diff --git a/ohmpi/ohmpi.py b/ohmpi/ohmpi.py
index a20908f19a53c441400c99645965666dbbba7110..b18f4406ef57882e7d3d82cf48e0d7141a84a7da 100644
--- a/ohmpi/ohmpi.py
+++ b/ohmpi/ohmpi.py
@@ -491,7 +491,7 @@ class OhmPi(object):
         # tx_volt = float(kwargs.pop('tx_volt', self.settings['tx_volt']))
         bypass_check = kwargs['bypass_check'] if 'bypass_check' in kwargs.keys() else False
         if self.switch_mux_on(quad, bypass_check=bypass_check, cmd_id=cmd_id):
-            tx_volt = self._hw._compute_tx_volt(tx_volt=tx_volt, strategy=strategy)
+            tx_volt,_ ,_ = self._hw._compute_tx_volt(tx_volt=tx_volt, strategy=strategy)
             self._hw.vab_square_wave(tx_volt, cycle_duration=injection_duration*2/duty_cycle, cycles=nb_stack, duty_cycle=duty_cycle)
             if 'delay' in kwargs.keys():
                 delay = kwargs['delay']