InnovatorsGuru AC Communication Module PZEM-004T V3.0 User Manual

AC communication module

Overview

This document describes the specification of the PZEM-004T AC communication module,
the module is mainly used for measuring AC voltage, current, active power, frequency, power
factor and active energy, the module is without display function, the data is read through the TTL
interface.

PZEM-004T-10A: Measuring Range 10A (Built-in Shunt)

PZEM-004T-100A: Measuring Range 100A (external transformer)

1.Function description

1.1 Voltage

1.1.1 Measuring range:80～260V

1.1.2 Resolution: 0.1V

1.1.3 Measurement accuracy: 0.5%

1.2 Current

1.2.1 Measuring range: 0～10A(PZEM-004T-10A); 0～100A(PZEM-004T-100A)

1.2.2 Starting measure current: 0.01A(PZEM-004T-10A); 0.02A(PZEM-004T-100A)

1.2.3 Resolution: 0.001A

1.2.4 Measurement accuracy: 0.5%

1.3 Active power

1.3.1 Measuring range: 0～2.3kW(PZEM-004T-10A); 0～23kW(PZEM-004T-100A)

1.3.2 Starting measure power: 0.4W

1.3.3 Resolution: 0.1W

1.3.4 Display format:

＜1000W, it display one decimal, such as: 999.9W

≥1000W, it display only integer, such as: 1000W

1.3.5 Measurement accuracy: 0.5%

PZEM-004T V3.0 User Manual

PZEM004T

1.4 Power factor

1.4.1 Measuring range: 0.00～1.00

1.4.2 Resolution: 0.01

1.4.3 Measurement accuracy: 1%

1.5 Frequency

1.5.1 Measuring range: 45Hz～65Hz

1.5.2 Resolution: 0.1Hz

1.5.3 Measurement accuracy: 0.5%

1.6 Active energy

1.6.1 Measuring range: 0～9999.99kWh

1.6.2 Resolution: 1Wh

1.6.3 Measurement accuracy: 0.5%

1.6.4 Display format:

＜10kWh, the display unit is Wh(1kWh=1000Wh), such as: 9999Wh

≥10kWh, the display unit is kWh, such as: 9999.99kWh

1.6.5 Reset energy: use software to reset.

1.7 Over power alarm

Active power threshold can be set, when the measured active power exceeds the threshold, it
can alarm

1.8 Communication interface

RS485 interface。

2 Communication protocol

2.1 Physical layer protocol

Physical layer use UART to RS485 communication interface

Baud rate is 9600, 8 data bits, 1 stop bit, no parity

2.2 Application layer protocol

The application layer use the Modbus-RTU protocol to communicate. At present, it only
supports function codes such as 0x03 (Read Holding Register), 0x04 (Read Input Register), 0x06
(Write Single Register), 0x41 (Calibration), 0x42 (Reset energy).etc.

0x41 function code is only for internal use (address can be only 0xF8), used for factory
calibration and return to factory maintenance occasions, after the function code to increase 16-bit
password, the default password is 0x3721

The address range of the slave is 0x01 ~ 0xF7. The address 0x00 is used as the broadcast
address, the slave does not need to reply the master. The address 0xF8 is used as the general
address, this address can be only used in single-slave environment and can be used for calibration
etc.operation.

2.3 Read the measurement result

The command format of the master reads the measurement result is(total of 8 bytes):

Slave Address + 0x04 + Register Address High Byte + Register Address Low Byte + Number
of Registers High Byte + Number of Registers Low Byte + CRC Check High Byte + CRC Check
Low Byte.

The command format of the reply from the slave is divided into two kinds:

Correct Reply: Slave Address + 0x04 + Number of Bytes + Register 1 Data High Byte +
Register 1 Data Low Byte + ... + CRC Check High Byte + CRC Check Low Byte

Error Reply: Slave address + 0x84 + Abnormal code + CRC check high byte + CRC check
low byte

Abnormal code analyzed as following (the same below)

⚫ 0x01,Illegal function

⚫ 0x02,Illegal address

⚫ 0x03,Illegal data

⚫ 0x04,Slave error

The register of the measurement results is arranged as the following table

Register

address

Description

Resolution

0x0000

Voltage value

1LSB correspond to 0.1V

0x0001

Current value low 16 bits

1LSB correspond to

0.001A

0x0002

Current value high 16 bits

0x0003

Power value low 16 bits

1LSB correspond to 0.1W

0x0004

Power value high 16 bits

0x0005

Energy value low 16 bits

1LSB correspond to 1Wh

0x0006

Energy value high 16 bits

0x0007

Frequency value

1LSB correspond to 0.1Hz

0x0008

Power factor value

1LSB correspond to 0.01

0x0009

Alarm status

0xFFFF is alarm，
0x0000is not alarm