From db9138c5509b37b17a1097f559b17242fde396e7 Mon Sep 17 00:00:00 2001 From: Andrei Mateescu Date: Mon, 12 Oct 2026 20:34:25 +0300 Subject: [PATCH] [bl0939] Add current transformer measurement mode support (#13350) Co-authored-by: ShuishengPeng <63339353+ackPeng@users.noreply.github.com> Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com> --- esphome/components/bl0939/bl0939.cpp | 6 ++- esphome/components/bl0939/bl0939.h | 37 +++++++++++++++++-- esphome/components/bl0939/sensor.py | 15 ++++++++ .../components/bl0939/test-ct.esp32-idf.yaml | 26 +++++++++++++ 4 files changed, 79 insertions(+), 5 deletions(-) create mode 100644 tests/components/bl0939/test-ct.esp32-idf.yaml diff --git a/esphome/components/bl0939/bl0939.cpp b/esphome/components/bl0939/bl0939.cpp index 3a34fad1400..e8dc09abba7 100644 --- a/esphome/components/bl0939/bl0939.cpp +++ b/esphome/components/bl0939/bl0939.cpp @@ -129,7 +129,11 @@ void BL0939::received_package_(const DataPacket *data) const { } void BL0939::dump_config() { // NOLINT(readability-function-cognitive-complexity) - ESP_LOGCONFIG(TAG, "BL0939:"); + ESP_LOGCONFIG(TAG, + "BL0939:\n" + " Mode: %s", + this->mode_ == BL0939Mode::BL0939_MODE_CURRENT_TRANSFORMER ? LOG_STR_LITERAL("current_transformer") + : LOG_STR_LITERAL("direct")); LOG_SENSOR("", "Voltage", this->voltage_sensor_); LOG_SENSOR("", "Current 1", this->current_sensor_1_); LOG_SENSOR("", "Current 2", this->current_sensor_2_); diff --git a/esphome/components/bl0939/bl0939.h b/esphome/components/bl0939/bl0939.h index a22d96ad406..257d9459b5e 100644 --- a/esphome/components/bl0939/bl0939.h +++ b/esphome/components/bl0939/bl0939.h @@ -8,13 +8,32 @@ namespace esphome::bl0939 { // https://datasheet.lcsc.com/lcsc/2108071830_BL-Shanghai-Belling-BL0939_C2841044.pdf // (unfortunately chinese, but the formulas can be easily understood) +// The datasheet has one set of formulas for direct mode (current shunt) and one for current transformer mode. + +// Direct mode. // Sonoff Dual R3 V2 has the exact same resistor values for the current shunts (RL=1miliOhm) // and for the voltage divider (R1=0.51kOhm, R2=5*390kOhm) // as in the manufacturer's reference circuit, so the same formulas were used here (Vref=1.218V) -static const float BL0939_IREF = 324004 * 1 / 1.218; -static const float BL0939_UREF = 79931 * 0.51 * 1000 / (1.218 * (5 * 390 + 0.51)); -static const float BL0939_PREF = 4046 * 1 * 0.51 * 1000 / (1.218 * 1.218 * (5 * 390 + 0.51)); -static const float BL0939_EREF = 3.6e6 * 4046 * 1 * 0.51 * 1000 / (1638.4 * 256 * 1.218 * 1.218 * (5 * 390 + 0.51)); +static constexpr float BL0939_IREF = 324004 * 1 / 1.218; +static constexpr float BL0939_UREF = 79931 * 0.51 * 1000 / (1.218 * (5 * 390 + 0.51)); +static constexpr float BL0939_PREF = 4046 * 1 * 0.51 * 1000 / (1.218 * 1.218 * (5 * 390 + 0.51)); +static constexpr float BL0939_EREF = 3.6e6 * 4046 * 1 * 0.51 * 1000 / (1638.4 * 256 * 1.218 * 1.218 * (5 * 390 + 0.51)); + +// Current transformer mode. +// Values from the Seeed Studio XIAO 2-Channel Wi-Fi AC Energy Meter V1.0 schematic (Vref=1.218V). +// Current: 100A:50mA CT (2000:1) into a 0.6Ohm burden (2 * 0.3Ohm), so 0.3mV per primary amp. +// That is the same as a 0.3mOhm shunt in the direct mode formula. +// Voltage: ZMPT107-1 2mA:2mA voltage transformer with R2=5*22kOhm on the primary and R1=24.9Ohm on +// the secondary. The transformer isolates R1 from R2, so the divider is R1/R2 instead of R1/(R1+R2). +static constexpr float BL0939_IREF_CT = 324004 * 0.3 / 1.218; +static constexpr float BL0939_UREF_CT = 79931 * 24.9 * 1000 / (1.218 * 5 * 22000); +static constexpr float BL0939_PREF_CT = 4046 * 0.3 * 24.9 * 1000 / (1.218 * 1.218 * 5 * 22000); +static constexpr float BL0939_EREF_CT = 3.6e6 * 4046 * 0.3 * 24.9 * 1000 / (1638.4 * 256 * 1.218 * 1.218 * 5 * 22000); + +enum class BL0939Mode : uint8_t { + BL0939_MODE_DIRECT = 0, + BL0939_MODE_CURRENT_TRANSFORMER = 1, +}; struct ube24_t { // NOLINT(readability-identifier-naming,altera-struct-pack-align) uint8_t l; @@ -67,6 +86,15 @@ class BL0939 final : public PollingComponent, public uart::UARTDevice { void set_energy_sensor_2(sensor::Sensor *energy_sensor_2) { energy_sensor_2_ = energy_sensor_2; } void set_energy_sensor_sum(sensor::Sensor *energy_sensor_sum) { energy_sensor_sum_ = energy_sensor_sum; } void set_internal_temperature_sensor(sensor::Sensor *sensor) { this->internal_temperature_sensor_ = sensor; } + // Inline so a constant mode from codegen folds down to plain stores. + void set_mode(BL0939Mode mode) { + this->mode_ = mode; + const bool current_transformer = mode == BL0939Mode::BL0939_MODE_CURRENT_TRANSFORMER; + this->power_reference_ = current_transformer ? BL0939_PREF_CT : BL0939_PREF; + this->voltage_reference_ = current_transformer ? BL0939_UREF_CT : BL0939_UREF; + this->current_reference_ = current_transformer ? BL0939_IREF_CT : BL0939_IREF; + this->energy_reference_ = current_transformer ? BL0939_EREF_CT : BL0939_EREF; + } void loop() override; @@ -95,6 +123,7 @@ class BL0939 final : public PollingComponent, public uart::UARTDevice { float current_reference_ = BL0939_IREF; // Divide by this to turn into kWh float energy_reference_ = BL0939_EREF; + BL0939Mode mode_{BL0939Mode::BL0939_MODE_DIRECT}; static uint32_t to_uint32_t(ube24_t input); diff --git a/esphome/components/bl0939/sensor.py b/esphome/components/bl0939/sensor.py index 401fafedd5e..248002d185f 100644 --- a/esphome/components/bl0939/sensor.py +++ b/esphome/components/bl0939/sensor.py @@ -4,6 +4,7 @@ import esphome.config_validation as cv from esphome.const import ( CONF_ID, CONF_INTERNAL_TEMPERATURE, + CONF_MODE, CONF_VOLTAGE, DEVICE_CLASS_CURRENT, DEVICE_CLASS_ENERGY, @@ -33,11 +34,22 @@ CONF_ENERGY_TOTAL = "energy_total" bl0939_ns = cg.esphome_ns.namespace("bl0939") BL0939 = bl0939_ns.class_("BL0939", cg.PollingComponent, uart.UARTDevice) +BL0939Mode = bl0939_ns.enum("BL0939Mode", is_class=True) +MODE_OPTIONS = { + "direct": BL0939Mode.BL0939_MODE_DIRECT, + "current_transformer": BL0939Mode.BL0939_MODE_CURRENT_TRANSFORMER, +} +# Must match the mode_ member initializer in bl0939.h; set_mode() is skipped +# when the config already equals it. +DEFAULT_MODE = "direct" CONFIG_SCHEMA = ( cv.Schema( { cv.GenerateID(): cv.declare_id(BL0939), + cv.Optional(CONF_MODE, default=DEFAULT_MODE): cv.enum( + MODE_OPTIONS, lower=True + ), cv.Optional(CONF_VOLTAGE): sensor.sensor_schema( unit_of_measurement=UNIT_VOLT, accuracy_decimals=1, @@ -105,6 +117,9 @@ async def to_code(config: ConfigType) -> None: await cg.register_component(var, config) await uart.register_uart_device(var, config) + if (mode := config[CONF_MODE]) != DEFAULT_MODE: + cg.add(var.set_mode(mode)) + sensors = sensor.sub_sensors(config) await sensors(CONF_VOLTAGE, var.set_voltage_sensor) await sensors(CONF_CURRENT_1, var.set_current_sensor_1) diff --git a/tests/components/bl0939/test-ct.esp32-idf.yaml b/tests/components/bl0939/test-ct.esp32-idf.yaml new file mode 100644 index 00000000000..8401f221636 --- /dev/null +++ b/tests/components/bl0939/test-ct.esp32-idf.yaml @@ -0,0 +1,26 @@ +substitutions: + tx_pin: GPIO12 + rx_pin: GPIO14 + +packages: + uart: !include ../../test_build_components/common/uart/esp32-idf.yaml + +sensor: + - platform: bl0939 + mode: current_transformer + voltage: + name: BL0939 Voltage + current_1: + name: BL0939 Current 1 + current_2: + name: BL0939 Current 2 + active_power_1: + name: BL0939 Active Power 1 + active_power_2: + name: BL0939 Active Power 2 + energy_1: + name: BL0939 Energy 1 + energy_2: + name: BL0939 Energy 2 + energy_total: + name: BL0939 Total energy