diff --git a/measure.py b/measure.py
index 42b175b0b014a092f92dd5d915be00d2e34f8f9f..a316796308b470106a62022cd475cc0c63c22da8 100644
--- a/measure.py
+++ b/measure.py
@@ -53,12 +53,12 @@ class OhmPiHardware:
     def _vab_pulse(self, vab, length, sampling_rate=None, polarity=None):
         """ Gets VMN and IAB from a single voltage pulse
         """
-        def inject(duration):
+        def inject(self, duration):
             self.tx_sync.set()
             self.tx.voltage_pulse(length=duration)
             self.tx_sync.clear()
 
-        def read_values(sampling_rate): # noqa
+        def read_values(self, sampling_rate): # noqa
             _readings = []
             self.tx_sync.wait()
             start_time = datetime.datetime.utcnow()
@@ -73,8 +73,8 @@ class OhmPiHardware:
         if polarity is not None and polarity != self.tx.polarity:
             self.tx.polarity = polarity
         self.tx.voltage = vab
-        injection = Thread(target=inject, kwargs={'duration':length})
-        readings = Thread(target=read_values, kwargs={'sampling_rate': sampling_rate})
+        injection = Thread(target=inject, args=self, kwargs={'duration':length})
+        readings = Thread(target=read_values, args=self, kwargs={'sampling_rate': sampling_rate})
         # set gains automatically
         self.tx.adc_gain_auto()
         self.rx.adc_gain_auto()
diff --git a/test_ohmpi_card_3_15.py b/test_ohmpi_card_3_15.py
index 6630608491528ed75feb72ad183693ee6adc65ec..5df2caf436d8b09d3cf55de08ffe0362820abd4b 100644
--- a/test_ohmpi_card_3_15.py
+++ b/test_ohmpi_card_3_15.py
@@ -34,5 +34,5 @@ from utils import change_config
 
 change_config('config_ohmpi_card_3_15.py', verbose=False)
 k = OhmPiHardware()
-k._vab_pulse(vab=12, length=2., polarity=1)
+k._vab_pulse(vab=12, length=2., sampling_rate=20., polarity=1)
 change_config('config_default.py', verbose=False)
\ No newline at end of file