0 u201d if the drive 26 is activated by the control means 50 u201c 0 u2192 1 u201d the routing valve 23 will pass into the switching position u201c 1 u201d this means that the routing valves 20 and 21 are also operated and move over into the on position the columns u201c 27 u201d u201c 41 u201d and u201c 42 u201d indicate the signals sent by the pressure sensors 27 41 and 42 to the control means 50 u201c 0 u201d meaning u201c no pressure present u201d and u201c 1 u201d meaning control pressure applied u201d in the case of digitally operating pressure sensors here an u201c x u201d stands for an irregular or non defined intermediate value of the acting pressure the digital or binary manner of signalizing u201c 0 u201d or u201c 1 u201d is however only by way of example for the pressure sensors 27 41 and 42 can given a suitable design thereof also signalize exact intermediate or analog values for the respective acting pressure thereat the columns u201c 16 u201d and u201c 17 u201d indicate the messages from the sensor 16 and 17 in this case u201c 0 u201d means that the piston 11 is clear of the respective sensor and the respective sensor is sending a digital signal u201c 0 u201d to the control means 50 whereas the.