PZEM-004T v3.0 Arduino Library

The PZEM-004T v3.0 supports 247 unique programmable slave addresses, allowing multiple devices to share the same Serial interface.

To use multiple devices:

1. Set a unique custom address for each device using the PZEMChangeAddress example.
2. Use the PZEMMultiDevice pattern to address them individually.
3. Note: You may need external transistors to drive multiple devices on a single bus due to GPIO current limitations on some MCUs.

If you are experiencing issues with the module, check the following:

• Power Requirement: The PZEM device must be connected to 230V AC power. The 5V pin only powers the optocouplers, not the main chip.
• Wiring: Ensure both 5V and GND are connected; these are essential for the optocouplers.
• Communication Errors: If you receive NaN values and only the TX LED is blinking, try swapping the RX/TX wires.
• Address Mismatch: Ensure you are using the correct address. The default address is PZEM_DEFAULT_ADDR (0xF8), which only works for a single device on the ModBus bus. For multiple devices, you must set a custom address for each.
• High Current Readings: If current readings are unexpectedly high (e.g., 0.5A for a 60W device), it is likely due to a low power factor (< 1).

Use the PZEM004Tv30 constructor with a hardware serial object. On boards like the ESP32, you can specify the RX and TX pins directly in the constructor. Note that on boards like the Arduino Uno, using Hardware Serial may conflict with debug output on the Serial console.

#include <PZEM004Tv30.h>

#if defined(ESP32)
PZEM004Tv30 pzem(Serial2, 16, 17);
#else
PZEM004Tv30 pzem(Serial2);
#endif

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

For MCUs without sufficient hardware serial ports, use the <SoftwareSerial.h> library. Pass the SoftwareSerial instance to the PZEM004Tv30 constructor.

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

SoftwareSerial pzemSWSerial(11, 12); // RX, TX
PZEM004Tv30 pzem;

void setup() {
  Serial.begin(115200);
  pzem = PZEM004Tv30(pzemSWSerial);
}

The library provides methods to read various electrical parameters. If a reading fails, the method returns NaN.

Available measurement methods:

• pzem.voltage(): Voltage (V)
• pzem.current(): Current (A)
• pzem.power(): Active Power (W)
• pzem.energy(): Active Energy (kWh)
• pzem.frequency(): Frequency (Hz)
• pzem.pf(): Power Factor
• pzem.readAddress(): Returns the current Modbus slave address.

float voltage = pzem.voltage();
float current = pzem.current();
float power = pzem.power();
float energy = pzem.energy();
float frequency = pzem.frequency();
float pf = pzem.pf();

if(isnan(voltage)) {
    // Handle error
}

You can reset the accumulated energy counter on the PZEM module using the resetEnergy() method.

pzem.resetEnergy();

You can enable debug logging by defining PZEM004TV30_DEBUG in your build configuration. This enables the following macros:

• DEBUG(...): Prints formatted text to the debug serial port.
• DEBUGLN(...): Prints formatted text followed by a newline.
• DEBUGBUF(buf, len): Prints a hex dump of a buffer.

By default, PZEM004TV30_DEBUG_SERIAL is set to Serial. You can override this by defining PZEM004TV30_DEBUG_SERIAL to a different HardwareSerial instance.

// In your build flags or at the top of your sketch
#define PZEM004TV30_DEBUG
#define PZEM004TV30_DEBUG_SERIAL Serial1

// Usage in code
DEBUG("Initializing...");
DEBUGBUF(myBuffer, 10);

If you are looking for software implementations or integrations for PZEM energy meters, consider these resources:

• ESP32 RTOS (Non-blocking): Vortigont's pzem-edl lib is a non-blocking, event-driven library designed for PZEM-004Tv3.0 and PZEM-003 on ESP32.
• Arduino (Legacy): Oleh's PZEM-004T lib is the original Arduino library for legacy versions of the device.
• DC Version: Maxzerker's PZEM-017-v1 lib is for the DC version (PZEM-017-v1).
• Tasmota Integration: Tasmota documentation provides details on embedded support for PZEM within the Tasmota firmware.
• Zabbix Monitoring: zabbuino is a Zabbix agent firmware for Arduino that supports PZEM meters.

Use the following methods to retrieve real-time electrical measurements. These methods return float values representing the measured parameters.

float v = pzem.voltage();     // Voltage
float i = pzem.current();     // Current
float p = pzem.power();       // Power
float e = pzem.energy();     // Energy
float f = pzem.frequency();   // Frequency
float pf = pzem.pf();         // Power Factor

The library provides methods to modify the device's Modbus address, reset accumulated energy, and manage power alarms.

// Address management
bool success = pzem.setAddress(0x12);
uint8_t addr = pzem.getAddress();

// Energy management
pzem.resetEnergy();

// Power alarm management
pzem.setPowerAlarm(1000); // Set alarm at 1000 Watts
bool alarmActive = pzem.getPowerAlarm();

// Scan for devices on the bus
pzem.search();