS(PS_ON1_EDM) && ENABLED(PSU_OFF_REDUNDANT))
+  #define PSU_TRACK_STATE_MS 1
+#endif
 
-#if ANY(AUTO_POWER_CONTROL, POWER_OFF_TIMER)
+#if ANY(AUTO_POWER_CONTROL, POWER_OFF_TIMER, PSU_TRACK_STATE_MS)
   #include "../core/millis_t.h"
 #endif
 
@@ -37,6 +40,10 @@ class Power {
     static void power_on();
     static void power_off();
 
+    #if PSU_TRACK_STATE_MS
+      static millis_t last_state_change_ms;
+    #endif
+
     #if ANY(POWER_OFF_TIMER, POWER_OFF_WAIT_FOR_COOLDOWN)
       #if ENABLED(POWER_OFF_TIMER)
         static millis_t power_off_time;

Marlin/src/inc/SanityCheck.h

@@ -3641,6 +3641,8 @@ static_assert(_PLUS_TEST(3), "DEFAULT_MAX_ACCELERATION values must be positive."
     #error "POWER_OFF_DELAY must be a positive value."
   #elif ENABLED(POWER_OFF_WAIT_FOR_COOLDOWN) && !(defined(AUTO_POWER_E_TEMP) || defined(AUTO_POWER_CHAMBER_TEMP) || defined(AUTO_POWER_COOLER_TEMP))
     #error "POWER_OFF_WAIT_FOR_COOLDOWN requires AUTO_POWER_E_TEMP, AUTO_POWER_CHAMBER_TEMP, and/or AUTO_POWER_COOLER_TEMP."
+  #elif ENABLED(PSU_OFF_REDUNDANT) && !PIN_EXISTS(PS_ON1)
+    #error "PSU_OFF_REDUNDANT requires PS_ON1_PIN."
   #endif
 #endif
 

Marlin/src/lcd/language/language_en.h

@@ -155,6 +155,7 @@ namespace LanguageNarrow_en {
   LSTR MSG_SPINDLE_REVERSE                = _UxGT("Spindle Reverse");
   LSTR MSG_SWITCH_PS_ON                   = _UxGT("Switch Power On");
   LSTR MSG_SWITCH_PS_OFF                  = _UxGT("Switch Power Off");
+  LSTR MSG_POWER_EDM_FAULT                = _UxGT("Power EDM Fault");
   LSTR MSG_EXTRUDE                        = _UxGT("Extrude");
   LSTR MSG_RETRACT                        = _UxGT("Retract");
   LSTR MSG_MOVE_AXIS                      = _UxGT("Move Axis");

Marlin/src/pins/pinsDebug_list.h

@@ -901,6 +901,9 @@
 #if PIN_EXISTS(PS_ON)
   REPORT_NAME_DIGITAL(__LINE__, PS_ON_PIN)
 #endif
+#if PIN_EXISTS(PS_ON1)
+  REPORT_NAME_DIGITAL(__LINE__, PS_ON1_PIN)
+#endif
 
 //
 // LCD

Marlin/src/pins/pins_postprocess.h

@@ -477,6 +477,10 @@
   #undef PS_ON_PIN
   #define PS_ON_PIN -1
 #endif
+#if DISABLED(PSU_OFF_REDUNDANT) || !defined(PS_ON1_PIN)
+  #undef PS_ON1_PIN
+  #define PS_ON1_PIN -1
+#endif
 #ifndef KILL_PIN
   #define KILL_PIN -1
 #endif