Operation confirmation device for linear motor-operated valve

Abstract

A control device (100) comprises: an output port (110) which is connected to a stepping motor (34a) of a shutoff valve (34) via four control lines (41-44); an input port (120) which is connected to four detection lines (51-54) respectively connected to the four control lines (41-44), and to which detection signals corresponding to the electric potentials of the four control lines (41-44) are input via the four detection lines (51-54); and a microcomputer (130). In an operation confirmation mode for confirming an operation of the shutoff valve (34), the microcomputer (130) causes control commands, including four pulse signals which are equal to the number of control lines (41-44), to be output from the output port 110 to the control lines (41-44), and determines an abnormality of a control circuit of the shutoff valve (34) on the basis of whether or not the control commands output to the control lines (41-44) and the detection signals input from the detection lines (51-54) match.

Description

Linear electric valve operation confirmation device

[0001] The present disclosure relates to an operation checking device for a linear electric valve whose opening is adjusted by driving a stepping motor.

[0002] For example, Japanese Patent Laid-Open Publication No. 9-287801 (Patent Document 1) discloses an air conditioner equipped with a solenoid valve (on-off valve) that opens and closes a refrigerant flow path.

[0003] Japanese Patent Application Publication No. 9-287801

[0004] Some air conditioners are equipped with a linear electric valve whose opening is adjusted by driving a stepping motor. A linear electric valve used as an expansion valve in an air conditioner is also called a "linear expansion valve (LEV)." The stepping motor includes multiple coils, which rotate when excited in a predetermined sequence.

[0005] Conventionally, when checking the operation of a linear electric valve whose opening is adjusted by driving a stepping motor, it has been common to change the linear electric valve between a fully open state and a fully closed state.

[0006] However, in conventional operation checks, the linear electric valve temporarily enters a fully closed state, which can sometimes require the operation of the device it is used in to be stopped.For example, when the linear electric valve is used as a linear expansion valve (LEV) in an air conditioner, there have been cases where the linear expansion valve temporarily enters a fully closed state during operation checks, cutting off the refrigerant piping and requiring the operation of the air conditioner to be stopped.

[0007] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to enable the operation of a linear electric valve, the opening of which is adjusted by driving a stepping motor, to be checked without stopping the operation of the device in which the linear electric valve is used.

[0008] The present disclosure provides an operation confirmation device for a linear electric valve whose opening is adjusted by driving a stepping motor. The device includes an output port connected to the linear electric valve via a plurality of first wires, an input port connected to a plurality of second wires connected to the plurality of first wires, and a detection signal corresponding to the potential of the plurality of first wires is input via the plurality of second wires, and a microcomputer for controlling the opening of the linear electric valve. The opening of the linear electric valve changes depending on the number of pulse signals included in a control command output from the output port to the plurality of first wires. In an operation confirmation mode for checking the operation of the linear electric valve, the microcomputer outputs a control command including a predetermined number of pulse signals from the output port to the plurality of first wires, and determines an abnormality in the control circuit of the linear electric valve based on whether the control command output to the plurality of first wires matches the detection signals input from the plurality of second wires. The predetermined number is equal to or greater than the number of the plurality of first wires, but is less than the number of pulse signals required to change the linear electric valve from one state to the other.

[0009] According to the present disclosure, it is possible to check the operation of a linear electric valve whose opening is adjusted by driving a stepping motor without stopping the operation of the device in which the linear electric valve is used.

[0010] FIG. 1 is a diagram showing the configuration of an air conditioning system. FIG. 2 is a diagram showing an overview of the configuration of a shutoff unit. FIG. 3 is a diagram (part 1) showing an example of a detailed configuration of a shutoff valve and a control device. FIG. 4 is a diagram comparing a conventional method for checking the operation of a shutoff valve with a microcomputer according to the present embodiment for checking the operation of a shutoff valve. FIG. 5 is a flowchart showing an example of a processing procedure of a microcomputer. FIG. 6 is a diagram summarizing abnormal cases of the shutoff valve that can be determined by a microcomputer. FIG. 7 is a diagram (part 2) showing an example of a detailed configuration of a shutoff valve and a control device.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings will be denoted by the same reference numerals, and description thereof will not be repeated.

[0012] FIG. 1 is a diagram showing the configuration of an air conditioning system 1 including an operation confirmation device (a control board 101, described below) according to this embodiment. The air conditioning system 1 includes an outdoor unit 10, which is an example of a heat source unit; two indoor units 20, which are respectively disposed in different rooms A and B; and two shutoff units 30. Hereinafter, in order to distinguish between the two indoor units 20 and the two shutoff units 30, the indoor units 20 and the shutoff units 30 may be referred to as indoor units 20a and 20b and shutoff units 30a and 30b, respectively. Note that while FIG. 1 shows an example in which two indoor units 20 are connected in parallel to one outdoor unit 10, the number of outdoor units 10 connected to one outdoor unit 10 is not limited to two and may be one, or three or more.

[0013] The outdoor unit 10, the indoor unit 20, and the shutoff unit 30 are connected by piping 12. The piping 12 includes a pair of piping 121 connected to the outdoor unit 10, a pair of branch pipes 122a connected to the indoor unit 20a, and a pair of branch pipes 122b connected to the indoor unit 20b. The branch pipes 122a and 122b are connected in parallel to the piping 121.

[0014] A refrigerant circulates between the outdoor unit 10 and the indoor unit 20a via the pipe 121 and the branch pipe 122a. A refrigerant circulates between the outdoor unit 10 and the indoor unit 20b via the pipe 121 and the branch pipe 122b. The indoor units 20a and 20b exchange heat with the refrigerant supplied from the outdoor unit 10 to air-condition rooms A and B, respectively.

[0015] A shutoff unit 30a that adjusts the flow rate of the refrigerant flowing through the branch pipe 122a is disposed in the branch pipe 122a, and a shutoff unit 30b that adjusts the flow rate of the refrigerant flowing through the branch pipe 122b is disposed in the branch pipe 122b.

[0016] In the air conditioning system 1 according to this embodiment, the shutoff units 30a and 30b can individually adjust the amount of refrigerant supplied to the indoor units 20a and 20b. For example, the shutoff unit 30a can shut off the supply of refrigerant to the indoor unit 20a in room A while continuing to supply refrigerant to the indoor unit 20b in room B.

[0017] 2 is a diagram showing an outline of the configuration of the breaking unit 30a. The basic structure of the breaking unit 30b is the same as that of the breaking unit 30a.

[0018] The shutoff unit 30a includes two shutoff valves 34 disposed in each of the pair of branch pipes 122a, and two control boards 101 for controlling the opening degrees of the two shutoff valves 34. Each control board 101 is mounted with a control device 100 and four detection lines (second wiring) 51 to 54. The control board 101 according to the present embodiment can correspond to an example of the "operation confirmation device" of the present disclosure.

[0019] Refrigerant supplied from the outdoor unit 10 to the indoor unit 20a flows through one of the pair of branch pipes 122a (the left branch pipe in FIG. 2), and refrigerant returning from the indoor unit 20 to the outdoor unit 10 flows through the other (the right branch pipe in FIG. 2). When the outdoor unit 10 functions as a condenser and the indoor unit 20 functions as an evaporator, room A is cooled. When the outdoor unit 10 functions as an evaporator and the indoor unit 20 functions as a condenser, room A is heated.

[0020] In the following, one shutoff valve 34 and one control board 101 that controls the shutoff valve 34 will be described.

[0021] The shutoff valve 34 is a linear expansion valve (LEV) whose opening is adjusted by driving a stepping motor. The stepping motor includes multiple coils, each of which is excited by a pulse signal, and rotates when the multiple coils are excited in a predetermined order. The opening of the shutoff valve 34 is adjusted by the rotation of the stepping motor.

[0022] The shutoff valve 34 is connected to the control device 100 of the control board 101 via four control lines (first wiring) 41 to 44. The stepping motor of the shutoff valve 34 rotates by an amount corresponding to the number of pulse signals included in the control command sent from the control device 100 via the four control lines 41 to 44. Note that in this embodiment, an example will be described in which the number of control lines connecting the shutoff valve 34 and the control device 100 is four, but the number of control lines is determined depending on the number of coils included in the stepping motor, etc., and is not limited to four. In other words, the number of control lines may be five or more, or may be two.

[0023] Furthermore, as described above, the control board 101 according to this embodiment is equipped with the four detection lines 51 to 54. One end of each of the detection lines 51 to 54 is connected to the control lines 41 to 44, respectively, and the other end of each of the detection lines 51 to 54 is connected to the control device 100.

[0024] 3 is a diagram schematically illustrating an example of the detailed configuration of the shutoff valve 34 and the control device 100. The shutoff valve 34 is equipped with a stepping motor 34a. The stepping motor 34a includes four coils C1 to C4. One end of each of the four coils C1 to C4 is connected to a power source 35, and the other end of each of the four coils C1 to C4 is connected to one end of each of control lines 41 to 44 via connectors. The other ends of each of the control lines 41 to 44 are connected to an output port 110 of the control device 100.

[0025] The stepping motor 34a of the shutoff valve 34 rotates when four coils C1 to C4 are excited in a predetermined order by pulse signals input via control lines 41 to 44, respectively.

[0026] When pulse signals that change the opening degree of the shutoff valve 34 in the opening direction are input to the stepping motor 34a via the control lines 41 to 44, the opening degree of the shutoff valve 34 changes in the opening direction by an amount corresponding to the number of pulse signals. When pulse signals that change the opening degree of the shutoff valve 34 in the closing direction are input to the stepping motor 34a via the control lines 41 to 44, the opening degree of the shutoff valve 34 changes in the closing direction by an amount corresponding to the number of pulse signals. Note that, in order to stabilize the behavior of the shutoff valve 34, it is desirable to stagger the timing at which the pulse signals are sent to each of the control lines 41 to 44 by a certain amount.

[0027] The number of pulse signals required to change the shutoff valve 34 from one of the fully open and fully closed states (hereinafter also referred to as the "number of full opening / closing pulses") is predetermined by design. For example, if the number of full opening / closing pulses is "2000," applying 2000 pulse signals to the fully open shutoff valve 34 in the closing direction will change the shutoff valve 34 from the fully open state to the fully closed state. Similarly, applying 2000 pulse signals to the fully closed shutoff valve 34 in the opening direction will change the shutoff valve 34 from the fully closed state to the fully open state.

[0028] The control device 100 includes switching elements S1 to S4 for generating control commands, an output port 110 for outputting the control commands to control lines 41 to 44, an input port 120 to which detection signals from detection lines 51 to 54 are input, a microcomputer (CPU; Central Processing Unit) 130, and a memory 140.

[0029] The switching elements S1 to S4 are connected to the control lines 41 to 44, respectively, via the output port 110. The switching elements S1 to S4 are formed of, for example, transistors. The switching elements S1 to S4 are sequentially switched (on / off) in response to commands from the microcomputer 130, and control commands including pulse signals are output to the control lines 41 to 44 via the output port 110.

[0030] When all of the switching elements S1 to S4 are in a non-conductive state (off state), one end of the control lines 41 to 44 is connected to the power supply 35 via the coils C1 to C4, and the other end of the control lines 41 to 44 is open and not grounded, so that the potential of the control lines 41 to 44 becomes the output potential Hi (for example, 12 volts) of the power supply 35.

[0031] When switching element S1 of switching elements S1 to S4, for example, is turned on, control line 41 is grounded via switching element S1, so that the potential of control line 41 becomes ground level potential Low, and the potentials of the other control lines 42 to 44 are maintained at the output potential Hi of power supply 35. When switching element S1 is switched between conductive and non-conductive states, a pulse signal is output to control line 41. The same applies to the other switching elements S2 to S4 (control lines 42 to 44).

[0032] The input port 120 is connected to the four control lines 41 to 44 via the four detection lines 51 to 54. Detection signals corresponding to the potentials of the control lines 41 to 44 are input to the input port 120 via the detection lines 51 to 54.

[0033] During air conditioning operation of the air conditioning system 1, the microcomputer 130 sequentially turns on and off the switching elements S1 to S4 in accordance with the command opening degree received from another control device (not shown) that controls the entire air conditioning system 1. As a result, a control command for setting the opening degree of the shutoff valve 34 to the command opening degree is output from the output port 110 via the control lines 41 to 44 to the shutoff valve 34, and the opening degree of the shutoff valve 34 is controlled to the command opening degree.

[0034] Furthermore, the microcomputer 130 operates in an operation check mode in which it checks the operation of the shutoff valve 34 every time a predetermined condition is met (for example, every 24 hours), regardless of whether the air conditioning system 1 is in air conditioning operation. The operation check of the shutoff valve 34 performed by the microcomputer 130 will be described in detail below.

[0035] <Checking the Operation of the Shutoff Valve 34> Conventionally, when checking the operation of the shutoff valve 34, it has been common to change the shutoff valve 34 between a fully open state and a fully closed state.

[0036] However, in conventional operation checks, the shutoff valve 34 temporarily enters a fully closed state, blocking the branch pipe 122 and preventing refrigerant from circulating. As a result, there have been cases where the air conditioning operation of the indoor unit 20, where refrigerant no longer circulates, must be stopped in order to check the operation of the shutoff valve 34. Furthermore, the number of pulse signals (the above-mentioned number of full opening / closing pulses) required to change the shutoff valve 34 from one of the fully open and fully closed states to the other is quite large (for example, 2000), which correspondingly lengthens the time required for operation checks.

[0037] Therefore, in the operation check mode for checking the operation of the shutoff valve 34, the microcomputer 130 according to the present embodiment does not change the opening degree of the shutoff valve 34 between a fully open state and a fully closed state, but rather minimizes the range of change in the opening degree of the shutoff valve 34 as described below. As a result, in this embodiment, the operation of the shutoff valve 34 can be checked even during air conditioning operation of the air conditioning system 1.

[0038] 4 is a diagram comparing the operation check of the shutoff valve 34 performed by the conventional method with the operation check of the shutoff valve 34 performed by the microcomputer 130 according to the present embodiment. Note that FIG. 4 shows an example in which the total number of opening and closing pulses is 2000.

[0039] In a conventional operation check, first the shutoff valve 34 is fully opened, then the opening of the shutoff valve 34 is changed in the closing direction by 2000 pulses to fully close the shutoff valve 34. Thereafter, the opening of the shutoff valve 34 is changed in the opening direction by 2000 pulses to return the shutoff valve 34 to the fully open state. During this series of operations, a sensor (not shown) or the like is used to confirm that the opening of the shutoff valve 34 is fully opened and fully closed as instructed.

[0040] In conventional operation checks, the shutoff valve 34 temporarily becomes fully closed, preventing refrigerant from circulating, and therefore, it was necessary to stop the air conditioning operation of the indoor unit 20, at which point refrigerant no longer circulates, in order to check the operation of the shutoff valve 34. Furthermore, because the opening of the shutoff valve 34 is changed from fully open to fully closed to fully open again, the number of pulses required to check the operation is 4,000 pulses or more (= number of fully open / closed pulses x 2), which correspondingly lengthens the time required to check the operation.

[0041] In contrast, detection signals are input to the control device 100 according to the present embodiment from detection lines 51 to 54, which are not present in the prior art. The microcomputer 130 operates in an operation check mode each time a predetermined condition is met (for example, every 24 hours), regardless of whether the air conditioning system 1 is in operation. In the operation check mode, the microcomputer 130 checks the operation of the shutoff valve 34 using the detection signals, as will be described below.

[0042] Microcomputer 130 changes the opening of shutoff valve 34 from the opening at the start of the operation check mode in the closing direction by four pulses, the same number as the number of control lines 41 to 44. At this time, microcomputer 130 checks for each pulse whether the control command output to control lines 41 to 44 matches the detection signal input from detection lines 51 to 54, thereby determining whether or not there is an abnormality in the control circuit (control device 100 and control lines 41 to 44) of shutoff valve 34.

[0043] The reason why the opening degree of the shutoff valve 34 is changed by only four pulses is because this is the minimum number of pulses required to determine whether the control circuit (control device 100 and four control lines 41 to 44) of the shutoff valve 34 is functioning normally. In other words, when the opening degree of the shutoff valve 34 is changed by four pulses, a pulse signal is output from the control device 100 once to each of the four control lines 41 to 44 in a predetermined order. Therefore, by checking the operation of four pulses, it can be confirmed whether the control command (pulse signal) from the control device 100 is being output normally to the shutoff valve 34 via the four control lines 41 to 44.

[0044] As described above, in the operation check according to this embodiment, the opening degree of the shutoff valve 34 is changed only by four pulses, which is the same as the number of control lines 41 to 44. Therefore, the operation of the shutoff valve 34 can be checked without fully closing the shutoff valve 34. As a result, the operation of the shutoff valve 34 can be checked without stopping the air conditioning operation of the air conditioning system 1.

[0045] Thereafter, the microcomputer 130 changes the opening of the shutoff valve 34 in the open direction by only four pulses, returning the opening of the shutoff valve 34 to the opening at the start of the operation check mode. Therefore, in the operation check according to this embodiment, the total number of pulses required for the operation check and the number of pulses required to return to the starting opening is only eight pulses (= four pulses x 2). Therefore, the time required for the operation check can be significantly reduced compared to the conventional method.

[0046] The indoor unit 20 may be configured to determine that an abnormality has occurred and shut down if it receives a signal from the shutoff unit 30 indicating that the shutoff valve 34 is not fully open. If such an operation restriction is set in the indoor unit 20, the microcomputer 130 may set the shutoff valve 34 to the fully open position at the start of the operation check mode and return the shutoff valve 34 to the fully open position at the end of the operation check mode without informing the indoor unit 20 or other devices that the shutoff valve 34 opening position is being changed experimentally during the operation check mode. This prevents the indoor unit 20 from receiving a signal from the shutoff unit 30 indicating that the shutoff valve 34 is not fully open, allowing the indoor unit 20 to continue operating. This prevents the indoor unit 20 from being unnecessarily shut down even when the shutoff valve 34 opening position is only slightly changed experimentally during the operation check mode.

[0047] Alternatively, the microcomputer 130 may be operated so that the shutoff valve 34 is fully closed at the start of the operation check mode, and a pulse signal is output during the operation check mode to change the shutoff valve 34's opening further in the closing direction than fully closed. In this case, the shutoff valve 34 is configured so that it cannot physically be moved further in the closing direction than fully closed, so the shutoff valve 34 remains fully closed, but this pulse signal can be detected, making it possible to check operation. Furthermore, because the shutoff valve 34 remains fully closed at the start of the operation check mode, there is no need to return it to its original opening when the operation check mode is completed.

[0048] 5 is a flowchart showing an example of a processing procedure executed in the above-described operation check mode by the microcomputer 130. This flowchart is executed every time a predetermined condition is met (for example, every 24 hours), regardless of whether the air conditioning system 1 is in air conditioning operation or not.

[0049] The microcomputer 130 stores the opening degree of the shutoff valve 34 at the start of the operation check mode in the memory 140 (step S10).

[0050] Next, the microcomputer 130 outputs a control command to the control lines 41 to 44 to change the opening degree of the shutoff valve 34 in the closing direction by one pulse (step S11). Specifically, the microcomputer 130 turns on and off the switching element that is the target of this current operation, among the switching elements S1 to S4, once. As a result, the control command output to the control lines 41 to 44 outputs a pulse signal only to the control line that is the target of this current operation, and does not output a pulse signal to the other control lines.

[0051] Next, the microcomputer 130 acquires (samples) the detection signals input from the detection lines 51 to 54 to the input port 120 (step S12). The period in which the microcomputer 130 acquires (samples) the detection signals is shorter than the period in which the microcomputer 130 outputs the pulse signals. This makes it possible to appropriately prevent the detection signals from being missed during sampling.

[0052] Next, the microcomputer 130 determines whether the control command output in step S11 matches the detection signal acquired in step S12 (step S13). For example, if the potential of the control line from which the current pulse signal is output is the ground level low potential and the potentials of the other control lines are the output potential of the power supply 35 high, the microcomputer 130 determines that the control command output in step S11 matches the detection signal acquired in step S12. On the other hand, if the potential of the control line from which the current pulse signal is output is not the ground level low potential or if the potentials of the other control lines are not the output potential of the power supply 35 high, the microcomputer 130 determines that the control command output in step S11 does not match the detection signal acquired in step S12.

[0053] If the control command and the detection signal match (YES in step S13), the microcomputer 130 determines that the control circuit of the shutoff valve 34 is normal (step S14). More specifically, the microcomputer 130 determines that the control circuit related to the output of the current pulse signal among the electrical control circuits of the shutoff valve 34 is normal.

[0054] On the other hand, if the control command and the detection signal do not match (NO in step S13), the microcomputer 130 determines that the control circuit of the shutoff valve 34 is abnormal (step S15). More specifically, the microcomputer 130 determines that the control circuit related to the output of the current pulse signal among the electrical control circuits of the shutoff valve 34 is abnormal.

[0055] Next, the microcomputer 130 determines whether the operation check for four pulses has been completed (step S16). If the operation check for four pulses has not been completed (NO in step S16), the microcomputer 130 returns the process to step S11 and repeats the processes of steps S11 to S15 until the operation check for four pulses has been completed.

[0056] When the operation check for four pulses is completed (YES in step S16), the microcontroller 130 outputs a control command to the control lines 41 to 44 to change the opening of the shut-off valve 34 in the opening direction by four pulses, thereby returning the opening of the shut-off valve 34 to the opening at the start of the operation check mode (step S17).

[0057] FIG. 6 is a diagram summarizing abnormality cases of the shutoff valve 34 that can be determined by the microcomputer 130 in the operation check mode.

[0058] The following (1) to (5) are assumed to be the main abnormal cases in which the shutoff valve (LEV) 34 does not operate.

[0059] (1) The control system in which the microcomputer 130 turns on and off the switching elements S1 to S4 is not functioning.

[0060] (2) Some of the control lines 41 to 44 are broken. (3) The connector of the shutoff valve 34 is not properly inserted (forgotten to be inserted or disconnected).

[0061] (4) There is a malfunction in one of the coils C1 to C4 of the shutoff valve 34. (5) The shutoff valve 34 is stuck or the like and cannot be mechanically moved.

[0062] The microcomputer 130 according to this embodiment can detect the abnormalities (1) to (4) among the abnormalities (1) to (5) above, excluding (5). That is, the microcomputer 130 according to this embodiment cannot detect a mechanical failure of the shutoff valve 34, but can detect a failure of the electrical control circuit of the shutoff valve 34.

[0063] Furthermore, the microcomputer 130 according to this embodiment can distinguish to some extent between the abnormalities (1) to (4) above. That is, if it is determined in the operation check that some of the coils C1 to C4 of the shutoff valve 34 are not excited, it can be assumed that one of the abnormalities (1), (2), or (4) above has occurred. On the other hand, if it is determined that all of the coils C1 to C4 of the shutoff valve 34 are not excited, it can be assumed that one of the abnormalities (1) or (3) above has occurred.

[0064] As described above, in the operation check mode for checking the operation of the shutoff valve 34, the microcomputer 130 according to the present embodiment outputs a control command including four pulse signals, the same number as the number of control lines 41 to 44, from the output port 110 to the control lines 41 to 44, and determines an abnormality in the control circuit of the shutoff valve 34 based on whether the control command output to the control lines 41 to 44 matches the detection signals input from the detection lines 51 to 54. Therefore, the operation of the shutoff valve 34 can be checked without bringing the shutoff valve 34 into a fully closed state. As a result, the operation of the shutoff valve 34 can be checked without stopping the air conditioning operation of the air conditioning system 1.

[0065] <Variation 1> In the above embodiment, an example has been described in which, in the operation check mode, four pulse signals, the same as the number of control lines 41 to 44, are output in order to minimize the range of change in the opening degree of the shut-off valve 34.

[0066] However, the number of pulse signals output in the operation check mode is not necessarily limited to be the same as the number of control lines 41 to 44, as long as it is equal to or greater than the number of control lines 41 to 44. In other words, the number of pulse signals output in the operation check mode is equal to or greater than the number of control lines 41 to 44, and is less than the upper limit number. Here, the upper limit number is a number that is less than the above-mentioned total number of opening and closing pulses, and is a pulse number that allows the air conditioning system 1 to continue operating (a pulse number that suppresses the change in opening degree to have almost no effect on the operation of the air conditioning system 1).

[0067] In this way, if the number of pulse signals output in the operation check mode is set to a range equal to or greater than the number of control lines 41 to 44 and less than the upper limit, it is possible to check the operation of the shutoff valve 34 without stopping the air conditioning operation of the air conditioning system 1. For example, by setting the number of pulse signals output in the operation check mode to about several times the number of control lines 41 to 44, it is possible to check the operation of the shutoff valve 34 with greater accuracy.

[0068] Furthermore, the number of pulse signals output to each of the control lines 41 to 44 in the operation check mode does not necessarily have to be the same. For example, one pulse may be output to the control line 41, two pulses to the control line 42, three pulses to the control line 43, and four pulses to the control line 42.

[0069] <Modification 2> In the above embodiment, an example of checking the operation of the shutoff valve 34 of the air conditioning system 1 has been described, but the target of operation check according to the present disclosure may be any linear motor-operated valve whose opening degree is adjusted by driving a stepping motor, and is not necessarily limited to the shutoff valve 34 of the air conditioning system 1. For example, the target of operation check according to the present disclosure may be an expansion valve disposed inside the outdoor unit 10 or indoor unit 20 of the air conditioning system 1, or a linear motor-operated valve used in a device other than an air conditioner.

[0070] <Modification 3> In the above embodiment, an example has been described in which the detection lines 51 to 54 are arranged outside the control device 100, but as shown in Fig. 7, the detection lines 51 to 54 may also be arranged inside the control device 100. In this way, the control lines 41 to 44 and the detection lines 51 to 54 can be connected by a circuit pattern on a single board.

[0071] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0072] 1 Air conditioning system, 10 Outdoor unit, 12, 121 Pipe, 20, 20a, 20b Indoor unit, 30, 30a, 30b Shutoff unit, 34 Shutoff valve, 34a Stepping motor, 35 Power supply, 41 to 44 Control line, 51 to 54 Detection line, 100 Control device, 101 Control board, 110 Output port, 120 Input port, 122a, 122b Branch pipe, 130 Microcomputer, 140 Memory, C1 to C4 Coil, S1 to S4 Switching element.

Claims

1. An operation confirmation device for a linear electric valve whose opening is adjusted by driving a stepping motor, comprising: an output port connected to the linear electric valve via a plurality of first wirings; a plurality of second wirings connected to the plurality of first wirings, respectively; an input port connected to the plurality of second wirings, and into which detection signals corresponding to the potentials of the plurality of first wirings are input via the plurality of second wirings; and a microcomputer that controls the opening of the linear electric valve, wherein the opening of the linear electric valve changes according to the number of pulse signals included in the control command output from the output port to the plurality of first wirings, and wherein, in an operation confirmation mode for checking the operation of the linear electric valve, the microcomputer outputs a control command including a predetermined number of pulse signals from the output port to the plurality of first wirings, and determines an abnormality in the control circuit of the linear electric valve based on whether the control command output to the plurality of first wirings and the detection signals input from the plurality of second wirings are consistent. An operation confirmation device for a linear electric valve, wherein the predetermined number is equal to or greater than the number of the plurality of first wirings and is less than the number of pulse signals required to change the linear electric valve from one fully open state to the other fully closed state.

2. The linear electric valve operation checking device according to claim 1, wherein the predetermined number is the number of the plurality of first wirings.

3. The operation confirmation device for a linear electric valve as described in claim 1, wherein the microcomputer stores a starting opening, which is the opening of the linear electric valve at the start of the operation confirmation mode, changes the opening of the linear electric valve in the closing or opening direction by the predetermined number of pulse signals during the operation confirmation mode, and returns the opening of the linear electric valve to the starting opening when the operation confirmation mode ends.

4. A linear electric valve operation confirmation device according to any one of claims 1 to 3, wherein the linear electric valve is an expansion valve used in an air conditioning system.

5. An operation confirmation device for a linear electric valve as described in any one of claims 1 to 3, wherein the period in which the microcomputer samples the detection signal is shorter than the period in which the microcomputer outputs the pulse signal.

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