DE102019135575A1 - Valve terminal with diagnostic module - Google Patents

Abstract

The invention relates to an assembly (10) with a plurality of process valves (30, 31, 32, 33), a controller (40) and a diagnostic module (22), the process valves (30, 31, 32, 33) being controlled by the controller (40) can be controlled so that they can open or close a media passage, the process valves (30, 31, 32, 33) each having at least one sensor (30d, 30e, 31d, 31e, 32d, 32e, 33d, 33e) have, with which the reaching of a switching position can be detected, and wherein the diagnostic module (22) is provided and designed to determine a cycle time of the process valves (30, 31, 32, 33) and to analyze it.

Description

The invention relates to an assembly with a plurality of process valves and a controller.

Process valves can be used in a wide variety of applications. One example is the food industry. There filling systems are used to fill yoghurt into yoghurt pots, to fill beverages into bottles or beverage cartons, etc. The filling system has process valves, which in turn are controlled by solenoid valves. For example, the process valves are controlled pneumatically, and the pneumatic pressure required for this is controlled by means of the solenoid valves.

The process valves can thus be combined into so-called valve islands. These are characterized by the fact that either the process valves or mostly the solenoid valves that control the process valves are arranged on a common carrier. The carrier can be used to provide electrical energy or a switching fluid that is switched by the solenoid valves and passed on to the process valves so that they close or open a media passage, for example to fill the yogurt into the yogurt cup or the drink into the bottle or the Beverage carton.

A valve terminal can have a large number of process valves. Due to wear and tear during long operating times, individual process valves may malfunction, which then require manual intervention. If this leads to an interruption in the filling process, for example, it can lead to a loss of production.

Various approaches are known from the prior art in order to ensure the correct functioning of process valves as far as possible.

The EP 1 555 472 A shows a method for function monitoring in the fluid control serving valves, which have at least one electrical actuator for valve actuation, which is coupled to an operating status display for displaying the current operating status of the actuator. The method initially comprises the optical detection of a change in the displayed operating state by means of an optical sensor, and setting the change in operating state as starting time t ₀ . Furthermore, a pressure change at the valve outlet as a result of the change in operating state is measured by means of a detection _{device from the start time t 0} and a pressure-dependent signal assigned to the pressure change is generated. The switching state of the valve is now verified by checking whether a specific pressure-dependent signal is present _{after a specific time from the starting time t 0.}

The EP 0 708 389 A describes a method for detecting a fault and identifying the component in which the fault occurs in an automatically operated valve assembly of the type having a plurality of components including at least an actuator, a valve element and a positioner controlled by a control signal. The method characterizes the definition of a mathematical model for the operation of a control valve arrangement, the model being formed from at least one equation and critical parameters for at least one actuator, the valve element and the positioner, each parameter describing the operation of one of the components of the valve arrangement. Furthermore, the method collects several values of the control signal and corresponding positions of the valve element. The critical parameters of the model are now calculated on the basis of measured data, so that the model reproduces the current mode of operation of the valve arrangement. In the next step, the changes in the critical parameters are monitored or observed on the basis of parameters adapted to these, and the faulty components of the valve arrangement are localized by determining a significant change in the corresponding critical parameters.

The task is to avoid a failure of a process valve during operation.

To solve this problem, the invention provides an assembly with a plurality of process valves, a controller and a diagnostic module, the process valves being able to be activated by the controller so that they can open or close a media passage, the process valves each having at least one sensor, with which the reaching of a switching position can be detected, and wherein the diagnostic module is provided and designed to determine a cycle time of the process valves and to analyze this.

The invention is based on the basic idea of continuously monitoring the cycle times and thus in particular the switching times of the process valves. In this way, deviations that indicate wear can be detected at an early stage. Accordingly, an exchange can be initiated in good time, for example when the filling system is converted to a new product, that is to say at a time when the filling system is at a standstill anyway.

The sensor can in particular be a position sensor with which the position of an armature, a valve element, a piston or another component that is essential for a switching process can be detected. A position sensor can be used to directly detect whether this component is in a certain position. As a result, the measurement accuracy is higher than with methods that are based on indirectly determining where the component is located.

Two position sensors are preferably provided so that the component can be detected in every end position (that is, with the process valve fully open and the process valve fully closed).

The assembly can contain a display on which errors or maintenance requirements for the process valves can be shown individually. This display can be integrated directly into the valve island, arranged in a nearby switch cabinet or part of a control station from which the system in which the assembly according to the invention is used is controlled.

According to a preferred embodiment, a pressure sensor is provided which detects a supply pressure with a switching fluid and is connected to the diagnostic module. This ensures that the diagnostic module does not incorrectly interpret deviations in the cycle times that result from a change in the supply pressure with the switching fluid (for example, a pneumatic pressure that is too low) as a defect in the process valves. At the same time, the diagnostic module can output a warning that the supply with the switching fluid should be checked.

The diagnostic module preferably has a memory for different operating modes, in which values of “target cycle times” for different operating modes are stored; these differ depending on the operating mode of the system in which the process valves are used.

It can also be provided that the diagnostic module has a memory for different cycle times in which the results of previous measurements are stored so that the diagnostic module can recognize whether the cycle times change by comparing the previous measured values with the current measured values.

According to one embodiment of the invention, the diagnostic module has an input for a test signal. When a test signal is received, the diagnostic module can carry out a test sequence in which current cycle times are recorded and compared with stored values. A test sequence can be triggered, for example, when the systems in which the process valves are installed have been switched from one product to another.

According to the invention, the diagnostic module is integrated into a valve terminal so that it is possible to detect changes in the process, in the present case the switching time of process valves. For this purpose, digital inputs for monitoring the status of the process valves are already integrated in the valve terminal. The main task of these is to report the end positions of the process valves back to the diagnostic module of the valve terminal. The digital inputs are assigned directly to the respective pneumatic valve position or process valve on the valve terminal.

With the diagnostic initialization according to the invention, software in the valve terminal can be used to determine the duration of how long a process valve needs to move from one end position to the other.

For example, 20 measurements are carried out on the duration or switching time and then the arithmetic mean of the switching time is calculated and saved by the valve terminal's diagnostic module.

Depending on how many process valves are switched at the same time, each individual process valve connected to the valve terminal will have a different runtime. With the same processes, this time difference is already determined when determining the process runtime and is also saved as a reference. With the switching time monitoring, the duration can be determined in the actual application and compared with each new switching. If there is any sign of wear, it can be detected at an early stage. As a result, preventive measures can be taken.

If, for example, the switching time has changed by more than the defined tolerance range (e.g. 20%) when executing the diagnosis or while the process is running, the valve terminal visualizes this information via a display on the diagnosis module of the valve terminal and thus in a control cabinet close to the production plant. At the same time, it reports the information back to a controller (PLC). The control can output an error message with precise details of the position in the process and thus enable remote maintenance.

A pressure sensor integrated in the valve terminal (more precisely, in a connection module) can be used to distinguish errors that arise from a collapse in the compressed air supply from errors caused by wear. Process-related pressure fluctuations can be filtered by the software.

• - Integration der Diagnosefunktion in die Ventilinsel durch Nutzung von vorhandener Elektronik (digitale Eingänge und Anzeige)
• - Anzeigeoption, welcher Ventilplatz der Ventilinsel bzw. welches daran angeschlossene Prozessventil möglicherweise defekt ist.
• - Die Messung der Zykluszeit bzw. Laufzeit zwischen den Endstellungen der an die Ventilinsel angeschlossenen Prozessventile mittels der Detektion von Positionssensoren über die digitalen Eingänge der Ventilinsel ist vorliegend die entscheidende Neuerung.

• - Es ist kein Einrichtebetrieb notwendig. Die Initialisierung (neue Laufzeitmessung) kann im laufenden Produktionsbetrieb jederzeit gestartet und durchgeführt werden.
• - Die Diagnose ist jederzeit auf neue Prozessparameter ohne zusätzlichen Aufwand einstellbar: Bei Umstellung einer Prozesslandschaft (z.B. größere Verpackungseinheit bei Joghurtbechern oder Getränkekartons) kann mit einem Tastendruck eine neue Laufzeitmessung angestoßen werden.
• - Durch einen eingebauten Drucksensor können Fehler auf Grund von unzureichender Druckluftversorgung ausgeschlossen werden. Ausgabe eines Hinweises auf einem Display der Ventilinsel zur Überprüfung der Druckluftversorgung
• - Regelmäßig wiederkehrende Schaltungen können hinterlegt werden.
• - Erkennen von möglichen Fehlern im Voraus. Dies hat folgende Vorteile:
  • - Optimierung der Wartungsrate
  • - Verkürzung der Stillstandszeit
  • - Verschleiß des Prozessventils erkennen
  • - Optimierung der Verschleißteilbeschaffung

Further advantages of the invention are:

• - Integration of the diagnostic function in the valve terminal by using existing electronics (digital inputs and display)
• - Display option indicating which valve position on the valve terminal or which process valve connected to it is possibly defective.
• - The measurement of the cycle time or runtime between the end positions of the process valves connected to the valve terminal by means of the detection of position sensors via the digital inputs of the valve terminal is the decisive innovation here.

• - No setup operation is necessary. The initialization (new runtime measurement) can be started and carried out at any time during ongoing production operations.
• - The diagnosis can be set to new process parameters at any time without additional effort: When a process landscape is changed (e.g. larger packaging units for yoghurt cups or beverage cartons), a new runtime measurement can be initiated at the touch of a button.
• - With a built-in pressure sensor, errors due to insufficient compressed air supply can be excluded. Output of a message on a display of the valve terminal to check the compressed air supply
• - Regularly recurring switching operations can be stored.
• - Detection of possible errors in advance. This has the following advantages:
  • - Optimization of the maintenance rate
  • - Reduction of the downtime
  • - Detect wear of the process valve
  • - Optimization of the procurement of wearing parts

• - 1 ein Blockschaltbild einer erfindungsgemäßen Baugruppe;
• - 2 schematisch verschiedene Betriebsmodi der Baugruppe von 1; und
• - 3 ein Zeit-Weg-Diagramm für ein Prozessventil der Baugruppe von 1.

The invention is described below with reference to an embodiment which is shown in the accompanying drawings. In these show:

• - 1 a block diagram of an assembly according to the invention;
• - 2 schematically different operating modes of the assembly of 1 ; and
• - 3 a time-distance diagram for a process valve of the assembly of 1 .

In 1 is a block diagram of an assembly 10 shown according to the invention. It is a fluidic system with a valve terminal 20th , several process valves 30th , 31 , 32 , 33 and a controller 40 .

The valve terminal 20th is via several fluidic connections 11a , 11b , 11c , 11d and electrical connections 12a , 12b , 12c , 12d with the process valves 30th , 31 , 32 , 33 connected. These are symbolized here by actuators, which will be explained in more detail later.

The valve terminal 20th has several solenoid valves 21a , 21b , 21c , 21d , a diagnostic module 22nd with multiple ads 22a , 22b , 22c , 22d , two connection modules 23 , 24 and a gateway 25th on.

In this case, for example, a first solenoid valve 21a the diagnostic module 22nd with a first advertisement 22a functionally assigned. Via the fluidic connection 11a is the first solenoid valve 21a with the actuator 30th fluidically connected. Furthermore is about the electrical connection 12a the actuator 30th with the diagnostic module 22nd interconnected, with the display 22a a status of the actuator 30th indicates. The diagnostic module 22nd thus shows on the respective display 22a , 22b , 22c , 22d the status of the actuators 30th , 31 , 32 , 33 at. For example, the switching status of the actuator is under the status 30th to understand. The display can be an LC display.

The connection modules 23 , 24 serve for the internal distribution of the fluid to the solenoid valves 21a , 21b , 21c , 21d . The first connection module 23 has a fluid connection 23a as well as a pressure sensor 23b on. The fluid connection 23a enables a fluid supply line to be attached. The pressure sensor 23b is set up to prevent a drop in the fluid pressure at the fluid connection 23a to detect.

The diagnostic module 22nd can be used to correct errors caused by a collapse in the fluid supply at the fluid connection 23a arise and from the pressure sensor 23b can be detected to distinguish from wear-related errors. Process-related pressure fluctuations can be filtered by software.

Furthermore, the gateway 25th a microprocessor 25a and an analog-to-digital converter 25b on. The gateway 25th is electric with the controller 40 interconnected. In the control 40 it can be a programmable logic controller (PLC).

The analog / digital converter 25b is used to convert the analog input signals via the electrical connections 12a , 12b , 12c , 12d of the actuators 30th , 31 , 32 , 33 into a digital data stream.

The majority of actuators 30th are in the present case designed as a single-acting cylinder which is retracted in the initial state, ie when the fluid pressure is not applied. In one embodiment, however, a single-acting cylinder with the opposite function or a double-acting cylinder is also conceivable.

The following is an example of the structure and interconnection of an actuator 30th with the valve terminal 20th explained. The actuator 30th has a control fluid inlet E0 , a first vent R0 , a piston 30a , a feather 30b , a piston rod 30c and first and second position sensors 30d , 30e on. The control fluid inlet E0 is with a control fluid outlet A0 the valve terminal 20th fluidically connected. The piston 30a can be via the control fluid inlet E0 are acted upon with the fluid. When the fluid is applied, the piston moves 30a in one axis X and acts against the spring 30b and their spring force. The piston rod 30c is with the piston 30a positively connected and transmits the force as well as the movement of the cylinder to the outside. The movement of the piston rod 30c in the axis X can at the output of the actuator 30th can be used for controlling and regulating media flows. For example, a valve element connected to the piston rod and a valve seat assigned to the valve element are not shown. The valve element can be adjusted by the piston rod between a state in which the media passage is open through the valve seat and a state in which the media passage is closed.

Furthermore, two position sensors are provided at the two end positions, that is to say at the position of the retracted piston 30a a first position sensor 30d and at the position of the extended piston 30a a second position sensor 30e . The two position sensors 30d , 30e are therefore in the axis X offset on the travel of the piston 30a . The first and second position sensors 30d , 30e are set up to send a signal to the diagnostic module 22nd and the associated display 22a output and thereby the position of the piston 30a specify.

The 2 and 3 show a flow chart or a time-path diagram of the method according to the invention.

The 2 shows two operating modes, a setup mode 100 and a production facility 200 , 210 . You can switch between the two operating modes either via an actuating device on the valve terminal or via software-supported remote access via the control 40 in the fluidic system 10 be switched.

The method according to the invention only occurs in production 200 , 210 is used and has an initialization mode and a diagnostic mode. As soon as the initialization mode is completed, the system changes 10 automatically goes into diagnostic mode.

The initialization mode for runtime measurement of the actuators can only be carried out in parallel with production 200 , 210 be performed. Provided the first production plant 200 to another production facility 210 is changed, the system has to be re-initialized 10 required.

The production plant 200 has several production steps 201 , 202 , 203 , 204, 205 on. The steps 200a to 200e represent the initialization mode by means of a runtime measurement. The initialization mode can be used for various production steps 201 , 202 , 203 , 204, 205 start. The steps for runtime measurement can be repeated just like the production steps. The following are the steps for runtime measurement for the actuator 30th described.

For the runtime measurement it is crucial that the actuator to be initialized 30th is controlled and at least once the piston 30a extends or retracts and both position sensors 30d , 30e actuated.

As in 1 shown and in 2 by the step 200a is represented by the piston that is not acted upon by fluid 30a of the actuator 30th via the vent connection R0 vented and is thus in a retracted position. The control fluid outlet A0 of the solenoid valve 21a is also depressurized. The solenoid of the solenoid valve 21a is thus in a de-energized state. The ad 22a shows an actuation of the first position sensor 30d at. For a first cycle time T1 is this the start time to.

According to step 200b there is now a change in the operating state of the actuator 30th brought about. This is done using the coil of the solenoid valve 21a energized. This switches the solenoid valve 21a , and there is consequently a fluid pressure at the control fluid outlet A0 at. This causes a fluid pressure at the control fluid inlet E0 of the actuator 30th . As a result, the piston moves 30a in the direction X . At a time t ₁ reaches the piston 30a the second position sensor 30e and is extended to the maximum.

The change in the operating state of the actuator 30th is via the second position sensor 30e detected and converted into a signal that is sent to the diagnostic module 22nd is transmitted. In the diagnostic module 22nd this signal becomes the first intermediate point in time t ₁ set. The diagnostic module 22nd records the end time t ₁ and calculated from the difference in the start time t ₁ and t ₀ the cycle time T1 of the actuator 30th . The ad 22a shows an actuation of the second position sensor 30e at.

In step 200c is a rest time of the actuator 30th conceivable. For example, the actuator may remain in the same position for a certain period of time during production operation, that is to say, for example, the piston remains 30a stand in the extended state.

By the drop in excitation of the coil of the solenoid valve 21a it comes in the crotch 200d at a time t ₂ again to a switching process of the actuator 30th . The pressure at the control fluid outlet A0 drops, and with it the pressure at the control fluid inlet E0 of the actuator 30th . This causes the fluid to pass through the vent R0 into the piston chamber of the actuator 30th can flow and the spring 30b the piston 30a in its starting position towards X moved back. At a time t ₃ reaches the piston 30a the first position sensor 30d .

When the first position sensor is reached 30e is a cycle time T2 expired. In step 200e recorded by the diagnostic module 22nd the end time t ₃ and calculated from the difference in the start time t ₃ and t ₂ the cycle time T2 of the actuator 30th . The ad 22a shows an actuation of the first position sensor 30d at.

The steps 200a to 200e can run through a defined number of repetitions for the initialization. The cycle times are repeated during the runtime measurement T1 and T2 for the actuator 30th determines the cycle time T1 the difference T1 = t ₁ -t ₀ and the cycle time T2 the difference T2 = t ₃ -t ₂ is. As soon as the runtime measurement is repeated, the majority becomes cycle times T1 , T2 an average value is determined and in the diagnostic module 22nd saved. The system then switches 10 automatically switches to diagnostic mode.

By determining the actual cycle time several times in succession, it is possible to determine whether this changes over time, in particular whether it increases, which means that the actuator is wearing 30th speaks.

The actual cycle times give way in diagnostic mode 200 , 210 of saved cycle times T1 , T2 from the initialization mode, the diagnostic module outputs 22nd about his ad 22a a message that the actuator 30th has a run-time deviation, and whether this deviation affects the cycle time T1 or T2 concerns. As a result, this deviation indicates a required maintenance of the relevant actuator / the corresponding process valve.

List of reference symbols

10

fluidic system

11 a, b, c, d

fluidic connection

12 a, b, c, d

electrical connection

20th

Valve terminal

21a, b, c, d

magnetic valve

22nd

Diagnostic module

22 a, b, c, d

Display of the diagnostic module (of the connected process valve)

23

first connection module

23a

Fluid connection

23b

Pressure sensor

24

second connection module

25th

Gateway

25a

microprocessor

25b

Analog / digital converter

30, 31, 32, 33

Actuator / process valve

30a, 31a, 32a, 33a

piston

30b, 31b, 32b, 33b

feather

30c, 31c, 32c, 33c

Piston rod

30d, 31d, 32d, 33d

first position sensor

30e, 31e, 32e, 33e

second position sensor

40

Control (PLC)

100

Set-up company

200, 210

Production plant

201, 202, 203

Production steps

200a, 200b, 200c, 200d, 200e

Steps for runtime measurement (initialization mode)

E0, E1, E2, E3

Control fluid inlet

A0, A1, A2, A3

Control fluid output

R0, R1, R2, R3

Venting

T1, T2

Cycle time / switching time / runtime of the first actuator

t0

Start time

t1

first intermediate point

t2

second intermediate point

t3

End time

X

Axis of motion

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 1555472 A [0006]
• EP 0708389 A [0007]

Claims (9)

Assembly (10) with a plurality of process valves (30, 31, 32, 33), a controller (40) and a diagnostic module (22), the process valves (30, 31, 32, 33) from the controller (40) as can be controlled so that they can open or close a media passage, the process valves (30, 31, 32, 33) each having at least one sensor (30d, 30e, 31d, 31e, 32d, 32e, 33d, 33e) with which reaching a switching position can be detected, and wherein the diagnostic module (22) is provided and designed to determine a cycle time of the process valves (30, 31, 32, 33) and to analyze it. Assembly (10) after Claim 1 , characterized in that the sensor is a position sensor (30d, 30e, 31d, 31e, 32d, 32e, 33d, 33e). Assembly (10) after Claim 2 , characterized in that two position sensors (30d, 30e, 31d, 31e, 32d, 32e, 33d, 33e) are provided. Assembly (10) according to one of the preceding claims, characterized in that there is a display (22a, 22b, 22c, 22d) on which errors or maintenance requirements for the process valves (30, 31, 32, 33) can be shown individually. Assembly (10) according to one of the preceding claims, characterized in that a pressure sensor (23b) is provided which detects a supply pressure with a switching fluid and is connected to the diagnostic module (22). Assembly (10) according to one of the preceding claims, characterized in that the diagnostic module (22) has a memory for different operating modes. Module (10) according to one of the preceding claims, characterized in that the diagnostic module (22) has a memory for different cycle times. Assembly (10) according to one of the preceding claims, characterized in that the diagnostic module (22) has an input for a test signal. Assembly (10) according to one of the preceding claims, characterized in that the process valves (30, 31, 32, 33) are combined to form a valve island (20).

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