diff --git a/ohmpi/ohmpi.py b/ohmpi/ohmpi.py
index ea8710f1f3f8bcf9756e96b517de4c0c65401195..0fe6a95ccc635aa9aa5ae598b49897521aa62d22 100644
--- a/ohmpi/ohmpi.py
+++ b/ohmpi/ohmpi.py
@@ -541,7 +541,7 @@ class OhmPi(object):
                 # "R_per_stack [Ohm]": np.mean([np.diff(np.mean(vmn_stack[i*2:i*2+2], axis=1)) / 2 for i in range(nb_stack)]) / np.array([np.mean(i_stack[i*2:i*2+2]) for i in range(nb_stack)]),
                 # "PS_per_stack [mV]":  np.array([np.mean(np.mean(vmn_stack[i*2:i*2+2], axis=1)) for i in range(nb_stack)]),
                 # "PS_stack [mV]": ps_stack_mean,
-                # "R_ab [ohm]": Rab
+                "R_ab [ohm]": tx_volt / I
             }
 
             # to the data logger