From 7fc3efe6066f82d9da055fbd3091756eb9cd06be Mon Sep 17 00:00:00 2001
From: Nathael Pajani <nathael.pajani@ed3l.fr>
Date: Mon, 16 Sep 2024 19:59:07 +0200
Subject: [PATCH] Add hysteresys to max water temp handling

---
 v10/main.c | 38 +++++++++++++++++++++++++++++++++-----
 1 file changed, 33 insertions(+), 5 deletions(-)

diff --git a/v10/main.c b/v10/main.c
index 6f60cbb..8d5e66f 100644
--- a/v10/main.c
+++ b/v10/main.c
@@ -69,14 +69,16 @@ volatile char mode = mode_heat;
 volatile char old_mode = mode_heat;
 
 /* Water temperature */
-int water_centi_degrees = 0;
+volatile int water_centi_degrees = 0;
+#define T_HYST  200  /* 2°C */
+#define T_HYST_DELAY  1800  /* 1800 * DEC_PERIOD : 180 seconds : 3 minutes */
+volatile int temp_OK_hysteresys = 0;
+
 
 /* Internal temperatures */
 int deci_degrees_power = 0; /* Power board sensor */
 int deci_degrees_disp = 0; /* Display board sensor */
 
-/* Set to ABSOLUTE_MAX_WATER_TEMP - 1.5°C when enabling max temp hysteresis */
-int max_temp_hysteresys = 0;
 
 /* Value in mA computed upon startup from config ext_source_power_limit */
 int32_t max_intensity = 0;
@@ -111,6 +113,12 @@ void handle_dec_request(uint32_t curent_tick)
 			overvoltage--;
 		}
 	}
+	/* Decrease temp hysteresys only when getting bellow max configuration temperature by T_HYST */
+	if (temp_OK_hysteresys > 0) {
+		if (water_centi_degrees < (sc_conf.conf_max_temp - T_HYST)) {
+			temp_OK_hysteresys--;
+		}
+	}
 }
 
 
@@ -231,6 +239,10 @@ void handle_cmd_update(uint32_t curent_tick)
 				force_fan = 1;
 			}
 			break;
+		case mode_water_critical:
+			/* Water over-temperature limit reached */
+			cmd = 0;
+			break;
 		case mode_manual:
 		case mode_forced:
 			/* Forced heating mode */
@@ -394,14 +406,30 @@ void mode_update(void)
 	}
 	/* Mosfet temperature limit reached or internal temperature above max internal temp */
 	if ((mosfet_temp_shutdown != 0) || (internal_temp_error_shutdown < 0)) {
-		old_mode = mode;
-		mode = mode_overtemp;
+		if (mode != mode_overtemp) {
+			old_mode = mode;
+			mode = mode_overtemp;
+		}
+		return;
+	}
+	/* Water temperature above absolute maximum limit ? */
+	if (water_centi_degrees >= ABSOLUTE_MAX_WATER_TEMP) {
+		if (mode != mode_water_critical) {
+			old_mode = mode;
+			mode = mode_water_critical;
+		}
 		return;
 	}
 
 	/* Water temperature reached config limit ? */
 	if (water_centi_degrees >= sc_conf.conf_max_temp) {
 		mode = mode_temp_OK; /* Max temperature reached */
+		temp_OK_hysteresys = T_HYST_DELAY;
+		return;
+	}
+	if (temp_OK_hysteresys > 0) {
+		mode = mode_temp_OK; /* Max temperature reached */
+		/* Do not decrease temp hysteresys here to get more precise duration */
 		return;
 	}
 
-- 
2.43.0