Pymodbus read and save to database

[buran]

for i in range(len(meters)):
    sql = ("INSERT INTO meter (meter, power, energy, date_of_reading) VALUES (%s, %s, %s, %s)",
    (meters[i], power_calculation[i], energy_calculation[i], date_of_reading))
 
mycursor.execute(*sql)

This will insert just the values for the last meter. You either move the execute inside the loop, or look at changing your code to using executemany

---

Something like this (code not tested):

import mysql.connector
from pymodbus.client import ModbusTcpClient
from datetime import datetime

 
M01 = '192.168.30.156' #LOCATION 1
M02 = '192.168.22.95' #LOCATION 2
 
ips = [M01, M02]
 
date_of_reading = datetime.now()
meters = [ModbusTcpClient(ip) for ip in ips]
readings = []
 
for meter in meters:
    power_register = meter.read_holding_registers(23322, 2)
    energy_register = meter.read_holding_registers(20480, 4)
    power_calculation = round((power_register.registers[0] * pow(2, 16) + power_register.registers[1]) * 0.01 / 1000, 2)
    energy_calculation = round((energy_register.registers[2] * pow(2, 16) + energy_register.registers[3]) * 0.01, 2)
    reading = meter, power_calculation, energy_calculation, date_of_reading
    readings.append(reading)
 
sql = "INSERT INTO meter (meter, power, energy, date_of_reading) VALUES (%s, %s, %s, %s)"

mydb = mysql.connector.connect(
  host="192.168.25.2",
  user="xxxx",
  password="xxxx",
  database="energetics"
)
 
mycursor = mydb.cursor()
mycursor.executemany(sql, readings)
mydb.commit()
mycursor.close()

print("Success !")

From here you can improve the code - using e.g. named tuple for readings, make your code use functions and/or OOP, etc.