diff --git a/hardware/ohmpi_card_3_15.py b/hardware/ohmpi_card_3_15.py
index f5fc89be3966ea95a294e45d761934e81a8f1ef8..064a99f7482229da188579c28cfe744e2394ffa6 100644
--- a/hardware/ohmpi_card_3_15.py
+++ b/hardware/ohmpi_card_3_15.py
@@ -125,7 +125,7 @@ class Tx(TxAbstract):
     def current(self):
         """ Gets the current IAB in Amps
         """
-        return AnalogIn(self._ads_current, ads.P0).voltage * 1000. / (50 * TX_CONFIG['R_shunt'])  # noqa measure current
+        return AnalogIn(self._ads_current, ads.P0).voltage * 1000. / (50 * TX_CONFIG['r_shunt'])  # noqa measure current
 
     @ current.setter
     def current(self, value):