Documentation

// PZEM-004T V3 - Arduino Example
// TX->D10, RX->D11 (Uno, SoftwareSerial) | Library: "PZEM004Tv30"

#include <PZEM004Tv30.h>
#include <SoftwareSerial.h>

SoftwareSerial pzemSerial(10, 11);   // RX, TX
PZEM004Tv30 pzem(pzemSerial);

void setup() {
  Serial.begin(115200);
  Serial.println("PZEM-004T energy monitor");
}

void loop() {
  float voltage = pzem.voltage();
  float current = pzem.current();
  float power   = pzem.power();
  float energy  = pzem.energy();
  float freq    = pzem.frequency();
  float pf      = pzem.pf();

  if (isnan(voltage)) {
    Serial.println("No response - check wiring and mains presence");
  } else {
    Serial.print(voltage);  Serial.print(" V | ");
    Serial.print(current);  Serial.print(" A | ");
    Serial.print(power);    Serial.print(" W | ");
    Serial.print(energy, 3);Serial.print(" kWh | ");
    Serial.print(freq);     Serial.print(" Hz | PF ");
    Serial.println(pf);
  }
  delay(1000);
}

// PZEM-004T V3 - ESP32 Example (hardware UART2)
// TX->GPIO16, RX->GPIO17 | Library: "PZEM004Tv30"

#include <PZEM004Tv30.h>

PZEM004Tv30 pzem(Serial2, 16, 17);   // UART2, RX=16, TX=17

void setup() {
  Serial.begin(115200);
}

void loop() {
  float v = pzem.voltage();
  if (isnan(v)) {
    Serial.println("No response from PZEM");
  } else {
    Serial.printf("%.1f V  %.3f A  %.1f W  %.3f kWh  %.1f Hz  PF %.2f\n",
                  v, pzem.current(), pzem.power(),
                  pzem.energy(), pzem.frequency(), pzem.pf());
  }
  delay(1000);

  // pzem.resetEnergy();   // uncomment once to zero the kWh counter
}

#!/usr/bin/env python3
# PZEM-004T V3 - Raspberry Pi Example (raw Modbus-RTU)
# TX->GPIO15, RX->GPIO14 (or use /dev/ttyUSB0)
# Install: pip3 install pyserial

import serial, struct, time

def crc16(data):
    crc = 0xFFFF
    for byte in data:
        crc ^= byte
        for _ in range(8):
            if crc & 1:
                crc = (crc >> 1) ^ 0xA001
            else:
                crc >>= 1
    return crc

port = serial.Serial("/dev/serial0", 9600, timeout=1)

# Read 10 input registers from address 0xF8
request = bytes([0xF8, 0x04, 0x00, 0x00, 0x00, 0x0A])
request += struct.pack("<H", crc16(request))

while True:
    port.write(request)
    resp = port.read(25)
    if len(resp) == 25:
        regs = struct.unpack(">10H", resp[3:23])
        voltage = regs[0] / 10
        current = (regs[1] + (regs[2] << 16)) / 1000
        power   = (regs[3] + (regs[4] << 16)) / 10
        energy  = (regs[5] + (regs[6] << 16)) / 1000
        freq    = regs[7] / 10
        pf      = regs[8] / 100
        print(f"{voltage:.1f} V  {current:.3f} A  {power:.1f} W  "
              f"{energy:.3f} kWh  {freq:.1f} Hz  PF {pf:.2f}")
    else:
        print("No/short response - check wiring and mains")
    time.sleep(1)

# PZEM-004T V3 - Pico MicroPython Example (raw Modbus-RTU)
# TX->GP1, RX->GP0, 5V->VBUS

from machine import UART, Pin
import struct, time

uart = UART(0, baudrate=9600, tx=Pin(0), rx=Pin(1), timeout=300)

def crc16(data):
    crc = 0xFFFF
    for byte in data:
        crc ^= byte
        for _ in range(8):
            crc = (crc >> 1) ^ 0xA001 if crc & 1 else crc >> 1
    return crc

req = bytes([0xF8, 0x04, 0x00, 0x00, 0x00, 0x0A])
req += struct.pack("<H", crc16(req))

while True:
    uart.write(req)
    time.sleep_ms(200)
    resp = uart.read()
    if resp and len(resp) >= 25:
        regs = struct.unpack(">10H", resp[3:23])
        voltage = regs[0] / 10
        current = (regs[1] + (regs[2] << 16)) / 1000
        power   = (regs[3] + (regs[4] << 16)) / 10
        energy  = (regs[5] + (regs[6] << 16)) / 1000
        print("{:.1f} V  {:.3f} A  {:.1f} W  {:.3f} kWh".format(
            voltage, current, power, energy))
    else:
        print("No response - check wiring and mains")
    time.sleep(1)