diff --git a/ohmpi/ohmpi.py b/ohmpi/ohmpi.py
index 074acc5e40b5a97c69bd6b1f97abfb1048dd0976..6ede54e0b9f85c8affd1720748e4a0d44f132e00 100644
--- a/ohmpi/ohmpi.py
+++ b/ohmpi/ohmpi.py
@@ -500,7 +500,7 @@ class OhmPi(object):
         bypass_check = kwargs['bypass_check'] if 'bypass_check' in kwargs.keys() else False
         d = {}
         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=.5, strategy=strategy, voltage_max=5.)
             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']