Systems and methods for calibrating an electrohydraulic device of a hydraulic control system

Abstract

A hydraulic control system comprises an electrohydraulic valve and a control device. The electrohydraulic valve is in fluid communication with a control chamber of a control valve and has an electromagnet and a valve element actuated by the electromagnet. The control device is connected to the electromagnet and is configured to detect a change in an electromagnetic property of the electromagnet that correlates with a hydraulic disturbance within the hydraulic system.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS Not applicable NOTICE OF FEDERALLY FUNDED RESEARCH Not applicable BACKGROUND So-called off-highway machines / vehicles or all-terrain utility vehicles typically have one or more functions that can be hydraulically controlled via a hydraulic control system that includes one or more electro-hydraulic devices. SHORT DESCRIPTION The present disclosure provides systems and methods for calibrating an electrohydraulic device of a hydraulic control system. For example, an electrohydraulic device of a hydraulic control system can be configured to detect the initiation of movement of a main spool of a control valve of the hydraulic control system. Furthermore, the electrohydraulic device thus configured can be used to calibrate another electrohydraulic device of the hydraulic control system. In contrast to conventional systems and methods for calibrating one or more electrohydraulic devices of a hydraulic control system, the systems and methods disclosed herein do not require any additional sensors (such as a linear variable differential transformer ("LVDT"), a pressure sensor, a flow sensor, etc.).) or a movement of a machine having the hydraulic control system, which provides improved performance of the hydraulic control system and offers the possibility of calibration in the stationary state of the machine. One aspect of the present disclosure provides for a hydraulic control system. The hydraulic control system comprises an electrohydraulic valve that is fluidically connected to a control chamber of a control valve. The electrohydraulic valve has an electromagnet and a valve element actuated by the electromagnet. The hydraulic control system further comprises a control device connected to the electromagnet. The control device is configured to detect a change in an electromagnetic property of the electromagnet that correlates with a hydraulic disturbance within the hydraulic system. The electromagnet has an armature. The electromagnetic property is based on a movement of the armature within the electromagnet. The control device is further configured to monitor the electromagnetic property of the electromagnet for the detection of the hydraulic disturbance.The electromagnetic property is a measured current feedback from the electromagnet. Changes in the electromagnetic property can be detected by comparing the measured current feedback with a predetermined duty cycle of the electromagnet. Hydraulic disturbances can be caused by movement of a control element of the control valve and / or a change in volume or pressure within the hydraulic control system. The control element of the control valve is a main spool, a valve disc, and / or a piston. If the control element of the control valve is a main spool and the electromagnet of the electrohydraulic valve has an armature, movement of the main spool displaces fluid in the control chamber and causes a corresponding movement of the armature in the electromagnet of the electrohydraulic valve.The control element of the control valve is a main spool that is adjustable by an electrical actuator of the hydraulic control system. The control device is further configured to identify a calibration point of the electrical actuator based on a movement of the main spool. The control device is also configured to apply a rising or falling control current to the electrical actuator until the main spool moves in response to the control current. The rising or falling control current consists of a series of pulses with varying amplitude or duration. If the electrohydraulic valve is a first electrohydraulic valve and the control chamber is a first control chamber of the control valve, the electrical actuator is a second electrohydraulic valve of the control valve connected to the control device.The second electrohydraulic valve of the control valve is also in fluid communication with the main spool via a second control chamber. The main spool can be adjusted in a first direction by the first electrohydraulic valve and in a second direction opposite to the first by the second electrohydraulic valve. The control device is further configured to identify a first calibration point of the first electrohydraulic valve based on the movement of the main spool in the first direction and a second calibration point of the second electrohydraulic valve based on the movement of the main spool in the second direction. The control valve has the second control chamber. The electrohydraulic valve is an electrohydraulic pressure regulating valve, an electrohydraulic proportional valve, or an electrohydraulic pressure relief valve.The change in the electromagnetic properties of the electromagnet occurs independently of any change in the control current made by the control device. Another aspect of the present disclosure provides a method for detecting a hydraulic fault in a hydraulic control system. The method comprises the steps of detecting a change in the electromagnetic property of an electromagnet of an electrohydraulic valve of the hydraulic control system and determining the occurrence of the hydraulic fault based on the detected change in the electromagnetic property of the electromagnet. The electrohydraulic valve is in fluid communication with a control chamber of a control valve of the hydraulic control system and has a valve element that can be actuated by the electromagnet. Before detecting the change in the electromagnetic property of the electromagnet, the method further comprises the step of driving the electromagnet to a set current, which corresponds to actuation of the electrohydraulic valve. The electromagnet has an armature.The electromagnetic property is based on the movement of the armature within the electromagnet. The method also includes the step of monitoring the electromagnet using a control unit connected to it. The electromagnetic property of the electromagnet detects changes in its electromagnetic properties. These electromagnetic properties are measured as current feedback from the electromagnet. The method further includes the steps of controlling the electromagnet for a predetermined duty cycle via the control unit and comparing the measured current feedback with the predetermined duty cycle using the control unit to detect changes in the electromagnetic properties. The hydraulic disturbance is caused by movement of a control element of the control valve and / or a change in volume or pressure within the hydraulic control system.The control element of the control valve is a main spool, a valve disc, or a piston. If the control element of the control valve is a main spool and the electromagnet has an armature, movement of the main spool displaces fluid within the control chamber and causes a corresponding movement of the armature in the electromagnet. The control element is a main spool that is adjustable by an electrical actuator of the hydraulic control system. The method further comprises the step of applying a rising or falling control current to the electrical actuator via a control device connected to the electrical actuator until the main spool moves in response to the control current. The rising or falling control current consists of a series of pulses with varying amplitude or duration.The method further comprises the step of identifying a calibration point of the electrical actuator by means of the control device based on the movement of the main spool. The electrohydraulic valve is a first electrohydraulic valve, the electromagnet is a first electromagnet, and the control chamber is a first control chamber of the control valve. The electrical actuator is a second electrohydraulic valve, which is in fluid communication with the main spool via a second control chamber of the control valve, the second electrohydraulic valve having a second electromagnet. The main spool is further adjustable in a first direction by the first electrohydraulic valve and in a second direction opposite to the first by the second electrohydraulic valve.The procedure further includes the step of identifying a calibration point for the second electrohydraulic valve using a control device connected to the first and second electromagnets, based on the movement of the main spool in the second direction. The electrohydraulic valve is an electrohydraulic pressure regulating valve, an electrohydraulic proportional valve, and / or an electrohydraulic pressure relief valve. Another aspect of the present disclosure provides for an electrohydraulic system. The electrohydraulic system comprises a hydraulic valve with a first control chamber, a second control chamber, and a main spool arranged between the first and second control chambers. When the first control chamber is pressurized, the main spool is adjustable in a first direction towards the second control chamber. When the second control chamber is pressurized, the main spool is adjustable in a second direction towards the first control chamber. The electrohydraulic system further comprises a first electrohydraulic valve with a first electromagnet. The pressure in the first control chamber can be controlled by means of the first electrohydraulic valve. The electrohydraulic system further comprises a second electrohydraulic valve with a second electromagnet.The pressure in the second control chamber can be controlled by means of the second electrohydraulic valve. The electrohydraulic system also includes a control unit for calibrating the system. This control unit is operatively connected to both the first and second electrohydraulic valves. The control unit is configured to apply a first, varying voltage signal to the first electrohydraulic valve and a second, varying voltage signal to the second electrohydraulic valve, in order to switch the current of the second electromagnet between a first and a second level. The first and second levels define the currents by which the main spool is held in a specific position. The second level is higher than the first level.The control device is further configured to raise the second current level of the second electromagnet until the main valve moves in the second direction, thereby causing a hydraulic disturbance in the first control chamber. The control device is also configured to detect a change in an electromagnetic property of the first electromagnet of the first electrohydraulic valve caused by the hydraulic disturbance. The method also includes the step of determining the second current level of the second electromagnet of the second electrohydraulic valve, which corresponds to the change in the electromagnetic property of the first electromagnet of the first electrohydraulic valve.The control device is further configured to determine the second current level of the second electromagnet of the second electrohydraulic valve, corresponding to the change in the electromagnetic property of the first electromagnet of the first electrohydraulic valve, as a calibration point corresponding to the second electrohydraulic valve. The electromagnetic property is a current of the first electromagnet of the first electrohydraulic valve. The electrohydraulic system also includes a current feedback circuit connected to the first and second electrohydraulic valves. The control device is configured to measure the change in the current of the first electromagnet of the first electrohydraulic valve along the current feedback circuit caused by the hydraulic disturbance.The hydraulic disturbance in the first control chamber is a change in pressure and / or flow rate. The first and second electrohydraulic valves are each an electrohydraulic pressure regulating valve, an electrohydraulic proportional valve, or an electrohydraulic pressure relief valve. The second electrohydraulic valve is an electrohydraulic pressure regulating valve. The first current level of the second electromagnet correlates with the start of pressure generation by the second electrohydraulic valve. Another aspect of the present disclosure provides for a further method for calibrating an electrohydraulic control system. This method comprises the step of applying a first varying voltage signal to a first electrohydraulic device comprising a first electromagnet. By means of the first electrohydraulic device, a pressure corresponding to a first current of the first electromagnet can be controlled in a first control chamber of a hydraulic valve. The first control chamber is arranged opposite a second control chamber, with a main spool being arranged between the first and the second control chamber. The second control chamber is connected to a second electrohydraulic device comprising a second electromagnet, by means of which a pressure corresponding to a second current of the second electromagnet can be controlled in the second control chamber.The main valve is adjustable such that when the first control chamber is pressurized, it moves in a first direction towards the second control chamber. When the second control chamber is pressurized, the main valve moves in a second direction opposite to the first, towards the first control chamber. The method further includes applying a second varying voltage signal to the second electrohydraulic device to switch the second current between a first and a second level. The second level is higher than the first level. The method also includes increasing the level of the second current until the main valve moves in the second direction, thereby causing a hydraulic disturbance in the first control chamber. The method then determines a calibration point for the second electrohydraulic device.The calibration point corresponds to the second level of the second current of the second electromagnet of the second electrohydraulic device, which corresponds to the detected change in the electromagnetic properties of the first electromagnet of the first electrohydraulic device. The first and second varying voltage signals are pulse-width modulation (PWM) voltage signals. The first electromagnet has an armature. The hydraulic disturbance in the first control chamber is a change in pressure in the first control chamber and / or a change in the flow rate through the first control chamber. The hydraulic disturbance causes the change in the electromagnetic properties of the first electromagnet by inducing movement of the armature of the first electromagnet.The first and second electrohydraulic devices are each an electrohydraulic pressure control valve, an electrohydraulic proportional valve, or an electrohydraulic pressure relief valve. The first electrohydraulic device is a first electrohydraulic pressure control valve. The second electrohydraulic device is a second electrohydraulic pressure control valve. The first varying voltage signal controls the first electromagnet of the first electrohydraulic pressure control valve, which correlates with the start of pressure generation in the first control chamber by the first electrohydraulic pressure control valve. The first current level of the second electromagnet of the second electrohydraulic pressure control valve correlates with the start of pressure generation by the second electrohydraulic pressure control valve.The hydraulic disturbance in the first control chamber is a change in pressure and / or flow rate within the first control chamber. This initial hydraulic disturbance is a change in flow rate caused by a pressure release operation of the first electrohydraulic device. The electrohydraulic control system calibration procedure further includes the step of reducing the second current from the second electromagnet until the main valve moves in the first direction, thereby causing a second hydraulic disturbance in the first control chamber.The method further includes the step of detecting a change in the electromagnetic properties of the first electromagnet of the first electrohydraulic device caused by the second hydraulic disturbance in the first control chamber. The method further includes the step of determining the second current of the second electromagnet of the second electrohydraulic device, which corresponds to the change in the electromagnetic properties of the first electromagnet of the first electrohydraulic device caused by the second hydraulic disturbance. In addition, the method includes the step of determining a time interval between the first and the second hydraulic disturbance in the first control chamber.The method then compares the specific time interval between the first and second hydraulic disturbances in the first control chamber with the specific second currents of the second electromagnet of the second electrohydraulic device, corresponding to the first and second hydraulic disturbances. The first hydraulic disturbance in the first control chamber is a pressure increase in the first control chamber. The second hydraulic disturbance in the second control chamber is a pressure drop in the first control chamber following the first hydraulic disturbance. Another aspect of the present disclosure provides for a further electrohydraulic system. This electrohydraulic system comprises a control valve having a control element that is adjustable between a first position and a second position for controlling fluid flow through the electrohydraulic system. The control valve further comprises an electrohydraulic device that can be operated either in an active or a passive operating mode. The electrohydraulic system also includes a control unit connected to the electrohydraulic device of the control valve.The control unit is configured to apply a control current to the electrohydraulic device in its active operating mode, causing the electrohydraulic device to move the control element to the first or second position and thus controlling the fluid flow through the electrohydraulic system. Furthermore, the control unit is configured to monitor, in the passive operating mode of the electrohydraulic device, any change in current feedback from the electrohydraulic device caused by an independent movement of the control element to the first or second position. Additionally, in the passive operating mode of the electrohydraulic device, the control unit is configured to apply a target current to the electrohydraulic device. The target current is lower than the control current. The foregoing and further aspects and advantages of the disclosure are evident from the following description. The description refers to the accompanying drawings, which form an integral part of this disclosure and in which a preferred embodiment of the disclosure is shown for illustration. However, such an embodiment does not necessarily represent the full scope of the disclosure, and therefore, for an interpretation of the scope of the disclosure, reference is made to the claims and the present description. BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the disclosed technology and further aspects and advantages beyond those disclosed above will become apparent from the following detailed description, which refers to the following drawings. Fig. 1A shows a schematic block diagram of a hydraulic system comprising a hydraulic control system with an electrohydraulic device according to aspects of the present disclosure. Fig. 1B shows a schematic block diagram of another exemplary hydraulic system comprising a hydraulic control system with a control valve with an electrohydraulic device according to aspects of the present disclosure. Fig. 2 shows a flowchart of a method for detecting a hydraulic fault in a hydraulic control system according to aspects of the present disclosure. Fig. 3 shows a cross-sectional view of another exemplary control valve of the hydraulic system according to Fig. 1. Fig. 4A, Fig.Figures 4B and 5 show different current feedback curves of current feedback and disturbance of a first electrohydraulic device and a second electrohydraulic device of the control valve according to Figure 3. Figure 6 shows a flowchart of a method for calibrating an electrohydraulic control system according to aspects of the present disclosure. Figure 7 shows a flowchart of another exemplary method for calibrating an electrohydraulic control system according to aspects of the present disclosure. DETAILED DESCRIPTION Before individual aspects of this disclosure are explained in detail, it should be noted that the application of this disclosure is not limited to the design details and component arrangements set forth in the following description or illustrated in the following drawings. This disclosure can also be realized in other embodiments and implemented or executed in various ways. Furthermore, it is understood that the language and terminology used herein serve the purpose of description and should not be considered restrictive. The use of "feature," "include," or "with," and variations thereof, is intended to encompass the elements listed thereafter and their equivalents, as well as other elements.Unless otherwise specified or limited, the terms "mounted," "connected," "supported," and "coupled," as well as their variants, are used in a broader sense and include both direct and indirect assemblies, connections, supports, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings. The following discussion is intended to enable a person skilled in the art to manufacture and utilize aspects of the present disclosure. Various modifications of the embodiments shown will be readily apparent to the person skilled in the art, and the general principles contained herein can be applied to other embodiments and applications without departing from aspects of the present disclosure. Therefore, aspects of the present disclosure should not be limited to the embodiments shown, but should be granted the broadest possible scope that is compatible with the principles and features disclosed herein. The following detailed description should be read with reference to the figures, in which identical elements in different figures are designated with the same reference numerals.The figures, which are not necessarily to scale, show selected embodiments and are not intended to limit the scope of this disclosure. Those skilled in the art will recognize that the non-limiting examples given here represent many useful alternatives and fall within the scope of this disclosure. The terms "downstream" and "upstream" used here refer to the direction relative to the flow of a fluid. "Downstream" corresponds to the direction of the fluid flow, while "upstream" refers to the direction opposite or in the opposite direction to the fluid flow. As briefly mentioned at the beginning, electronically controlled actuation of hydraulic consumers (e.g., typically via one or more control valves) is desirable in hydraulic control systems. In some non-restrictive examples, a control valve of a hydraulic control system may use one or more electrohydraulic devices (e.g., a solenoid valve, for example, an electrohydraulic pressure regulating valve, "EDRV," an electrohydraulic proportional valve, "EHPV," or the like) to displace or actuate a main spool of the control valve in order to control flow through the hydraulic control system for the operation of one or more hydraulic consumers (e.g., an actuator, a drive motor, etc.).Many electrohydraulic devices require calibration to ensure accurate and predictable movement of the main spool of a corresponding control valve for a given application, taking into account a variety of unknown calibration factors. Examples of calibration factors might include the pressure-flow curve of a particular EDRV or variations in one or more springs that can bias the main spool of a control valve, which, if improperly calibrated, can lead to "dead zones" in a control stick / lever. However, conventional calibration procedures and systems for an electrohydraulic device within a hydraulic control system may require additional sensors (e.g.,This may require, among other things, one or more flow sensors, pressure sensors, and / or LVDT sensors to detect the movement of the main spool (or the pressure or flow resulting from its movement) and to calibrate the electrohydraulic devices. These additional sensors may interfere with the normal operation of the control valve and, furthermore, may require full actuation or movement of the hydraulic consumers of a machine connected to the hydraulic control system to complete the calibration process. In general, the present disclosure provides systems and methods for configuring an electrohydraulic device (e.g., a solenoid valve) of a hydraulic control system such that it functions as a "sensing device" for detecting the initial actuation in a control valve of the hydraulic control system. For example, an electrohydraulic device of a hydraulic control system can be used to determine the initial movement of a main spool of a control valve of the hydraulic control system by monitoring one or more electromagnetic properties of the electrohydraulic device. Furthermore, in some non-limiting examples, the "sensing" electrohydraulic device thus configured can also be used to calibrate an "actuator" electrohydraulic device of the hydraulic control system.For example, a first or "drive" electro-hydraulic device of a hydraulic control system, configured to drive a main spool of a control valve, can be calibrated by configuring a second or "sensing" electro-hydraulic device of the hydraulic control system to sense the initial movement of the main spool of the control valve and to monitor one or more electromagnetic properties of the second electro-hydraulic device in response to one or more hydraulic disturbances in the hydraulic control system caused by the movement of the main spool by the first or "drive" electro-hydraulic device. In some non-limiting examples, the devices or systems disclosed herein (e.g., a hydraulic control system or a control valve of a hydraulic control system) can be used, manufactured, or installed using methods that embody aspects of this disclosure. Accordingly, the present description of certain features, capabilities, or intended purposes of a device or system is generally intended to include, by its very nature, the disclosure of a method for using such features for the intended purposes, a method for implementing such capabilities, a method for manufacturing relevant components of such a device or system (or the device or system as a whole), and a method for installing disclosed (or otherwise known) components to support these purposes or capabilities.Likewise, unless otherwise specified or limited, the present discussion of a corresponding method for manufacturing or using a particular device or system, including the installation of the device or system, shall by its very nature include, as examples of the present disclosure, the disclosure of the features used and capabilities implemented of such device or system. Figure 1A shows a non-limiting example of a hydraulic system with a hydraulic control system according to aspects of the present disclosure. In the illustrated non-limiting example, a hydraulic system 10 has a hydraulic control system 12, which may be configured to control one or more flow characteristics (such as flow paths, fluid pressure, fluid volume, etc.) within the hydraulic system 10. It is understood that the hydraulic system 10 can have a wide variety of configurations and components and that only a specific non-limiting exemplary section of the hydraulic system 10 is shown in Figure 1A. Specifically, in the non-limiting example according to Figure 1A, the hydraulic system 10 has at least one flow channel 20 with a bore 20A in which a control element 18 (e.g., a piston) is movable (e.g.,(due to pressure in other sections of the hydraulic system 10, via an actuating device not shown, etc.) to enable or block flow along the flow channel 20 through the bore 20A. The flow channel 20 is in fluid communication with a control chamber 16. In particular, the control chamber 16 is in fluid communication with the bore 20A such that changes in flow characteristics within the flow channel 20 are transmitted to the control chamber 16 (e.g., displacement of fluid within the control chamber 16 as a result of movement of the piston 18). Referring further to Fig. 1A, the hydraulic control system 12 can include at least one electrohydraulic device 26. In the illustrated, non-limiting example, the electrohydraulic device 26 is in fluid communication with the control chamber 16 and has a valve element 28 (e.g., a spool) that can be actuated by an electromagnet 30. The electromagnet 30 can have an armature 32 and a coil 34. The armature 32 of the electromagnet 30 is connected to the valve element 28 and is linearly movable within the coil 34 when the coil 34 generates a specific magnetic field resulting from a predetermined current supplied to the coil 34 (e.g., by an electronic control unit 40). The movement of the valve element 28 by the movement of the armature 32 leads to a pressure change, which is transmitted to the control chamber 16 via a hydraulic control port 36 of the electro-hydraulic device 26.Furthermore, in the illustrated, non-restrictive example, the electrohydraulic device 26 is configured to control the fluid pressure within the control chamber 16 (e.g., to release the pressure in the control chamber 16 in response to a pressure change within it if the pressure exceeds a predetermined release setpoint). However, as will be explained in more detail below, the electrohydraulic device 26 can be one of a variety of electrohydraulic devices with different configurations and consumers. Further referring to Fig. 1A, the hydraulic control system 12 may also include an electronic control device 40, which is electrically connected to the electromagnet 30 of the electrohydraulic device 26. Specifically, in the illustrated, non-limiting example, the control device 40 may be configured to send and receive signals from the coil 34 of the electromagnet 30 via a circuit 42 of the hydraulic control system 12. As explained in more detail below, in some non-limiting examples, the control device 40 may be configured to determine a current or a range of currents (i.e., a setpoint current) that correlates with the commencement of actuation of the electrohydraulic device 26 or with any other control state of the electrohydraulic device 26.For example, the start of the actuation can trigger the movement of the valve element 28 prior to a relief process (via the electrohydraulic device 26) within the control chamber 16. As explained in more detail below, the set current of the electromagnet 30 of the electrohydraulic device 26 can be particularly advantageous in that current feedback from the electromagnet 30 resulting from a hydraulic disturbance can be detected more easily. Furthermore, the control device 40 can be configured to receive or monitor signals from the coil 34, which may correlate with one or more electromagnetic properties of the electromagnet 30, via a current feedback circuit (e.g., the circuit 42). For example, the electromagnetic properties may include inductance or current feedback of the electromagnet 30 (or the coil 34). In some non-limiting examples, the control device 40 may also be configured to detect a change in the signal received from the coil 34, which may correlate with a movement of the armature 32 within the coil 34, which may be caused by a hydraulic disturbance within the hydraulic system 10 (i.e., within the flow channel 20).For example, in the illustrated, non-restrictive example, a hydraulic disturbance can cause movement of the armature 32 relative to the coil 34. A hydraulic disturbance can result from one or more sources, including, for example, a displacement of fluid within the control chamber 16 by movement of the piston 18. In some non-restrictive examples, the control device 40 may be communicatively connected to a computer or computer network, which may be located outside the hydraulic control system 12 (e.g., wirelessly or hardwired). In some such examples, the computer or computer network may be connected to a plurality of control devices 40 of a plurality of electrohydraulic devices 26 of the hydraulic control system 12 and configured to control the plurality of control devices so that they send and receive signals from the plurality of electrohydraulic devices 26. In some non-restrictive examples, the control device 40 and / or the current feedback circuit 42 may be included as part of the hydraulic control system 12, such as within the electrohydraulic device 26 or the electromagnet 30 thereof.In some non-restrictive examples, the control device 40 may be included in a control unit on a machine having the hydraulic system 10 (e.g., an off-highway machine). In other non-restrictive examples, the control device 40 may be a stand-alone control unit that may be connected to the hydraulic system 10 of the machine or to a control unit of the machine (e.g., via the current feedback circuit 42). As explained in more detail below, in some non-limiting examples, the electro-hydraulic device 26 can be configured via the control device 40 to detect or determine changes in one or more flow characteristics within the flow channel 20 (e.g., as a result of the movement of the piston 18 and / or other components of the hydraulic system 10). This use of the electro-hydraulic device 26 can be particularly advantageous in some applications because it can enable calibration of the hydraulic system 10 (or one or more of its components, including the electro-hydraulic device 26 itself) by determining relatively precise times at which a particular hydraulic disturbance occurs in the hydraulic system 10. In such non-limiting examples, the electro-hydraulic device 26 can, in particular, be used as a “detection device” in a calibration mode (e.g.,a passive operating mode) in addition to a normal operating mode of the electro-hydraulic device 26 (e.g. an active operating mode). It is conceivable that an electro-hydraulic device may be included at a control valve of a hydraulic control system. In this context, Fig. 1B illustrates another non-limiting example of a hydraulic system 100 with a hydraulic control system 102 according to aspects of the present disclosure. The hydraulic control system 102 has a control valve 104 configured to selectively control a working fluid (e.g., hydraulic fluid or oil) supplied from a tank or reservoir 106 and which can be pressurized to the control valve 104 via a pump 108. The hydraulic control system 102, and in particular the control valve 104, is configured to selectively control a flow of the working fluid to one or more consumers 110 and, in some cases, from the one or more consumers back to the tank 106.The consumer 110 can be any hydraulically controlled component of an off-highway vehicle / machine (e.g., an actuator, a drive motor, etc.). In the illustrated, non-restrictive example, the hydraulic control system 102 includes a control valve 104 that controls the fluid flow between the tank 106 and a consumer 110; however, other configurations are also possible. For example, in some non-restrictive examples, a single control valve 104 can control the fluid flow between the tank 106 and a plurality of consumers 110, a plurality of control valves 104 can control the fluid flow between the tank 106 and a single consumer 110, or a plurality of control valves 104 can control the fluid flow between a plurality of tanks 106 and a corresponding plurality of consumers 110. In the non-limiting example shown in Fig. 1B, the control valve 104 has a tank working port, a consumer working port, a control chamber 116, and a control element 118 (e.g., a slide valve) arranged within a control channel 120 of the control valve 104. In this non-limiting example, the consumer working port has a first consumer working port 114A, corresponding to the extended position of the consumer 110, and a second consumer working port 114B, corresponding to the retracted position of the consumer 110. Likewise, the tank working port has a first tank working port 112A, which receives fluid from the pump 108, and a second tank working port 112B, which returns fluid from the control valve 104 to the tank 106.In other words, the first tank working port 112A is in fluid connection with the pump 108, while the second tank working port 112B is in fluid connection with the tank 106, and the first and second consumer working ports 114A, 114B are in fluid connection with the consumer 110. The control element 118 is movable within the control channel 120 to selectively establish a fluid connection between two or more of the following ports: the first tank working port 112A, the second tank working port 112B, the first consumer working port 114A and the second consumer working port 114B. Specifically, when the control element 118 is in a first position in the direction of a first end 122A of the control channel 120, fluid is allowed to flow from the tank 106 from the first tank working port 112A through the control channel 120 to the first consumer working port 114A and to the consumer 110 (as shown by the solid arrows in Fig. 1B) and fluid is allowed to flow from the consumer 110 from the second consumer working port 114B through the control channel 120 to the second tank working port 112B and to the tank 106 (as shown by the dashed arrows in Fig. 1B).If, on the other hand, the control element 118 is in a second position in the direction of a second end 122B of the control channel 120, which is opposite the first end 122A, a flow of fluid from the tank 106 from the first tank working port 112A through the control channel 120 to the second consumer working port 114B and to the consumer 110 is enabled, and a flow of fluid from the consumer 110 from the first consumer working port 114A through the control channel 120 to the second tank working port 112B and to the tank 106 is enabled. In some non-restrictive examples, the control element 118 can be moved into a variety of positions between the first and second positions, which at least partially restrict the flow between the first and second tank working ports 112A, 112B and the first and second consumer working ports 114A, 114B through the control channel 120.For example, in such non-restrictive examples, the control element 118 may be movable into a third position between the first and second positions, in which each of the consumer working ports 114A, 114B is blocked or disconnected from one or both of the tank working ports 112A, 112B. In some non-restrictive examples, the control valve 104 may have a plurality of control chambers 116 with a plurality of control elements 118, which are in fluid communication with the control channel 120. In some non-restrictive examples, the control valve 104 may have a plurality of first and second consumer working ports 114A, 114B for a plurality of consumers 110, which are in fluid communication with a plurality of control channels 120 and one or more control chambers 116 with one or more control elements 118. In some non-restrictive examples, the control element 118 may be biased in the first or second position, or in a neutral position between the first and second positions, within the control channel 120. In some non-restrictive examples, the control element 118 may be a sliding gate valve, a disc valve assembly, a rotary valve, or the like. With further reference to Fig. 1B, the control valve 104 of the hydraulic control system 102 of the hydraulic system 100 comprises an electrohydraulic device 126. In the illustrated, non-limiting example, the electrohydraulic device 126 is in fluid communication with the control chamber 116 of the control valve 104 and comprises a valve element 128 (e.g., a spool) that can be actuated by an electromagnet 130, which has an armature 132 and a coil 134. The armature 132 of the electromagnet 130 is connected to the valve element 128 and is linearly movable within the coil 134 when the coil 134 exhibits a specific magnetic field resulting from a predetermined current supplied to the coil 134 (e.g., by an electronic control device).Movement of the valve element 128 by movement of the armature 132 leads to a pressure change, which is transmitted via a hydraulic control port 136 of the electrohydraulic device 126 to the control chamber 116 of the control valve 104. Furthermore, in the illustrated, non-limiting example, the electrohydraulic device 126 is configured to control the pressure within the control chamber 116 (e.g., to release the pressure in the control chamber 116 in response to the pressure change within the control chamber 116). In some non-limiting examples, the electromagnet 130 may include a spring (not shown) configured to bias the armature 132 toward one end of the electromagnet 130. In some non-limiting examples, the electrohydraulic device 126 may be an electrohydraulic pressure relief valve (EDRV) configured to move the control element 118 into the first and / or second position and / or any intermediate position within the control channel 120 by regulating the pressure within the control chamber 116. In further non-limiting examples, the electrohydraulic device 126 may be an electrohydraulic pressure relief valve (EPRV) configured to release the pressure within the control chamber 116 when the control element 118 is moved into the first and / or second position as a result of another process within the control valve 104.In another non-restrictive example, the electro-hydraulic device 126 can be an electro-hydraulic pressure control valve (EHPV) configured to continuously adjust the flow volume of fluid from the control chamber 116 (or at another location on the control valve 104) when the control element 118 is moved into the first and / or second position within the control channel 120 by variably positioning a slide of the EHPV. In yet another non-restrictive example, the electro-hydraulic device 126 can be an electro-hydraulic flow control valve configured to regulate the flow of fluid from the control chamber 116 (or at another location on the control valve 104) when the control element 118 is moved into the first and / or second position within the control channel 120.In further non-restrictive examples, the electro-hydraulic device 126 of the control valve 104 may not include a control element and the electro-hydraulic device 126 may otherwise control the pressure or flow within a control chamber connected to one or more control channels of the control valve 104 (such as similar to the hydraulic system 10 according to Fig. 1A). Further referring to Fig. 1B, the hydraulic control system 102 can also include an electronic control unit 140, which is electrically connected to the electromagnet 130 of the electrohydraulic device 126 of the control valve 104. Specifically, in the illustrated, non-limiting example, the control unit 140 can be configured to send and receive signals from the coil 134 of the electromagnet 130 via a circuit (e.g., similar to the current feedback circuit 142) of the hydraulic control system 102. For example, the control unit 140 can be configured to supply the coil 134 of the electromagnet 130 with a signal (e.g., a varying voltage signal, a pulse width modulation signal ("PWM"), etc.).) to provide a current command that results in a specific magnetic field within the coil 134 to drive the armature 132 to a linear movement (or to remain in a specific position) within the electromagnet 130. In some non-restrictive examples, the control device 140 may be configured to determine a current or a range of currents (i.e., a set current) that correlates with the commencement of actuation of the electrohydraulic device 126. For example, the commencement of actuation may be the commencement of pressure generation by the electrohydraulic device 126 or the commencement of fluid flow through the electrohydraulic device 126. Furthermore, the control device 140 can be configured to receive or monitor signals from the coil 134 via a current feedback circuit 142, which correlate with one or more electromagnetic properties of the electromagnet 130. These electromagnetic properties can include, for example, inductance or current feedback of the electromagnet 130 (or the coil 134). In some non-limiting examples, the control device 140 can also be configured to detect a change in the received signal from the coil 134, which may correlate with a movement of the armature 132 within the coil 134, potentially resulting from a hydraulic disturbance within the control valve 104.For example, a hydraulic disturbance that can cause movement of the armature 132 within the coil 134 may include movement of the control element 118, a pressure change within the control chamber 116, or a flow change within the control chamber 116. In some non-limiting examples, the control device 140 may have an input 144 that can be connected to a computer or computer network, which may be located outside the hydraulic control system 102 (e.g., wirelessly or via a fixed connection). In some non-limiting examples, the control device 140 and / or the current feedback circuit 142 may be included as part of the control valve 104, such as within the electrohydraulic device 126 or the electromagnet 130 thereof.In some non-restrictive examples, the control device 140 may be included in a control unit on a machine having the hydraulic system 100 (e.g., an off-highway machine). In other non-restrictive examples, the control device 140 may be a stand-alone control unit that may be connected to the hydraulic system 100 of the machine or to a control unit of the machine (e.g., via the current feedback circuit 142 and / or the input 144). In some non-restrictive examples, the electro-hydraulic device 126 of the control valve 104 can be configured via the control unit 140 to detect or determine an initial displacement or movement of the control element 118. This use of the electro-hydraulic device 126 of the control valve 104 can be particularly advantageous in some applications because it may not require any sensor(s) located outside the control valve 104 (or not required for its normal operation) to calibrate the electro-hydraulic device 126. Consequently, in such non-restrictive examples, an electro-hydraulic device 126 can function as a "detection device" in a calibration mode (e.g., a passive operating mode in which a control current is supplied to the electro-hydraulic device 126 that does not correspond to any actuation (e.g., not the set current)) and as a "control device" in an operating mode (e.g., a passive operating mode in which the electro-hydraulic device 126 is supplied with a control current that does not correspond to any actuation (e.g., not the set current)).B. an active operating mode in which a control current corresponding to an actuation is supplied to the electrohydraulic device 126). In this context, Fig. 2 illustrates a non-limiting example of a method 200 for detecting a hydraulic fault in a hydraulic control system according to aspects of the present disclosure. The method 200 is described here by way of example with reference to the hydraulic control system 102 with the control valve 104 in Fig. 1B. However, according to further embodiments of the disclosed method, other hydraulic control systems, including other control valves and electrohydraulic devices, can also be used. In the non-restrictive example shown in Fig. 2, the method 200 can begin at block 210, which may include controlling an electromagnet of an electrohydraulic valve of a hydraulic control system to a setpoint current. Referring to the control valve 104 in Fig. 1B, the electromagnet 130 of the electrohydraulic device 126 of the hydraulic control system 102 may, for example, be controlled to a setpoint current by the control device 140. The setpoint current may be a predetermined (or variable) value or range of values, which may correspond to an initial actuation of the electrohydraulic device. In some non-restrictive examples, the electrohydraulic device may, for example, be an EDRV, and the setpoint current controlled in block 210 of the method 200 may correlate with a current value (e.g., an amperage) that results in the generation of a setpoint pressure by the EDRV.In such non-restrictive examples, controlling an electromagnet of the EDRV to the set current may therefore not result in any movement or displacement of a control element of the control valve by the set pressure. In other non-restrictive examples, the electro-hydraulic device may be an EHÜV, and the set current controlled in block 210 of procedure 200 may correlate with a current value just below a current corresponding to a minimum pressure release setpoint of the EHÜV. In some non-restrictive examples, the electro-hydraulic device 126 may be an EHPV, and the set current controlled in block 210 of procedure 200 may correlate with a current value just below a current that triggers an adjustment of a fluid flow volume by the EHPV. It is understood that aspects of Method 200 can be used with other electrohydraulic valves or devices configured to operate differently from the electrohydraulic device 126 of the control valve 104 described with reference to Fig. 1B. For example, in some non-restrictive examples, the electrohydraulic device may be configured to be actuated (i.e., pressure generation, fluid flow volume adjustment, etc.) when the applied current falls below a current threshold. In some such examples, the set current applied in block 210 of Method 200 may correlate with a current value just above a current that triggers the actuation of the electrohydraulic device. In some non-restrictive examples, the electrohydraulic device does not require an applied set current, so Method 200 may be used, if necessary, to operate without a set current.does not include block 210 (which is represented as a dashed box). From block 210, the method 200 can then proceed to block 220 (or, if no block 210 is included, begin with it), which may include monitoring an electromagnetic property of the electromagnet. Referring to the hydraulic control system 102 in Fig. 1B, the control device 140 may, for example, be configured to monitor an electromagnetic property of the electromagnet 130 of the electrohydraulic device 126 of the control valve 104. Accordingly, the electromagnetic property monitored in block 220 of the method 200 may be a plurality of properties of the electromagnet (or one or more of its components). For example, in some non-limiting examples, the electromagnet may have an armature and a coil (e.g., the armature 132 and the coil 134 of the electromagnet 130 in Fig. 1B).1B), and the electromagnetic property can be an inductance of the coil 134 of the electromagnet 130, which can be monitored in block 220 of method 200. In some non-restrictive examples, the current feedback measured by a control device along a current feedback circuit (e.g., the current feedback circuit 142 in Fig. 1B) of the hydraulic control system or electrohydraulic device can be the electromagnetic property monitored in block 220 of method 200. From block 220, the method 200 can then proceed to block 230, which may include detecting a change in the electromagnetic properties of the electromagnet. From block 230, the method can then proceed to block 240, which may include determining the occurrence of a hydraulic fault within the hydraulic control system based on the change in the electromagnetic properties of the electromagnet detected in block 230. Referring again to the hydraulic control system 102 in Fig.1B The control device 140 can, for example, be configured to detect a change in an electromagnetic property of the electromagnet 130 of the electrohydraulic device 126, as in block 230, and to determine a hydraulic disturbance within the hydraulic control system 102 or its control valve 104 based on the detected change in the electromagnetic property of the electromagnet 130, as in block 240. In some non-restrictive examples, the steps carried out in blocks 230 and 240 can be performed simultaneously. As described above, a hydraulic disturbance detected in block 240 of method 200 in the hydraulic control system can be the result of a variety of pressure or flow events. For example, a hydraulic disturbance can result from a displacement of the control element 118 within the control channel 120 (e.g., from the first position to the second position or vice versa) of the control valve 104, which can cause a change in the electromagnetic properties of the electromagnet 130 of the electrohydraulic device 126 (e.g., a pressure change or a change in the flow rate in the control chamber 116 or as a result of a discharge process of the electrohydraulic device 126). Thus, the change in the electromagnetic properties of the electromagnet 130 by the control device 140 can be correlated with the hydraulic disturbance within the control valve 104 or other parts of the hydraulic system 100.For example, a pressure change in the control chamber 116 (i.e., the hydraulic disturbance) resulting from the movement of the control element 118 within the control channel 120 can act on the valve element 128 of the electrohydraulic device 126 and cause the armature 132 of the electromagnet 130 to move with the valve element 128. This movement of the armature 132 caused by the hydraulic disturbance can be measured by the control device 140 as a change in an electromagnetic property of the electromagnet 130. For example, a change in current feedback or inductance of the coil 134 of the electromagnet 130 can be received as signals by the control device 140 via the current feedback circuit 142. In some non-limiting examples, one or more steps of the method 200 can be implemented using one or more computer algorithms located in a processor of a control device (e.g., a computer).the control unit 140 in Fig. 1B) of the hydraulic control system or on one or more computers or computer networks outside the hydraulic control system. In general, in some non-limiting examples, Method 200 can broadly enable the detection of the commencement of movement of a control element of a control valve using an integrated current feedback circuit of a control device of a hydraulic control system by driving an electromagnet of an electrohydraulic device (of the hydraulic control system or the associated control valve) to a pressure generation threshold (i.e., via the set current in block 210 of Method 200 in Fig. 2) and by monitoring a change in an electromagnetic property (e.g., current feedback) of the electrohydraulic device. If the commencement of movement of a control element (e.g., the control element 118 of the control valve 104 of the hydraulic control system 102 in Fig. 1B) is detected (e.g., via Method 200 in Fig. 2), the commencement of movement of a consumer of the hydraulic system (e.g.,of the consumer 110 of the hydraulic system 100 in Fig. 1B). Accurate prediction of the start of the consumer's movement (e.g., by detecting the start of the movement of the control element in block 240 of method 200) of the hydraulic system can enable a user to calibrate one or more other electrohydraulic devices or actuators of the hydraulic control system without requiring actual movement of the consumer. As generally noted above, the processes shown in the figures can be carried out in different sequences in some non-restrictive examples, including in parallel or simultaneous operation. For example, controlling an electromagnet to a set current, detecting a change in an electromagnetic property of the electromagnet, and / or determining the occurrence of a hydraulic disturbance in other phases of the process 200 can be carried out in parallel with other processes shown for the process 200 or with other processes not shown in Fig. 2. In some non-limiting examples, a control valve of a hydraulic control system may comprise a plurality of electro-hydraulic devices that are fluidically connected to a control chamber of the control valve (or other sections of the control valve). In such examples, one electro-hydraulic device of the control valve (i.e., an electro-hydraulic sensing device) may be used to calibrate another electro-hydraulic device of the control valve (i.e., an electro-hydraulic actuating device). Accordingly, Fig. 3 shows another non-limiting example of a control valve 304 of the hydraulic control system 102 of the hydraulic system 100 according to Fig. 1B, based on aspects of the present disclosure. The control valve 304 corresponds in some aspects to the control valve 104 in Fig.1B , wherein corresponding components are designated with the same reference numerals, unless otherwise described below or evident from the figures. In the non-restrictive example shown in Fig. 3, the control valve 304 has a first, a second and a third tank working port 312A, 312B, 312C, a first and a second consumer working port 314A, 314B, a first control chamber 316A, a second control chamber 316B and a control element 318 (e.g. a main gate valve) arranged between the first and the second control chamber 316A, 316B within a control channel 320. The main slide valve 318 is adjustable within the control channel 320 when the first control chamber 316A is pressurized in a first direction 350 towards the second control chamber 316B (i.e. towards a first end 322B of the control channel 320) and when the second control chamber 316B is pressurized in a second direction 352 (e.g. opposite to the first direction 350) towards the first control chamber 316A (i.e. towards a second end 322A of the control channel 320). The control valve 304 has a spring 338 arranged in the second control chamber 316B, which is configured to bias the main valve 318 into a neutral position (as shown in Fig. 3) between the control chambers 316A, 316B. In other words, the spring 338 is configured to hold or move the main valve 318 into the neutral position unless the pressure in either the first or the second control chamber 316A, 316B is sufficient to overcome the spring force of the spring 338 and cause the main valve 318 to move or shift within the control channel 320 in the first direction 350 towards the second control chamber 316B or in the second direction 352 towards the first control chamber 316A.In some non-restrictive examples, the control valve 304 may further comprise a second spring arranged in the first control chamber 316A, configured to axially counteract the spring 338 in the second control chamber 316B. In such non-restrictive examples, the second spring may thus be configured to bias the main valve 318 in the first direction 350, while the spring 338 may bias the main valve 318 in the second direction 352 to position the main valve 318 in a neutral position between the first and second positions, unless the pressure in either the first or the second control chamber 316A, 316B is sufficient to overcome a spring force of either the spring 338 or the second spring.In such non-restrictive examples, spring 338 and the second spring can have spring constants that are equal to each other and thus exert the same but opposite spring forces on the main slide 318. In other non-restrictive examples, spring 338 and the second spring can have spring constants that are different and thus exert different and opposite spring forces on the main slide 318. Referring further to Fig. 3, the first tank working port 312A is fluidly connected to the pump 108 (see Fig. 1), the second tank working port 312B is fluidly connected to the tank 106 (see Fig. 1), and the first or the second consumer working port 314A, 314B is fluidly connected to the consumer 110 (see Fig. 1). Furthermore, the main valve 318 is designed to allow flow between the first or the second tank working port 312A, 312B and the first or the second consumer working port 314A, 314B, depending on the position of the main valve 318. Specifically, from the neutral position (as in Fig.3 shown) in the first direction 350 towards the second control chamber 316B, the main valve 318 is adjusted via a flow bridge 356 to allow a flow between the first tank working port 312A and the second consumer working port 314B, while at the same time allowing a flow between the first consumer working port 314A and the second tank working port 312B. With the main valve 318 moved from the neutral position in the second direction 352 towards the first control chamber 316A, a flow between the first tank working port 312A and the first consumer working port 314A is enabled via the flow bridge 356, while at the same time a flow between the second consumer working port 314B and the third tank working port 312C (which in the illustrated example provides a flow from the control valve 304 to the tank 106, corresponding to the second tank working port 312B) is enabled.In some non-restrictive examples, the main spool 318 can be adjusted in the first or second direction to a variety of neutral positions between the first and second positions. In some non-restrictive examples, the control valve 304 can have three or more control chambers with a variety of spools. In some non-restrictive examples, the control valve 304 can have six or more working ports connected to three or more control chambers with three or more spools in fluid communication. With further reference to Fig. 3, the control valve 304 has a first electrohydraulic device or electrohydraulic sensing device 326A and a second electrohydraulic device or electrohydraulic drive device 326B. The electrohydraulic sensing device 326A is connected to the first control chamber 316A via a first hydraulic control port 336A, and the second electrohydraulic device or electrohydraulic drive device 326B is connected to the second control chamber 316B via a second hydraulic control port 336B. In the illustrated, non-restrictive embodiment, the detection and drive devices 326A, 326B are designed to correspond to each other and also to the electro-hydraulic devices 26, 126 according to Fig. 1A and 1B respectively, including the valve element 28, 128 and the electromagnet 30, 130 with the armature 32, 132 and the coil 34, 134.Thus, the electrohydraulic sensing device 326A comprises a first valve spool (e.g., the valve spool 128 according to Fig. 1B) and a first electromagnet 330A with a first armature and a first coil (e.g., the electromagnet 130 with the armature 132 and the coil 134 according to Fig. 1B), and the electrohydraulic drive device 326B comprises a second valve spool corresponding to the first valve spool and a second electromagnet 330B corresponding to the first electromagnet 330A, with a second armature and a second coil. Thus, the electrohydraulic sensing device 326A is configured to control the pressure in the first control chamber 316A, and the electrohydraulic drive device 326B is configured to control the pressure in the second control chamber 316B. In some non-limiting examples, the first and / or second electromagnet 330A, 330B may have a spring (not shown) configured to bias the first or second armature toward one end of the electromagnet 330A, 330B. In some non-limiting examples, the first and / or second electromagnet 330A, 330B may be configured such that the armature is rotatable within the coil when the coil has a certain magnetic field. In some non-limiting examples, the electro-hydraulic sensing device and the electro-hydraulic drive device 326A, 326B may each be an EDRV, an EHPV, or an EHÜV. In some non-limiting examples, the electro-hydraulic sensing device 326A may differ from the electro-hydraulic drive device 326B.For example, in some non-restrictive examples, the electro-hydraulic detection device 326A may be an EHÜV and the electro-hydraulic drive device 326B may be an EDRV. Referring further to Fig. 3, the first and second electromagnets 330A, 330B of the electrohydraulic sensing device and the electrohydraulic drive device 326A and 326B, respectively, can each be electrically conductive and operatively connected to the control unit 140 (see Fig. 1B) of the hydraulic control system 102. Specifically, the control unit 140 can be configured to send and receive signals from the first and / or the second coil of the first and second electromagnets 330A, 330B of the electrohydraulic sensing device and the electrohydraulic drive device 326A, 326B, respectively. For example, the control device 140 can be configured to send or control signals or a current of the first and / or the second coil of the first or second electromagnet 330A, 330B (e.g., by providing a varying voltage signal (such as a PWM signal)), which leads to a magnetic field that causes the first or second electromagnet 330A, 330B to move.The second armature of the first or second electromagnet 330A, 330B is moved linearly within the first or second coil, respectively (or remains in a specific position). Furthermore, the control device 140 can be configured to receive or monitor signals from the first and / or second coil of the first or second electromagnet 330A, 330B, respectively, which correlate with one or more electromagnetic properties (such as inductance or current feedback) of the first or second electromagnet 330A, 330B (or the coil in question). In some non-limiting examples, the control device 140 can also be configured to detect a change in the received signal from the first and / or second coil of the first or second electromagnet 330A, 330B, which may correlate with a movement of the first or second armature within the first or second coil, respectively (e.g.,as a consequence of an event within the control valve 304, such as a movement or displacement of the main spool 318 in the first or second direction 350, 352). In some non-restrictive examples, the control device 140 (or the hydraulic control system 102) may have an integrated current feedback circuit (e.g., the current feedback circuit 142 according to Fig. 1B) which is connected to the first and second electromagnets 330A and 330B, respectively. In some non-restrictive examples, the control device 140 can be configured to determine currents of the first and second electromagnets 330A, 330B of the sensing and drive electro-hydraulic devices 326A, 326B, respectively, which correspond to the start of pressure generation by the sensing and drive electro-hydraulic devices 326A, 326B in the first and second control chambers 316A, 316B, respectively. In particular, the control device 140 can be configured to calibrate at least the electro-hydraulic drive device 326B of the control valve 304 using feedback from the electro-hydraulic sensing device 326A. In some non-restrictive examples, the control device 140 may, for instance, be configured to determine a current or a range of currents that correlates with the commencement of an actuation of the electro-hydraulic sensing device 326A (i.e., a set current).In some non-restrictive examples, the commencement of the actuation of the electro-hydraulic detection device 326A can be, for example, the commencement of pressure generation in the first control chamber 316A by the electro-hydraulic detection device 326A. In a non-restrictive example, the start of pressure generation in the first control chamber 316A by the electro-hydraulic sensing device 326A can be determined by setting a corresponding current (i.e., a target current of the electro-hydraulic sensing device 326A) using data (e.g., data monitored or determined by the control unit 140 according to Fig. 1B). In some non-restrictive examples, the target current can be an average current value from a range of corresponding currents. For example, the current of the first coil 330A of the electro-hydraulic sensing device 326A can be increased until the electro-hydraulic sensing device 326A causes the main valve 318 to move in the first direction, which in turn leads to a hydraulic disturbance in the second control chamber 316B.A difference between a current command to the first coil of the electrohydraulic sensing device 326A and a measured current feedback from the first coil can indicate when the main valve 318 is set in motion by the electrohydraulic sensing device 326A (causing the hydraulic disturbance). Therefore, the increasing current command to the first coil of the electrohydraulic sensing device 326A, together with the measured current feedback from the first coil, can be monitored while the main valve 318 is being moved by the electrohydraulic sensing device 326A. In this context, the current command to the second coil of the electrohydraulic actuator 326B, together with the measured current feedback from the second coil, can be used to correlate the first coil with the second coil. Thus, (e.g., by the control device 140 according to Fig.1B) A target current of the electrohydraulic sensing device 326A can be determined by calculating the average current of the first coil of the electrohydraulic sensing device 326A between the onset and cessation of the hydraulic disturbance. As briefly mentioned above, the target current of the electrohydraulic sensing device 326A can be particularly advantageous in that current feedback from the first electromagnet 330A resulting from a hydraulic disturbance can be more easily detected (e.g., by bringing the first armature to the threshold of movement by the first electromagnet 330A and thus making it more sensitive to the hydraulic disturbance). In a specific, non-limiting example, the current corresponding to the onset of pressure generation in the first control chamber 316A by the electrohydraulic sensing device 326A (i.e.,The target current of the electro-hydraulic sensing device 326A), for example, in a range of about 100 mA to over 400 mA, in a range of about 150 mA to about 300 mA, or in a range of about 175 mA to about 225 mA. Furthermore, in some non-restrictive examples, a similar procedure can be used to determine a current corresponding to the start of pressure generation in the second control chamber 316B by the electro-hydraulic drive device 326B (i.e., a target current of the electro-hydraulic drive device 326B). Referring further to Fig. 3, the control device 140 (see Fig. 1B) can be configured to send or provide a first varying voltage signal to the electrohydraulic sensing device 326A of the control valve 304. For example, the control device 140 can apply the first varying voltage signal to the electrohydraulic sensing device 326A to drive the first electromagnet 330A (e.g., as described above) to (or close to) the set current. The first varying voltage signal can be a signal that causes a specific current in the first coil of the first electromagnet 330A or a PWM signal. The control device 140 can further be configured to apply a second varying voltage signal to the electrohydraulic actuator 326B to drive a current of the second electromagnet 330B between a first or lower level and a second or higher level.to switch to a higher level, which is higher than the first level. The first and second levels of the current of the second electromagnet 330B can define currents designed to hold the main valve 318 in a specific position (e.g., the neutral position shown in Fig. 3). In some non-restrictive examples, the first level and an initial second level can, for example, be at or near a specific target current, which corresponds to the pressure generated in the second control chamber 316B by the second electrohydraulic device 326B. The control device 140 can further be configured to increase the second level of the current of the second electromagnet 330B until the main valve 318 moves in the second direction 352 towards the first control chamber 316A. This movement of the main valve 318 in the second direction 352 can lead to a first hydraulic disturbance in the first control chamber 316A.Specifically, the first hydraulic disturbance could be, for example, a pressure increase in the first control chamber 316A, an increase in the flow rate of fluid through the first control chamber 316A, or a pressure drop in the first control chamber 316A caused by a relief process of the electrohydraulic detection device 326A. Referring further to Fig. 3, the control device 140 (see Fig. 1B) can also be configured to detect a change in an electromagnetic property of the first electromagnet 330A of the electrohydraulic sensing valve 326A, which is caused by a first hydraulic disturbance, and to determine the second level of the current of the second electromagnet 330B of the electrohydraulic actuator valve 326B, which corresponds to the change in the electromagnetic property of the first electromagnet 330A of the electrohydraulic sensing valve 326A. Furthermore, the control device 140 can also be configured to determine a calibration point of the electrohydraulic actuator 326B.The calibration point of the electrohydraulic drive device 326B can, in particular, correspond to the second current level of the second electromagnet 330B of the electrohydraulic drive device 326B, which corresponds to a measured change in the electromagnetic properties of the first electromagnet 330A of the electrohydraulic sensing device 326A caused by the first hydraulic disturbance. In addition to the second current level of the second electromagnet 330B of the electrohydraulic drive device 326B, the calibration point can also correspond to variable spring coefficients of one or more springs (e.g., spring 338) arranged on the main valve 318 and acted upon by the movement of the main valve 318 resulting from the hydraulic disturbance. In this context, Figs. 4A and 4B show non-restrictive exemplary comparisons 400 between a current / time curve 410 of the electro-hydraulic drive device 326B and a current feedback disturbance / time curve 420 of the electro-hydraulic sensing device 326A of the control valve 304 in Fig. 3. In the comparisons 400, the time functions of the curves 410 and 420 are synchronized. In some non-restrictive examples, the curves 410 and 420 (or the data represented in the curves 410 and 420) can be generated, monitored, or compared in the control unit 140 of the hydraulic control system 102 according to Fig. 1B or in other components outside the hydraulic control system 102. Referring in particular to Fig. 4A, a first point 430 in the current / time curve 410 can indicate the time at which the current applied to the second electromagnet 330B rises to a level sufficient to cause the main slide 318 of the control valve 304 to begin moving in the second direction 352 towards the first control chamber 316A. Similarly, a second point 440 in the current feedback disturbance / time curve 420 can indicate the time at which a first hydraulic disturbance (such as an increased pressure or flow rate in the first control chamber 316A) occurs in the first control chamber 316A, which is caused by the movement of the main valve 318 in the second direction 352 and is measured in Fig. 4A as a rise or peak of the current feedback during a linear displacement of the first armature of the first electromagnet 330A. It is understood that the change in the control current and the resulting disturbance can be negative and their directions do not necessarily correlate. Referring in particular to Fig. 4B, a third point 450 in the current / time curve 410 can, for example, alternatively indicate a time at which the current applied to the second electromagnet 330B drops to a level sufficient to cause the main spool 318 of the control valve 304 to begin moving in the second direction 352 towards the first control chamber 316A (see Fig. 3). Similarly, a fourth point 460 in the current feedback disturbance / time curve 420 can indicate the time at which the first hydraulic disturbance occurs in the first control chamber 316A, caused by the movement of the main spool 318 in the second direction 352, as shown in Fig. 4B.4B, during a linear displacement of the first armature of the first electromagnet 330A, is measured as a fall or trough of the current feedback. Thus, using the current / time curve 410, a change in the current feedback of the first armature of the first electromagnet 330A can be identified either as a peak (e.g., second point 440 in Fig. 4A) or as a trough (e.g., fourth point 460 in Fig. 4B). In some non-restrictive examples, the change in the drive current and the resulting disturbance may be reversed (e.g., due to potentially different configurations of the electromagnet 330A). For example, in some such examples, a measured positive disturbance (e.g.,Point 430 in the current / time curve 410), which indicates the time at which the current applied to the second electromagnet 330B rises to a level sufficient to cause the main slider 318 to begin moving in the second direction 352, corresponds to a drop or a valley of the current feedback value (e.g. fourth point 460 in Fig. 4B) during a linear displacement of the first armature of the first electromagnet 330A. Referring again to Fig. 3, the control device 140 of the hydraulic control system 102 (see Fig. 1B) with the control valve 304 can further be configured to reduce the current of the second electromagnet 330B after the movement of the main valve 318 in the first direction 350, until the main valve 318 moves in the second direction 352 and causes a second hydraulic disturbance in the first control chamber 316A. Specifically, the movement of the main valve 318 back to the neutral position in the first direction 350 following its movement in the second direction 352 (e.g., by reducing the current of the second electromagnet 330B and thus reducing the pressure in the second control chamber 316B) can lead to a second hydraulic disturbance in the first control chamber 316A.The second hydraulic disturbance may, for example, be in particular an increase in a flow rate or a decrease in pressure in the first control chamber 316A, which may result from the filling of the control chamber 316A after the movement of the main valve 318 in the first direction 350 away from the first control chamber 316A. Referring further to Fig. 3, the control device 140 (see Fig. 1) can further be configured to detect, after the movement of the main slide 318 in the first direction 350, which leads to the second hydraulic disturbance in the first control chamber 316A, a second change in the electromagnetic properties of the first electromagnet 330A of the electrohydraulic sensing valve 326A caused by the second hydraulic disturbance in the first control chamber 316A, and to determine the current of the second electromagnet 330B of the electrohydraulic actuator valve 326B, which corresponds to the second change in the electromagnetic properties of the first electromagnet 330A of the electrohydraulic sensing device 326A caused by the second hydraulic disturbance in the first control chamber 316A.Furthermore, the control device 140 can also be configured to determine a time interval between the first and the second hydraulic disturbance in the first control chamber 316A. The specific time interval between the first and second hydraulic disturbances in the first control chamber 316A can be repeated multiple times to provide trend data, enabling more accurate calibration of the electrohydraulic actuator 326B with respect to the movement of the main spool 318 during normal operation of the control valve 304. In this context, Fig. 5 shows a comparison 500 between a current / time curve 510 of the electrohydraulic actuator 326B of the control valve 304 in Fig. 3 and a current feedback disturbance / time curve 520 of the electrohydraulic sensing device 326A. In the comparison 500, the time functions of curves 510 and 520 are synchronized. Furthermore, curves 510 and 520 include a trend line 530.In some non-restrictive examples, the curves 510, 520 (or the data shown in the curves 510, 520) can be generated, monitored or compared in the control device 140 of the hydraulic control system 102 according to Fig. 1B or in other components outside the hydraulic control system 102. As shown by line 530 in Fig. 5, the onset of a disturbance in the current feedback can be correlated in the current feedback disturbance / time curve 520 with a corresponding value in the control parameter or in the applied current in the current / time curve 510. Thus, by repeated cycles with numerous lines 530, a trend line or trend data can be determined to more accurately calibrate the electrohydraulic actuator 326B. The trend line or trend data can represent a correlation between the known timing of the drive current of the electrohydraulic actuator 326B and the measured disturbance in the electrohydraulic sensing device 326A. For example, the absence of a correlation in the trend line or trend data may indicate mere noise in the feedback circuit. On the other hand, a correlation in the trend line or trend data may indicate an actual delay time (i.e.,the time between the command of the target current and the resulting movement of the main slide valve), which can be used to determine the calibration point. In general, a control device of a hydraulic control system can be used to calibrate an electrohydraulic actuator of a control valve of the hydraulic control system by configuring an electrohydraulic sensing device of the control valve to detect one or more hydraulic disturbances in the control valve caused by the electrohydraulic actuator moving a control element (e.g., a main spool) of the control valve. Accordingly, Fig. 6 illustrates a non-limiting example of a method 600 for calibrating an electrohydraulic system according to aspects of the present disclosure. The method 600 is described here by way of example with reference to the hydraulic control system 102 of Fig. 1B with the control valve 304 of Fig. 3.However, other hydraulic control systems, including other control valves and electro-hydraulic devices, can also be used according to further embodiments of the disclosed method. In the non-restrictive example according to Fig. 6, the method 600 can begin at block 610, which comprises applying a first varying voltage signal to a first electrohydraulic device having a first electromagnet. For example, with reference to the control valve 304 in Fig. 3, block 610 of the method 600 can comprise applying a first varying voltage signal to the electrohydraulic sensing device 326A with the first electromagnet 330A via the control unit 140 (see Fig. 1B). From block 610, the method 600 can proceed to block 620, which can comprise applying a second varying voltage signal to a second electrohydraulic device to switch the current of a second electromagnet of the second electrohydraulic device between a first level and a second level (which is, for example, higher than the first level). Again referring to the control valve 304 in Fig.Referring to Figure 3, block 620 of method 600 may, for example, include applying a second varying voltage signal (which differs, for example, from the first level) to the electrohydraulic actuator 326B with the second electromagnet 330B via the control device 140. In some non-limiting examples, the first and / or the second varying voltage signal may be a PWM voltage signal. From block 620, method 600 may transition to block 630, which may include the step of monitoring a change in an electromagnetic property of the first electromagnet of the first electrohydraulic device caused by the movement of the main spool of the control valve. Again referring to the control valve 304 according to Figure 3, block 630 of method 600 may, for example, include the step of monitoring (e.g., via the control device 140 according to Figure 1B) a change in an electromagnetic property (e.g.,a feedback current) of the first electromagnet 330A of the electrohydraulic sensing device 326A, which is caused by the movement of the main slide 318 of the control valve 304. It is understood that blocks 620 and 630 of the method 600 can be combined or carried out simultaneously in some non-limiting examples. From block 630, procedure 600 can proceed to block 640, which may include the step of determining whether the second level of current from the second electromagnet of the second electrohydraulic device results in movement of a main spool of the control valve (e.g., the main spool 318 of control valve 304). If the answer in block 640 is "no," procedure 600 can proceed to block 650, which may include the step of increasing the second level of current from the second electromagnet, and then return to block 620. If the answer in block 640 is "yes," procedure 600 can proceed to block 660, which may include the step of determining a calibration point of the second electrohydraulic device corresponding to the second level of current from the second electromagnet that resulted in movement of the main spool in block 640. In some non-limiting examples, a control device of a hydraulic control system may be configured to determine a current of one or more electrohydraulic devices (e.g., a first EDRV) corresponding to the commencement of actuation or pressure generation by the electrohydraulic device, and this determined current may be used as one or more setpoint currents or as a first level current of the electrohydraulic device. In this context, Fig. 7 illustrates another non-limiting example of a method 700 for calibrating an electrohydraulic system according to aspects of the present disclosure. Method 700 is also described here by way of example with reference to the hydraulic control system 103 of Fig. 1 with the control valve 302 of Fig. 3.However, other hydraulic control systems, including other control valves and electro-hydraulic devices, can also be used according to further embodiments of the disclosed method. In the non-restrictive example shown in Fig. 7, the method 700 can begin at block 710, which may include: determining (i) a current of a first electromagnet of a first EDRV (e.g., the electrohydraulic sensing device 326A with the first electromagnet 330A of the control valve 304 in Fig. 3), corresponding to the start of pressure generation by the first EDRV, and (ii) determining a current of a second electromagnet of a second EDRV (e.g., the electrohydraulic actuator 326B with the second electromagnet 330B of the control valve 304), corresponding to the start of pressure generation by the second EDRV. From block 710, the method 700 can proceed to block 720, which includes the application of a first PWM voltage signal (e.g., via the control device 140 shown in Fig. 3).1B) to the first EDRV to drive the first electromagnet to the specified current corresponding to the start of pressure generation by the first EDRV in block 710. From block 720, method 700 can transition to block 730, which may include applying a second PWM voltage signal to the second EDRV (e.g., via control device 140) to switch the current of a second electromagnet of the second EDRV between a first level and a second level, the first level being the current determined in block 710, corresponding to the start of pressure generation by the second EDRV. From block 730, method 700 can transition to block 740, which may include monitoring (e.g., via control device 140) a change in an electromagnetic property of the first electromagnet of the first EDRV caused by the hydraulic disturbance in a first control chamber (e.g., the first control chamber 316A of control valve 304). It is understood that blocks 730 and 740 of procedure 700 may be combined or executed simultaneously in some non-restrictive examples. Further referring to Fig. 7, the method 700 can proceed from block 740 to block 750, which may include the step of determining whether the second level of the current of the second electromagnet of the second EDRV results in a movement of a main spool of the control valve (e.g., the main spool 318 of control valve 304) that causes a hydraulic disturbance in the first control chamber (e.g., the first control chamber 316A of control valve 304). If the answer in block 750 is "no", the method 700 can proceed to block 760, which may include the step of increasing the second level of the current of the second electromagnet, and then return to block 730.If the answer in block 750 is “yes”, procedure 700 may proceed to block 770, which may include the step of determining the second level of the current of the second electromagnet, which corresponds to the change in the electromagnetic property of the first electromagnet monitored in block 740. In some non-limiting examples, aspects of the present disclosure, including computer-based implementations of methods according to the present disclosure, may be implemented as a system, method, device or product using standard programming or development techniques for producing software, firmware, hardware or any combination thereof for controlling a control device, such as a processor device, a computer (e.g., a processor device operatively connected to a memory) or any other electronically operated control device, in order to implement the aspects described in detail herein.Accordingly, for example, aspects of the present disclosure may be implemented as a set of instructions embodied on a non-volatile, computer-readable medium, such that a processor device can execute the instructions based on reading the instructions from the computer-readable medium. Some non-limiting examples according to aspects of the present disclosure may, in accordance with the discussion below, include (or utilize) a control device, such as an automation device, a special-purpose or general-purpose computer, including various computer hardware, software, firmware, etc. The term "product" as used herein is intended to encompass a computer program that can be accessed by any computer-readable device, carrier (e.g., non-volatile signals), or medium (e.g., non-volatile media). For example, computer-readable media may include, among others, magnetic storage devices (e.g., hard disk, floppy disk, magnetic stripe, etc.), optical data carriers (e.g., compact disc (CD), digital versatile disc (DVD), etc.), smart cards, and flash memory devices (e.g., card, USB drive, etc.). Furthermore, it is understood that a carrier wave can be used to transmit computer-readable electronic data, such as that used, for example, in sending and receiving emails or accessing a network like the Internet or a local area network (LAN). The person skilled in the art will recognize that numerous modifications can be made to these embodiments without deviating from the scope or spirit of the claimed subject matter.Certain processes of procedures according to aspects of this disclosure, or of systems executing these procedures, may be schematically depicted in the figures or otherwise discussed herein. Unless otherwise specified or limited, the depiction of certain processes in the figures, in particular their spatial arrangement, does not necessarily imply that these processes must be carried out in a specific sequence corresponding to the respective spatial arrangement. Accordingly, certain processes depicted in the figures or otherwise disclosed herein may, depending on their suitability for certain implementations of aspects of this disclosure, be carried out in a different sequence than expressly shown or described.Furthermore, in some non-restrictive examples, certain operations can be performed in parallel, including through dedicated parallel processing devices or separate computing devices designed to work together as part of a large system. Unless otherwise specified or limited, the terms "component," "system," "module," and the like, in the context of computer implementation, shall encompass parts or all of computer-related systems that include hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, among other things, a processor device, a process executed (or executable) by a processor device, an object, an executable file, an execution thread, a computer program, or a computer. For illustration, both an application running on a computer and the computer itself may be a component. One or more components (or one or more systems, one or more modules, etc.)) can be located within a process or execution thread, be localized on one computer, be distributed across two or more computers or other processing devices, or be contained in another component (or another system, another module, etc.). As used here, unless otherwise restricted or defined, "or" denotes a non-exhaustive list of components or operations that may exist in any combination, rather than an exhaustive list of components that may exist only as alternatives to one another. For example, a list of "A, B, or C" denotes the options: A; B; C; A and B; A and C; B and C; and A, B, and C. Accordingly, the term "or," as used here, is intended to denote exclusive alternatives only when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of." An enumeration of "one of A, B, or C" denotes the options: A, but not B and C; B, but not A and C; and C, but not A and B. An enumeration of "one or more" (and variations thereof, e.g.,A list preceded by "at least one of" and containing "or" to separate the listed elements indicates, for example, options that include one or more of the listed elements, or all of them. For example, the phrases "one or more of A, B, or C" and "at least one of A, B, or C" denote the following options: one or more A's; one or more B's; one or more C's; one or more A's and one or more B's; one or more B's and one or more C's; one or more A's and one or more C's; and one or more of A, one or more of B, and one or more of C. Similarly, a list preceded by "a multitude of" (and variations thereof) and containing "or" to separate the listed elements denotes options for multiple instances of any one or all of the listed elements.For example, the expressions “a plurality of A, B or C” and “two or more of A, B or C” refer to options such as: A and B; B and C; A and C; and A, B and C. In the present description, non-restrictive exemplary embodiments of aspects of the present disclosure have been described in a manner that makes it possible to formulate a clear and concise description; however, it is intended and understood that aspects of the present disclosure may be combined or separated in various ways without departing from the scope of the present disclosure. For example, it is understood that all preferred features described herein are applicable to all aspects of the present disclosure described herein. Although the present disclosure has been described in connection with certain embodiments and examples, it is therefore not necessarily limited to these, and it is intended that numerous further embodiments, examples, uses, modifications and deviations from the embodiments, examples and uses of the attached claims are covered. Various features and advantages of the present disclosure are set forth in the following claims.

Claims

Hydraulic control system comprising: an electrohydraulic valve in fluid communication with a control chamber of a control valve, the electrohydraulic valve having an electromagnet and a valve element actuated by the electromagnet; and a control device connected to the electromagnet, configured to detect a change in an electromagnetic property of the electromagnet that correlates with a hydraulic disturbance within the hydraulic control system. Hydraulic control system according to claim 1, wherein the electromagnet has an armature and wherein the electromagnetic property is based on a movement of the armature in the electromagnet. Hydraulic control system according to claim 2, wherein the control device is further configured to monitor the electromagnetic property of the electromagnet for the detection of the hydraulic fault. Hydraulic control system according to claim 3, wherein the electromagnetic property is a measured current feedback of the electromagnet. Hydraulic control system according to claim 4, wherein the change in the electromagnetic property can be detected by comparing the measured current feedback with a predetermined duty cycle of the electromagnet. Hydraulic control system according to claim 1, wherein the hydraulic disturbance is caused by a movement of a control element of the control valve and / or a change in volume or pressure within the hydraulic control system. Hydraulic control system according to claim 6, wherein the control element of the control valve is a main slide, a valve disc or a piston. Hydraulic control system according to claim 6, wherein the control element of the control valve is a main spool and the electromagnet of the electrohydraulic valve has an armature, and wherein a movement of the main spool displaces a fluid in the control chamber and causes a corresponding movement of the armature in the electromagnet of the electrohydraulic valve. Hydraulic control system according to claim 6, wherein the control element of the control valve is a main spool which is adjustable by an electrical actuator of the hydraulic control system. Hydraulic control system according to claim 9, wherein the control device is further configured to identify a calibration point of the electrical actuator based on a movement of the main valve. Hydraulic control system according to claim 9, wherein the control device is further configured to apply an increasing or decreasing control current to the electrical actuator until the main valve moves in response to the control current. Hydraulic control system according to claim 11, wherein the rising or falling control current is a series of pulses with varying amplitude or length. Hydraulic control system according to claim 9, wherein the electrohydraulic valve is a first electrohydraulic valve and the control chamber is a first control chamber of the control valve, and wherein the electrical actuating device is a second electrohydraulic valve of the control valve, which is connected to the control device and which is in fluid communication with the main spool via a second control chamber. Hydraulic control system according to claim 13, wherein the main valve is further adjustable in a first direction by the first electrohydraulic valve and in a second direction opposite to the first direction by the second electrohydraulic valve, and wherein the control device is further configured to: identify a first calibration point of the first electrohydraulic valve based on the movement of the main valve in the first direction; and identify a second calibration point of the second electrohydraulic valve based on the movement of the main valve in the second direction. Hydraulic control system according to claim 14, wherein the control valve has the second control chamber. Hydraulic control system according to claim 1, wherein the electrohydraulic valve is an electrohydraulic pressure regulating valve (“EDRV”), an electrohydraulic proportional valve (“EHPV”) or an electrohydraulic pressure relief valve (“EHÜV”). Hydraulic control system according to claim 1, wherein the change in the electromagnetic property of the electromagnet occurs independently of a change in a control current made by the control device. Method for detecting a hydraulic fault in a hydraulic control system, comprising: detecting a change in an electromagnetic property of an electromagnet of an electrohydraulic valve of the hydraulic control system; and determining the occurrence of the hydraulic fault based on the detected change in the electromagnetic property of the electromagnet, wherein the electrohydraulic valve is in fluid communication with a control chamber of a control valve of the hydraulic control system and has a valve element actuated by the electromagnet. The method according to claim 18, further comprising, prior to detecting the change in the electromagnetic property of the electromagnet: controlling the electromagnet to a target current corresponding to actuation of the electrohydraulic valve. Method according to claim 18, wherein the electromagnet has an armature and wherein the electromagnetic property is based on a movement of the armature in the electromagnet. The method of claim 20, further comprising: monitoring the electromagnetic property of the electromagnet by means of a control device connected to the electromagnet for detecting changes in the electromagnetic property. Method according to claim 21, wherein the electromagnetic property is a measured current feedback of the electromagnet. The method of claim 21, further comprising: controlling a predetermined duty cycle of the electromagnet via the control device; and comparing a measured current feedback with the predetermined duty cycle using the control device to detect the change in the electromagnetic property. Method according to claim 18, wherein the hydraulic disturbance is caused by a movement of a control element of the control valve and / or a change in volume or pressure within the hydraulic control system. Method according to claim 24, wherein the control element of the control valve is a main slide, a valve disc or a piston. Method according to claim 24, wherein the control element of the control valve is a main slide and the electromagnet has an armature, and wherein a movement of the main slide displaces a fluid within the control chamber and causes a corresponding movement of the armature in the electromagnet. Method according to claim 24, wherein the control element is a main valve which is adjustable by an electrical actuator of the hydraulic control system. Method according to claim 27, further comprising: applying an increasing or decreasing control current to the electrical actuator via a control device connected to the electrical actuator until the main slide moves in response to the control current. Method according to claim 28, wherein the rising or falling control current is a series of pulses with varying amplitude or length. Method according to claim 28, further comprising: identifying a calibration point of the electrical actuator by means of the control device based on the movement of the main slide. Method according to claim 27, wherein the electrohydraulic valve is a first electrohydraulic valve, the electromagnet is a first electromagnet, and the control chamber is a first control chamber of the control valve, wherein the electrical actuating device is a second electrohydraulic valve which is in fluid communication with the main spool via a second control chamber of the control valve, wherein the second electrohydraulic valve has a second electromagnet, and wherein the main spool is further adjustable in a first direction by the first electrohydraulic valve and in a second direction opposite to the first direction by the second electrohydraulic valve. Method according to claim 31, further comprising: identifying a calibration point of the second electrohydraulic valve by means of a control device connected to the first and the second electromagnet based on the movement of the main slide in the second direction. Method according to claim 18, wherein the electrohydraulic valve is an electrohydraulic pressure regulating valve (“EDRV”), an electrohydraulic proportional valve (“EHPV”) or an electrohydraulic pressure relief valve (“EHÜV”). Electro-hydraulic system comprising: a hydraulic valve with a first control chamber, a second control chamber and a main spool arranged between the first and the second control chamber, wherein the main spool is adjustable in a first direction towards the second control chamber when the first control chamber is pressurized and in a second direction towards the first control chamber when the second control chamber is pressurized; a first electro-hydraulic valve with a first electromagnet, wherein a pressure in the first control chamber can be controlled by means of the first electro-hydraulic valve; a second electro-hydraulic valve with a second electromagnet, wherein a pressure in the second control chamber can be controlled by means of the second electro-hydraulic valve;and a control device for calibrating the electrohydraulic system, wherein the control device is operatively connected to the first and the second electrohydraulic valves and is configured to: apply a first varying voltage signal to the first electrohydraulic valve; apply a second varying voltage signal to the second electrohydraulic valve to switch a current of the second electromagnet between a first level and a second level which is higher than the first level, wherein the first and the second levels define currents by means of which the main spool can be held in an actual position; raise the second level of the current of the second electromagnet until the main spool moves in the second direction and causes a hydraulic disturbance in the first control chamber;Detecting a change in the electromagnetic property of the first electromagnet of the first electrohydraulic valve caused by the hydraulic disturbance; and determining the second level of the current of the second electromagnet of the second electrohydraulic valve, which corresponds to the change in the electromagnetic property of the first electromagnet of the first electrohydraulic valve. Electrohydraulic system according to claim 34, wherein the control device is further configured to: determine the second level of the current of the second electromagnet of the second electrohydraulic valve corresponding to the change in the electromagnetic property of the first electromagnet of the first electrohydraulic valve as a calibration point corresponding to the second electrohydraulic valve. Electrohydraulic system according to claim 34, wherein the electromagnetic property is a current of the first electromagnet of the first electrohydraulic valve. Electrohydraulic system according to claim 36, further comprising a current feedback circuit connected to the first and the second electrohydraulic valve, and wherein the control device is configured to measure the change in current of the first electromagnet of the first electrohydraulic valve along the current feedback circuit caused by the hydraulic disturbance. Electro-hydraulic system according to claim 34, wherein the hydraulic disturbance in the first control chamber is a change in the pressure in the first control chamber and / or a change in the flow rate in the first control chamber. Electrohydraulic system according to claim 34, wherein the first and second electrohydraulic valves are each an electrohydraulic pressure regulating valve (“EDRV”), an electrohydraulic proportional valve (“EHPV”) or an electrohydraulic pressure relief valve (“EHÜV”). Electrohydraulic system according to claim 39, wherein the second electrohydraulic valve is an EDRV and wherein the first level of the current of the second electromagnet correlates with the commencement of pressure generation by the second electrohydraulic valve. A method for calibrating an electrohydraulic control system, comprising: applying a first varying voltage signal to a first electrohydraulic device having a first electromagnet, wherein a pressure corresponding to a first current of the first electromagnet can be controlled in a first control chamber of a hydraulic valve by means of the first electrohydraulic device, wherein the first control chamber is arranged opposite a second control chamber, wherein a main valve is arranged between the first and the second control chamber, wherein the second control chamber is connected to a second electrohydraulic device having a second electromagnet, by means of which a pressure corresponding to a second current of the second electromagnet can be controlled in the second control chamber, wherein the main valve is adjustable in such a way as to:that the main valve, when pressurized in the first control chamber, moves in a first direction towards the second control chamber, and that, when pressurized in the second control chamber, the main valve moves in a second direction opposite to the first direction towards the first control chamber; applying a second varying voltage signal to the second electrohydraulic device to switch the second current between a first level and a second level, the second level being higher than the first level; raising the second level of the second current,until the main valve moves in the second direction and causes a hydraulic disturbance in the first control chamber; detecting a change in an electromagnetic property of the first electromagnet of the first electrohydraulic device caused by the hydraulic disturbance in the first control chamber; and determining a calibration point of the second electrohydraulic device, wherein the calibration point corresponds to the second level of the second current of the second electromagnet of the second electrohydraulic device, which corresponds to the detected change in the electromagnetic property of the first electromagnet of the first electrohydraulic device. Method according to claim 41, wherein the first and the second varying voltage signal are pulse width modulation voltage signals (PWM voltage signals). The method of claim 41, wherein the first electromagnet has an armature, wherein the hydraulic disturbance in the first control chamber is a change in the pressure in the first control chamber and / or a change in the flow rate in the first control chamber, and wherein the hydraulic disturbance causes the change in the electromagnetic property of the first electromagnet by causing a movement of the armature of the first electromagnet. Method according to claim 41, wherein the first and second electrohydraulic devices are each an electrohydraulic pressure regulating valve (“EDRV”), an electrohydraulic proportional valve (“EHPV”) or an electrohydraulic overpressure valve (“EHÜV”). Method according to claim 44, wherein the first electrohydraulic device is a first EDRV and the second electrohydraulic device is a second EDRV, wherein the first electromagnet of the first EDRV can be controlled by means of the first varying voltage signal, which correlates with the commencement of pressure generation in the first control chamber by the first EDRV, and wherein the first level of the current of the second electromagnet of the second EDRV correlates with the commencement of pressure generation by the second EDRV. Method according to claim 41, wherein the hydraulic disturbance in the first control chamber is a change in the pressure in the first control chamber and / or a change in the flow rate in the first control chamber. The method of claim 46, wherein the hydraulic disturbance is a first hydraulic disturbance in the first control chamber, which is a change in the flow rate in the first control chamber caused by a discharge operation of the first electrohydraulic device, and wherein the method for calibrating the electrohydraulic control system further comprises: reducing the second current of the second electromagnet until the main valve moves in the first direction and causes a second hydraulic disturbance in the first control chamber; detecting a change in the electromagnetic properties of the first electromagnet of the first electrohydraulic device caused by the second hydraulic disturbance in the first control chamber;Determining the second current of the second electromagnet of the second electrohydraulic device, which corresponds to the change in the electromagnetic properties of the first electromagnet of the first electrohydraulic device caused by the second hydraulic disturbance; and determining a time interval between the first and the second hydraulic disturbance in the first control chamber. Method according to claim 47, further comprising: comparing the determined time interval between the first and the second hydraulic disturbance in the first control chamber and the determined second currents of the second electromagnet of the second electrohydraulic device corresponding to the first and the second hydraulic disturbance. Method according to claim 48, wherein the first hydraulic disturbance in the first control chamber is a pressure increase in the first control chamber; and wherein the second hydraulic disturbance in the second control chamber is a pressure drop in the first control chamber after the first hydraulic disturbance. An electrohydraulic system comprising: a control valve with: a control element adjustable between a first position and a second position for controlling fluid flow through the electrohydraulic system; and an electrohydraulic device that can be operated either in an active operating mode or in a passive operating mode; and a control device connected to the electrohydraulic device of the control valve, wherein the control device is configured to: in the active operating mode of the electrohydraulic device, apply a control current to the electrohydraulic device so that the electrohydraulic device moves the control element to the first position or to the second position and controls the fluid flow through the electrohydraulic system;and, in the passive operating mode of the electrohydraulic device, to monitor a change in current feedback from the electrohydraulic device caused by an independent movement of the control element into the first position or the second position. Electrohydraulic system according to claim 50, wherein the control device is further configured to apply a set current to the electrohydraulic device in the passive operating mode of the electrohydraulic device. Electro-hydraulic system according to claim 51, wherein the set current is lower than the control current.

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