Reading PZEM-004t power sensor (new version v3.0) through Modbus-RTU protocol over TTL UART

pzem_004t.py

# Reading PZEM-004t power sensor (new version v3.0) through Modbus-RTU protocol over TTL UART
# Run as:
# python3 pzem_004t.py

# To install dependencies: 
# pip install modbus-tk
# pip install pyserial

import serial
import modbus_tk.defines as cst
from modbus_tk import modbus_rtu

# Connect to the sensor
sensor = serial.Serial(
    port='/dev/PZEM_sensor',
    baudrate=9600,
    bytesize=8,
    parity='N',
    stopbits=1,
    xonxoff=0
)

master = modbus_rtu.RtuMaster(sensor)
master.set_timeout(2.0)
master.set_verbose(True)

data = master.execute(1, cst.READ_INPUT_REGISTERS, 0, 10)

voltage = data[0] / 10.0 # [V]
current = (data[1] + (data[2] << 16)) / 1000.0 # [A]
power = (data[3] + (data[4] << 16)) / 10.0 # [W]
energy = data[5] + (data[6] << 16) # [Wh]
frequency = data[7] / 10.0 # [Hz]
powerFactor = data[8] / 100.0
alarm = data[9] # 0 = no alarm

print('Voltage [V]: ', voltage)
print('Current [A]: ', current)
print('Power [W]: ', power) # active power (V * I * power factor)
print('Energy [Wh]: ', energy)
print('Frequency [Hz]: ', frequency)
print('Power factor []: ', powerFactor)
print('Alarm : ', alarm)

# Changing power alarm value to 100 W
# master.execute(1, cst.WRITE_SINGLE_REGISTER, 1, output_value=100)

try:
    master.close()
    if sensor.is_open:
        sensor.close()
except:
    pass

Wow, thanks connermacleod69!! That's great info to have at hand. Would you mind sharing what model(s) from the catalog you have used?

Saia PCD ALD1B5F

…

On Tue, Jul 5, 2022, 19:39 José L. Ortiz ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ Wow, thanks connermacleod69 <https://gist.github.com/connermacleod69>!! That's great info to have at hand. Would you mind sharing what model(s) from the catalog you have used? — Reply to this email directly, view it on GitHub <https://gist.github.com/134c9d84ae9bd317297e96dcc0b9c860#gistcomment-4222149>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AIBALPJYJFNZBJGYMRFY2PLVSRXL5ANCNFSM4KFCH5SQ> . You are receiving this because you commented.Message ID: ***@***.***>

Merci @bandaangosta !

this only print the data once right and not a loop? what does the .close() method do?

this only print the data once right and not a loop?

Hi, @FujiwaraKengo . That is correct, data is printed out only once and then the scripts ends, closing the communication channel. You could put the reading part in a loop (lines 27 to 43), allowing for a reasonable waiting time between iterations, or call the full script periodically.