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, and frequency. It is specifically built to work with current transformers (CTs), making it ideal for monitoring AC electrical systems. This component provides real-time data, enabling users to analyze energy consumption and improve energy efficiency.

• Home and industrial energy monitoring
• Smart energy management systems
• Renewable energy systems (e.g., solar inverters)
• Load analysis and optimization
• Electrical fault detection and diagnostics

The CT PZEM004T is a versatile and reliable energy meter with the following key specifications:

The CT PZEM004T module has the following pinout:

1. Connect the Voltage Input:

   • Connect the V+ pin to the live wire of the AC system.
   • Connect the V- pin to the neutral wire of the AC system.

2. Connect the Current Transformer (CT):

   • Attach the CT to the AC line you want to monitor.
   • Connect the CT's output wires to the A+ and A- pins of the PZEM004T.

3. Power the Module:

   • The module is self-powered from the AC voltage input. However, if needed, you can provide an external 5V DC power supply to the 5V and GND pins.

4. Establish Communication:

   • Use the TX and RX pins to connect the module to a microcontroller or RS485-to-USB adapter for data communication.
   • Ensure the baud rate is set to 9600 bps for proper communication.

5. Read Data:

   • Use the Modbus RTU protocol to query the module for real-time measurements of voltage, current, power, energy, and frequency.

• Ensure the CT is properly rated for the current range of your application (e.g., 100A CT for loads up to 100A).
• Avoid exposing the module to extreme temperatures or humidity to maintain accuracy and reliability.
• Use proper insulation and safety precautions when working with high-voltage AC systems.
• If connecting to an Arduino or other microcontroller, use an RS485-to-TTL converter for communication.

Below is an example of how to interface the CT PZEM004T with an Arduino UNO using an RS485-to-TTL converter:

• Connect the TX pin of the PZEM004T to the DI pin of the RS485 module.
• Connect the RX pin of the PZEM004T to the RO pin of the RS485 module.
• Connect the GND pin of the PZEM004T to the GND pin of the RS485 module.
• Connect the VCC pin of the RS485 module to the 5V pin of the Arduino.
• Connect the GND pin of the RS485 module to the GND pin of the Arduino.

#include <ModbusMaster.h>

// Create an instance of the ModbusMaster library
ModbusMaster node;

// Define the RS485 enable pin
#define MAX485_DE 2
#define MAX485_RE 3

void preTransmission() {
  digitalWrite(MAX485_DE, HIGH); // Enable RS485 driver
  digitalWrite(MAX485_RE, HIGH);
}

void postTransmission() {
  digitalWrite(MAX485_DE, LOW);  // Disable RS485 driver
  digitalWrite(MAX485_RE, LOW);
}

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  Serial.println("PZEM004T Energy Meter Test");

  // Initialize Modbus communication
  node.begin(1, Serial); // Set Modbus ID to 1
  node.preTransmission(preTransmission);
  node.postTransmission(postTransmission);

  // Configure RS485 enable pins
  pinMode(MAX485_DE, OUTPUT);
  pinMode(MAX485_RE, OUTPUT);
  digitalWrite(MAX485_DE, LOW);
  digitalWrite(MAX485_RE, LOW);
}

void loop() {
  uint8_t result;
  uint16_t data[6];

  // Read voltage (register 0x0000)
  result = node.readInputRegisters(0x0000, 1);
  if (result == node.ku8MBSuccess) {
    Serial.print("Voltage: ");
    Serial.print(node.getResponseBuffer(0) / 10.0); // Convert to volts
    Serial.println(" V");
  }

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

1. No Data Output:

   • Ensure the module is properly powered (check voltage input or external 5V supply).
   • Verify the RS485 connections and ensure the baud rate is set to 9600 bps.

2. Incorrect Readings:

   • Check that the CT is securely clamped around the AC line and connected to the correct pins.
   • Ensure the CT is rated for the current range of your application.

3. Communication Errors:

   • Verify the Modbus ID of the PZEM004T (default is 1).
   • Check the wiring between the RS485 module and the microcontroller.

Q: Can the PZEM004T measure DC voltage or current?
A: No, the PZEM004T is designed specifically for AC systems and cannot measure DC parameters.

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

Q: Can I use multiple PZEM004T modules in the same system?
A: Yes, you can use multiple modules by assigning unique Modbus IDs to each device.

Q: What is the maximum cable length for RS485 communication?
A: RS485 supports cable lengths up to 1200 meters, but ensure proper termination resistors are used for long distances.