diff --git a/lasp/device/lasp_device_common.py b/lasp/device/lasp_device_common.py
index 40c9bde..b8368e3 100644
--- a/lasp/device/lasp_device_common.py
+++ b/lasp/device/lasp_device_common.py
@@ -17,7 +17,8 @@ class DaqChannel:
     channel_metadata: str = ''
 
     def __post_init__(self):
-        self.qty = SIQtys.default
+        self._qty = SIQtys.default
+        self._store('qty', self._qty)
 
     @property
     def qty(self):