esphome/esphome/components/ct_clamp/ct_clamp_sensor.cpp
Andrew Zaborowski c8ccb06f11 ct_clamp: Check sample() return value is not NaN (#921)
Don't try to update CT clamp's state with NaN values returned from the
underlaying sensor.  A single IO error in the sensor code will cause a
NaN to be returned and if we use that in CTClampSensor's floating point
maths both sample_sum_ and offset_ will become NaN and from there every
future calculation will use the NaN offset_ and return NaN too.
2019-12-17 12:08:37 +01:00

90 lines
2.3 KiB
C++

#include "ct_clamp_sensor.h"
#include "esphome/core/log.h"
#include <cmath>
namespace esphome {
namespace ct_clamp {
static const char *TAG = "ct_clamp";
void CTClampSensor::setup() {
this->is_calibrating_offset_ = true;
this->high_freq_.start();
this->set_timeout("calibrate_offset", this->sample_duration_, [this]() {
this->high_freq_.stop();
this->is_calibrating_offset_ = false;
if (this->num_samples_ != 0) {
this->offset_ = this->sample_sum_ / this->num_samples_;
}
});
}
void CTClampSensor::dump_config() {
LOG_SENSOR("", "CT Clamp Sensor", this);
ESP_LOGCONFIG(TAG, " Sample Duration: %.2fs", this->sample_duration_ / 1e3f);
LOG_UPDATE_INTERVAL(this);
}
void CTClampSensor::update() {
if (this->is_calibrating_offset_)
return;
// Update only starts the sampling phase, in loop() the actual sampling is happening.
// Request a high loop() execution interval during sampling phase.
this->high_freq_.start();
// Set timeout for ending sampling phase
this->set_timeout("read", this->sample_duration_, [this]() {
this->is_sampling_ = false;
this->high_freq_.stop();
if (this->num_samples_ == 0) {
// Shouldn't happen, but let's not crash if it does.
this->publish_state(NAN);
return;
}
float raw = this->sample_sum_ / this->num_samples_;
float irms = std::sqrt(raw);
ESP_LOGD(TAG, "'%s' - Raw Value: %.2fA", this->name_.c_str(), irms);
this->publish_state(irms);
});
// Set sampling values
this->is_sampling_ = true;
this->num_samples_ = 0;
this->sample_sum_ = 0.0f;
}
void CTClampSensor::loop() {
if (!this->is_sampling_ && !this->is_calibrating_offset_)
return;
// Perform a single sample
float value = this->source_->sample();
if (isnan(value))
return;
if (this->is_calibrating_offset_) {
this->sample_sum_ += value;
this->num_samples_++;
return;
}
// Adjust DC offset via low pass filter (exponential moving average)
const float alpha = 0.001f;
this->offset_ = this->offset_ * (1 - alpha) + value * alpha;
// Filtered value centered around the mid-point (0V)
float filtered = value - this->offset_;
// IRMS is sqrt(∑v_i²)
float sq = filtered * filtered;
this->sample_sum_ += sq;
this->num_samples_++;
}
} // namespace ct_clamp
} // namespace esphome