handle blank serial data

main.py

@@ -47,8 +47,10 @@ def main():
         shutdown_triggered = False
         while running:
             line = ser.readline().decode(errors="ignore").strip()
-
-            if line == "0":
+            if line == "":
+                logger.warning("No serial data")
+                continue
+            elif line == "0":
                 logger.debug("Inverter Online")
                 inverter_offline_counter = 0
             elif inverter_offline_counter >= shutdown_timer: