How to Use CT PZEM004T: Examples, Pinouts, and Specs

The CT PZEM004T is a multifunctional energy meter designed to measure key electrical parameters such as voltage, current, power, energy, frequency, and power factor. It is commonly used in conjunction with a current transformer (CT) to monitor AC electrical systems. This component is ideal for applications requiring real-time energy monitoring, such as home automation, industrial energy management, and renewable energy systems.

• Home energy monitoring systems
• Industrial equipment energy analysis
• Renewable energy systems (e.g., solar inverters)
• Smart grid and IoT-based energy management
• Power consumption tracking for appliances

The CT PZEM004T is a compact and efficient energy meter with the following key specifications:

The CT PZEM004T module has a simple pinout for easy integration into circuits:

1. Power Supply: Connect the VCC pin to a 5V DC power source and the GND pin to ground.
2. Current Transformer (CT) Connection: Attach the external CT to the AC line you wish to monitor. Ensure the CT is properly oriented to measure current flow.
3. Voltage Measurement: Connect the AC voltage input terminals of the PZEM004T to the live and neutral wires of the AC system.
4. Communication: Use the TX and RX pins for UART communication or RS485-A and RS485-B for Modbus RTU communication. Ensure proper termination for RS485 lines.
5. Data Reading: Use a microcontroller (e.g., Arduino UNO) or a PC with an RS485-to-USB converter to read data from the module.

• Safety First: Always handle AC connections with care. Ensure the circuit is powered off during installation.
• CT Orientation: The current transformer must be installed in the correct direction to ensure accurate readings.
• Isolation: Use proper electrical isolation when interfacing with high-voltage systems.
• Communication Protocol: Configure the baud rate and Modbus address correctly to avoid communication errors.
• Calibration: Verify the accuracy of the module by comparing its readings with a calibrated energy meter.

Below is an example Arduino sketch to read data from the CT PZEM004T using UART communication:

#include <SoftwareSerial.h>

// Define RX and TX pins for SoftwareSerial
SoftwareSerial pzemSerial(10, 11); // RX = Pin 10, TX = Pin 11

// Include PZEM004T library (install via Arduino Library Manager)
#include <PZEM004Tv30.h>

// Initialize PZEM004T object
PZEM004Tv30 pzem(&pzemSerial);

void setup() {
  Serial.begin(9600); // Initialize Serial Monitor
  pzemSerial.begin(9600); // Initialize PZEM communication
  Serial.println("PZEM004T Energy Meter Example");
}

void loop() {
  // Read voltage
  float voltage = pzem.voltage();
  if (!isnan(voltage)) {
    Serial.print("Voltage: ");
    Serial.print(voltage);
    Serial.println(" V");
  } else {
    Serial.println("Error reading voltage!");
  }

  // Read current
  float current = pzem.current();
  if (!isnan(current)) {
    Serial.print("Current: ");
    Serial.print(current);
    Serial.println(" A");
  } else {
    Serial.println("Error reading current!");
  }

  // Read power
  float power = pzem.power();
  if (!isnan(power)) {
    Serial.print("Power: ");
    Serial.print(power);
    Serial.println(" W");
  } else {
    Serial.println("Error reading power!");
  }

  // Read energy
  float energy = pzem.energy();
  if (!isnan(energy)) {
    Serial.print("Energy: ");
    Serial.print(energy);
    Serial.println(" kWh");
  } else {
    Serial.println("Error reading energy!");
  }

  // Wait 1 second before next reading
  delay(1000);
}

1. No Data Output:

   • Ensure the module is powered correctly (5V DC to VCC and GND).
   • Verify the UART or RS485 connections are secure and correctly configured.
   • Check the baud rate (default is 9600 bps) and Modbus address.

2. Incorrect Readings:

   • Verify the CT is installed in the correct orientation.
   • Ensure the voltage input terminals are securely connected to the AC system.
   • Check for electrical noise or interference in the system.

3. Communication Errors:

   • Ensure proper termination resistors are used for RS485 communication.
   • Verify the TX and RX pins are correctly connected to the microcontroller.

Q: Can the CT PZEM004T measure DC systems?
A: No, the CT PZEM004T is designed for AC systems only.

Q: What is the maximum current it can measure?
A: The module can measure up to 100A when used with the appropriate current transformer.

Q: Can I use multiple PZEM004T modules in the same system?
A: Yes, but each module must have a unique Modbus address to avoid communication conflicts.

Q: How do I reset the energy counter?
A: The energy counter can be reset via a Modbus command. Refer to the module's datasheet for details.

Q: Is the module compatible with 3-phase systems?
A: The CT PZEM004T is designed for single-phase systems. For 3-phase systems, multiple modules can be used, one for each phase.