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mhsw-espurna/code/espurna/sensors/PZEM004TV30Sensor.h

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/*
PZEM004T V3 Sensor
Adapted for ESPurna based on:
- https://github.com/mandulaj/PZEM-004T-v30 by Jakub Mandula
- https://innovatorsguru.com/wp-content/uploads/2019/06/PZEM-004T-V3.0-Datasheet-User-Manual.pdf
- http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf
Copyright (C) 2020 by Maxim Prokhorov <prokhorov dot max at outlook dot com>
*/
#include "BaseEmonSensor.h"
#include "../debug.h"
#include "../utils.h"
#include "../terminal.h"
#include <cstdint>
#include <array>
#define PZEM_DEBUG_MSG_P(...) if (_debug) DEBUG_MSG_P(__VA_ARGS__)
class PZEM004TV30Sensor : public BaseEmonSensor {
private:
PZEM004TV30Sensor() : BaseEmonSensor(0) {
_sensor_id = SENSOR_PZEM004TV30_ID;
_error = SENSOR_ERROR_OK;
_count = 6;
}
~PZEM004TV30Sensor() {
PZEM004TV30Sensor::instance = nullptr;
}
public:
static PZEM004TV30Sensor* instance;
static PZEM004TV30Sensor* create() {
if (PZEM004TV30Sensor::instance) return PZEM004TV30Sensor::instance;
PZEM004TV30Sensor::instance = new PZEM004TV30Sensor();
return PZEM004TV30Sensor::instance;
}
static constexpr unsigned long Baudrate = 9600u;
// per MODBUS application protocol specification
// > 4.1 Protocol description
// > ...
// > The size of the MODBUS PDU is limited by the size constraint inherited from the first
// > MODBUS implementation on Serial Line network (max. RS485 ADU = 256 bytes).
// > Therefore:
// > MODBUS PDU for serial line communication = 256 - Server address (1 byte) - CRC (2
// > bytes) = 253 bytes.
// However, we only ever expect very small payloads. Maximum being 10 registers at the same time.
static constexpr size_t BufferSize = 25u;
// stock address, cannot be used with multiple devices on the line
static constexpr uint8_t DefaultAddress = 0xf8;
// XXX: pzem manual does not specify anything, these are arbitrary values (ms)
static constexpr unsigned long DefaultReadTimeout = 200u;
static constexpr unsigned long DefaultUpdateInterval = 200u;
// Device uses Modbus-RTU protocol and implements the following function codes:
// - 0x03 (Read Holding Register) (NOT IMPLEMENTED)
// - 0x04 (Read Input Register) (measurements readout)
// - 0x06 (Write Single Register) (set device address, set alarm is NOT IMPLEMENTED)
// - 0x41 (Calibration) (NOT IMPLEMENTED)
// - 0x42 (Reset energy) (can only reset to 0)
static constexpr uint8_t ReadInputCode = 0x04;
static constexpr uint8_t WriteCode = 0x06;
static constexpr uint8_t ResetEnergyCode = 0x42;
static constexpr uint8_t ErrorMask = 0x80;
// We **can** reset PZEM energy, unlike the original PZEM004T
// However, we can't set it to a specific value, we can only start from 0
void resetEnergy(unsigned char, sensor::Energy) override {}
void resetEnergy() override {
_reset_energy = true;
}
void resetEnergy(unsigned char) override {
_reset_energy = true;
}
double getEnergy(unsigned char index) override {
return _energy;
}
sensor::Energy totalEnergy(unsigned char index) override {
return getEnergy(index);
}
size_t countDevices() override {
return 1;
}
// ---------------------------------------------------------------------
using buffer_type = std::array<uint8_t, BufferSize>;
// - PZEM manual "2.7 CRC check":
// > CRC check use 16bits format, occupy two bytes, the generator polynomial is X16 + X15 + X2 +1,
// > the polynomial value used for calculation is 0xA001.
// - Note that we use a simple function instead of a table to save space and RAM.
static uint16_t crc16modbus(uint8_t* data, size_t size) {
auto crc16_update = [](uint16_t crc, uint8_t value) {
crc ^= static_cast<uint16_t>(value);
for (size_t index = 0; index < 8; ++index) {
if (crc & 1) {
crc = (crc >> 1) ^ 0xa001;
} else {
crc = (crc >> 1);
}
}
return crc;
};
uint16_t crc = 0xffff;
for (size_t index = 0; index < size; ++index) {
crc = crc16_update(crc, data[index]);
}
return crc;
}
struct adu_builder {
adu_builder(uint8_t device_address, uint8_t fcode) :
buffer({device_address, fcode}),
size(2)
{}
adu_builder& add(uint8_t value) {
if (!locked && (size < buffer.size())) {
buffer[size] = value;
size += 1;
}
return *this;
}
adu_builder& add(uint16_t value) {
if (!locked && ((size + 1) < buffer.size())) {
buffer[size] = static_cast<uint8_t>((value >> 8) & 0xff);
buffer[size + 1] = static_cast<uint8_t>(value & 0xff);
size += 2;
}
return *this;
}
// Note that CRC order is reversed in comparison to every other value
adu_builder& end() {
static_assert(BufferSize >= 4, "Cannot fit the minimal request");
if (!locked) {
uint16_t value = crc16modbus(buffer.data(), size);
buffer[size] = static_cast<uint8_t>(value & 0xff);
buffer[size + 1] = static_cast<uint8_t>((value >> 8) & 0xff);
size += 2;
locked = true;
}
return *this;
}
buffer_type buffer;
size_t size { 0 };
bool locked { false };
};
void modbusDebugBuffer(const String& message, buffer_type& buffer, size_t size) {
hexEncode(buffer.data(), size, _debug_buffer, sizeof(_debug_buffer));
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] %s: %s (%u bytes)\n"), message.c_str(), _debug_buffer, size);
}
static size_t modbusExpect(const adu_builder& builder) {
if (!builder.locked) {
return 0;
}
switch (builder.buffer[1]) {
case ReadInputCode:
if (builder.size >= 6) {
return 3 + (2 * ((builder.buffer[4] << 8) | (builder.buffer[5]))) + 2;
}
return 0;
case WriteCode:
return builder.size;
case ResetEnergyCode:
return builder.size;
default:
return 0;
}
}
template <typename Callback>
void modbusProcess(const adu_builder& builder, Callback callback) {
if (!builder.locked) {
return;
}
_stream->write(builder.buffer.data(), builder.size);
size_t expect = modbusExpect(builder);
if (!expect) {
return;
}
uint8_t code = builder.buffer[1];
uint8_t error_code = ErrorMask | code;
size_t bytes = 0;
buffer_type buffer;
// In case we need multiple devices, we need to manually set each one with an unique address **and** also provide
// a way to distinguish between bus messages based on addresses received. Multiple instances **could** work,
// based on the idea that we never receive replies from unknown addresses i.e. we never NOT read responses fully
// and leave something in the serial buffers.
// TODO: testing is much easier, b/c we can just grab any modbus simulator and set up multiple devices
auto ts = millis();
while ((bytes < expect) && (millis() - ts <= _read_timeout)) {
int c = _stream->read();
if (c < 0) {
continue;
}
if ((0 == bytes) && (_address != c)) {
continue;
}
if (1 == bytes) {
if (error_code == c) {
expect = 5;
} else if (code != c) {
bytes = 0;
continue;
}
}
buffer[bytes++] = static_cast<uint8_t>(c);
}
if (bytes && _debug) {
modbusDebugBuffer(F("Received"), buffer, bytes);
}
if (bytes != expect) {
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] ERROR: Expected %u bytes, got %u\n"), expect, bytes);
_error = SENSOR_ERROR_OTHER; // TODO: more error codes
return;
}
uint16_t received_crc = static_cast<uint16_t>(buffer[bytes - 1] << 8) | static_cast<uint16_t>(buffer[bytes - 2]);
uint16_t crc = crc16modbus(buffer.data(), bytes - 2);
if (received_crc != crc) {
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] ERROR: CRC invalid: expected %04X expected, received %04X\n"), crc, received_crc);
_error = SENSOR_ERROR_CRC;
return;
}
if (buffer[1] & ErrorMask) {
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] ERROR: %s (0x%02X)\n"),
errorToString(buffer[2]).c_str(), buffer[2]);
return;
}
callback(std::move(buffer), bytes);
}
// Energy reset is a 'custom' function, and it does not take any function params
bool modbusResetEnergy() {
auto request = adu_builder(_address, ResetEnergyCode)
.end();
// quoting pzem user manual: "Set up correctly, the slave return to the data which is sent from the master.",
bool result = false;
modbusProcess(request, [&](buffer_type&& buffer, size_t size) {
result = std::equal(request.buffer.begin(), request.buffer.begin() + size, buffer.begin());
});
return result;
}
// Address setter is only needed when we are using multiple devices.
// Note that we would no longer be able to receive replies without changing _address member too
bool modbusChangeAddress(uint8_t to) {
if (_address == to) {
return true;
}
auto request = adu_builder(_address, WriteCode)
.add(static_cast<uint16_t>(2))
.add(static_cast<uint16_t>(to))
.end();
// same as for resetEnergy, we receive echo
bool result = false;
modbusProcess(request, [&](buffer_type&& buffer, size_t size) {
result = std::equal(request.buffer.begin(), request.buffer.begin() + size, buffer.begin());
});
return result;
}
// For more, see MODBUS application protocol specification, 7 MODBUS Exception Responses
String errorToString(uint8_t error) {
const __FlashStringHelper *ptr = nullptr;
switch (error) {
case 0x01:
ptr = F("Illegal function");
break;
case 0x02:
ptr = F("Illegal data address");
break;
case 0x03:
ptr = F("Illegal data value");
break;
case 0x04:
ptr = F("Device failure");
break;
case 0x05:
ptr = F("Acknowledged");
break;
case 0x06:
ptr = F("Busy");
break;
case 0x08:
ptr = F("Memory parity error");
break;
default:
ptr = F("Unknown");
break;
}
return ptr;
}
// Quoting the README.md of the original library repo and datasheet, we have:
// (name, measuring range, resolution, accuracy)
// 1. Voltage 80~260V 0.1V 0.5%
// 2. Current 0~10A or 0~100A* 0.01A or 0.02A* 0.5%
// 3. Active power 0~2.3kW or 0~23kW* 0.1W 0.5%
// 4. Active energy 0~9999.99kWh 1Wh 0.5%
// 5. Frequency 45~65Hz 0.1Hz 0.5%
// 6. Power factor 0.00~1.00 0.01 1%
void parseMeasurements(buffer_type&& buffer, size_t size) {
if (25 != size) {
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] Expected measurements ADU size to be at least 25 bytes, but got only %u\n"), size);
return;
}
auto it = buffer.begin() + 3;
auto end = buffer.end();
auto take_2 = [&]() -> double {
double value = 0.0;
if (std::distance(it, end) >= 2) {
value = (static_cast<uint32_t>(*(it)) << 8)
| static_cast<uint32_t>(*(it + 1));
}
it += 2;
return value;
};
auto take_4 = [&]() -> double {
double value = 0.0;
if (std::distance(it, end) >= 4) {
value = (
((static_cast<uint32_t>(*(it + 2)) << 24)
| (static_cast<uint32_t>(*(it + 3)) << 16))
| ((static_cast<uint32_t>(*it) << 8)
| static_cast<uint32_t>(*(it + 1))));
}
it += 4;
return value;
};
// - Voltage: 2 bytes, in 0.1V (we return V)
_voltage = take_2();
_voltage /= 10.0;
// - Current: 4 bytes, in 0.001A (we return A)
_current = take_4();
_current /= 1000.0;
// - Power: 4 bytes, in 0.1W (we return W)
_power = take_4();
_power /= 10.0;
// - Energy: 4 bytes, in Wh (we return kWh)
_energy = take_4();
_energy /= 1000.0;
// - Frequency: 2 bytes, in 0.1Hz (we return Hz)
_frequency = take_2();
_frequency /= 10.0;
// - Power Factor: 2 bytes in 0.1% (we return %)
_power_factor = take_2();
_power_factor /= 100.0;
// - Alarms: 2 bytes, (NOT IMPLEMENTED)
// XXX: it seems it can only be either 0xffff or 0 for ON and OFF respectively
// XXX: what this does, exactly?
_alarm = (0xff == *it) && (0xff == *(it + 1));
}
// Reading measurements is a standard modbus function:
// - addr, 0x04, rhigh, rlow, rnumhigh, rnumlow, crchigh, crclow
// ReadInput reply can be one of:
// - addr, 0x04, nbytes, rndatahigh, rndatalow, rndata..., crchigh, crclow (on success)
// - addr, 0x84, error_code, crchigh, crclow (on error. modbus rtu sets high bit to 1 i.e. 0b00000100 becomes 0b10000100)
void modbusReadValues() {
_error = SENSOR_ERROR_OK;
auto request = adu_builder(_address, ReadInputCode)
.add(static_cast<uint16_t>(0))
.add(static_cast<uint16_t>(10))
.end();
modbusProcess(request, [this](buffer_type&& buffer, size_t size) {
parseMeasurements(std::move(buffer), size);
});
}
void flush() {
while (_stream->read() >= 0) {
}
}
// ---------------------------------------------------------------------
// Note that the device (aka slave) address needs be changed first via
// - some external tool. For example, using USB2TTL adapter and a PC app
// - `pzem.address` with **only** one device on the line
// (because we would change all 0xf8-addressed devices at the same time)
void setAddress(uint8_t address) {
_address = address;
}
void setDebug(bool debug) {
_debug = debug;
}
void setStream(Stream* stream) {
_stream = stream;
_stream->setTimeout(_read_timeout);
}
void setReadTimeout(unsigned long value) {
_read_timeout = value;
}
void setUpdateInterval(unsigned long value) {
_update_interval = value;
}
template <typename T>
void setDescription(T&& description) {
_description = std::forward<T>(description);
}
// ---------------------------------------------------------------------
void begin() override {
_ready = (_stream != nullptr);
_last_reading = millis() - _update_interval;
#if TERMINAL_SUPPORT
terminalRegisterCommand(F("PZ.ADDRESS"), [](const terminal::CommandContext& ctx) {
if (ctx.argc != 2) {
terminalError(ctx.output, F("PZ.ADDRESS <ADDRESS>"));
return;
}
uint8_t updated = settings::internal::convert<uint8_t>(ctx.argv[1]);
PZEM004TV30Sensor::instance->flush();
if (PZEM004TV30Sensor::instance->modbusChangeAddress(updated)) {
PZEM004TV30Sensor::instance->setAddress(updated);
setSetting("pzemv30Addr", updated);
terminalOK(ctx.output);
return;
}
terminalError(ctx.output, F("Could not change the address"));
});
#endif
}
String description() override {
static const String base(F("PZEM004T V3.0"));
return base + " @ " + _description + ", 0x" + String(_address, 16);
}
String description(unsigned char) override {
return description();
}
String address(unsigned char) override {
return String(_address, 16);
}
unsigned char type(unsigned char index) override {
switch (index) {
case 0: return MAGNITUDE_VOLTAGE;
case 1: return MAGNITUDE_CURRENT;
case 2: return MAGNITUDE_POWER_ACTIVE;
case 3: return MAGNITUDE_ENERGY;
case 4: return MAGNITUDE_FREQUENCY;
case 5: return MAGNITUDE_POWER_FACTOR;
}
return MAGNITUDE_NONE;
}
double value(unsigned char index) override {
switch (index) {
case 0: return _voltage;
case 1: return _current;
case 2: return _power;
case 3: return _energy;
case 4: return _frequency;
case 5: return _power_factor;
}
return 0.0;
}
void pre() override {
flush();
if (_reset_energy) {
if (!modbusResetEnergy()) {
PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] Energy reset failed\n"));
}
_reset_energy = false;
flush();
}
if (millis() - _last_reading >= _update_interval) {
modbusReadValues();
_last_reading = millis();
}
}
private:
String _description;
bool _debug { false };
char _debug_buffer[(BufferSize * 2) + 1];
Stream* _stream { nullptr };
uint8_t _address { DefaultAddress };
bool _reset_energy { false };
unsigned long _read_timeout { DefaultReadTimeout };
unsigned long _update_interval { DefaultUpdateInterval };
unsigned long _last_reading { 0 };
double _voltage { 0.0 };
double _current { 0.0 };
double _power { 0.0 };
double _energy { 0.0 };
double _frequency { 0.0 };
double _power_factor { 0.0 };
bool _alarm { false };
};
PZEM004TV30Sensor* PZEM004TV30Sensor::instance = nullptr;
#undef PZEM_DEBUG_MSG_P