8502ee3c5c
For now only the proportional (Kp) and derivative (Kd) components are used, the integral term is 0.
71 lines
1.3 KiB
C
71 lines
1.3 KiB
C
/* Copyright (c) 2025 Rodrigo Arias Mallo <rodarima@gmail.com>
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* SPDX-License-Identifier: GPL-3.0-or-later */
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#include "heater.h"
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#define HEATER_MIN 500UL /* ms */
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#define HEATER_MAX 2000UL /* ms */
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#define HEATER_PERIOD 5000UL /* ms */
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void
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heater_on(struct heater *h, unsigned long t_ms, float duty)
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{
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unsigned long dt_on = duty * HEATER_MAX;
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if (dt_on < HEATER_MIN)
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dt_on = 0;
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else if (dt_on > HEATER_MAX)
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dt_on = HEATER_MAX;
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h->next_on_dt = dt_on;
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if (h->st == HEATER_OFF) {
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h->st = HEATER_ON;
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h->t0_on = t_ms;
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h->t0_off = t_ms + h->next_on_dt;
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h->cycle = CYCLE_ON;
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}
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}
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void
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heater_off(struct heater *h)
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{
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h->st = HEATER_OFF;
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}
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int
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heater_state(struct heater *h, unsigned long t_ms)
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{
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if (h->st == HEATER_OFF)
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return 0;
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/* Switch state if current time exceeds time limit
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* in the current state */
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/* FIXME: Integer overflow can cause the heater to turn on forever */
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while (1) {
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int changed = 0;
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if (h->cycle == CYCLE_ON) {
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if (t_ms >= h->t0_off) {
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h->cycle = CYCLE_OFF;
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h->t0_on += HEATER_PERIOD;
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changed = 1;
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}
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} else if (h->cycle == CYCLE_OFF) {
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if (t_ms >= h->t0_on) {
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/* Compute current cycle t0_off */
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h->cycle = CYCLE_ON;
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h->t0_off = h->t0_on + h->next_on_dt;
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changed = 1;
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}
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}
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if (!changed)
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break;
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}
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if (h->cycle == CYCLE_ON)
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return 1;
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return 0;
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}
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