diff --git a/NodeRed/NodeRedFiles/dbus-fzsonick-48tl/dbus-fzsonick-48tl.py b/NodeRed/NodeRedFiles/dbus-fzsonick-48tl/dbus-fzsonick-48tl.py
index b4c055856..aa61b3532 100755
--- a/NodeRed/NodeRedFiles/dbus-fzsonick-48tl/dbus-fzsonick-48tl.py
+++ b/NodeRed/NodeRedFiles/dbus-fzsonick-48tl/dbus-fzsonick-48tl.py
@@ -881,7 +881,10 @@ import random
     logging.debug('finished update cycle\n')
     return True'''
 
+start_time = time.time()
+
 def update(modbus, batteries, dbus, signals, csv_signals):
+    global start_time
     # type: (Modbus, Iterable[Battery], DBus, Iterable[Signal]) -> bool
     """
     Main update function
@@ -910,7 +913,11 @@ def update(modbus, batteries, dbus, signals, csv_signals):
     #print(update_state_from_dictionaries(current_warnings, current_alarms))
     status_message, alarms_number_list, warnings_number_list = update_state_from_dictionaries(current_warnings, current_alarms, node_numbers)
     publish_values(dbus, signals, statuses)
-    create_csv_files(csv_signals, statuses, node_numbers, alarms_number_list, warnings_number_list)
+    elapsed_time = time.time() - start_time
+    if elapsed_time >= 30:
+        create_csv_files(csv_signals, statuses, node_numbers, alarms_number_list, warnings_number_list)
+        start_time = time.time()
+    print(f"Elapsed time: {elapsed_time:.2f} seconds")
     logging.debug('finished update cycle\n')
     return True
 
@@ -975,7 +982,7 @@ def get_installation_name(file_path):
         return file.read().strip()
 
 def manage_csv_files(directory_path, max_files=20):
-    csv_files = [f for f in os.listdir(directory_path)]
+    csv_files = [f for f in os.listdir(directory_path) if os.path.isfile(os.path.join(directory_path, f))]
     csv_files.sort(key=lambda x: os.path.getctime(os.path.join(directory_path, x)))
     # Remove oldest files if exceeds maximum
     while len(csv_files) > max_files: