the following is a detailed description of example embodiments of the invention depicted in the accompanying drawings . the example embodiments are presented in such detail as to clearly communicate the invention and are designed to make such embodiments obvious to a person of ordinary skill in the art . however , the amount of detail offered is not intended to limit the anticipated variations of embodiments ; on the contrary , the intention is to cover all modifications , equivalents , and alternatives falling within the spirit and scope of the present invention , as defined by the appended claims . according to fig1 , a module 10 comprises a control circuit , which is preferably formed out of electronic components . in the exemplary embodiment shown , module 10 comprises a pid - regulator that includes a non - oscillatable time - delay element of the second order serving as a controlling section . in signal contact with the module 10 is an operating terminal 11 of a high - performance baler which in this context is not described in more detail . the baler , for example , may be a square baler . the operating terminal 11 can be installed in a traction vehicle of the baler . likewise , in signal contact with the module 10 is a pressing pressure sensor 12 . pressure sensor 12 senses the piston pressure of a pressing piston of the square baler and directs it to the module 10 for evaluating its signals . the module also evaluates the sensor signals of a binding twine load sensor 13 , which is preferably embodied as force sensor . the signals of a straw measuring wheel 14 also are provided to the module 10 . module 10 , in addition to the control circuit , also comprises an evaluation unit and which , via its control circuit , controls the throughput of a valve 15 for the pressing pressure of the pressing piston . accordingly , at the start of the pressing operation , after the maximum tensile strength of the binding twine has been entered as maximum value in the operating terminal 11 by an operating person , the operating terminals 11 or the module 10 predetermines a so - called standard pressing pressure . the standard pressing pressure is always selected so that neither tearing of the binding twine nor damaging of mechanical press components are accompanied by this pressing operation . based on this preset pressing pressure , the module 10 , by means of the pressing pressure sensor signals and , based on the signals of the binding twine force sensor 13 . controls a valve 15 at a predetermined press meter monitored by the straw measuring wheel sensor 14 to a pressing pressure for the pressing piston of the square baler . this ensures an optimised utilisation of the baler and of the binding twine , without the binding twine and / or the baler being damaged . according to fig2 , a block diagram for a second embodiment of a pressing pressure regulation for a high - pressure baler is shown that differs from the fig1 embodiment only in that the straw wheel as sensor is omitted . in view of the fact that present pressing pressure regulation the input signal of the straw wheel is omitted , the standard pressing pressure that manifests itself based on the load input ( particularly the input of the maximum tensile strength in the operating terminal 11 on the module 10 ), is not controlled according to a predetermined number of press meters but instead , immediately after the start of the pressing operation , the pressing pressure is controlled through the control circuit provided in the module 10 for the pressing twine and the square baler with respect to their optimised utilisation . fig3 shows a large square baler 20 with a pressing channel 21 in which , by means of a pressing piston 22 linearly moved therein , the pressing operation of the straw - like crop 23 conveyed via a feeding channel ( not shown ), is compacted into a square bale 24 . after a certain number of charges of the straw - like crop 23 , a knotter operation is triggered on a knotter device 26 arranged on an upper wall 25 of the pressing channel 21 . for this purpose , the knotter device 26 is provided with a knotter beak 27 , on which a force sensor 28 is provided . the force sensor 28 serves for detecting forces which occur on a binding twine 29 sensed by the knotter beak 27 . the forces on the binding twine 29 detected by the force sensor 28 are passed on to a processing electronic device 30 for their further processing , which device in the present case is connected to an operating terminal 32 via lines 31 for the exchange of data . furthermore , the processing electronic device 30 is connected via a signal line ( not shown ) to a sensor for sensing the revolutions of a straw measuring wheel 33 ( which sensor is not shown in more detail . at the start of the pressing operation , an operating person sets the maximum load limit , particularly the maximum permissible tensile strength of the binding twine selected for an intended pressing operation on the operating terminal 32 . subsequently , the processing electronic device 30 outputs a so - called standard pressing pressure as preliminary reference variable to a control circuit ( not shown in more detail ) that is preferably integrated in the module 10 for controlling the pressing pressure . once a predetermined number of press metres has been signalled to the processing electronic device 30 by the straw measuring wheel 33 , the processing electronic device 30 releases the preset standard pressing pressure and controls the pressing pressure based on the force sensor signals of the binding twine force sensor and the sensor signals of the pressing piston force sensor for the further pressing operations . the pressing pressure , based on the force sensor signals of the force sensors , is then controlled to a quantity which ensures that neither the binding twine nor the square baler , particularly sensitive mechanical components of this baler , are damaged upon a permanent pressing of a straw - like crop . the following list of reference signs of various elements mentioned above is included ( as follows ), for ease of explanation : as will be evident to persons skilled in the art , the foregoing detailed description and figures are presented as examples of the invention , and that variations are contemplated that do not depart from the fair scope of the teachings and descriptions set forth in this disclosure . the foregoing is not intended to limit what has been invented , except to the extent that the following claims so limit that .
a method for operating a baler with a pressing chamber which serves for the pressing of a straw - like crop includes compacting the crop using an adjustable pressing pressure and binding the crop through a holding material . the pressing pressure is limited to a maximum value and controlled through a control circuit . a control circuit reference variable is a load variable of the holding material . the load variable is adjustable and is smaller than or equal to the maximum value .