diff --git a/pyscada/device.py b/pyscada/device.py
index 8dbaf9d4..bc14c572 100644
--- a/pyscada/device.py
+++ b/pyscada/device.py
@@ -48,6 +48,7 @@ def connect(self):
             return False
 
         # self.accessibility()
+        return True
 
     def accessibility(self):
         if self.inst is not None:
@@ -67,8 +68,7 @@ def accessibility(self):
     def disconnect(self):
         if self.inst is not None:
             self.inst = None
-            return True
-        return False
+        return True
 
     def before_read(self):
         """
@@ -98,13 +98,13 @@ def read_data_and_time(self, variable_instance):
 
         return self.read_data(variable_instance), self.time()
 
-    def read_data_all(self, variables_dict):
+    def read_data_all(self, variables_dict, erase_cache=True):
         output = []
 
         if self.before_read():
             for item in variables_dict.values():
                 value, read_time = self.read_data_and_time(item)
-                if value is not None and item.update_values([value], [read_time]):
+                if value is not None and read_time is not None and item.update_values(value, read_time, erase_cache=erase_cache):
                     output.append(item)
         self.after_read()
         return output
diff --git a/pyscada/models.py b/pyscada/models.py
index 074b14b6..b64bbd0f 100755
--- a/pyscada/models.py
+++ b/pyscada/models.py
@@ -1916,7 +1916,11 @@ def _update_value(self, value=None, timestamp=None):
             self.value = value
         else:
             self.value = self.scaling.scale_value(value)
-        self.timestamp = timestamp
+        try:
+            self.timestamp = float(timestamp)
+        except ValueError as e:
+            logger.error(f"{self} - wrong timestamp : {e}")
+            return False
         self.store_value = False
         if self.prev_value is None:
             # no prev value in the cache, always store the value
@@ -1947,18 +1951,28 @@ def update_values(self, value_list, timestamp_list, erase_cache=True):
         if erase_cache:
             self.cached_values_to_write = []
         has_value = False
-        if isinstance(value_list.__class__, list):
-            logger.error(
-                f"{self} - Value list must be a list, it is a {type(value_list)}"
-            )
-            return False
-        if isinstance(timestamp_list.__class__, list):
-            logger.error(
-                f"{self} - Timestamp list must be a list, it is a {type(timestamp_list)}"
-            )
-            return False
+        if not isinstance(value_list, list):
+            if isinstance(value_list, bool) or isinstance(value_list, int) or isinstance(value_list, float) or isinstance(value_list, str):
+                value_list = [value_list]
+            else:
+                logger.warning(
+                    f"{self} - Value list wrong type : {type(value_list)}"
+                )
+                return False
+        if not isinstance(timestamp_list, list):
+            if isinstance(timestamp_list, bool) or isinstance(timestamp_list, int) or isinstance(timestamp_list, float) or isinstance(timestamp_list, str):
+                try:
+                    timestamp_list = [float(timestamp_list)]
+                except ValueError as e:
+                    logger.warning(f"{self} - wrong timestamp : {e}")
+                    return False
+            else:
+                logger.warning(
+                    f"{self} - Timestamp list wrong type : {type(timestamp_list)}"
+                )
+                return False
         if len(value_list) != len(timestamp_list):
-            logger.error(
+            logger.warning(
                 f"{self} - value and timestamp lists have not the same length ({len(value_list)}, {len(timestamp_list)})"
             )
             return False