diff --git a/pyLSV2/client.py b/pyLSV2/client.py
index cce2b1a..15fb0bf 100644
--- a/pyLSV2/client.py
+++ b/pyLSV2/client.py
@@ -1391,7 +1391,7 @@ def read_plc_address(self, address: str) -> Union[None, int, float, str]:
         m_type, m_num = lm.decode_plc_memory_address(address)
 
         if m_type is None or m_num is None:
-            raise ValueError()
+            raise LSV2InputException("could not translate address %s to valid memory location" % address)
 
         return self.read_plc_memory(m_num, m_type, 1)[0]
 
@@ -1647,7 +1647,7 @@ def get_file_list(self, path: str = "", descend: bool = True, pattern: str = "")
             return []
 
         if self.change_directory(path) is False:
-            self._logger.warning("could not change to directory %s" % path)
+            self._logger.warning("could not change to directory %s", path)
             return []
 
         if len(pattern) == 0: