diff --git a/pyheatpump/models/__init__.py b/pyheatpump/models/__init__.py
index e69de29..ce24d1e 100644
--- a/pyheatpump/models/__init__.py
+++ b/pyheatpump/models/__init__.py
@@ -0,0 +1,4 @@
+from .variable import Variable
+from .variable_type import VariableType
+from .variable_value import VariableValue
+__all__ = ['Variable', 'VariableType', 'VariableValue']
diff --git a/pyheatpump/models/variable.py b/pyheatpump/models/variable.py
index 58d0ec6..60e897e 100644
--- a/pyheatpump/models/variable.py
+++ b/pyheatpump/models/variable.py
@@ -1,27 +1,66 @@
 from pyheatpump.db import RowClass
 from pyheatpump.db import sql
 from datetime import date
+from pyheatpump.modbus import rtu
 
 from .variable_type import VariableType
+from .variable_value import VariableValue
 
 class Variable(RowClass):
     address: int = None
     unit: str = None
     last_update: date = None
     type: str = None
- 
+
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
+
     @staticmethod
     def getall():
         return dict([
-            (row.slabel, Variable.getall_of_type(row.slabel))
-            for row in VariableType.getall().values()
+            (row.slabel, Variable.getall_of_type(row))
+            for _, row in VariableType.getall().items()
         ])
 
-    def getall_of_type(type: str):
-        return [
-            row['address'] for row in
-            sql(f"SELECT address FROM variable WHERE type LIKE '{type}'")
-        ]
+
+    @staticmethod
+    def getall_of_type(type: VariableType) -> dict:
+        return dict([
+            (row['address'], Variable(**dict(row)))
+            for row in sql(
+            """
+            SELECT * FROM variable
+            WHERE type = '{}'
+                AND address >= {}
+                AND address <= {}
+            """.format(type.slabel, type.start_address, type.end_address))
+        ])
+
+
+    @staticmethod
+    def getall_values_of_type(type: VariableType) -> dict:
+         return dict([
+            (row['address'], row['value'])
+            for row in sql(
+            """
+            SELECT var.address, val.value FROM variable var
+            LEFT JOIN var_value val ON
+                var.type = val.type
+                AND var.address = val.address
+                AND var.last_update = var.time
+            WHERE
+                var.type = '{}'
+                AND var.address >= {}
+                AND var.address <= {}
+            """.format(type.slabel, type.start_address, type.end_address))
+        ])
+
+
+    def modbus_update(self):
+        if self.type == 'A':
+            pass
+        elif self.type == 'I':
+            pass
+        elif self.type == 'D':
+            pass
diff --git a/pyheatpump/models/variable_type.py b/pyheatpump/models/variable_type.py
index e08e7e0..91f208b 100644
--- a/pyheatpump/models/variable_type.py
+++ b/pyheatpump/models/variable_type.py
@@ -1,13 +1,14 @@
 from pyheatpump.db import RowClass
 from pyheatpump.db import sql
 
+
 class VariableType(RowClass):
     slabel: str = None
     label: str = None
     type: str = None
     start_address: int = None
     end_address: int = None
- 
+
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
@@ -31,10 +32,18 @@ class VariableType(RowClass):
         if len(updates) == 0:
             return
         q.append(','.join(updates))
-        q.append(f"WHERE slabel LIKE '{self.slabel}'")
+        q.append(f"WHERE slabel = '{self.slabel}'")
 
         return sql(' '.join(q))
 
+
+    def get_variables(self):
+        from .variable import Variable
+        return Variable.getall_of_type(self)
+
+    def get_variables_values(self):
+        return Variable.getall_values_of_type(self)
+
     @staticmethod
     def getall():
         return dict([
diff --git a/pyheatpump/models/variable_value.py b/pyheatpump/models/variable_value.py
index 1407bbe..ed03c84 100644
--- a/pyheatpump/models/variable_value.py
+++ b/pyheatpump/models/variable_value.py
@@ -1,18 +1,32 @@
 from pyheatpump.db import RowClass
 from pyheatpump.db import sql
+from datetime import datetime
+from pprint import pprint
 
-class VariableType(RowClass):
-    slabel: str = None
-    label: str = None
+class VariableValue(RowClass):
     type: str = None
-    start_address: int = None
-    end_address: int = None
- 
+    address: int = None
+    time: datetime = None
+    value: int = None
+
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
     @staticmethod
-    def getall():
-        return dict([
-            (row['label'], VariableType(**dict(row)))
-            for row in sql('SELECT * FROM var_type') ])
+    def get(type, address, time=datetime.now()):
+        try:
+            row = next(sql(
+            """
+                SELECT * FROM var_value
+                WHERE
+                    type = '{}'
+                    AND address = {}
+                    AND time <= {}
+                ORDER BY time DESC
+                LIMIT 1
+            """.format(
+                type, address, int(time.strftime('%s'))+1)
+            ))
+            return VariableValue(**dict(row))
+        except StopIteration as e:
+            raise e