diff --git a/ohmpi/hardware_components/abstract_hardware_components.py b/ohmpi/hardware_components/abstract_hardware_components.py
index 4cd0c6554f730f29ad576d3afc30a2a7ae6dd89d..4868a0081c309a0e44abb9768cd88c986fe83f95 100644
--- a/ohmpi/hardware_components/abstract_hardware_components.py
+++ b/ohmpi/hardware_components/abstract_hardware_components.py
@@ -19,6 +19,7 @@ class CtlAbstract(ABC):
         self.exec_logger.debug(f'{self.board_name} Ctl initialization')
         self._cpu_temp_available = False
         self.max_cpu_temp = np.inf
+        self.connection = None
 
     @property
     def cpu_temperature(self):