diff --git a/test_measure_with_ohmpi_card_3_15.py b/test_measure_with_ohmpi_card_3_15.py
index 8a36a9827fb483e88790c6946af8454d258f74c2..925f91d044d5752b7417e676bf6c7b8e8a4d749b 100644
--- a/test_measure_with_ohmpi_card_3_15.py
+++ b/test_measure_with_ohmpi_card_3_15.py
@@ -9,7 +9,7 @@ k._vab_pulse(vab=12, length=1., sampling_rate=10., polarity=1)
 r = k.readings[:,2]/k.readings[:,1]
 print(f'Mean resistance: {np.mean(r):.3f} Ohms, Dev. {100*np.std(r)/np.mean(r):.1f} %')
 fig, ax = plt.subplots()
-ax.plot(r[:,0], r[:, 1], '-r', label='current')
+ax.plot(k.readings[:,0], k.readings[:, 1], '-r', label='current')
 ax2 = ax.twinx()
-ax.plot(r[:,0], r[:, 2], '-b', label='voltage')
+ax.plot(k.readings[:,0], k.readings[:, 2], '-b', label='voltage')
 change_config('config_default.py', verbose=False)