Valve open / close position detection device, and method for starting valve open / close position learning program

Abstract

The present invention provides a device for easily knowing the angular position when a valve is fully closed and the angular position when the valve is fully opened, for example, by means of a valve state monitoring device for remotely monitoring the state of the valve. A valve open / close position detection device according to the present disclosure comprises: a magnetic angle sensor that detects an operating angle of a valve on the basis of a magnetic field generated by a magnet that rotates in accordance with a rotating operation of the valve; and a processor. The processor can execute a program for open / close position learning by which a plurality of angles of the magnet rotated in accordance with valve opening and closing operations are determined and stored in a memory. The processor starts the program for open / close position learning when a predetermined time elapses from the occurrence of a state in which the magnetic angle sensor cannot detect the magnet.

Description

Valve position detection device and method for starting a valve position learning program

[0001] The present disclosure relates to a valve position detection device and a method for starting a valve position learning program.

[0002] Valves are used in various locations in various plants and factories. After being installed in the plant or factory equipment, the valves used are required to operate stably for a long period of time. However, the installed valves are often placed in locations, places, or environments that make it difficult for operators or inspectors to directly contact them.

[0003] Therefore, valve status monitoring devices have recently been developed that remotely monitor the status of valves to monitor the operational health of plants and factory equipment and help prevent unexpected trouble or breakdowns.

[0004] JP 2018-73154 A JP 2019-191760 A JP 2004-169887 A

[0005] There is a demand for a valve status monitoring device for remotely monitoring the status of a valve that can easily determine the angle and position related to the opening and closing of the valve, for example, the angle and position when the valve is fully closed and the angle and position when the valve is fully open.

[0006] The valve position detection device disclosed herein includes a magnetic angle sensor that detects the valve operating angle using a magnetic field generated by a magnet that rotates in accordance with the rotation of the valve, and a processor. The processor can execute a program for learning the valve position, which program is stored in memory and determines multiple angles of the magnet's rotation related to the opening and closing of the valve. In this valve position detection device, the processor starts the program for learning the valve position when a predetermined time has passed since the magnetic angle sensor was unable to detect the magnet.

[0007] By utilizing the valve position detection device and / or the method for launching the valve position learning program disclosed herein, a valve status monitoring device can easily determine the angle and position of the valve when it is open or closed. For example, the valve status monitoring device can easily determine the angle and position of the valve when it is fully closed and when it is fully open. This enables the valve status monitoring device to remotely monitor the state of the valve.

[0008] FIG. 1 is a block diagram illustrating the configuration of a valve position detection device and peripheral devices according to an embodiment. FIG. 2A is a perspective view of a valve position detection device according to an embodiment. FIG. 2B is a perspective view of a configuration including a valve position detection device 2, a cylinder 12, and a valve unit 22 according to an embodiment. FIG. 2C is an enlarged view of a portion of the configuration within the dashed frame shown in FIG. 2B. FIG. 3 is a top view of a cylinder located above the valve unit, showing an opening indicator unit and, in particular, a sensor magnet (magnet), which are configured to rotate in accordance with the operation of the cylinder and the rotation of the valve disc (valve) in the valve unit. FIG. 4 is a flowchart of processing in an open / close position learning mode of a valve position detection device according to an embodiment. FIG. 5 is a flowchart of a processing procedure for auto-recovery learning, which automatically transitions to the open / close position learning mode, of a valve position detection device according to an embodiment. FIG. 6A is a schematic cross-sectional view of a three-way valve. FIG. 6B is a schematic cross-sectional view of a three-way valve showing ball valve positions (1) to (4) and the state of the flow path at each position.

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0010] The inventors provide the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and do not intend them to limit the subject matter recited in the claims.

[0011] 1. [Background to the present disclosure] The valve open / close position detection device in this disclosure is also called a valve state monitoring device. A valve state monitoring device is a monitoring unit for, for example, remotely monitoring the state of a valve, and is a data logger that records a time-series profile of the angle related to the opening and closing of the valve.

[0012] The valve position detection device uses a magnetic angle sensor with a sensor magnet to monitor the position of the valve in response to the opening and closing operation, i.e., the transition of the angle of the valve relative to the flow path between fully open and fully closed. The magnetic angle sensor here is, for example, a TMR (Tunneling Magneto Resistance) sensor. The valve status monitoring device monitors the transition of the angle in response to the opening and closing operation of the valve in real time using the magnetic angle sensor, and stores the transition of the angle as an angle profile in a memory as a data log.

[0013] Incidentally, when a valve position detection device operates, a process is required for each individual valve as a type of initial setting. Specifically, the rotation angle of the sensor magnet when the valve is opened or closed, for example, when the valve is fully open or fully closed, is determined and recorded in the memory of the valve position detection device. The process of recording the angle of the sensor magnet rotated in response to the opening or closing of the valve in the memory of the valve position detection device is referred to as "position learning" in this specification. The main reasons for performing position learning for each individual valve are as follows (1) and (2).

[0014] (1) Each valve has a different operating range from fully closed to fully open. Suppose a valve is designed to have a 90° operating range from fully open to fully closed. Because the components that make up the valve and actuator include processing tolerances, the operating range between fully open and fully closed for valves, which are industrial products, is not necessarily 90°. For example, the operating range may be 89°, 89.5°, 90.2°, etc. In order to accurately and reliably determine the fully open and fully closed positions of a valve using a sensor magnet and magnetic angle sensor, it is necessary to determine the operating range from fully closed to fully open for each valve.

[0015] (2) The positions of the south and north poles of the sensor magnet attached to the cylinder are not consistent. Figure 3 is a top view of the cylinder 12 located above the valve section 22. Figure 3 also shows the position indicator unit 13, more specifically, the sensor magnet 14, which is a magnet. The position indicator unit 13 is configured to rotate in accordance with the movement of the cylinder 12 (not shown) and, further, the rotation of the valve body (valve) in the valve section 22 (not shown). The sensor magnet 14 is attached above the cylinder 12, with the position indicator unit 13 sandwiched between the sensor magnet 14 and the cylinder 12. As the inventors have discovered, when the sensor magnet 14 is attached, the positions and directions of the south and north poles may vary due to installation errors and the like. Therefore, it is necessary to determine and record the positions and directions (i.e., angles) of the south and north poles of the sensor magnet 14 in accordance with the opening and closing operation of the valve, for example, when the valve is fully open and fully closed.

[0016] The open / close position learning performed for the reasons described above in (1) and (2) is usually performed by the processor of the valve condition monitoring device executing a computer program. The valve condition monitoring device may be equipped with a wireless and / or wired line. The valve condition monitoring device receives commands from an external personal computer, tablet terminal, smartphone, or the like via the wireless or wired line. As a result, the processor can execute the program for open / close position learning, and the valve condition monitoring device enters "open / close position learning mode."

[0017] Therefore, after initially installing a sensor magnet and a valve state monitoring device for the valve and cylinder, an open / close position learning mode is activated by a communication command from an external device via a wireless or wired line.

[0018] However, due to communication conditions or information security considerations, wireless or wired communication may not be available at certain times in field equipment where valves are installed. In such cases, it is not possible to send communication commands to the valve condition monitoring device from an external device near the field equipment where the valves are installed. To switch the valve condition monitoring device to the "open / close position learning mode," it is necessary to take steps such as moving the valve condition monitoring device sufficiently away from the field equipment where the valves are installed and then sending a communication command to the valve condition monitoring device from an external terminal. Such steps are cumbersome and incur additional costs.

[0019] There is a need for a valve state monitoring device that can easily determine the angle corresponding to the opening and closing operation of the valve (i.e., the magnet), for example, the angle at full close and the angle at full open. This situation led the inventors of the present application to conceive of the auto-recovery learning of the present invention. This auto-recovery learning program realizes automatic transition to the opening and closing position learning mode.

[0020] Valves known as three-way valves and five-way valves are also used in various plants and factories. A three-way valve is a type of ball valve with three inlets and outlets for fluid. FIG. 6A is a schematic cross-sectional view of an exemplary three-way valve 22′. The exemplary three-way valve 22′ shown in FIG. 6A has a front inlet / outlet 23u, a right inlet / outlet 23r, and a left inlet / outlet 23l. In the three-way valve 22′, the position and angle of the ball valve 22′ can take four states to allow fluid to flow, as shown in FIG. 6B. First, in (1) of FIG. 6B, the position and angle of the ball valve 22′ are 0 rotations, and in this state, the fluid flows between the front inlet / outlet 23u, the right inlet / outlet 23r, and the left inlet / outlet 23l. In addition, (2) of FIG. 6B shows the position and angle of the ball valve 22' at a quarter turn, whereby fluid flows between the front inlet / outlet 23u and the right inlet / outlet 23r. In addition, (3) of FIG. 6B shows the position and angle of the ball valve 22' at a half turn, whereby fluid flows between the right inlet / outlet 23r and the left inlet / outlet 23l. Furthermore, (4) of FIG. 6B shows the position and angle of the ball valve 22' at a three-quarter turn, whereby fluid flows between the left inlet / outlet 23l and the front inlet / outlet 23u. When operating a position detection device for such a three-way valve, it is also essential to determine the above-mentioned four rotational positions and angles of the sensor magnet 14 and record them in the memory of the valve position detection device for each individual valve. Therefore, a program for learning the position of the three-way valve can be prepared and operated in a timely manner.

[0021] A five-way valve is also a type of ball valve, and is a valve with five inlet and outlet ports for fluid. Of course, a program for learning the open / close positions can also be prepared for a five-way valve, and it can be operated in a timely manner.

[0022] More generally, an N-way valve (N is a natural number equal to or greater than 2) may also be envisioned. In such a case, it is assumed that the number of positions and angles to be grasped and stored as initial settings is, for example, M (M is a natural number equal to or greater than 2 and is not necessarily equal to N). For such an N-way valve, a program for learning the open / close positions may be prepared and operated in a timely manner.

[0023] The auto-recovery learning program according to the present disclosure realizes automatic transition to the opening / closing position learning mode by any of the above-described programs for opening / closing position learning.

[0024] 2. [Embodiments] Preferred embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0025] 2.1. [Configuration of the Valve Position Detection Device] Figure 1 is a block diagram showing the configuration of a valve position detection device 2 and peripheral devices according to an embodiment. As will be described later using Figures 2A to 2C, the valve position detection device 2, which is a valve state monitoring device, is provided in the valve section 22, particularly above the cylinder 12 that operates the valve element (valve).

[0026] The valve position detection device 2 includes an angle sensor 4 , a processor 6 , a memory 8 , and a communication circuit 10 .

[0027] The angle sensor 4 is a sensor that detects the rotational movement of the sensor magnet 14 (via the position indicator unit 13) provided on the upper part of the cylinder 12 in a non-contact manner and is primarily composed of a TMR element. The sensor magnet 14 is configured to rotate via the position indicator unit 13 shown in FIG. 3 in accordance with the movement of the cylinder 12 and the rotational movement of the valve in the valve unit 22. Therefore, the angle sensor 4 can detect the operating angle of the valve. The sensor magnet 14 is generally assumed to be ring-shaped, but may also be other shapes such as a rod or a fan shape. The angle sensor 4 here is a magnetic angle sensor that pairs with the sensor magnet 14. A typical angle sensor is not limited to a magnetic angle sensor. For example, an angle sensor using a potentiometer, an angle sensor using a rotary encoder, or a gyro sensor, which is an angular velocity sensor, may also be used. The angle sensor 4 in the present disclosure is a magnetic angle sensor that pairs with a magnet.

[0028] The processor 6 is configured by a CPU (Central Processing Unit). The functions of the valve position detection device 2 according to this embodiment are realized by the processor 6 executing various programs. Note that these functions may be realized by an ASIC (Application Specific Integrated Circuit) or a combination of an ASIC and a CPU that loads various programs.

[0029] The memory 8 is a rewritable storage device within the valve position detection device 2, and is configured, for example, by a random access memory (RAM) including a large number of semiconductor memory elements. The memory 8 temporarily stores specific computer programs, variable values, parameter values, etc. used when the processor 6 executes various processes. The memory 8 also stores, for example, intermediate data and result data of valve state monitoring, such as (valve) opening / closing trend data, angle profile data, histogram data, and operation data, as well as various setting data.

[0030] Here, (valve) opening / closing trend data is a collection of information that indicates the operating status of a valve, such as the date and time of valve operation, the time required for operation, the direction of operation, the initial angle, and the final angle.Angle profile data is two-dimensional data that is shown by plotting a single valve operation with the valve angle (from fully open to fully closed, or from fully closed to fully open) on the vertical axis and the (elapsed) time on the horizontal axis.The angle profile data indicates how the valve moved during opening and closing operations.

[0031] The memory 8 may include a so-called ROM (Read Only Memory). The ROM pre-stores a computer program that realizes the processing of the valve position detection device 2, which will be described below. The processor 6 reads the computer program from the ROM and loads it into RAM, thereby enabling the processor 6 to execute the computer program.

[0032] The communication circuit 10 is a circuit that performs wired and / or wireless communication with the outside, and is an interface circuit that includes various network terminals, a USB terminal, etc., and is capable of outputting data to the outside and acquiring data from the outside. Wired and wireless communication includes Bluetooth (registered trademark), RS485, USB, etc. Intermediate data and result data regarding the valve state monitoring can be transmitted to, for example, a PC (personal computer) 16 via the wired communication function of the communication circuit 10. Similarly, intermediate data and result data regarding the valve state diagnosis can be transmitted to, for example, a smartphone 18 via the wireless communication function of the communication circuit 10. The smartphone 18 may be a tablet terminal or the like.

[0033] Furthermore, communication commands can be sent to the processor 6 via the communication circuit 10 by wired communication and wireless communication from an external device such as a PC (personal computer) 16, a smartphone 18, or a tablet terminal.

[0034] In this embodiment, it is assumed that each process related to valve position detection is performed by the processor 6 of the valve position detection device 2.

[0035] Fig. 2A is a perspective view of a valve position detection device 2 according to an embodiment. Fig. 2B is a perspective view of a configuration including the valve position detection device 2 according to an embodiment, a cylinder 12, and a valve unit 22. Fig. 2C is a partially enlarged view of the configuration within the dashed frame shown in Fig. 2B. The partially enlarged view particularly shows the relationship between the valve position detection device 2 and the ring-shaped sensor magnet 14 provided above the cylinder 12 with the opening indicator unit 13 interposed therebetween. Inside the valve position detection device 2 above the sensor magnet 14, three layers that make up the magnetic angle sensor are provided (from bottom to top, however, not shown): a magnetic free layer film, a non-magnetic insulating film, and a magnetic pinned layer film.

[0036] As shown in FIG. 2B, the valve position detection device 2 is also provided with a USB connector 24 and a power supply and RS485 connector 26, which are configured to be connected to a USB communication cable 28 and an RS485 communication cable 30, respectively.

[0037] The valve position detection device 2 is attached to the cylinder 12 using the mounting holes 34, the screws 32, and the screw holes in the upper part of the cylinder 12. There are at least one pair of mounting holes 34, screws 32, and screw holes, but only one of the pair is shown in the perspective views of Figures 2A and 2B.

[0038] Fig. 3 is a top view of the cylinder 12. A ring-shaped sensor magnet 14 is attached to the rotation shaft at the top of the opening indicator part 13 shown in the center of Fig. 3. As shown in Fig. 3, when the sensor magnet 14 is attached to the rotation shaft of the opening indicator part 13, the positions and directions of the south and north poles of the sensor magnet 14 are not constant but may vary.

[0039] 2.2 Operation of the Valve Position Detection Device 2.2.1 Processing in Position Learning Mode Fig. 4 is a flowchart of processing in the position learning mode of the valve position detection device 2 according to the embodiment.

[0040] When the valve position detection device 2 enters the position learning mode, the processor 6 starts executing a program for position learning (step S52). That is, the process shown in Fig. 4 is executed by the processor 6. The position learning mode in the valve position detection device 2 is activated by either of the following two events: (1) when the valve position detection device 2 receives a communication command transmitted wirelessly or via a wired line from an external device such as the PC 16 or smartphone 18; or (2) when the angle sensor 4 is unable to detect the sensor magnet 14 for a predetermined period of time.

[0041] The above (1) is a manual transition in which the user inputs a communication command. The above (2) is an automatic transition for recovering the data stored in the memory 8 when it is assumed that the angle (position) of the sensor magnet 14 has changed. The position of the sensor magnet 14 changes, for example, when the valve is fully closed and / or fully open. In particular, the above (2) will be described in detail later using FIG. 5.

[0042] When execution of the program for learning the open / close positions is started (step S52), the processor 6 monitors the position of the sensor magnet 14 and checks whether an event has occurred in which the sensor magnet 14 has stopped at a certain angle (position) for a predetermined time or longer (step S54 / NO or YES). If it is determined that an event in which the sensor magnet 14 has stopped for a predetermined time or longer has occurred (step S54 / YES), the processor 6 temporarily stores the certain angle as a first angle (step S56).

[0043] Subsequently, the processor 6 checks whether an event has occurred in which the sensor magnet 14 has stopped for a similar predetermined time or longer at an angle (position) different from the first angle (step S58 / NO or YES). If the processor 6 determines that an event in which the sensor magnet 14 has stopped for a predetermined time or longer has occurred (step S58 / YES), the processor 6 temporarily stores the different angle as a second angle (step S60).

[0044] Subsequently, the processor 6 checks whether an event has occurred in which the sensor magnet 14 has stopped for a similar period of time or longer at an angle (position) different from the first angle and the second angle (NO or YES in step S62). If the processor 6 determines that an event in which the sensor magnet 14 has stopped for a predetermined period of time or longer has occurred (YES in step S62), the processor 6 temporarily stores the different angle as a third angle (step S64).

[0045] The processor 6 verifies whether the first angle, the second angle, and the third angle are the angles when the valve is at its widest opening (i.e., the fully open angle) or the angles when the valve is at its widest closing (i.e., the fully closed angle) (step S66).

[0046] When power is applied to the valve unit 22, the valve may be stationary in an intermediate position that is neither fully open nor fully closed. For this reason, in the operation process of the open / close position learning mode shown in the flowchart of Figure 4, the stationary states of the first angle, the second angle, and the third angle are confirmed and stored three times, and then the fully open angle (position) and the fully closed angle (position) are determined by verification.

[0047] The processor 6 stores the determined fully open angle (position) and fully closed angle (position) in the memory 8 (step S68), and ends the open / close position learning mode of the valve open / close position detection device 2 (step S70).

[0048] 4 is an example. A different procedure may be used to determine the rotation angle of the sensor magnet 14 when the valve is fully open and fully closed and to record the angle in the memory 8.

[0049] According to the flowchart of the processing in the opening / closing position learning mode shown in FIG. 4 described above, the processor 6 checks the stationary states of the first angle, the second angle, and the third angle three times and temporarily stores the information in order to determine and store the angle (position) when fully open and the angle (position) when fully closed.

[0050] As described above in [Background to the Disclosure], there are valves for which it is assumed that there are, for example, M positions and angles (M is a natural number equal to or greater than 2) to be grasped and stored as initial settings. In the case of such valves, the processor 6 may execute the processes in the following order: Process [1] to Process [M+1], and Process [Verification and Storage]. Process [1]: The processor 6 checks whether an event has occurred in which the sensor magnet 14 has stopped at a certain angle (position) for a predetermined period of time or longer. If the processor 6 determines that an event in which the sensor magnet 14 has stopped for a predetermined period of time or longer has occurred, the processor 6 temporarily stores the angle of the stopped sensor magnet 14 as a first angle. Process [2]: Subsequently, the processor 6 checks whether an event has occurred in which the sensor magnet 14 has stopped for a similar predetermined period of time at an angle (position) different from the first angle. If the processor 6 determines that an event in which the sensor magnet 14 has stopped for a similar predetermined period of time or longer has occurred, the processor 6 temporarily stores the different angle as a second angle. This process is repeated according to the value of M. Process [M+1]: Subsequently, processor 6 checks whether an event has occurred in which sensor magnet 14 has stopped for a similar predetermined time or longer at an angle (position) different from any of the first angle to the Mth angle. If processor 6 determines that an event in which sensor magnet 14 has stopped for a predetermined time or longer has occurred, this further different angle is set as the (M+1)th angle and temporarily stored.

[0051] Process [Verification and Storage]: The processor 6 verifies whether the first angle through the (M+1)th angle indicate angles or positions corresponding to the opening and closing operation of the valve, and determines M angles or positions corresponding to the opening and closing of the valve. Data indicating the determined M angles or positions corresponding to the opening and closing of the valve is stored in the memory 8. This ends the opening and closing position learning mode for the valve for which it is assumed that the number of positions / angles to be grasped and stored as the initial setting is M.

[0052] 2.2.2. [Auto-recovery Learning Processing Procedure] Next, the "auto-recovery learning processing" will be described with reference to FIG. 5. FIG. 5 is a flowchart of the auto-recovery learning processing procedure for automatically transitioning to the valve position learning mode in the valve position detection device 2 according to the embodiment. After the auto-recovery learning processing starts (step S02), the processor 6 checks whether the angle sensor 4 is in a state in which it cannot detect the sensor magnet 14 (non-detection state) (step S10, NO) or whether it is in a state in which it cannot detect the sensor magnet 14 (step S10, YES). If the processor 6 confirms the non-detection state (step S10, YES), it stores data on the time the non-detection state occurred. The processor 6 then checks whether a predetermined time (e.g., one second) has elapsed since the non-detection state occurred (step S20, YES) or whether it is in a state in which it cannot detect the sensor magnet 14 (step S20, NO).

[0053] If the processor 6 confirms that the non-detection state of the angle sensor 4 (YES in step S10) continues for a predetermined time or longer (YES in step S20), the mode automatically transitions to the "open / close position learning mode" shown in Fig. 4 (step S50). When the "open / close position learning mode" ends, the processor 6 ends the auto-recovery learning process (step S80). The "open / close position learning mode" here may be the operating mode of the "valve for which M positions and angles are expected to be grasped and stored as initial settings" described above.

[0054] 2.2.3. [Circumstances in which auto-recovery learning is necessary and situations in which it can be beneficially utilized] Circumstances in which auto-recovery learning is necessary include the above-mentioned situation (2) in which the angle sensor 4 is unable to detect the sensor magnet 14 for a predetermined period of time. Additionally, other situations include situations in which it is possible that the angle (position) of the sensor magnet 14 has changed in response to the opening and closing of the valve. Specific examples include the following situations [1] to [3].

[0055] [1] When the valve position detection device 2 is removed from the cylinder 12 to which the sensor magnet 14 is attached while current is being applied. [2] When the valve position detection device 2 is attached and current is applied without attaching the sensor magnet 14 to the cylinder 12. [3] When current is applied under conditions where the valve position detection device 2 cannot detect the magnetic field generated by the sensor magnet 14.

[0056] Regarding [1] above, even if the valve position detection device 2 is removed and then reattached to the cylinder 12, the angle (position) of the valve may fluctuate slightly. This may result in a change in the fully closed and fully open positions of the valve, for example, when the valve is opened or closed. The position may change due to slight play or gaps in the mounting holes 34, screws 32, and screw holes. Regarding [2] above, it may be assumed that data on the angle (position) of the sensor magnet 14 corresponding to the opening and closing of the valve was not stored before this situation. For example, it may be assumed that data for the fully closed and fully open states of the valve does not exist. In such a situation, auto-recovery learning processing is necessary. Regarding [3] above, it may be assumed that an electromagnetic shield, such as an iron plate or piece of iron, is inserted between the sensor magnet 14 and the angle sensor 4, preventing the angle sensor 4 from detecting the magnetic field generated by the sensor magnet 14.

[0057] Furthermore, there are other situations in which the auto-recovery learning process can be beneficially utilized. Specifically, there are situations in which wireless communication such as Bluetooth or wired communication such as USB or RS485 cannot be used at certain times in the field equipment where the valve is installed due to communication conditions or information security considerations. In such situations, the processor 6 cannot execute the program for open / close position learning using communication commands.

[0058] In such a situation, a program for learning the valve position can be easily executed by intentionally creating a state in which the valve position detection device 2 cannot detect the magnetic field generated by the sensor magnet 14. Specifically, for example, creating the following states [A] and [B] will cause the auto-recovery learning process to be performed. [A] A state in which the valve position detection device 2 is removed from the cylinder 12 to which the sensor magnet 14 is attached while power is being supplied. This is the same state as in [1] above. [B] A state in which power is supplied to the valve position detection device 2 at a location away from the valve. This is a state included in the state [3] above.

[0059] In the above [A], once the valve position detection device 2 switches to the position learning mode by the auto-recovery learning function, the processor 6 can execute the program for position learning even if the power supply is subsequently turned off. In this case, the valve position detection device 2 can be reattached to the cylinder 12 and the valve position detection device 2 can be turned on. In the above [B], once the valve position detection device 2 switches to the position learning mode by the auto-recovery learning function, the processor 6 can execute the program for position learning even if the power supply is subsequently turned off. In this case, as in the above [A], the valve position detection device 2 can be reattached to the cylinder 12 and the valve position detection device 2 can be turned on.

[0060] 2.3 Summary of the embodiment The valve position detection device 2 according to the embodiment includes a magnetic angle sensor 4 that detects the valve operating angle from a magnetic field generated by a sensor magnet 14 that rotates in accordance with the rotation of the valve, and a processor 6. The processor 6 is capable of executing a program for learning the open / close position, which determines multiple angles of the sensor magnet 14 that have rotated in accordance with the opening and closing of the valve and stores them in the memory 8. The processor 6 starts the program for learning the open / close position when a predetermined time has elapsed since the magnetic angle sensor 4 was unable to detect the sensor magnet 14.

[0061] By utilizing the valve opening / closing position detection device 2 according to the embodiment, a valve state monitoring device for remotely monitoring the state of a valve can easily grasp the angle and position related to the opening and closing of the valve, for example, the angle and position when the valve is fully closed and the angle and position when the valve is fully open.

[0062] 3. [Other Embodiments] As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0063] Furthermore, the accompanying drawings and detailed description are provided to explain the embodiments. Therefore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to illustrate the above technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately indicating that these non-essential components are essential.

[0064] Furthermore, since the above-described embodiments are intended to illustrate the technology of the present disclosure, various modifications, substitutions, additions, omissions, etc. can be made within the scope of the claims or their equivalents.

Claims

1. A valve opening / closing position detection device comprising: a magnetic angle sensor that detects the operating angle of a valve from a magnetic field generated by a magnet that rotates in accordance with the rotation of the valve; and a processor, wherein the processor is capable of executing a program for opening / closing position learning that stores in a memory a plurality of angles of the magnet that have rotated in accordance with the opening and closing of the valve, and activates the program for opening / closing position learning when a predetermined time has elapsed since the occurrence of a state in which the magnetic angle sensor is unable to detect the magnet.

2. A valve opening / closing position detection device as described in claim 1, wherein the multiple angles are three or more angles including the angles of the magnet when the valve is fully open and when it is fully closed.

3. The valve opening / closing position detection device according to claim 2, wherein the processor executing the program determines an angle when the valve is fully open and an angle when the valve is fully closed from among the three or more angles, and stores the angle when the valve is fully open and the angle when the valve is fully closed in the memory.

4. The valve opening / closing position detection device of claim 3, wherein the processor executing the program: when the magnet is stopped at a first angle for the predetermined period of time or longer, stores the first angle in the memory; when the magnet is stopped at a second angle different from the first angle for the predetermined period of time or longer, stores the second angle in the memory; when the magnet is stopped at a third angle different from the first angle and the second angle for the predetermined period of time or longer, stores the third angle in the memory; and verifies which of the first angle, second angle, and third angle is the angle when the valve is fully open or the angle when the valve is fully closed.

5. A method for starting a valve opening / closing position learning program, comprising: when a predetermined time has elapsed since a magnetic angle sensor that detects the operating angle of a valve is unable to detect the magnet due to the magnetic field generated by the magnet that rotates in accordance with the rotational movement of the valve, causing a processor to start a program for opening / closing position learning that determines and stores in memory multiple angles of the magnet that have rotated in accordance with the opening and closing movement of the valve.

6. The method of claim 5, wherein the plurality of angles includes angles of the magnet when the valve is fully open and when the valve is fully closed.

7. The method according to claim 6, further comprising causing the processor to execute the program to determine a fully open angle of the valve and a fully closed angle of the valve from among the three or more angles, and storing the fully open angle and the fully closed angle in the memory.

8. The method of claim 7, further comprising causing the processor to: store the first angle in the memory if the magnet remains at a first angle for the predetermined period of time or longer; store the second angle in the memory if the magnet remains at a second angle different from the first angle for the predetermined period of time or longer; store the third angle in the memory if the magnet remains at a third angle different from the first angle and the second angle for the predetermined period of time or longer; and verify which of the first angle, the second angle, and the third angle is the angle when the valve is fully open or the angle when the valve is fully closed.

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