diff --git a/hardware_components/ohmpi_card_3_15.py b/hardware_components/ohmpi_card_3_15.py
index ccce50e53811e5a40355da4f39923fe051129a90..a49b9fc34c9b1de0e7a4005b8ea9b04ee1a1b6f6 100644
--- a/hardware_components/ohmpi_card_3_15.py
+++ b/hardware_components/ohmpi_card_3_15.py
@@ -211,7 +211,7 @@ class Tx(TxAbstract):
     def voltage(self, value):
         assert isinstance(value, float)
         value = np.max([TX_CONFIG['voltage_min'], np.min([value, TX_CONFIG['voltage_max']])])
-        super().voltage = value
+        super().voltage.fset(value)
 
 class Rx(RxAbstract):
     def __init__(self, **kwargs):