Valve control device and method for operating a valve control device

Abstract

The invention relates to a valve control device (2) for actuating a magnetic coil (12) of a magnetic valve (4), comprising a control device (7) having a current measuring device for determining a coil current, the control device (7) being designed to determine a resistance of the magnetic coil (12), and selecting, as a function of the determined resistance, at least one parameter from the group consisting of the actuation current, the actuation time, the holding current and the holding time from a numerical table stored in the control device (7) for the subsequent actuation of the magnetic valve (4). The control device (7) is configured to determine a parameter in the group comprising a pull-in current, a pull-in time, a hold current and a hold time. The invention further relates to a method for operating a valve control device for actuating a magnetic coil of a magnetic valve.

Description

Technical Field

[0001] The invention relates to a valve control device for actuating a magnetic coil of a magnetic valve and a method for operating the valve control device. Background Art

[0002] DE 10 2019 203 574 A1 discloses a valve assembly comprising at least one coupling section for coupling a valve unit comprising a magnetic valve, wherein the valve assembly is configured to identify the type of valve unit coupled to the coupling section based on an electrical variable associated with the magnetic valve. Summary of the Invention

[0003] The object of the present invention is to provide a valve control device for actuating a magnetic coil and a method for operating a valve control device for actuating a magnetic coil of a magnetic valve with improved control quality.

[0004] According to the invention, this object is achieved by a valve control device for controlling a magnetic coil of a magnetic valve, which has a control device with a current measuring device for determining the coil current, wherein the control device is configured to determine the resistance of the magnetic coil and, depending on the determined resistance, select at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time from a table of values ​​stored in the control device for subsequent control of the magnetic coil, and / or wherein the control device is configured to determine a parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time.

[0005] To effectively control a magnetic valve, parameters that characterize the magnetic coil in its interaction with other components of the magnetic valve must be taken into account. These parameters include, in particular, the pull-in current, pull-in time, holding current, and holding time. These parameters vary from one magnetic valve to another and may also change during operation. For example, in complex installations with multiple magnetic valves, manually identifying each of the magnetic valves used (e.g., by a user) and optimally controlling them can be extremely difficult. Therefore, valve control devices are often pre-set with parameters that apply to multiple magnetic valves. However, this results in lower control quality.

[0006] In principle, the magnetic valve to be actuated comprises a magnetic coil, a valve armature, and a sealing element kinetically coupled to the valve armature. In particular, it can be designed as a seat valve or a slide valve. The sealing element is designed to interact with a valve seat surrounding a valve opening of a fluid channel. The fluid channel extends in the valve housing of the magnetic valve between an inlet port and an outlet port.

[0007] The sealing element can be fastened directly to the valve armature and, in this case, is surrounded by the pressurized fluid (which is provided at the inlet connection and flows to the outlet connection), as long as the valve seat is not blocked by the sealing element. Such valves can be used, in particular in the field of automation technology, as pilot valves for downstream, compressed air-controlled main valves or directly for controlling compressed air consumers, where compressed air is used, in particular, as the pressurized fluid. Alternatively, a diaphragm, in particular a rubber-elastic diaphragm, can be arranged between the assembly consisting of the magnetic coil and the valve armature and the fluid channel with the valve seat. This diaphragm ensures a sealed separation between the fluid channel and the assembly consisting of the magnetic coil and the valve armature and is also referred to as a media-separating magnetic valve. Such magnetic valves are particularly used to control the flow of pressurized liquids, for example in the field of laboratory technology, in particular for metering liquids.

[0008] In the deactivated state of the magnetic valve, the valve armature is in the deactivated end position, which is configured as a closed position, for example. In this closed position, a sealing element coupled to the valve armature seals against the valve seat, thereby blocking fluid flow through the valve opening. In the activated state of the magnetic valve, the valve armature is in the activated end position, which is referred to as the open position. The sealing element is spaced apart from the valve seat and the valve opening is released for fluid flow. A magnetic valve configured in this manner is also referred to as a "normally closed" valve or NC valve. Alternatively, the magnetic valve can be configured so that the valve seat is released in the deactivated state and sealed in the activated state. A magnetic valve configured in this manner is also referred to as a "normally open" valve or NO valve.

[0009] To move the valve armature from the deactivated end position to the activated end position, a control unit supplies a coil current to the magnetic coil, which then generates an electromagnetic field that moves the valve armature to the activated end position. If the coil current is switched off, the valve armature should return to the deactivated end position. For this purpose, a valve spring arranged in the magnetic valve can be provided. This valve spring deforms when the valve armature moves from the deactivated end position to the activated end position, thereby exerting a greater restoring force on the valve armature in the activated end position than in the deactivated end position.

[0010] The control device can be designed as a microprocessor, on which a program mirroring the functions of the control device is executed. The program is stored in a memory connected to the microprocessor or integrated into the microprocessor.

[0011] To determine the coil current, the control unit has a current measuring device, which can be a separate (discrete) current measuring sensor or integrated directly into the control unit. The current measuring device measures the current intensity present at the magnetic coil, converts this current intensity into a measured value, and supplies this measured value to a program running in the control unit for further processing.

[0012] The pull-in current is the current intensity required to move the valve armature from the deactivated end position into the activated end position by means of the electromagnetic field generated by the magnetic coil and thus enable a fluid flow through the magnetic valve in the case of an NC valve.

[0013] The pull-in current varies for different magnetic valve designs, particularly those with differently configured components from the group consisting of the magnetic coil, valve armature, and sealing element. Furthermore, the pull-in current may also vary during operation due to heating of the magnetic coil. If too little current is supplied to the magnetic coil, the magnetic valve may not open or may only open partially.

[0014] The parameter "pull-in time ta" is the time elapsed from the supply of coil current until the valve armature reaches its end position, i.e., until the valve armature reaches its active end position from its inactive end position. The movement of the valve armature requires at least the presence of a pull-in current and the ability of the magnetic coil to generate a correspondingly strong electromagnetic field. The pull-in time is therefore derived as the time interval between the time the coil current is supplied to the magnetic coil and the time the valve armature reaches its active end position, thereby completing its movement. To ensure complete opening of the magnetic valve, the pull-in current must be supplied during actuation of the magnetic coil for at least a period corresponding to the pull-in time of the magnetic valve connected to the valve control device.

[0015] If the valve armature is in the active end position, a current intensity that is lower than the pull-in current is sufficient to hold the valve armature in this position. In the context of this application, this current intensity is referred to as the holding current. For safe operation, in which the magnetic valve does not close accidentally, the holding current should not be lowered. A holding current that is lower than the pull-in current prevents the magnetic coil of the magnetic valve from heating up too much when the current present at the magnetic coil decreases from the pull-in current to the holding current, thus saving energy.

[0016] In the context of the present application, the holding time is the time period during which a holding current is present at the magnetic coil. More precisely, the holding time is derived from the difference between the time at which the current present at the magnetic coil decreases from the pull-in current to the holding current and the time at which the current present at the magnetic coil decreases to enable the valve armature to move from the activated end position to the deactivated end position and, in the case of the magnetic valve being designed as an NC valve, to block the flow of fluid.

[0017] The above parameters are valve-specific and / or specific to the magnetic coil used in the magnetic valve. Therefore, for optimal actuation of the magnetic valve, it should be provided that these parameters are selected according to the properties of the magnetic valve and are taken into account during actuation.

[0018] In order to achieve optimized operation of different solenoid valves together with the valve control device, the invention provides that the valve control device automatically identifies the solenoid valve and in particular the solenoid coil of the coupled solenoid valve and performs parameter selection coordinated with the identified solenoid coil.

[0019] A characteristic feature of a magnetic coil is its resistance, so that determining this resistance enables identification of the magnetic coil. Accordingly, the valve control device is configured to determine the resistance of the magnetic coil during commissioning in order to identify the magnetic coil of the connected magnetic valve. After identifying the magnetic coil, the control device selects at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current, and a holding time from a value table stored in the control device's memory for subsequent control of the magnetic coil. The value table can be stored as a file in the control device's memory or in a similar manner.

[0020] When a valve control device is used with a magnetic valve whose parameters from the group consisting of pull-in current, pull-in time, holding current, and holding time are not stored in a value table, and / or when the magnetic coil cannot be identified or is unknown to the valve control device when determining its resistance, the valve control device according to the present invention can determine the parameters from the group consisting of pull-in current, pull-in time, holding current, and holding time. For example, it is possible to connect the valve control device to a flow meter for signal processing, which measures the flow rate through the magnetic valve connected to the valve control device. If the flow rate measured during this measurement corresponds to the maximum flow rate of the connected magnetic valve, the valve armature is in the open position, so that the time period between zero flow and maximum flow represents a measure for the pull-in time. This time period can be corrected by the control device for any delay time caused by the inertia of the fluid system.

[0021] Advantageous developments of the invention are the subject matter of the dependent claims.

[0022] Preferably, the control device is designed to determine the pull-in current by supplying a continuously increasing coil current to the magnetic coil and to determine the pull-in current by detecting a first directional change in the measured coil current, in particular a current drop, which indicates a valve movement.

[0023] For the purposes of this application, a continuously rising coil current is understood to mean a coil current that increases over a measurement period, whether this increase occurs continuously or in steps (as in the case of a digital signal, for example). As already described, the magnetic coil of a magnetic valve generates an electromagnetic field at a coil current that corresponds at least to the pull-in current, which is sufficient to cause movement of the valve armature. When the valve armature moves from the deactivated end position to the activated end position, the measured coil current decreases due to the motion absorption of the valve armature, since this motion absorption generates a counter-induction in the magnetic coil that is opposite to the coil current. Accordingly, the movement of the valve armature (which may also be referred to as valve movement) produces a directional change in the course of the measured coil current, with the current intensity at which this directional change begins corresponding to the pull-in current of the magnetic coil. Accordingly, the pull-in current of a magnetic valve connected to a control device can be determined by measuring the coil current. The determined pull-in current can be stored in the control device for subsequent control operations, so that even if the solenoid valve cannot be identified based on the determined pull-in current, it can be used for adjusting the solenoid valve in new switching operations.

[0024] When the determined pickup current is used for the subsequent switching of the magnetic valve, the magnetic coil of the magnetic valve is prevented from being loaded with an unnecessarily high coil current, which could lead to undesired heating of the magnetic coil. To avoid errors in the determination of the pickup current, appropriate signal filtering, in particular signal smoothing, of the measured coil current and / or of a signal corresponding to the measured coil current can preferably be performed in the control unit to reduce the influence of signal noise. The measured coil current is preferably converted into a digital signal by means of an analog / digital converter integrated in the control unit or the current sensor.

[0025] In a further embodiment of the present invention, the control device is configured to determine a further change in direction in the measured coil current, which indicates the end of the valve movement, in order to determine the pull-in time, and to determine the pull-in time from the time difference between the provision of the coil current and the further change in direction of the measured coil current. If the movement of the valve armature ends upon reaching the activation end position, the measured coil current rises again until it reaches a predetermined maximum current intensity. This is due to the fact that upon reaching the activation end position, there is no further relative movement of the valve armature relative to the magnetic coil, and therefore no further back-induction. Therefore, after the movement of the valve armature ends, a new change in direction in the measured coil current occurs, indicating the end of the movement of the valve armature (i.e., the end of the valve movement). The pull-in time can therefore be determined from the difference between the time of provision of the coil current and the time of the end of the movement of the valve armature.

[0026] Knowing the pull-in time ensures that, during subsequent switching operations of the magnetic valve, the current required for the valve movement is supplied for a sufficiently long period (which corresponds at least to the pull-in time) to ensure error-free operation of the magnetic valve. At the same time, it can be ensured that the pull-in current is not supplied for an unnecessarily long period of time, thus avoiding unnecessary energy consumption and unnecessary heating of the magnetic coil.

[0027] Further preferably, the control device is configured to continuously reduce the coil current supplied to the magnetic coil to determine the holding current, and to determine the holding current by detecting a directional change, particularly an increase, in the measured coil current that indicates valve movement. As the coil current supplied to the magnetic coil of the magnetic valve continuously decreases, the magnetic force acting on the valve armature by the magnetic coil decreases, causing the valve armature to move from its start-up end position, for example, due to the restoring force of a restoring spring. In other words, at a specific point in time, the holding current required to maintain the start-up end position is lowered, and valve movement, i.e., movement of the valve armature, occurs. The movement of the valve armature in the electromagnetic field of the magnetic coil generates an increase in the measured coil current due to the back-induction associated with this movement. The directional change in the measured coil current serves as an indicator of valve movement. The measured coil current present at the start of movement of the valve armature corresponds to the holding current of the magnetic valve connected to the valve control device. Accordingly, the valve control device can determine the holding current required for the connected magnetic valve and take this into account in subsequent switching operations of the magnetic valve. Preferably, the control device is configured to increase the determined holding current by a predetermined value and to supply this increased holding current to the magnetic coil as soon as the valve armature reaches the activated end position. In this way, a sufficiently high holding current is provided and safe operation of the valve is achieved without having to supply an unnecessarily high holding current.

[0028] Advantageously, the control device is configured to store parameters from the group consisting of the pull-in current, pull-in time, holding current, and holding time in a value table in the control device and / or to update the value table stored in the control device. Thus, for example, initially unknown values ​​of a magnetic valve can be stored in the control device so that they are available for further operation without having to re-determine the individual parameters before each switching process. It is also possible to update parameters whose values ​​change due to the operation of the magnetic valve so that they are available for further operation.

[0029] Preferably, the control device is configured to increase one of the determined parameters from the group consisting of the pull-in current, the pull-in time, the holding current, and the holding time by a suitable safety factor before storing and / or updating the value table. To further improve operational safety and ensure the correct functioning of the magnetic valve, the control device may increase the determined parameter by, for example, 10% or another percentage, in order to, for example, compensate for variations in the magnetic coil over time of use and / or heating of the magnetic coil and / or operational influences (such as shaking).

[0030] In one advantageous embodiment of the valve control device, the control unit includes at least one controller, in particular a PID controller, wherein the control behavior of the controller is adapted as a function of at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current, and a holding time, and / or as a function of the determined resistance of the magnetic coil. In this case, the aforementioned parameters and / or the resistance of the magnetic coil are used, in particular, to select the P component, I component, D component, integral time, and / or derivative time of the controller. This, for example, allows the coil current supplied to the magnetic coil to be kept constant by adapting the controller even when the magnetic coil is heated and its resistance changes accordingly. Further parameters may also be used to adjust the controller or, due to their determination by the control unit, may also be present for regulating previously unknown magnetic valves.

[0031] In a preferred embodiment of the valve control device, the control device is designed to determine the resistance of the magnetic coil using a switching signal sent to the magnetic valve. To this end, the switching signal can trigger a resistance measurement, or a signal portion of the switching signal itself can be used to determine the resistance of the magnetic coil, with a time offset between the switching signal and the movement of the valve armature. Accordingly, the resistance of the magnetic coil can be repeatedly determined over the operating time of the magnetic valve, and temporal changes caused, in particular, by heating of the magnetic coil can be taken into account for control purposes.

[0032] The object defined above is also achieved by a method for operating a valve control device for actuating a magnetic coil of a magnetic valve. The method comprises the following steps: determining a resistance value of a magnetic coil of a magnetic valve connected to the valve control device by means of a switching signal transmitted to the magnetic valve; selecting, based on the determined resistance value, at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current, and a holding time from a value table stored in a control device for subsequent actuation of the magnetic valve; and / or determining a parameter of the magnetic valve from the group consisting of a pull-in current, a pull-in time, a holding current, and a holding time.

[0033] In an improved embodiment of the method for operating a valve control device having a control device for controlling a magnetic coil of a magnetic valve, the method further includes the following steps: providing a continuously rising coil current, measuring the continuously rising coil current, determining the pull-in current by determining a change in the direction of the measured coil current indicating the valve movement, and / or providing a continuously falling coil current, measuring the falling coil current, and determining the pull-in current by determining a change in the direction of the falling coil current indicating the valve movement.

[0034] In another embodiment, the method for operating a valve control device for operating a magnetic coil for controlling a magnetic valve further includes: determining a further directional change of the measured coil current that indicates the end of the valve movement, and determining the pull-in time from the time difference between the provision of the first coil current and the further directional change of the measured coil current.

[0035] Preferably, the method for operating a valve control device for operating a magnetic coil of a magnetic valve further comprises adapting the control behavior of a regulator of the control device according to selected and / or determined parameters from a group comprising pull-in current, pull-in time, holding current and holding time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention is explained in more detail below with reference to the accompanying drawings, in which:

[0037] Figure 1 A strict schematic diagram showing a valve assembly and a valve control device connected to the valve assembly,

[0038] Figure 2 Shown Figure 1 A strict schematic diagram of the magnetic valve in the valve assembly,

[0039] Figure 3 shows a strictly schematic diagram of the course (Verlauf, sometimes also called profile) of the coil current and the switching signal measured during a switching process of the magnetic valve,

[0040] Figure 4 shows a strict schematic diagram of the pickup current determination and the holding current determination, and

[0041] Figure 5 A strictly schematic diagram is shown of the course of a certain resistance, a switching signal and a movement of the valve armature. DETAILED DESCRIPTION

[0042] exist Figure 1, a valve assembly 1 and a valve control device 2 connected to the valve assembly 1 for signal technology are shown. Purely by way of example, the valve assembly 1 has a total of four disc-shaped valve units 3, which are arranged along the arrangement direction in such a way that one side of each valve unit 3 is in contact with at least one side of another valve unit 3. Suitably, each valve unit 3 has at least one magnetic valve 4 and a main valve 5, which is suitably a fluid-operated valve. The magnetic valve 4 is used to control the supply of fluid, via which the valve element (not shown) of the main valve 5 is operated. Accordingly, the magnetic valve 4 can also be referred to as a pilot valve. In order to connect the valve unit 3 to the valve assembly 1, the valve assembly 1 has a coupling section 6, into which the valve unit 3 can be inserted, for example, wherein it is provided in particular that the individual valve units 3 can be replaced by other valve units 3 for different configurations of the valve assembly 1.

[0043] The valve control device 2 has a control unit 7 with a regulator 8 and a current sensor 9 and is connected to each valve unit 3 for signaling via a control line 10. Purely by way of example, Figure 1 In the embodiment, the control device 7 is accommodated in a separate housing, in particular a housing designed as a connecting plug, and is designed as a microcontroller with a programmable memory 11. However, it is also conceivable for the control device 7 to be integrated in a higher-level control device and then be connected to the regulator 8 and / or the current sensor 9 for signaling purposes, provided these are not also integrated in the higher-level control device.

[0044] exist Figure 2 Strictly schematically shown in Figure 1 . A magnetic valve 4 of any valve unit 3 is shown. Purely by way of example, the magnetic valve 4 is configured as a 2 / 2-way valve and includes a magnetic coil 12, a valve armature 13, a valve element 14 kinetically coupled to the valve armature 13, and a valve opening 16 surrounded by a valve seat 15, which fluidically connects a valve inlet 17 to a valve outlet 18. The magnetic valve 4 is shown in an activated state, in which the valve armature 13 is in an open position. In this open position, the valve element 14 is lifted from the valve seat 15, thereby releasing the valve opening 16 for fluid flow, allowing fluid to flow from the valve inlet 17 to the valve outlet 18. In the deactivated state of the magnetic valve 4 (not shown), the valve armature 13 is in a closed position. In this closed position, the valve element 14 rests against the valve seat 15, thereby blocking the valve opening 16 for fluid flow. To provide a sufficiently high sealing force and to move the valve armature 13 from the open position to the closed position, a valve spring 21 is arranged between a housing wall 19 of a magnetic valve housing 20 and the valve armature 13.

[0045] If a sufficiently large current (which can also be referred to as pull-in current Ia) is supplied to the magnetic coil 12 during the switching process by the control device 7 and the magnetic coil 12 generates a corresponding electromagnetic field, so that the valve armature 13 moves from the closed position to the open position, the magnetic valve 4 is switched from the deactivated state or closed position. Figure 2 , or the open position of the valve armature 13. If the valve armature 13 is in the open position, the control device 7 can reduce the current supplied to the magnetic coil 12 to a current intensity at which the strength of the electromagnetic field created by the magnetic coil 4 is sufficient to counteract the spring action or restoring force of the valve spring 21 and hold the valve armature 13 in the open position. This current intensity may also be referred to as the holding current Ih. The transition from the deactivated state to the activated state and vice versa (i.e., from the activated state to the deactivated state) may be referred to herein as a switching process.

[0046] Figure 3 A strictly schematic diagram shows the course of the coil current I2 and the switching signal U measured during an exemplary switching process of a magnetic valve 4. The depicted courses, in particular the possible ratios, are greatly exaggerated for better visibility. During commissioning, the control device 7 determines the resistance W of the magnetic valve 4 in order to identify the magnetic valve 4 connected to the control device 7. If the magnetic valve 4 is identified as a known magnetic valve to the control device 7, the control device 7 retrieves the parameters for the pull-in current Ia, the pull-in time ta, the holding current Ih, and the holding time th from a table of values ​​stored in its memory 11 to take these into account when adjusting the connected magnetic valve 4. At time t1, the control device 7 receives the switching signal U and, via the control line 10, supplies the magnetic coil 12 with a coil current I1. This coil current is the maximum coil current Im, which corresponds to the pull-in current Ia with an increased safety factor.

[0047] Between times t1 and t2, the measured coil current I2 increases linearly until it reaches a current intensity corresponding to the pull-in current Ia at time t2. At time t2, the generated electromagnetic field is strong enough to initiate movement of the valve armature 13 from the closed position against any retaining forces between the valve element 13 and the valve seat 15 and the restoring force of the valve spring 21. The movement of the valve armature 13 in the magnetic coil 12 induces an induction in the magnetic coil 12, which causes a current drop and, therefore, a first change in direction in the measured coil current I2. When the movement of the valve armature ends at time t3, the measured coil current I2 increases until it reaches the maximum coil current Im provided by the control unit 7. The maximum coil current Im corresponds to the pull-in current Ia, which is increased by the control unit 7 by a safety factor. A further change in direction in the measured coil current I2 indicates the end of the movement of the valve armature 13. The movement of the valve armature 13 occurs between times t2 and t3. The difference between t1 and t3 corresponds to the pull-in time ta of the magnetic valve 4 .

[0048] At time t5, the control device 7 reduces the current supplied to the magnetic coil 12 to the holding current Ih selected for the magnetic valve 4, wherein the time difference between time t1 and time t5 corresponds to the pull-in time ta increased by the safety factor s. Figure 3 The holding current Ih shown in FIG also corresponds to the holding current increased by a safety factor. When the switching signal U ends at time t6, the control unit 7 no longer supplies the coil current I to the magnetic coil 12, and the measured coil current I2 decreases. The difference between times t5 and t6 corresponds to the previously selected holding time th. At time t7, the coil current I2 falls below the required holding current Ih, and the movement of the valve armature 13 from the open position to the closed position begins. The movement of the valve armature 13 between the magnetic coils 12 causes induction to occur again in the magnetic coils 12, resulting in an increase in the measured coil current I2. When the movement of the valve armature 13 ends at time t8 after reaching the closed position, the measured coil current I2 decreases further until, at time t9, there is no longer any coil current in the magnetic coil 12, and the switching process is completely completed.

[0049] exist Figure 4The diagram shows, strictly schematically, the curves of the provided coil current I1 and the measured coil current I2 for determining the parameters of the pull-in current Ia, the pull-in time ta, and the holding current Ih. The curves shown, in particular the possible ratios, are greatly exaggerated and smoothed for better visibility, and the provided coil current I1 and the measured coil current I2 are scaled accordingly. If the magnetic valve 4 connected to the valve control device 2 cannot be identified when determining its resistance W, the method is preferably carried out by the valve control device 2. This is particularly the case when the valve control device 2 is connected to the magnetic valve 4 for the first time or when the resistance of the magnetic valve has significantly changed due to prolonged operation or heating. To determine the aforementioned parameters, the control device 7 supplies a continuously increasing coil current I1 to the magnetic coil 12. The measured coil current I2 then increases until time t2, at which the movement of the valve armature 13 from the closed position to the open position begins. The coil current I2 measured at this time t2 corresponds to the pull-in current Ia of the magnetic valve 4 connected to the valve control device 2. The value of the pull-in current Ia is received by the control device 7 and stored for this solenoid valve 4 in the memory 11 of the control device 7 .

[0050] When the movement of the valve armature 13 ends at time t3, the measured coil current I2 increases again to match the applied coil current I1. The control device 7 determines the pull-in time ta from the difference between times t1 and t3 and stores this in the memory 11 for future use. After determining the pull-in current Ia and the pull-in time ta, the control device 7 continuously reduces the applied coil current I1, which in turn reduces the measured coil current I2. At time t7, the measured coil current I2 falls below the holding current Ih, which is representative of the magnetic valve 4 connected to the valve control device 2. The movement of the valve armature 13 from the open position back to the closed position begins, and the measured coil current I2 increases. The increase in coil current I2 ends at time t8, at which point the valve armature 13 has reached the closed position and its movement has ended. The holding current Ih is also stored in the memory 11 for future use. The above method is preferably repeated several times, for example five times, in order to eliminate possible disturbances in the determined parameters or to reduce their influence by averaging (Mittelung, sometimes also referred to as averaging).

[0051] exist Figure 5, the course of the determined resistance W of the magnetic coil 12, the switching signal U1 sent to the control device 7, and the movement U2 of the valve armature 13 is shown strictly schematically. The control device 7 first determines the resistance W of the magnetic coil 12 at time t0 in order to identify the magnetic valve 4. Subsequently, the switching signal U1 is provided at times tn, tn+1, and tn+2, respectively. The first signal portion is used to determine the resistance of the magnetic coil 12, as can be seen at the illustrated peaks in the course of the resistance W. Only after the resistance has been determined does the movement of the valve armature begin at times tn+tw, tn+1+tw, and tn+2+tw, where tw represents the time delay between providing the switching signal U1 and the start of the movement of the valve armature 13 and thus indicates the duration of the determination of the resistance W of the magnetic coil 12. Accordingly, the resistance W of the magnetic coil 12 can be determined during operation of the valve control device 2 without interrupting operation or sending a separate signal to the control device 7.

Claims

1. A valve control device (2) for actuating a magnetic coil (12) of a magnetic valve (4), comprising a control device (7) having a current measuring device for determining the coil current, wherein: The control device is configured to determine the resistance of the magnetic coil (12) and, based on the determined resistance, select at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time from a table of values ​​stored in the control device for subsequent actuation of the magnetic valve (4), and / or wherein the control device (7) is configured to determine a parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time.

2. The valve control device according to claim 1, characterized in that The control device (7) is designed to provide a continuously increasing coil current (I1) to the magnetic coil (12) for determining the pull-in current, and to determine the pull-in current (Ia) by determining a first directional change in the measured coil current (I2), indicative of a valve movement, in particular a current drop.

3. The valve control device according to claim 2, characterized in that: The control device (7) is designed to determine the pull-in time (ta) by determining a further change in direction of the measured coil current (I2) that indicates the end of the valve movement, and to determine the pull-in time (ta) from the time difference between the provision of the coil current (I1) and the further change in direction of the measured coil current (I2).

4. A valve control device according to any one of the preceding claims, characterized in that The control device (7) is designed to continuously reduce the coil current (I1) supplied to the magnetic coil (12) in order to determine the holding current, and to determine the holding current (Ih) by determining a change in direction, in particular an increase, in the measured coil current (I2) that indicates a valve movement.

5. The valve control device according to any one of the preceding claims, characterized in that The control device (7) is configured to store parameters from the group consisting of a pickup current, a pickup time, a holding current and a holding time in a value table in the control device and / or to update the same in the value table stored in the control device.

6. The valve control device according to claim 5, characterized in that: The control device (7) is configured to increase one of the determined parameters from the group consisting of pickup current, pickup time, holding current and holding time by an appropriate safety factor before storing and / or updating in the value table.

7. A valve control device according to any one of the preceding claims, characterized in that The control device (7) has at least one regulator, in particular a PID regulator, wherein the regulating behavior of the regulator is adapted as a function of at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time and / or as a function of a determined resistance of the magnetic coil.

8. A valve control device according to any one of the preceding claims, characterized in that The control device (7) is designed to determine the resistance of the magnetic coil (12) by means of a switching signal sent to the magnetic valve (4).

9. A method for operating a valve control device for actuating a magnetic coil of a magnetic valve, comprising the following steps: The resistance of a magnetic coil (12) of a magnetic valve (4) connected to the valve control device (2) is determined by means of a switching signal sent to the magnetic valve (4), and at least one parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time is selected from a value table stored in the control device (7) based on the determined resistance for subsequent control of the magnetic valve (4), and / or a parameter from the group consisting of a pull-in current, a pull-in time, a holding current and a holding time of the magnetic valve (4) is determined.

10. The method for operating a valve control device having a control unit for actuating a magnetic coil of a magnetic valve according to claim 9, further comprising: Providing a continuously rising coil current (I1), measuring the continuously rising coil current (I2), and determining the pull-in current (Ia) by determining a change in the direction of the measured coil current (I2) indicating valve movement, and / or providing a continuously falling coil current (I1), measuring the falling coil current (I2), and determining the pull-in current (Ia) by determining a change in the direction of the falling coil current (I2) indicating valve movement.

11. The method for operating a valve control device for actuating a magnetic coil of a magnetic valve according to claim 10, further comprising: A further change in direction of the measured coil current (I2) is determined, indicating the end of the valve movement, and a pull-in time (ta) is determined from a time difference between the provision of the first coil current (I1) and the further change in direction of the measured coil current (I2).

12. The method for operating a valve control device for actuating a magnetic coil of a magnetic valve according to any one of claims 9 to 11, further comprising: The regulating behavior of a regulator (8) of the control device (7) is adapted as a function of selected and / or determined parameters from the group consisting of a pickup current, a pickup time, a holding current and a holding time.

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