DE102021211938B3 - valve assembly - Google Patents

Abstract

A valve arrangement (1) is proposed which has a valve battery (6) which is equipped with a number of electro-pneumatically pilot-controlled directional valves (7), each directional valve (7) having a pilot control valve device (29) which has a pilot control - The supply channel (32) is connected to an electrically operated safety valve (33). The safety valve (33) can connect the pilot control supply channel (32) in a feed position to a pilot control feed channel (34) and in a ventilation position to a pilot control ventilation channel. The operational readiness of the safety valve (33) can be monitored with a venting diagnostic function and/or ventilation diagnostic function of the valve arrangement (1), evaluation electronics (48) being involved in the monitoring. With the venting diagnosis function, it can be monitored whether the venting function of the safety valve (33) is given when it is switched to the venting position by means of an electrical switch-off signal (AS). The ventilation diagnosis function allows a check to determine whether an undesired increased fluid pressure is present in the pilot control supply channel (32) when the safety valve (33) is switched over to the feed position.

Description

The invention relates to a valve arrangement with a plurality of electro-pneumatically pilot-controlled directional valves combined to form a valve battery and with an electrically actuable safety valve, the directional valves each having a main valve and a pilot valve device which can be actuated electrically to specify the operating state of the main valve, the Pilot control valve devices of the directional control valves are connected to a pilot control supply channel of the valve battery, which is connected to the safety valve and is provided to provide a pilot control fluid, and wherein the safety valve can be switched to a feed position by means of an electrical switch-on signal and to a venting position by means of an electrical switch-off signal, with the Pilot supply duct with a pilot supply duct providing a pilot fluid under a pilot pressure indet and in the venting position connects the pilot control supply channel for the purpose of venting it while separating it from the pilot control feed channel with a pilot control venting channel leading to a pressure sink under atmospheric pressure.

One from the DE 10 2013 016 652 A1 Known valve arrangement of this type contains a valve battery equipped with a plurality of electro-pneumatically pilot-controlled directional valves, the directional valves each having an electrically actuable pilot valve device through which an operating state of the main valve of the relevant directional valve can be specified. Each pilot valve device is supplied via a pilot supply channel with a pilot fluid at a pilot pressure, with which the associated main valve can be acted upon in a controlled manner in order to change its operating state. To avoid undesired valve actuation of the directional control valves, the pilot control supply channel is connected to a safety valve of the valve cluster, which can be switched to either a feed position or a venting position by means of control signals provided by an electronic control device. In the feed position, the directional control valves of the valve battery are ready for operation, since the pilot control supply channel is connected to a pilot control feed channel communicating with a pilot pressure source. In the vent position, the pilot supply duct is isolated from the pilot pressure source and vented to atmosphere via a pilot vent duct and is therefore depressurized. Thus, no pilot fluid is available to the pilot valve devices and they can no longer actuate the associated main valve even in the event of an unintentional electrical activation. In order to ensure this safety function, the safety valve must be able to function properly.

From the EP 3 222 855 A1 a fluid power control device is known which has a fluid distributor and is equipped with at least one pressure sensor with which a fluid pressure prevailing in a distributor fluid channel system can be detected. Electrical measured values that can be output by the pressure sensors can be transmitted to an external electronic control device, in which an evaluation takes place in order to carry out a functional diagnosis of the fluid power control device. Among other things, it can be determined in this way whether the pressure medium fed in ensures a desired ventilation or whether there are impairments in this respect possibly due to contamination of silencers.

In the DE 102 22 890 A1 an electrical device for controlling a multi-way valve is described, which is equipped with a state of wear detection. The multi-way valve can be actuated by means of electrical control signals. On the input side, an electrical control signal and an electrical reaction signal following a control pulse are fed to an electronics unit, with a switching delay being determined from the reaction time as a measure of the state of wear of an integrated switching mechanism of the multi-way valve.

In the WO 2009/151955 A1 describes a control valve system equipped with pressure sensors, a cycle parameter being determined based on the time elapsed between two sensor signals, and a logic unit generating a notification signal if the cycle parameter determined has a predetermined deviation from an expected cycle parameter.

the DE 10 2008 041 399 A1 relates to a method for operating a hydraulic or pneumatic control device of an automated manual transmission, the control device comprising actuating devices with actuating cylinders, the pressure chambers of the actuating cylinders being able to be connected to a pressure line via a control valve, the pressure line being selectively connectable to a main pressure line via redundant, parallel-connected main switching valves or can be shut off against this, and wherein the control device comprises at least one sensor. Here, at least one measurement signal is detected with the help of the or each sensor depending on the activation of the main switching valves, wherein the or each measurement signal detected with a for the respective Control of the main switching valves stored target signal is compared, and when a deviation between a measurement signal and the respective target signal is determined, at least one of the main switching valves is closed to a defect.

The invention is based on the object of taking measures with which a high degree of functional reliability of a valve arrangement equipped with a valve battery can be guaranteed.

To solve this problem, the invention provides, in connection with the features mentioned at the outset,
that the valve arrangement is equipped with a venting diagnostic function and/or venting diagnostic function for the safety valve that is implemented with the assistance of evaluation electronics,
wherein the venting diagnostic function enables an electrical venting error diagnostic signal to be generated if the fluid pressure prevailing in the pilot control supply channel at a predetermined venting monitoring time, which is after the provision of an electrical switch-off signal that causes the safety valve to switch from the infeed position to the venting position, is not is below a specified venting limit,
and wherein the ventilation diagnostic function enables an electrical ventilation fault diagnostic signal to be generated if the fluid pressure prevailing in the pilot control supply channel at a predetermined ventilation monitoring time which coincides with the provision of an electrical switch-on signal which causes the safety valve to switch from the venting position to the feeding position, or at the same time thereafter is not below a specified ventilation limit.

In this way, a simple and reliable diagnosis of the safety valve with regard to its proper functionality when venting and/or venting the pilot control supply channel is possible. Depending on the degree of equipment, the valve arrangement allows either a venting diagnostic function or a venting diagnostic function or--with preferred equipment--both a venting diagnostic function and a venting diagnostic function, with the participation of evaluation electronics in relation to the safety valve. It is advantageous that the respective diagnostic function can be activated when the safety valve is switched on and/or off as planned and thus does not impair the normal operation of the valve arrangement.

The venting diagnosis can take place when the safety valve is switched off if the safety valve is switched over from the feed position it had hitherto assumed to the venting position by means of an electrical switch-off signal. The electrical switch-off signal manifests itself, for example, in the removal of an actuating voltage that was previously applied as an electrical switch-on signal. In this case, it is monitored whether the fluid pressure prevailing in the pilot supply channel, which was present during the infeed position at the level of the pilot control pressure, has fallen below a predetermined venting limit value at a predetermined venting monitoring time, which concludes a venting monitoring time interval. If the fluid pressure is not below the specified venting limit value at the venting monitoring point in time, an electrical venting error diagnosis signal is generated with the cooperation of the evaluation electronics. This detects that the venting process is taking place more slowly than expected, which can be an indication that there is an undesired reduction in the venting cross section on the exhaust air side, for example caused by dirt or a muffler that is too small.

The ventilation diagnosis can take place when the safety valve is switched on and is initiated by the provision of the electrical switch-on signal to the safety valve, which causes the safety valve to switch from the venting position to the feeding position. In this case, it is monitored whether the fluid pressure prevailing in the pilot control supply channel at a specified ventilation monitoring time is still below a specified ventilation limit value. A higher fluid pressure in this regard is an indication that an unplanned high fluid pressure is present in the pilot control supply channel, which can in particular be the pilot control pressure, which is an indication that due to a malfunction or incorrect operation, for example due to a leak or due to an accidentally activated manual override device of the safety valve, safe venting is no longer guaranteed. In this case, an electrical ventilation fault diagnostic signal is generated. In particular, the time at which the electrical switch-on signal responsible for switching over to the feed position is provided acts directly as the ventilation monitoring time, with the monitoring process being able to start synchronously with the application of the electrical switch-on signal. However, the ventilation monitoring time can also be later in time, although the time difference between applying the switch-on signal is expediently very small and is in particular less than a period of time that elapses with proper valve operation until starting from the vented state, the pilot pressure has built up.

Since all measurements required for the respective diagnostic function can take place within the valve arrangement, local signal processing and, in particular, very precise time measurement is possible, so that even very small deviations from the regular operating state of the valve arrangement can be detected. All data determined and generated during the diagnosis can be read out without any problems if the evaluation electronics are equipped accordingly and, if necessary, can be fed into a long-term analysis.

Advantageous developments of the invention emerge from the dependent claims.

Although it is possible in principle to design the safety valve of the valve arrangement as a separate component with respect to the valve battery, it is nevertheless advantageous if the safety valve is part of the valve battery, which means that short distances are possible for the pneumatic and electrical connections.

The valve battery expediently has a valve carrier on which the directional control valves and the safety valve are mounted, in particular in a manner that is independent of one another. Fluidic and electrical connections to and between the directional control valves and the safety valve are expediently located inside the valve carrier, so that the valves can be easily replaced if necessary. To form a valve battery, the directional control valves and the safety valve can also be attached directly to one another without an additional valve carrier.

At least the pilot supply passage, the pilot feed passage and the pilot vent passage are preferably formed in the optional valve carrier.

In principle, the evaluation electronics of the valve arrangement can be provided separately from the valve battery. However, integration of the evaluation electronics into the valve battery is considered to be significantly more advantageous. For example, it can be embodied in an electronics module that is separate from the safety valve. It is considered particularly advantageous if the evaluation electronics are integrated into the safety valve. The latter allows specific adjustment to the characteristics of the safety valve.

To provide the switch-on signal and the switch-off signal for the safety valve, it is expedient if the valve battery has a communication interface that enables an electrical connection to an electronic control device that is separate from the valve battery and in which the electrical signals are generated.

The valve battery preferably has an output interface for outputting the electrical venting error diagnosis signal and/or the electrical ventilation error diagnosis signal. This enables simple external processing of the error diagnosis signals, in particular to cause error-dependent consequences, for example a visual and/or acoustic error message and/or an intervention in the control of the valve battery through to an emergency shutdown. The output interface can be formed by the above-mentioned communication interface, but can also easily be implemented as an individual interface.

The safety valve is expediently equipped with an electrical actuating device for actuation by means of the electrical switch-on signal and the electrical switch-off signal—referred to below simply as electrical control signals for the safety valve or safety valve control signals. The electrical actuating device is preferably an electromagnetic or a piezoelectric actuating device. The electrical actuation device is in particular a component of an electropneumatic pilot valve device of the safety valve, which, alternatively, can also be designed for direct electrical actuation.

In particular against the background of enabling setup measures or checking measures or maintenance measures, it is advantageous if the safety valve also has a manual override device designed for manual actuation. It can be used to switch the safety valve either to the feed position or to the venting position, regardless of the operating state of the electrical actuating device, purely by direct manual access. In particular, if the manual override device can be releasably fixed in an activated state in which the safety valve assumes the feed position for easier operation, the ventilation diagnostic function proves to be very advantageous because it can be used to reliably monitor whether a setup or checking or Maintenance measure, the manual override device was deactivated again to allow regular operation of the safety valve by means of the electric actuator.

The specified venting limit value of the venting diagnosis function is preferably a value that can be variably set with the cooperation of the evaluation electronics. In other words, the evaluation electronics enable customer-specific parameterization. The valve arrangement is expediently equipped with suitable input means for setting the pressure value used as the venting limit value, in order to enable manual input or software-based input, for example.

Ideally, the bleed diagnostic function's bleed limit is based on atmospheric pressure. However, since atmospheric pressure is subject to weather-related variations, it is preferred to use an air pressure as the venting limit that is at least slightly above practical atmospheric pressure, notwithstanding any weather-related air pressure variations. A venting limit value is preferably provided in a pressure range between 0.1 bar and 0.3 bar and in particular a pressure value of 0.2 bar.

The specified venting monitoring point in time of the venting diagnosis function can preferably be set variably with the cooperation of the evaluation electronics. Setting means of the type already mentioned above can be present for the setting. The user thus has the possibility for an individual setting of the monitoring in adaptation to the conditions existing in his application.

The venting monitoring point in time of the venting diagnosis function is preferably defined by the end of a predetermined venting monitoring time interval, which immediately follows the point in time at which the electrical switch-off signal for the safety valve is provided. This venting monitoring time interval can preferably be set variably, as a result of which the venting monitoring point in time can then also be set variably indirectly.

The predetermined ventilation limit value for the ventilation diagnostic function can correspond to the pilot pressure, but is preferably lower than the pilot pressure. A pressure value which is at least slightly higher than atmospheric pressure and which is preferably in a range between 0.1 bar and 0.3 bar and in particular 0.2 bar is used as the ventilation limit value.

If the valve arrangement advantageously has both the venting diagnostic function and the venting diagnostic function, it is advantageous in favor of a simple structure and a particularly effective evaluation if the venting limit value and the venting limit value for the fluid pressure prevailing in the pilot control supply channel are the same.

In order to detect the fluid pressure prevailing in the pilot control supply channel, the valve arrangement expediently contains at least one pressure sensor which interacts with the evaluation electronics and which is acted upon by the fluid pressure prevailing in the pilot control supply channel. Although this at least one pressure sensor can in principle be installed as an individual sensor component outside of the safety valve, it is preferably integrated into the safety valve, so that the pressure can be tapped directly in the safety valve, which enables short measurement paths and accordingly provides high measurement accuracy.

A single pressure sensor is preferably present. A single pressure sensor can be used for pressure monitoring in both diagnostic functions in a valve arrangement having both a venting diagnostic function and an aeration diagnostic function. In principle, however, it is possible to provide a separate pressure sensor for each of the two diagnostic functions.

It is favorable if the pressure sensor assumes a first detection state during the venting diagnostic function when the fluid pressure prevailing in the pilot control supply channel is greater than or equal to the specified venting limit value, and assumes a second detection state when the fluid pressure prevailing in the pilot control supply channel is below the specified one venting limit. In the ventilation diagnostic function, it is expedient if the pressure sensor assumes a first detection state when the fluid pressure prevailing in the pilot supply channel is greater than or equal to the specified ventilation limit value, and assumes a second detection state when the fluid pressure prevailing in the pilot supply channel is below the specified one ventilation limit.

It is advantageous for both diagnostic functions if the evaluation electronics have a diagnostic unit, through which a venting error diagnostic signal can be generated or is generated in the venting diagnostic function if the pressure sensor is in the first detection state at the venting monitoring time, and through which in the venting diagnostic function a vent failure diagnostic signal is or will be elicited when the pressure sensor is in the first detection state at the ventilation monitoring time.

The pressure sensor is designed in particular in such a way that it generates an electrical low sensor signal in the first detection state and an electrical high sensor signal in the second detection state. The sensor signals are constant during the associated detection state.

According to a preferred embodiment, the diagnostic unit of the evaluation electronics is designed to generate a venting confirmation signal in the venting diagnostic function, regardless of the time that has elapsed since the electrical switch-off signal was provided, if the pressure sensor changes from the first detection state to the second detection state. Such a venting confirmation signal is therefore also generated if a venting error diagnosis signal was already caused beforehand due to an error due to improper venting. In this way, a simple quantitative analysis and in particular a long-term analysis with regard to the venting behavior is possible. In this context, the venting time elapsed between the electrical switch-off signal and the venting confirmation signal is expediently stored in a memory of the evaluation electronics, which can be read out for the aforementioned analysis purposes. The evaluation electronics are preferably designed in such a way that the stored value is only available until the next time measurement begins. At the beginning of the next time measurement, the memory value is expediently set to "zero" until the time measurement is completed and the resulting venting time is registered as a new memory value. The stored value can be read out in particular by means of a connected electronic control device which is expediently provided externally and which is preferably a so-called programmable logic controller (“PLC”).

Another preferred feature of the valve arrangement consists in a design of the evaluation electronics such that in the case of the ventilation diagnostic function under the conditions described above, a ventilation error diagnostic signal is only generated or can be generated if there is a time interval between an electrical switch-off signal and a subsequent electrical switch-on signal. which is greater than a predetermined time interval referred to as the blocking time interval. This can prevent an exhaust failure diagnosis signal from being output when the time interval between the OFF signal and the ON signal is extremely short. Such short time intervals occur regularly when the voltage supply for the safety valve is briefly switched off by external influence using short test pulses. Such test pulses are normally applied by the user via a connected electronic control device in order to check whether the removal of the actuating voltage as required, ie the generation of an electrical switch-off signal, is functioning correctly. Without a suppression function for the venting fault diagnostic signal for a certain period of time after the actuating voltage is switched on again, a venting fault diagnostic signal would be output after each test pulse because the venting monitoring shows that the fluid pressure in the pilot control supply channel is still above the specified venting limit value. By establishing the lockout time interval, such spurious vent fault diagnostic signals can be suppressed.

If the valve arrangement has a ventilation diagnostic function, it can be equipped with a corresponding suppression function to avoid incorrect ventilation error diagnostic signals, analogously to the ventilation function. In principle, this is not necessary and therefore not provided, because the venting monitoring time has a much greater time interval to the switch-off signal than a test pulse and therefore the venting diagnostic function is normally not influenced by short voltage test pulses.

The valve arrangement is expediently designed for a variable setting of the predetermined blocking time interval. In particular, the evaluation electronics offer appropriate setting options. The setting option preferably includes an optional activation and deactivation of the blocking time interval in order to enable the user to easily adapt to local conditions.

If the valve arrangement is preferably equipped with both a venting diagnostic function and an aeration diagnostic function, both diagnostic functions are expediently constantly active. If, for example, a ventilation error diagnostic signal is generated by the ventilation diagnostic function due to an excessive fluid pressure in the pilot control supply channel and the user does not take any reaction measures such as switching off the valve arrangement, after the subsequent switchover to the ventilation position due to ventilation still not taking place Reaching the venting monitoring time point, a venting error diagnosis signal is also output as a new error message.

• 1 eine schematische Darstellung einer bevorzugten Ausführungsform der erfindungsgemäßen Ventilanordnung, und
• 2 ein Ablaufdiagramm, aus dem bei der Nutzung der Ventilanordnung auftretende zeitabhängige Betriebsabläufe ersichtlich sind.

The invention is explained in more detail below with reference to the attached drawing. In this show:

• 1 a schematic representation of a preferred embodiment of the valve assembly according to the invention, and
• 2 a flowchart showing the time-dependent operating sequences occurring when using the valve arrangement.

From the 1 a valve arrangement 1 can be seen, which is designed to actuate pneumatic drives 2 by means of controlled compressed air application. The pneumatic drives 2 have an output member 3, which can be driven pneumatically in a reciprocating output movement 4 indicated by an arrow. By way of example, the pneumatic drives 2 are linear drives.

Each pneumatic drive 2 has at least one drive chamber 5, the controlled application of compressed air to which causes the driven movement 4. Examples are double-acting drives 2 that have two drive chambers 5 .

The valve arrangement 1 includes a valve battery 6 in which several electro-pneumatically pilot-controlled directional control valves 7 are combined to form a unit that can be handled as a unit. By way of example, these are 5/2-way valves which each have two working outlets 8 which are fluidly connected via a working channel 9 to a drive chamber 5 of an associated pneumatic drive 2 .

The directional control valves 7 are expediently mounted in a detachable manner on a one-piece or modular, multi-piece valve carrier 12 of the valve battery 6 . The valve carrier 12 has an in 1 the viewer facing mounting surface 13 on which the directional control valves 7 sit. The directional control valves 7 are preferably arranged one after the other in a longitudinal direction 14 of the valve battery 6 indicated by a dot-dash line. The working channels 9 extend in the interior of the valve carrier 12 and each end on the mounting surface 13 on the one hand in such a way that they communicate with the working outlet 8 of one of the directional control valves 7 mounted on the mounting surface 13 in the correct assignment. On the other hand, the working channels 9 lead to working connection openings 16 arranged on an outer surface 15 of the valve carrier 12, to which fluid lines 19 leading to the pneumatic drives 2, in particular compressed air hoses, can be connected during operation of the valve arrangement 1.

Each directional control valve 7 has a feed inlet 17 which is fluidly connected to a main supply channel 18 extending inside the valve battery 6 . All directional control valves 7 are connected with their supply inlet 17 to this main supply channel 18 . If, as in the exemplary embodiment, a valve carrier 12 is present, the main supply channel 18 extends in the valve carrier 12. It opens out on the outer surface 15 with a connection opening 18a, to which a compressed air source, referred to as the working pressure source PA, is connected during operation of the valve arrangement 1. which provides compressed air at a working pressure.

Each directional control valve 7 also has one or, in accordance with the illustrated exemplary embodiment, two ventilation outlets 22 which are each connected to a main ventilation channel 23 which is formed in the valve carrier 12 and which extends, for example, in the valve carrier 12 . Each main ventilation duct 23 opens out on the outer surface 15 with a ventilation orifice 23a which communicates with a pressure sink R, which is in particular the atmosphere.

Each directional valve 7 is connected to at least one electrical valve control line 24 indicated by dashed lines, which runs in particular in the form of any number of electrical conductors inside the valve carrier 12 . Electrical valve control signals can be fed to the directional control valves 7 via the electrical valve control line 24, by means of which the directional control valves 7 can be switched to specify a desired operating state. The electrical valve control signals originate, for example, from an internal electronic control unit 25 that belongs to the valve battery 6 and is mounted, for example, on the valve carrier 12, which in turn can be connected via a communication interface 26 to an external electronic control device 27 and is connected when the valve arrangement 1 is ready for operation. The internal electronic control unit 25 preferably contains a fieldbus module for enabling the processing of serial signals which are provided by the electronic control device 27 via a fieldbus.

According to an exemplary embodiment that is not illustrated, the internal electronic control unit 25 can be omitted and the electrical valve control lines 24 can be routed directly to the communication interface 26 in order to receive valve control signals 24 from the external electronic control device 27 .

Each of the directional control valves 7 is equipped with a main valve 28 and an electrically actuatable pilot valve device 29 to enable electropneumatic pilot control. The working outlets 8, the feed inlet 17 and the ventilation outlets 22 are located on the main valve 28. The main valve 28 can be designed as a slide valve or as a seat valve.

The pilot valve device 29 has at least one electrically actuatable pilot valve 29a, 29b, the number of pilot valves 29a, 29b depending on the type of directional control valve 7. For example, each directional control valve 7 has two pilot valves 29a, 29b. The latter against the background that the exemplary directional control valves 7 are valves with a bistable switching function, which are also referred to as pulse valves. In the case of an embodiment as a monostable directional valve 7 with spring return, the pilot valve device 29 can contain only a single pilot valve. The pilot valves 29a, 29b are preferably electrically actuated solenoid valves or piezo valves.

The at least one electrical valve control line 24 is connected to the pilot valve devices 29 of all directional control valves 7 . Depending on the supplied valve control signals 24, the pilot valves 29a, 29b, each of which is in particular a 3/2-way valve, can be actuated. The pilot valve assembly 29 is capable of controlling the fluid loading of the associated main valve 28 with a pilot fluid at a pilot pressure VD, which is compressed air provided by an external pilot pressure source PV. The “pilot control pressure” is the pressure value of a fluid pressure that is required or sufficient to switch over the associated main valve 28 to specify the operating state of the directional control valve 7 and, if necessary, to hold it in the associated switching position for as long as desired.

Electrical actuation of the pilot valve devices 29 can only bring about a change in the switching state of the main valves 28 if the pilot control fluid at the pilot control pressure VD in question is present at the relevant pilot control valve device 29 . In order to provide the pilot fluid in this regard, all the directional control valves 7 are connected to a pilot control supply channel 32 of the valve battery 6 which, for example, runs inside the valve carrier 12 .

However, the pilot supply channel 32 is not directly connected to the pilot pressure source PV, but is connected to a safety valve 33 of the valve arrangement 1 that is present in addition to the directional control valves 7 . This safety valve 33 is also connected to a pilot feed channel 34, which leads to a connection opening 34a located on the outer surface 15, to which the pilot pressure source PV is connected during operation of the valve arrangement 1. With the valve carrier 12 present, the pilot feed passage 34 is preferably internal to the valve carrier 12, which is the case in the illustrated embodiment.

The pilot control supply channel 32 preferably has a plurality of branching points 31a at which it branches off for connection to the various pilot control valve devices 29 of the various directional control valves 7 . This happens in particular inside the valve carrier 12.

By way of example, the pilot control supply channel 32 has further branching points 31b assigned to the individual directional control valves 7 for connection to the two pilot control valves 29a, 29b of each directional control valve 7. However, this branching is also possible internally in the relevant directional control valve 7.

Although the safety valve 33 could in principle also be arranged separately from the valve battery 6, it is preferred to form the safety valve 33 as a component of the valve battery 6 so that it is part of a unit that can be handled uniformly together with the directional control valves 7 . If a valve carrier 12 is present, the safety valve 33 is expediently also mounted on the mounting surface 13, in particular in the longitudinal direction 14 adjoining the row of directional control valves 7.

Deviating from the illustrated embodiment, in which the pilot pressure source PV is designed as a separate pressure source with respect to the working pressure source PA, the pilot pressure source PV can also be formed by the working pressure source PA. In this case, the pilot fluid is branched off from the working fluid coming from the working pressure source PA. There is then no need for a separate connection opening 34a for the pilot pressure source PV, with the pilot feed channel 34 expediently being connected to the main supply channel 18 via a channel section 36 indicated by dashed lines inside the valve battery 6 .

The safety valve 33 also communicates with a pilot vent passage 35 which is connected to an atmospheric pressure sink R, which in particular is the immediate atmospheric environment of the valve assembly 1 . If the valve carrier 12 is present, the pilot control venting ca nal 35 expediently in the interior of the valve carrier 12 and opens out via an outlet opening 37 provided on the outer surface 15 to the environment. A silencer 38 is preferably mounted on the outlet opening 37 in order to reduce the air outlet noise.

The safety valve 33 has a supply port 39 connected to the pilot control supply channel 32, a feed port 40 connected to the pilot control feed channel 34 and a vent port 41 connected to the pilot control vent channel 35.

The safety valve 33 expediently has a 3/2-way valve function and is designed in particular as a 3/2-way valve, which applies to the illustrated embodiment.

The safety valve 33 can assume two switching positions between which it can be switched over by electrical control. Switching takes place by means of electrical control signals SSV, which are also referred to as safety valve control signals SSV in the following for better differentiation and can be fed to the safety valve 33 via an electrical control line 42 indicated by dot-dash lines.

One of the possible switching positions of the safety valve 33 is a vent position from 1 can be seen and in which the pilot supply duct 32 is connected to the pilot control ventilation duct 35 while being separated from the pilot control feed duct 34 .

The second switching position of the safety valve 33 is a feed position in which the pilot supply channel 32 is separated from the pilot vent channel 35 and connected to the pilot feed channel 34 .

The safety valve control signals SSV for operating the safety valve 33 are applied in the form of an operating voltage of variable magnitude. An electrical control signal that causes the feed position is referred to below as a switch-on signal ES, and an electrical control signal that causes the venting position is referred to as a switch-off signal AS.

For example, the venting position of the safety valve 33 is a basic position that is preloaded by a spring 43 . Preferably, the safety valve 33 is of a spring-return monostable type.

The switch-off signal responsible for taking the basic position defining the venting position corresponds to an actuating voltage of 0 volts. To switch to the feed position and to hold it, a higher operating voltage is applied as a switch-on signal, by means of which an electric operating device 44 of the safety valve 33 is able to generate a switching force that overcomes the restoring spring force of the spring 43 .

Preferably, the safety valve 33 according to the illustrated embodiment is of an electro-pneumatically piloted type. In this case, electrical actuating device 44 is formed by an electrically actuatable pilot valve device 45, to which the electrical control valve control signals SSV can be fed via electrical control line 42, and through which a main valve 33a of safety valve 33, which determines the connection pattern between ports 39, 40, 41 controlled by the fluid force of the pilot fluid can be actuated.

The pilot valve device 45 contains, for example, a single pilot valve 45a, which is constantly connected to the pilot feed channel 34 via a pilot channel 46, so that the pilot control pressure prevailing in the pilot feed channel 34 is constantly applied to the pilot valve 45a. The connection to the pilot feed channel 34 is preferably made through a branch 46a inside the safety valve 33. The above-mentioned electrical actuation of the pilot valve 45a allows the pilot pressure to be shut off or switched through with respect to the main valve 33a, in order to change the switching position of the safety valve 33 - that means either the feed position or the venting position - to be specified as required.

According to an exemplary embodiment that is not illustrated, the electrical actuating device 44 can alternatively be designed for a direct electrical actuation of the safety valve 33, for example for a purely electromagnetic actuation.

The switch-on signal ES and the switch-off signal AS are preferably made available by an electronic control device. By way of example, this is the external electronic control device 27 connected to the valve cluster 6. Additionally or alternatively, the optional internal electronic control unit 25 can also function as the electronic control device serving to provide the aforementioned control signals.

If the safety valve 33 is in the feed position, the pilot control pressure VD is present in the pilot control supply channel 32, so that the directional control valves 7 operate as intended are operable. When the safety valve 33 assumes the venting position, the pilot control supply channel 32 is pressureless due to its venting, so that the directional control valves 7 cannot be actuated by electrical valve control signals supplied via the valve control line 24 due to a lack of pilot control pressure VD. The valve arrangement 1 thus offers a safety function to the effect that, if necessary, the directional control valves 7 can be deactivated in such a way that even an unintentional electrical activation cannot cause a change in their operating state.

In addition to the electrical actuating device, the safety valve 33 is expediently equipped with a manual override device 47 that alternatively enables manual actuation. It contains, for example, a manual operating element 47a that can be actuated with the finger of one hand, with which, in particular mechanically, a temporary switchover of the safety valve 33 into the feed position can be brought about. By way of example, the manual operating member 47a can act on the pilot valve device 45 and in particular on a pilot valve member 45a, indicated only schematically, of the pilot valve device 45.

The manual override device 47 allows the safety valve 33 to be switched over to the feed position independently of the electrical control, in order to be able to carry out installation or maintenance work, for example. Preferably, the manual override 47 is of a type that allows the activated state of the manual override 47 to be releasably locked to maintain the energized position for as long as desired, independent of the electrical control signals applied to the safety valve 33.

The valve arrangement 1 is equipped with evaluation electronics 48, with the cooperation of which a venting diagnosis function and a venting diagnosis function for the safety valve 33 are implemented in the valve arrangement 1. Embodiments of the valve assembly 1 modified in this regard are only equipped with the ventilation diagnostic function or only with the ventilation diagnostic function. However, from the point of view of the greatest possible safety, the simultaneous realization of both the venting diagnosis function and the ventilation diagnosis function is preferred.

The two diagnostic functions are explained below, also including the in 2 illustrated flowchart explained in more detail.

At the top, the flowchart contains a diagram section (a) in which the electrical safety valve control signal SSV supplied to the safety valve 33 is plotted over time t. A time sequence of the switch-on signal ES and the switch-off signal AS can be seen. The switch-on signal ES is expressed in an initially rising signal edge, the switch-off signal AS in an initially falling signal edge.

The venting diagnosis function is initiated in that the safety valve 33 is supplied with a switch-on signal ES. The ventilation diagnosis function is initiated by the safety valve 33 being supplied with a switch-off signal AS. A switch-on signal ES is always present until a switch-off signal AS is issued, which in turn is present until a switch-on signal ES is made available again.

The evaluation electronics 48 contain a time measurement module 52, which starts a time measurement when each of the aforementioned safety valve control signals SSV is applied.

Both diagnostic functions evaluate the fluid pressure PF prevailing in the pilot control supply channel 32, which is also referred to below as the pilot control fluid pressure PF. The valve arrangement 1 contains at least one and preferably exactly one pressure sensor 53, by means of which the pilot fluid pressure PF can be detected and is detected during operation of the valve arrangement 1. By way of example, the pressure sensor 53 is advantageously integrated into the safety valve 33 . The pressure tapping preferably takes place from a pressure tapping channel 54 inside the valve, which is in particular a valve channel section of the safety valve 33 connected to the pilot control supply channel 32 . The pressure sensor 53 can be designed for analog or digital pressure recording.

The pressure sensor 53 cooperates with the evaluation electronics 48 and can feed this evaluation electronics 48 an electrical sensor signal representing a certain detection state. The electrical connection required for this between the pressure sensor 53 and the evaluation electronics 48 is indicated by a dashed signal line 55 . The evaluation electronics 48 can be combined at least partially to form a structural unit with the pressure sensor 53 . By way of example, it is designed separately with respect to pressure sensor 53 .

For example, the pressure sensor 53 in conjunction with the evaluation electronics 48 is able to generate an electrical low sensor signal to indicate a first detection state and an electrical high sensor signal to indicate a second detection state. In a diagram section (c) of the flow chart of 2 the diagnostic status DZ of the pressure sensor 53 is plotted as a function of the time t. The first diagnosis state is identified with DZ1, the second diagnosis state with DZ2.

In a diagram section (b) of the flowchart of FIG 2 the pilot fluid pressure PF detected by the pressure sensor 53 is plotted as a function of time t.

Both diagnosis functions are designed to output a specific error diagnosis signal FD when an error situation is determined electronically. The error situation can occur at any time. In the diagram section (e) of the flow chart of 2 the occurrence of a fault diagnosis signal FD is plotted as a function of time t. A ventilation error diagnosis signal EFD and a ventilation error diagnosis signal BFD come into question as error diagnosis signals FD in a manner yet to be explained.

In the venting diagnostic function, evaluation electronics 48 generate an electrical venting error diagnostic signal EFD if the fluid pressure PF prevailing in pilot control supply channel 32 and detected by pressure sensor 53 is not below a predefined venting limit value EG at a predefined venting monitoring time EUZ. The venting monitoring point in time EUZ is a certain time after the point in time at which the electrical switch-off signal AS is applied to the safety valve 33. In this way it can be monitored whether the venting function of the safety valve 33 is in order. If the venting function is impaired, there is no venting or venting is greatly slowed down in the pilot control supply channel 32, which can be seen from the fact that after a time interval following the switch-off signal AS has elapsed, which is also referred to below as the venting monitoring time interval UZI, the Pilot fluid pressure PF in the pilot supply channel 32 is still at an increased threshold. Such ventilation impairments can occur, for example, if the muffler 38 at the outlet of the pilot control ventilation channel 35 is dirty or, due to a mix-up, originally provides too small a flow cross section for the ventilation flow.

In the preferred exemplary embodiment of the valve arrangement 1, the venting limit value EG can be set variably with the cooperation of the evaluation electronics 48. One can therefore speak of a parameterization of the venting limit value EG. The evaluation electronics 48 are assigned input means 56 which enable the preset venting limit value EG to be set manually or using software. The input means 56 can be, for example, a keyboard or the communication interface 26 that enables external parameterization using the external electronic control device 27 .

A pressure value is expediently used as the venting limit value EG which, regardless of possible pressure fluctuations in the atmospheric pressure, is definitely above the atmospheric pressure. A venting limit value of 0.2 bar is particularly recommended. Reliable functioning is guaranteed in particular with a venting limit value EG, which lies in a pressure window between 0.1 bar and 0.3 bar.

The venting monitoring time EUZ is selected so that the venting monitoring time interval UZI between it and the application of the electrical switch-off signal is as short as possible, but at the same time sufficiently long to ensure reliable venting under error-free circumstances. Since the length of the venting monitoring time interval UZI can vary depending on the valve battery, in particular also depending on the number of directional control valves 7 present, it is advantageous if the specified venting monitoring time EUZ can be set variably with the cooperation of the evaluation electronics 48 . In particular, there is the possibility of determining the ventilation monitoring time EUZ indirectly by entering the desired ventilation monitoring time interval UZI, which is designed for a variable setting. The input means 56 already mentioned can be used for the setting.

A ventilation error diagnostic signal EFD can be generated with the ventilation diagnostic function if the fluid pressure PF detected by the pressure sensor 53 in the pilot control supply channel 32 at a specified ventilation monitoring time BUZ is not below a specified ventilation limit value BG. In particular, the time at which the electrical switch-on signal ES is applied to the safety valve 33 is used as the ventilation monitoring time BUZ. In this way it can be determined if, due to an error situation, switching to the venting position already has an excessive fluid pressure PF in the pilot control supply channel 32, although the pilot control supply channel 32 should actually have been vented and therefore should have been pressureless.

A fluid pressure that is at least slightly higher than the atmospheric pressure is expediently registered in the evaluation electronics 48 as the aeration limit value BG, analogous to the venting limit value EG, whereby it is expediently in is in a range from 0.1 bar to 0.3 bar and is preferably 0.2 bar.

In the illustrated exemplary embodiment, the venting limit value EG and the aeration limit value BG are stored as fluid pressure values of the same magnitude in order to simplify the evaluation measures.

The specified aeration limit value BG can expediently be variably adjusted analogously to the venting limit value EG with the cooperation of the evaluation electronics 48 . In particular, the input means 56 already mentioned can be used for this purpose.

In principle, any fluid pressure can be specified as the venting limit value BG, which is in a range above atmospheric pressure up to the pilot control pressure VD. For example, the pilot control pressure VD could be used directly as the ventilation limit value, which allows a clear verification that, due to an error situation, the safety valve 33 had not switched to the ventilation position despite the application of a switch-off signal AS.

A ventilation error can result, for example, from the fact that the manual override device 47 was activated for maintenance purposes and the manual override device 47 was inadvertently not deactivated after the maintenance work had been completed.

Basically, the ventilation monitoring time BUZ can also be after the provision of the electrical switch-on signal ES. However, the ventilation monitoring time interval that then elapses between the time when the safety valve 33 is switched on and the ventilation monitoring time BUZ should be very small and in any case less than a period of time that experience has shown elapses until after switching to the feed position in the pilot control supply channel 32 the pilot pressure VD has built up.

From the flow chart 2 It can be seen in diagram section (e) how a venting error diagnostic signal EFD is generated at any time t2. The starting point for the venting diagnosis was a switch-off signal AS applied at a point in time t1, by which the safety valve 33 was switched to the venting position, so that the pilot control supply channel 32 is vented. This venting leads to a pressure drop, which is reflected in the fluid pressure curve of diagram section (b) in a falling curve section 72. The time measuring module 52 was started when the switch-off signal AS was generated, and after the venting monitoring time interval UZI had expired, a comparison was made in a diagnostic unit 57 of the evaluation electronics 48 between the venting limit value EG and the diagnostic status DZ of the pressure sensor 53. This comparison led to the result that at the end of the venting monitoring time interval UZI, the venting monitoring time EUZ (time t2), the pressure sensor 53 assumes its first detection state DZ1, which stands for a fluid pressure PF that is greater than or equal to the specified venting limit value EG is. A venting error is therefore present, which causes the venting error diagnosis signal EFD to be output at time t2.

In diagram section (c), EZ designates the venting time, which elapses starting with the switch-off signal AS until the pressure sensor 53, which is in the first detection state at the time of the switch-off signal AS, switches to the second detection state DZ2 in order to report the completion of the venting, ie the drop in the fluid pressure PF prevailing in the pilot control supply channel 32 below the venting limit value EG. This venting time EZ expediently results in a venting confirmation signal EBS, which is used internally in the evaluation electronics 48 in order to determine the venting time EZ that has elapsed until venting has been completed. This venting time EZ, which is a time interval, is greater than the venting monitoring time interval UZI in the case of the venting error described above. However, it is preferably stored independently of the occurrence or non-occurrence of an error situation for purposes of further processing in a readable memory 58 of the evaluation electronics 48 as a memory value SPW, which is visualized in diagram section (d).

In the diagram section (d) of the flowchart of FIG 2 the storage values SPW of the memory 58 are plotted as a function of time. It can be seen that the memory value SPW stored up to that point is preferably overwritten with each new switch-off signal AS. First, the memory value is set to full ("zero") and set to the previously determined venting time EZ when the venting confirmation signal EBS is generated.

An output interface 62, which is in particular the communication interface 26, allows a user to read out the memory value SPW for long-term observations.

Of course, the memory 58 can also be designed in such a way that the successively determined venting times EZ are stored remain so that they can be called up for any time considerations.

Another example illustrates a venting diagnosis without an error message, which starts at any point in time t3 with a switch-off signal AS. At a point in time t4, which marks the venting monitoring point in time EUZ, the pressure sensor 53 is in its second detection state DZ2, which means that the fluid pressure PF in the pilot control supply channel is below the specified venting limit value EG.

A ventilation diagnosis can be found in the flowchart of 2 at an arbitrary point in time t5. Time t5 corresponds to the time at which a switch-on signal ES is applied. At the same time, in the present exemplary embodiment, this point in time corresponds to the ventilation monitoring point in time BUZ, at which it is checked whether the safety valve 33 had previously vented correctly.

Diagram section (b) shows that the fluid pressure PF in the pilot control supply channel 32 at the ventilation monitoring point in time BUZ - here the point in time t5 - is on a rising curve section 73 of the fluid pressure curve, in terms of pressure above the ventilation limit value BG. This is indicated by a small rectangle on the fluid pressure curve.

The pressure sensor 53 reports the excessive fluid pressure PF by assuming the first detection state DZ1. The diagnosis unit 57 therefore generates a ventilation error diagnosis signal BFD at the same time, which can be seen in diagram section (e).

In comparison, at time t6 a ventilation diagnosis without an error message can be seen, with the pressure sensor 53 assuming a second diagnosis state DZ2 at the ventilation monitoring time BUZ, which corresponds to proper pre-venting, so that a venting error diagnosis signal EFD is not output.

In connection with the error situation determined at time t5, it is further illustrated what happens if no consequences are drawn from the error message and the operation of the valve arrangement 1 continues unchanged. Since the manual override device 47 is not initially deactivated, the fluid pressure PF in the pilot supply channel 32 remains at the pilot pressure VD until the manual override device 47 is finally deactivated again at a point in time t7. If the switch-off signal AS is present at this point in time t7, as is the case according to diagram section (a), a proper venting process follows according to a falling curve section 74 of the fluid pressure curve, which causes the safety valve 33 to switch to the venting position.

If there is no error correction in response to the ventilation error diagnosis signal BFD, a ventilation diagnosis takes place after the ventilation diagnosis, beginning with the application of a switch-off signal AS, as is the case in the flowchart at time t8. Since this diagnosis also detects an error, a ventilation error diagnosis signal EFD is also generated in parallel with the ventilation error diagnosis signal BFD at a point in time t9.

It can be provided that the measurement of the venting time is aborted after a measurement interval that is too long (“time measurement overflow”) and the time that has elapsed up to that point is stored in the memory 58 in the form of a maximum value MX as a storage value SPW. In the flowchart of 2 this is shown in diagram section (d) in connection with the venting diagnosis beginning at time t8.

The output interface 62 is expediently designed to output the electrical ventilation fault diagnosis signal and the electrical ventilation fault diagnosis signal. In this way, there is the possibility of carrying out further signal processing in the electronic control device 27 in order, for example, to provide a visual and/or acoustic error message in a control center or to switch off the valve arrangement 1 .

The external electronic control device 27 is preferably designed such that an electrical switch-off/switch-on test pulse is applied at certain intervals to the electrical control valve control signal SSV intended for the safety valve 33 . Such a test pulse 75 is indicated by dashed lines in diagram section (a). This is to verify whether the switch-off function is guaranteed. The test pulse is usually evaluated externally and in particular in the electronic control device 27 or in a separate monitoring unit.

In order to prevent test pulses 75 from generating a ventilation fault diagnosis signal BFD, the evaluation electronics 48 have equipment that ensures that a ventilation fault diagnosis signal BFD can only be generated if there is a time interval between an electrical switch-off signal AS and a subsequent electrical switch-off signal AS Switch-on signal ES for the Safety valve 33 is greater than a predetermined blocking time interval SZI. The blocking time interval SZI is stored in the evaluation electronics 48, and it can be set in an unchangeable manner or, preferably, variably.

The effect of the blocking time interval SZI can be seen in diagram section (a) on the basis of the test pulse 75, which is initiated at a time t10 with a switch-off signal AS. The time up to the switch-on signal ES that concludes the test pulse is significantly shorter than the blocking time interval SZI visualized with a dashed arrow, so that in this case there is no ventilation diagnosis.

A similar provision may be made with respect to the bleed diagnostic function. As a rule and according to the illustrated exemplary embodiment, however, this functionality can regularly be omitted in the venting diagnosis function because the venting monitoring time interval UZI is inherently relatively large and exceeds the duration of the test pulse.

Claims (22)

Valve arrangement, with a plurality of electro-pneumatically pilot-controlled directional valves (7) combined to form a valve battery (6) to form a subassembly and with an electrically actuable safety valve (33), the directional valves (7) each having a main valve (28) and one for setting of the operating state of the main valve (28), the pilot valve devices (29) of the directional control valves (7) being connected to a pilot control supply channel (32) of the valve battery ( 6) are connected and wherein the safety valve (33) can be switched into a feed position by means of an electrical switch-on signal (ES) and into a venting position by means of an electrical switch-off signal (AS), wherein in the feed position it closes the pilot control supply channel (32) with a under a pilot pressure (VD) standing pilot f fluid and connects the pilot supply channel (32) in the venting position with a pilot control venting channel (35 ) connects, characterized in that the valve arrangement (1) is equipped with a venting diagnostic function and/or venting diagnostic function for the safety valve (33) implemented with the cooperation of evaluation electronics (48), the venting diagnostic function enabling an electrical venting error diagnostic signal (EFD) to be generated , if the fluid pressure (PF) prevailing in the pilot control supply channel (32) at a specified venting monitoring time (EUZ), the time after the provision of an electrical switch-off causing the safety valve (33) to switch from the feed position to the venting position switching signal (AS) is not below a specified ventilation limit value (EG), and the ventilation diagnostic function enables an electrical ventilation error diagnostic signal (BFD) to be generated if the fluid pressure prevailing in the pilot control supply channel (32) is at a specified ventilation monitoring time (BUZ), which coincides with the provision of an electrical switch-on signal (ES) that causes the safety valve (33) to switch from the venting position to the feeding position, or is later in time, is not below a specified ventilation limit value (BG). valve arrangement claim 1 , characterized in that the safety valve (33) is part of the valve battery (6). valve arrangement claim 1 or 2 , characterized in that the valve battery (6) has a valve carrier (12) on which the directional control valves (7) and the safety valve (33) are mounted. Valve arrangement according to one of Claims 1 until 3 , characterized in that the pilot control supply channel (32), the pilot control feed channel (34) and the pilot control ventilation channel (35) are formed in the valve carrier (12). Valve arrangement according to one of Claims 1 until 4 , characterized in that the evaluation electronics (48) is a part of the valve battery (6), wherein it is expediently integrated into the safety valve (33). Valve arrangement according to one of Claims 1 until 5 , characterized in that the valve cluster (6) has a communication interface (26) for communication with an electronic control device (27) that provides the electrical switch-on signal (ES) and the electrical switch-off signal (AS) for the safety valve (44). Valve arrangement according to one of Claims 1 until 6 , characterized in that the valve battery (6) has an output interface (62) for outputting the electrical ventilation error diagnostic signal (EFD) and/or the Electrical Vent Fault Diagnostic Signal (BFD). Valve arrangement according to one of Claims 1 until 7 , characterized in that the safety valve (33) has both an electrical actuating device (44) that can be actuated by the electrical switch-on signal (ES) and the electrical switch-off signal (AS) and a manual override device (47) designed for manual actuation of the safety valve (33). . Valve arrangement according to one of Claims 1 until 8th , characterized in that the specified venting limit value (EG) of the venting diagnosis function can be variably adjusted with the cooperation of the evaluation electronics (48). Valve arrangement according to one of Claims 1 until 9 , characterized in that the specified venting limit value (EG) of the venting diagnosis function is at least slightly higher than atmospheric pressure, expediently being in a range from 0.1 bar to 0.3 bar and preferably at 0.2 bar. Valve arrangement according to one of Claims 1 until 10 , characterized in that the specified venting monitoring time (EUZ) of the venting diagnosis function is variably adjustable with the cooperation of the evaluation electronics (48). Valve arrangement according to one of Claims 1 until 11 , characterized in that the venting monitoring time (EUZ) of the venting diagnosis function is defined by the end of a predetermined venting monitoring time interval (UZI), which immediately follows the time at which the electrical switch-off signal (AS) is provided and which is expediently variably adjustable. Valve arrangement according to one of Claims 1 to 1e, characterized in that the specified ventilation limit value (BG) of the ventilation diagnosis function can be variably adjusted with the cooperation of the evaluation electronics (48). Valve arrangement according to one of Claims 1 until 13 , characterized in that the specified ventilation limit value (BG) of the ventilation diagnosis function is at least slightly higher than the atmospheric pressure, it being expediently in a range from 0.1 bar to 0.3 bar and preferably at 0.2 bar. Valve arrangement according to one of Claims 1 until 14 , characterized in that the valve arrangement (1) has both the venting diagnostic function and the venting diagnostic function, the venting limit value (EG) and the venting limit value (BG) for the fluid pressure (PF) prevailing in the pilot control supply channel (32) being the same are. Valve arrangement according to one of Claims 1 until 15 , characterized in that for detecting the fluid pressure (PF) prevailing in the pilot control supply channel (32), at least one pressure sensor (53) interacting with the evaluation electronics (48) and acted upon by the fluid pressure (PF) prevailing in the pilot control supply channel (32) is present, which is suitably integrated into the safety valve (33). valve arrangement Claim 16 , characterized in that the pressure sensor (53) assumes a first detection state (DZ1) in the venting diagnostic function when the fluid pressure (PF) prevailing in the pilot control supply channel (32) is greater than or equal to the specified venting limit value (EG) and a second detection state (DZ2) when the fluid pressure (PF) prevailing in the pilot control supply channel (32) is below the specified venting limit value (EG), and that the pressure sensor (53) assumes a first detection state (DZ1) in the ventilation diagnostic function when the in the fluid pressure (PF) prevailing in the pilot control supply channel (32) is greater than or equal to the specified ventilation limit value (BG) and assumes a second detection state (DZ2) if the fluid pressure prevailing in the pilot control supply channel (32) is below the specified ventilation limit value (BG) is, wherein the evaluation electronics (48) has a diagnostic unit (57) through which the ventilation diagnosis function a venting fault diagnostic signal (BFD) can be generated if the pressure sensor (53) is in the first detection state (DZ1) at the venting monitoring time (BUZ) and by means of which a venting fault diagnostic signal (BFD) can be generated in the ventilation diagnostic function, if the pressure sensor (53) is in the first detection state (DZ1) at the ventilation monitoring time (BUZ). valve arrangement Claim 17 , characterized in that the pressure sensor (53) in the first detection state (DZ1) generates an electrical low sensor signal and in the second detection state (DZ2) generates an electrical high sensor signal. valve arrangement Claim 17 or 18 , characterized in that the diagnostic unit (57) is designed to be independent of a since provision in the venting diagnostic function Development of the electrical switch-off signal (AS) elapsed time to cause a venting confirmation signal (EBS) when the pressure sensor (53) changes from the first detection state (DZ1) to the second detection state (DZ2), wherein expediently the between the electrical switch-off signal (AS) and the venting confirmation signal (EBS) elapsed venting time (EZ) can be stored in a readable memory (58) of the evaluation electronics (48). Valve arrangement according to one of Claims 1 until 19 , characterized in that the evaluation electronics (48) are designed in such a way that a ventilation error diagnosis signal (BFD) is generated for the ventilation diagnosis function and/or a ventilation error diagnosis signal (EFD) for the ventilation diagnosis function only if there is a time interval between an electrical Switch-off signal (AS) and a subsequent electrical switch-on signal (ES) for the safety valve (33) is greater than a predetermined blocking time interval (SZI). valve arrangement claim 20 , characterized in that the predetermined blocking time interval (SZI) is variably adjustable. valve arrangement claim 20 or 21 , characterized in that the predetermined blocking time interval (SZI) is longer than an electrical switch-off/switch-on test pulse (75) for the safety valve (33 ) .

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