Laser Coolant Flow Meter / Safety Shutdown (MarlinFirmware#21431)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/Configuration_adv.h

@@ -204,6 +204,20 @@
   #endif
 #endif
 
+//
+// Laser Coolant Flow Meter
+//
+//#define LASER_COOLANT_FLOW_METER
+#if ENABLED(LASER_COOLANT_FLOW_METER)
+  #define FLOWMETER_PIN         20  // Requires an external interrupt-enabled pin (e.g., RAMPS 2,3,18,19,20,21)
+  #define FLOWMETER_PPL       5880  // (pulses/liter) Flow meter pulses-per-liter on the input pin
+  #define FLOWMETER_INTERVAL  1000  // (ms) Flow rate calculation interval in milliseconds
+  #define FLOWMETER_SAFETY          // Prevent running the laser without the minimum flow rate set below
+  #if ENABLED(FLOWMETER_SAFETY)
+    #define FLOWMETER_MIN_LITERS_PER_MINUTE 1.5 // (liters/min) Minimum flow required when enabled
+  #endif
+#endif
+
 /**
  * Thermal Protection provides additional protection to your printer from damage
  * and fire. Marlin always includes safe min and max temperature ranges which
@@ -1539,6 +1553,7 @@
   #define STATUS_CHAMBER_ANIM         // Use a second bitmap to indicate chamber heating
   //#define STATUS_CUTTER_ANIM        // Use a second bitmap to indicate spindle / laser active
   //#define STATUS_COOLER_ANIM        // Use a second bitmap to indicate laser cooling
+  //#define STATUS_FLOWMETER_ANIM     // Use multiple bitmaps to indicate coolant flow
   //#define STATUS_ALT_BED_BITMAP     // Use the alternative bed bitmap
   //#define STATUS_ALT_FAN_BITMAP     // Use the alternative fan bitmap
   //#define STATUS_FAN_FRAMES 3       // :[0,1,2,3,4] Number of fan animation frames

Marlin/src/core/language.h

@@ -130,6 +130,7 @@
 #define STR_COUNT_A                         " Count A:"
 #define STR_WATCHDOG_FIRED                  "Watchdog timeout. Reset required."
 #define STR_ERR_KILLED                      "Printer halted. kill() called!"
+#define STR_FLOWMETER_FAULT                 "Coolant flow fault. Flowmeter safety is active. Attention required."
 #define STR_ERR_STOPPED                     "Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)"
 #define STR_ERR_SERIAL_MISMATCH             "Serial status mismatch"
 #define STR_BUSY_PROCESSING                 "busy: processing"

Marlin/src/feature/cooler.cpp

@@ -27,11 +27,21 @@
 #include "cooler.h"
 Cooler cooler;
 
-uint16_t Cooler::flowrate;        // Flow meter reading in liters, 0 will result in shutdown if equiped
-uint8_t Cooler::mode = 0;         // 0 = CO2 Liquid cooling, 1 = Laser Diode TEC Heatsink Cooling
-uint16_t Cooler::capacity;        // Cooling capacity in watts
-uint16_t Cooler::load;            // Cooling load in watts
-bool Cooler::flowmeter = false;
-bool Cooler::state = false;       // on = true, off = false
+uint8_t Cooler::mode = 0;
+uint16_t Cooler::capacity;
+uint16_t Cooler::load;
+bool Cooler::enabled = false;
 
+#if ENABLED(LASER_COOLANT_FLOW_METER)
+  bool Cooler::flowmeter = false;
+  millis_t Cooler::flowmeter_next_ms; // = 0
+  volatile uint16_t Cooler::flowpulses;
+  float Cooler::flowrate;
 #endif
+
+#if ENABLED(FLOWMETER_SAFETY)
+  bool Cooler::flowsafety_enabled = true;
+  bool Cooler::fault = false;
+#endif
+
+#endif // HAS_COOLER

Marlin/src/feature/cooler.h

@@ -21,30 +21,91 @@
  */
 #pragma once
 
-#include <stdint.h>
+#include "../inc/MarlinConfigPre.h"
 
-#define _MSG_COOLER(M) MSG_COOLER_##M
-#define MSG_COOLER(M) _MSG_COOLER(M)
+#ifndef FLOWMETER_PPL
+  #define FLOWMETER_PPL      5880 // Pulses per liter
+#endif
+#ifndef FLOWMETER_INTERVAL
+  #define FLOWMETER_INTERVAL 1000 // milliseconds
+#endif
 
 // Cooling device
 
 class Cooler {
 public:
-  static uint16_t flowrate;        // Flow meter reading in liters, 0 will result in shutdown if equiped
-  static uint8_t mode;             // 0 = CO2 Liquid cooling, 1 = Laser Diode TEC Heatsink Cooling
-  static uint16_t capacity;        // Cooling capacity in watts
-  static uint16_t load;            // Cooling load in watts
-  static bool flowmeter;
-  static bool state;               // on = true, off = false
-
-  static bool is_enabled()                    { return state; }
-  static void enable()                        { state = true; }
-  static void disable()                       { state = false; }
-  static void set_mode(const uint8_t m)       { mode = m; }
-  static void set_flowmeter(const bool sflag) { flowmeter = sflag; }
-  static uint16_t get_flowrate()              { return flowrate; }
-  static void update_flowrate(uint16_t flow)  { flowrate = flow; }
-  //static void init() { set_state(false); }
+  static uint16_t capacity;   // Cooling capacity in watts
+  static uint16_t load;       // Cooling load in watts
+
+  static bool enabled;
+  static void enable()  { enabled = true; }
+  static void disable() { enabled = false; }
+  static void toggle()  { enabled = !enabled; }
+
+  static uint8_t mode;                  // 0 = CO2 Liquid cooling, 1 = Laser Diode TEC Heatsink Cooling
+  static void set_mode(const uint8_t m) { mode = m; }
+
+  #if ENABLED(LASER_COOLANT_FLOW_METER)
+    static float flowrate;                // Flow meter reading in liters-per-minute.
+    static bool flowmeter;                // Flag to monitor the flow
+    static volatile uint16_t flowpulses;  // Flowmeter IRQ pulse count
+    static millis_t flowmeter_next_ms;    // Next time at which to calculate flow
+
+    static void set_flowmeter(const bool sflag) {
+      if (flowmeter != sflag) {
+        flowmeter = sflag;
+        if (sflag) {
+          flowpulses = 0;
+          flowmeter_next_ms = millis() + FLOWMETER_INTERVAL;
+        }
+      }
+    }
+
+    // To calculate flow we only need to count pulses
+    static void flowmeter_ISR() { flowpulses++; }
+
+    // Enable / Disable the flow meter interrupt
+    static void flowmeter_interrupt_enable() {
+      attachInterrupt(digitalPinToInterrupt(FLOWMETER_PIN), flowmeter_ISR, RISING);
+    }
+    static void flowmeter_interrupt_disable() {
+      detachInterrupt(digitalPinToInterrupt(FLOWMETER_PIN));
+    }
+
+    // Enable / Disable the flow meter interrupt
+    static void flowmeter_enable()  { set_flowmeter(true); flowpulses = 0; flowmeter_interrupt_enable(); }
+    static void flowmeter_disable() { set_flowmeter(false); flowmeter_interrupt_disable(); flowpulses = 0; }
+
+    // Get the total flow (in liters per minute) since the last reading
+    static void calc_flowrate() {
+      //flowmeter_interrupt_disable();
+      //  const uint16_t pulses = flowpulses;
+      //flowmeter_interrupt_enable();
+      flowrate = flowpulses * 60.0f * (1000.0f / (FLOWMETER_INTERVAL)) * (1000.0f / (FLOWMETER_PPL));
+      flowpulses = 0;
+    }
+
+    // Userland task to update the flow meter
+    static void flowmeter_task(const millis_t ms=millis()) {
+      if (!flowmeter)       // !! The flow meter must always be on !!
+        flowmeter_enable(); // Init and prime
+      if (ELAPSED(ms, flowmeter_next_ms)) {
+        calc_flowrate();
+        flowmeter_next_ms = ms + FLOWMETER_INTERVAL;
+      }
+    }
+
+    #if ENABLED(FLOWMETER_SAFETY)
+      static bool fault;                // Flag that the cooler is in a fault state
+      static bool flowsafety_enabled;   // Flag to disable the cutter if flow rate is too low
+      static void flowsafety_toggle()   { flowsafety_enabled = !flowsafety_enabled; }
+      static bool check_flow_too_low() {
+        const bool too_low = flowsafety_enabled && flowrate < (FLOWMETER_MIN_LITERS_PER_MINUTE);
+        if (too_low) fault = true;
+        return too_low;
+      }
+    #endif
+  #endif
 };
 
 extern Cooler cooler;

Marlin/src/feature/spindle_laser.h

@@ -215,8 +215,7 @@ class SpindleLaser {
   static inline void disable() { isReady = false; set_enabled(false); }
 
   #if HAS_LCD_MENU
-
-    static inline void enable_with_dir(const bool reverse) {
+      static inline void enable_with_dir(const bool reverse) {
       isReady = true;
       const uint8_t ocr = TERN(SPINDLE_LASER_PWM, upower_to_ocr(menuPower), 255);
       if (menuPower)
@@ -245,8 +244,8 @@ class SpindleLaser {
        * If not set defaults to 80% power
        */
       static inline void test_fire_pulse() {
-        enable_forward();                  // Turn Laser on (Spindle speak but same funct)
         TERN_(USE_BEEPER, buzzer.tone(30, 3000));
+        enable_forward();                  // Turn Laser on (Spindle speak but same funct)
         delay(testPulse);                  // Delay for time set by user in pulse ms menu screen.
         disable();                         // Turn laser off
       }

Marlin/src/gcode/gcode.cpp

@@ -57,6 +57,10 @@ GcodeSuite gcode;
   #include "../feature/spindle_laser.h"
 #endif
 
+#if ENABLED(FLOWMETER_SAFETY)
+  #include "../feature/cooler.h"
+#endif
+
 #if ENABLED(PASSWORD_FEATURE)
   #include "../feature/password/password.h"
 #endif
@@ -278,6 +282,13 @@ void GcodeSuite::process_parsed_command(const bool no_ok/*=false*/) {
     }
   #endif
 
+  #if ENABLED(FLOWMETER_SAFETY)
+    if (cooler.fault) {
+      SERIAL_ECHO_MSG(STR_FLOWMETER_FAULT);
+      return;
+    }
+  #endif
+
   // Handle a known G, M, or T
   switch (parser.command_letter) {
     case 'G': switch (parser.codenum) {

Marlin/src/inc/SanityCheck.h

@@ -1895,6 +1895,10 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
   #error "TEMP_SENSOR_COOLER requires LASER_FEATURE and TEMP_COOLER_PIN."
 #endif
 
+#if ENABLED(LASER_COOLANT_FLOW_METER) && !(PIN_EXISTS(FLOWMETER) && ENABLED(LASER_FEATURE))
+  #error "LASER_COOLANT_FLOW_METER requires FLOWMETER_PIN and LASER_FEATURE."
+#endif
+
 #if ENABLED(CHAMBER_FAN) && !(defined(CHAMBER_FAN_MODE) && WITHIN(CHAMBER_FAN_MODE, 0, 2))
   #error "CHAMBER_FAN_MODE must be between 0 and 2."
 #endif

Marlin/src/lcd/HD44780/marlinui_HD44780.cpp

@@ -46,6 +46,10 @@
   #include "../../gcode/parser.h"
 #endif
 
+#if HAS_COOLER || HAS_FLOWMETER
+  #include "../../feature/cooler.h"
+#endif
+
 #if ENABLED(AUTO_BED_LEVELING_UBL)
   #include "../../feature/bedlevel/bedlevel.h"
 #endif
@@ -517,6 +521,7 @@ FORCE_INLINE void _draw_axis_value(const AxisEnum axis, const char *value, const
     lcd_put_u8str(value);
 }
 
+
 FORCE_INLINE void _draw_heater_status(const heater_id_t heater_id, const char prefix, const bool blink) {
   #if HAS_HEATED_BED
     const bool isBed = TERN(HAS_HEATED_CHAMBER, heater_id == H_BED, heater_id < 0);
@@ -550,6 +555,43 @@ FORCE_INLINE void _draw_heater_status(const heater_id_t heater_id, const char pr
   }
 }
 
+#if HAS_COOLER
+FORCE_INLINE void _draw_cooler_status(const char prefix, const bool blink) {
+  const float t1 = thermalManager.degCooler(), t2 = thermalManager.degTargetCooler();
+
+  if (prefix >= 0) lcd_put_wchar(prefix);
+
+  lcd_put_u8str(i16tostr3rj(t1 + 0.5));
+  lcd_put_wchar('/');
+
+  #if !HEATER_IDLE_HANDLER
+    UNUSED(blink);
+  #else
+    if (!blink && thermalManager.heater_idle[thermalManager.idle_index_for_id(heater_id)].timed_out) {
+      lcd_put_wchar(' ');
+      if (t2 >= 10) lcd_put_wchar(' ');
+      if (t2 >= 100) lcd_put_wchar(' ');
+    }
+    else
+  #endif
+      lcd_put_u8str(i16tostr3left(t2 + 0.5));
+
+  if (prefix >= 0) {
+    lcd_put_wchar(LCD_STR_DEGREE[0]);
+    lcd_put_wchar(' ');
+    if (t2 < 10) lcd_put_wchar(' ');
+  }
+}
+#endif
+
+#if HAS_FLOWMETER
+  FORCE_INLINE void _draw_flowmeter_status() {
+    lcd_put_u8str("~ ");
+    lcd_put_u8str(ftostr11ns(cooler.flowrate));
+    lcd_put_wchar('L');
+  }
+#endif
+
 FORCE_INLINE void _draw_bed_status(const bool blink) {
   _draw_heater_status(H_BED, TERN0(HAS_LEVELING, blink && planner.leveling_active) ? '_' : LCD_STR_BEDTEMP[0], blink);
 }
@@ -747,35 +789,46 @@ void MarlinUI::draw_status_screen() {
       //
       // Hotend 0 Temperature
       //
-      _draw_heater_status(H_E0, -1, blink);
-
-      //
-      // Hotend 1 or Bed Temperature
-      //
-      #if HAS_MULTI_HOTEND
-        lcd_moveto(8, 0);
-        _draw_heater_status(H_E1, LCD_STR_THERMOMETER[0], blink);
-      #elif HAS_HEATED_BED
-        lcd_moveto(8, 0);
-        _draw_bed_status(blink);
+      #if HAS_HOTEND
+        _draw_heater_status(H_E0, -1, blink);
+
+        //
+        // Hotend 1 or Bed Temperature
+        //
+        #if HAS_MULTI_HOTEND
+          lcd_moveto(8, 0);
+          _draw_heater_status(H_E1, LCD_STR_THERMOMETER[0], blink);
+        #elif HAS_HEATED_BED
+          lcd_moveto(8, 0);
+          _draw_bed_status(blink);
+        #endif
       #endif
 
     #else // LCD_WIDTH >= 20
 
       //
       // Hotend 0 Temperature
       //
-      _draw_heater_status(H_E0, LCD_STR_THERMOMETER[0], blink);
+      #if HAS_HOTEND
+        _draw_heater_status(H_E0, LCD_STR_THERMOMETER[0], blink);
+
+        //
+        // Hotend 1 or Bed Temperature
+        //
+        #if HAS_MULTI_HOTEND
+          lcd_moveto(10, 0);
+          _draw_heater_status(H_E1, LCD_STR_THERMOMETER[0], blink);
+        #elif HAS_HEATED_BED
+          lcd_moveto(10, 0);
+          _draw_bed_status(blink);
+        #endif
+      #endif
 
-      //
-      // Hotend 1 or Bed Temperature
-      //
-      #if HAS_MULTI_HOTEND
-        lcd_moveto(10, 0);
-        _draw_heater_status(H_E1, LCD_STR_THERMOMETER[0], blink);
-      #elif HAS_HEATED_BED
-        lcd_moveto(10, 0);
-        _draw_bed_status(blink);
+      #if HAS_COOLER
+        _draw_cooler_status('*', blink);
+      #endif
+      #if HAS_FLOWMETER
+        _draw_flowmeter_status();
       #endif
 
     #endif // LCD_WIDTH >= 20