diff --git a/applications/Hardware/ITAMotorControl/ClassStuff/itaMotorControl/itaMotorControlNanotec.m b/applications/Hardware/ITAMotorControl/ClassStuff/itaMotorControl/itaMotorControlNanotec.m
index 8aad0bec8cacc50094e985b6fee1f1fe85450674..44a421ffc677f853d8bb2559999213d93db7e502 100644
--- a/applications/Hardware/ITAMotorControl/ClassStuff/itaMotorControl/itaMotorControlNanotec.m
+++ b/applications/Hardware/ITAMotorControl/ClassStuff/itaMotorControl/itaMotorControlNanotec.m
@@ -216,6 +216,9 @@ classdef itaMotorControlNanotec < itaMotorControl
                error('Only HRTFArc or Turntable supported'); 
             end
             
+            if ~isempty(this.preparedList)
+                error('Already prepared?');
+            end
             % get the preangle and the speed
             sArgs.preAngle = 0;
             sArgs.speed = 2;