diff --git a/classes.py b/classes.py
new file mode 100644
index 0000000..4ea6af5
--- /dev/null
+++ b/classes.py
@@ -0,0 +1,131 @@
+import os
+import platform
+import socket
+from datetime import datetime
+from typing import Optional
+
+import pyodbc
+import snap7
+from dotenv import load_dotenv
+
+load_dotenv()
+
+
+# Entire scheduler config class
+class SchedulerConfig:
+    interval: int
+    next_read: datetime
+
+
+# PLC properties class (energy, air)
+class Plc:
+    id: int
+    name: str
+    ip: str
+    db_number: int  # Where the data is stored in the PLC
+    is_enabled: bool  # True if PLC will be read from
+    air_db_offset: int
+    energy_db_offset: int
+    state_db_offset: int
+    location: str  # H1 or H2
+    last_energy_read: float
+    last_air_read: float
+    last_state_read: bool
+    last_read_timestamp: datetime
+
+    def __init__(self, id: int, name: str, ip: str, db_number: int, 
+                 air_db_offset: int, energy_db_offset: int, 
+                 state_db_offset: int, location: str) -> None:
+        self.id = id
+        self.name = name
+        self.ip = ip
+        self.db_number = db_number
+        self.is_enabled = True  # default value
+        self.air_db_offset = air_db_offset
+        self.energy_db_offset = energy_db_offset
+        self.state_db_offset = state_db_offset
+        self.location = location
+        self.last_energy_read = 0.0
+        self.last_air_read = 0.0
+        self.last_state_read = False
+        self.last_read_timestamp = None
+        
+
+    def check_connection_snap(self) -> bool:
+        """Check if the PLC is reachable."""
+        try:
+            client = snap7.client.Client()
+            client.connect(self.ip, 0, 1)
+            client.disconnect()
+            return True
+        except Exception as e:
+            # logger.error(f"❌ Error checking PLC connection: {e}")
+            return False
+
+    def check_connection_socket(self) -> bool:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            sock.settimeout(1)
+            return sock.connect_ex((self.ip, 102)) == 0
+
+
+# PAC properties class (energy)
+class Pac:
+    id: int
+    name: str
+    ip: str
+    port: int
+    is_enabled: bool
+    location: str  # H1 or H2
+    last_energy_read: float
+    last_read_timestamp: datetime
+
+
+class Database:
+    # Private class attributes (internal use)
+    _sql_driver = (
+        "ODBC Driver 18 for SQL Server"
+        if platform.system() == "Linux"
+        else "SQL Server"
+    )
+    _instance: Optional["Database"] = None
+    _connection = None
+
+    def __new__(cls):
+        if cls._instance is None:
+            cls._instance = super(Database, cls).__new__(cls)
+        return cls._instance
+
+    # Public methods (external interface)
+    def __init__(self):
+        if self._connection is None:
+            self._connection = self._create_connection()
+
+    def execute_query(self, query: str, params: tuple = ()) -> pyodbc.Cursor:
+        """Execute SQL query and return cursor."""
+        cursor = self.get_connection().cursor()
+        cursor.execute(query, params)
+        return cursor
+
+    def get_connection(self) -> pyodbc.Connection:
+        """Get database connection, create new if needed."""
+        if not self._connection or not self._connection.connected:
+            self._connection = self._create_connection()
+        return self._connection
+
+    def close(self) -> None:
+        """Close database connection."""
+        if self._connection:
+            self._connection.close()
+            self._connection = None
+
+    # Private methods (internal use)
+    def _create_connection(self) -> pyodbc.Connection:
+        """Create new database connection."""
+        connection_string = (
+            "DRIVER={SQL Server};"
+            f"SERVER={os.getenv('DB_SERVER')};"
+            f"DATABASE={os.getenv('DB_NAME')};"
+            f"UID={os.getenv('DB_USER')};"
+            f"PWD={os.getenv('DB_PASSWORD')}"
+        )
+        return pyodbc.connect(connection_string)
diff --git a/snap7_test.py b/snap7_test.py
new file mode 100644
index 0000000..3c97818
--- /dev/null
+++ b/snap7_test.py
@@ -0,0 +1,17 @@
+import time
+import snap7
+import pprint
+
+LOOPS = 5
+counter = 0
+while counter < LOOPS:
+    try:
+        plc = snap7.client.Client()
+        plc.connect("172.16.3.231", 0, 1)
+        print(plc.get_cpu_state())
+    except Exception as e:
+        pprint.pprint(e)
+    finally:
+        plc.disconnect()
+    counter += 1
+    time.sleep(1)