github/esphome
2
0
Fork 0
mirror of https://github.com/esphome/esphome.git synced 2026-09-15 17:18:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

[sht4x] Ensure normal measurement between heater cycles

Browse Source 
When heater_interval < update_interval, the heater would fire on
nearly every update cycle, skipping almost all real measurements.
Push the next eligible heater time forward by at least one
update_interval to guarantee at least one ambient reading between
heater activations.
This commit is contained in:
J. Nick Koston
2026-03-20 12:55:01 -10:00
parent 43ff2157b9
commit a73b5cc94a
1 changed files with 9 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
esphome/components/sht4x/sht4x.cpp
+9 -6
View File
@@ -86,16 +86,19 @@ void SHT4XComponent::update() {
uint32_t now = millis();
if (now - this->last_heater_millis_ >= this->heater_interval_) {
use_heater = true;
this->last_heater_millis_ = now;
// Ensure at least one normal measurement between heater cycles by
// pushing the next eligible heater time forward by one update interval.
// The configured duty cycle is a maximum, not an exact target.
uint32_t interval = std::max(this->heater_interval_, this->get_update_interval());
this->last_heater_millis_ = now - this->heater_interval_ + interval;
}
}
if (use_heater) {
// Heater command heats the sensor to remove condensation, then takes a
// measurement (per datasheet section 4.9). The measurement is taken while
// the sensor is still hot, so we must discard it — it does not reflect
// ambient conditions. The next regular update() cycle will provide a
// valid reading after the sensor has cooled.
// Heater command heats the sensor to remove condensation (datasheet 4.9).
// The measurement it produces is taken while hot and does not reflect
// ambient conditions, so we skip this cycle. The next update() will
// take a regular reading after the sensor has cooled.
ESP_LOGD(TAG, "Heater turning on");
if (!this->write_command(this->heater_command_)) {
this->status_set_warning(LOG_STR("Failed to send heater command"));