Motor-driven valve control device and motor-driven valve control system

Abstract

To attain downsizing and space saving of a system, and to maintain compatibility with conventional systems while enabling unitary management.SOLUTION: A pulse converter 10A includes: an analog input 11 to which an analog signal indicating a valve opening of an electronic expansion valve 30 is input; a communication port 25 capable of receiving an opening instruction from a plurality of devices by communication; a microcomputer 18A that converts the analog signal input to the analog input 11 or the opening instruction received by the communication port 25 into a drive pulse and outputs the drive pulse; a driving circuit 24 for driving the electronic expansion valve 30 based on the drive pulse output from the microcomputer 18A; and a DIP switch 44 for switching between a first mode in which the analog input 11 and the communication port 25 are used in combination and a second mode in which only the communication port 25 is used.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an electric valve control device for controlling the valve opening degree of an electric valve such as an electronic expansion valve, and an electric valve control system including the electric valve control device.

Background Art

[0002] For example, electric valves such as electronic expansion valves are used in refrigerators, chillers for semiconductor manufacturing equipment, etc. This type of electric valve can perform precise opening and closing control by using a stepping motor.

[0003] And such an electric valve is driven and controlled by converting an analog signal output from a control device such as a temperature controller into a pulse signal by a pulse drive device (also referred to as a pulse output unit or a pulse converter) (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of the configuration described in Patent Document 1, one pulse drive device and one control device are required for one electric valve. Therefore, for example, when a plurality of electric valves are required due to a plurality of temperature control locations, a plurality of pulse drive devices and control devices are required, resulting in complicated wiring processing and a large-sized system.

[0006] Also, when using a plurality of pulse drive devices, if each is to be controlled individually by an analog signal, it becomes difficult to control the timing between the plurality of pulse drive devices and electric valves, and there has been a demand for unified management regardless of the analog signal.

[0007] Therefore, an object of the present invention is to enable miniaturization and space saving of a system, and to enable unified management while maintaining compatibility with a conventional system.

Means for Solving the Problems

[0008] The invention made to solve the above problems includes an input unit to which an analog signal indicating the valve opening degree of an electric valve is input, a communication unit capable of receiving valve opening degree information indicating the valve opening degree of the electric valve from a plurality of devices by a predetermined communication protocol, a control unit that converts the analog signal or the valve opening degree information into drive pulses and outputs them, a drive circuit that drives the electric valve based on the drive pulses output by the control unit, a first mode in which the input unit and the communication unit are used in combination, and a second mode in which only the communication unit is used, and a switching unit that switches between them.

Effects of the Invention

[0009] According to the present invention, since it can be dedicated to communication in the second mode, there is no need for a one-to-one connection, the wiring can be reduced, and the system can be miniaturized and space-saving. In addition, since an analog signal can also be used in the first mode, compatibility with a conventional system can be maintained. And, by controlling through communication, a control device or the like can be aggregated, enabling unified management.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0011] (First Embodiment) An electric valve control device according to a first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of an electric valve control system including the electric valve control device according to the present embodiment. FIG. 2 is a schematic configuration diagram of the electric valve control device shown in FIG. 1.

[0012] The electric valve control system 1 shown in FIG. 1 includes a pulse converter 10, a control device (CNT) 20, and an electronic expansion valve 30. In the example of FIG. 1, the pulse converter 10 includes three each of reference numerals 10a to 10c, the CNT 20 includes three each of reference numerals 20a to 20c, and the electronic expansion valve 30 includes three each of reference numerals 30a to 30c, but the number of each device is not limited to three. The pulse converter 10 functions as an electric valve control device according to the present embodiment.

[0013] The pulse converters 10a to 10c and the CNTs 20a to 20c are connected by a communication line CL. In the present embodiment, a daisy chain connection is made in the order of CNTs 20a, 20b, 20c, pulse converters 10c, 10b, 10a. Communication standards such as RS485 and RS422 can be used for the daisy chain connection. Also, bus connection or ring connection may be used. Since these connection forms are not connection forms in which the pulse converter 10 and the CNT 20 correspond one-to-one, the wiring for communication can be reduced.

[0014] Pulse converter 10 and CNT 20 may also be connected by analog signal line AL. In Fig. 1, pulse converter 10a and CNT 20a can be connected by analog signal line AL1, pulse converter 10b and CNT 20b can be connected by analog signal line AL2, and pulse converter 10c and CNT 20c can be connected by analog signal line AL3.

[0015] As shown in FIG. 2, the pulse converter 10 includes an analog input 11, an I / V conversion circuit 12, an operational amplifier circuit 14, a microcomputer 18, a power supply circuit 22, a drive circuit 24, a communication port 25, and a communication circuit 26.

[0016] The I / V conversion circuit 12 converts the signal current (valve position signal) relating to the opening of the motor-operated valve input from the analog input 11 into a voltage and outputs it to the operational amplifier circuit 14. This valve position signal current is output from the CNT 20 as a current of, for example, 4 to 20 mA. An analog signal line AL is connected to the analog input 11, and the valve position signal current output from the CNT 20, that is, the analog signal, is input. In other words, the analog input 11 functions as an input unit that inputs an analog signal that indicates the valve position of the electronic expansion valve 30 (motor-operated valve).

[0017] The operational amplifier circuit 14 converts the valve opening signal voltage output from the I / V conversion circuit 12 into a voltage value suitable for the microcomputer 18 and outputs it to the microcomputer 18 .

[0018] The microcomputer 18 includes an A / D conversion circuit 34, a CPU (Central Processing Unit) 36, an I / O circuit 38, a ROM (Read Only Memory) 40, and a RAM (Random Access Memory) 42.

[0019] The A / D conversion circuit 34 converts the valve opening signal voltage input to the microcomputer 18 from an analog signal to a digital signal.

[0020] The CPU 36 converts the valve opening signal converted into a digital signal by the A / D conversion circuit 34 or an opening instruction input from the communication circuit 26, which will be described later, into a drive pulse for driving the electronic expansion valve 30. The CPU 36 then controls the valve opening of the electronic expansion valve 30 using the converted drive pulse via the I / O circuit 38 and the drive circuit 24. The CPU 36 also prioritizes the opening instruction input from the communication circuit 26 over the valve opening signal converted into a digital signal by the A / D conversion circuit 34, as will be described later.

[0021] That is, the CPU 36 functions as a control unit that converts a valve opening signal (analog signal) or an opening instruction (valve opening information) into a drive pulse. The CPU 36 converts the opening instruction (valve opening information) input from the communication port 25 into a drive pulse with priority over the valve opening signal (analog signal) input from the analog input 11 (input unit).

[0022] The I / O circuit 38 outputs drive pulses generated by the CPU 36 to the drive circuit 24. The ROM 40 stores, for example, a program for converting a valve opening signal or an opening instruction into a drive pulse, the above-mentioned communication control program, etc. The RAM 42 is used as temporary storage required for the CPU 36 to execute the program written in advance in the ROM 40.

[0023] The power supply circuit 22 generates a voltage required to operate the internal circuits of the microcomputer 18 and the like from an external power supply (not shown), and outputs the power supply voltage to the microcomputer 18 and the like.

[0024] The drive circuit 24 drives the electronic expansion valve 30 based on the drive pulses output from the microcomputer 18, and controls the valve opening degree.

[0025] The drive pulses output from the drive circuit 24 can be changed as appropriate depending on the type of electronic expansion valve 30. For example, if the electronic expansion valve 30 uses a stepping motor of a 1-2 phase excitation type, drive pulses are output in accordance with the excitation pattern shown in Fig. 3. In this embodiment, one pulse corresponds to one step rotation of the stepping motor of the electronic expansion valve 30. For example, if excitation patterns 1 to 8 in Fig. 3 are output from the drive circuit 24, eight pulses will be output.

[0026] The communication circuit 26 performs communication such as receiving instructions such as an opening instruction via the communication port 25. An opening instruction is instruction information for valve opening information of the electronic expansion valve 30, and is transmitted from the control device 20. The communication circuit 26 communicates with the CNT 20 and the like using a communication protocol based on communication standards such as the above-mentioned RS485 and RS422. A communication line CL is connected to the communication port 25. In other words, the communication port 25 functions as a communication unit that can receive an opening instruction (valve opening information) for the electronic expansion valve 30 (motorized valve) from the CNTs 20a, 20b, and 20c (multiple devices) using a predetermined communication protocol.

[0027] The CNT 20 is a control device that controls the pulse converter 10. The CNT 20 can be configured as a temperature regulator that outputs a control signal based on a temperature measured at a predetermined location in, for example, a refrigerator or a chiller for semiconductor manufacturing equipment. The CNT 20 can also be configured as, for example, a PLC (Programmable Logic Controller).

[0028] The electronic expansion valve 30 is one form of the motor-operated valve in this embodiment. The electronic expansion valve 30 is installed in a refrigerator, a chiller for semiconductor manufacturing equipment, etc. As described above, the electronic expansion valve 30 has a stepping motor, and its opening and closing is controlled by the pulse converter 10.

[0029] Next, the communication operation in the pulse converter 10 configured as described above will be described with reference to the flowchart of Fig. 4. The flowchart shown in Fig. 4 is executed by the microcomputer 18.

[0030] First, the microcomputer 18 determines whether it has received an opening degree instruction by communication (step S1). Whether an opening degree instruction has been received by communication can be determined by whether the opening degree instruction has been input from the communication line CL via the communication port 25 and the communication circuit 26. As described above, this opening degree instruction is communication data indicating the valve opening degree information of the electronic expansion valve 30.

[0031] When the opening degree instruction is received by communication in step S1 (step S1: YES), the microcomputer 18 resets the elapsed time and sets the communication opening degree priority flag to be valid (step S2). The elapsed time indicates the time elapsed since the opening degree instruction was received. In step S2, since the opening degree instruction was received in step S1, the elapsed time is reset. In this embodiment, in order not to immediately shift to analog control, the elapsed time is set to, for example, a time of 1 to 3 minutes.

[0032] The communication opening degree priority flag is a flag indicating that the opening degree instruction received from the communication port 25 is prioritized over the analog signal input from the analog input 11, and is set to be valid when the opening degree instruction is received. When the communication opening degree priority flag is set to be valid, the opening degree instruction is prioritized, and the analog signal input from the analog input 11 during the valid period is invalidated. That is, the analog signal is not accepted during the valid period of the communication opening degree priority flag.

[0033] On the other hand, when the opening degree instruction is not received by communication in step S1 (step S1: NO), the microcomputer 18 advances the elapsed time and proceeds to step S4 described later (step S3).

[0034] Next, the microcomputer 18 determines whether a predetermined time has elapsed for the elapsed time or whether it has received a command to reset the communication opening degree priority flag to invalid (step S4). The command to reset the communication opening degree priority flag to invalid is a type of command input from the communication line CL via the communication port 25 and the communication circuit 26. When this command is received, the communication opening degree priority flag is reset, and the analog signal input from the analog input 11 becomes valid. That is, the command to reset the communication opening degree priority flag to invalid functions as switching information for switching to enable reception of the analog signal.

[0035] In step S4, when a predetermined time has elapsed for the elapsed time or a command to set the communication opening degree priority flag to invalid has been received (step S4: YES), the microcomputer 18 resets the communication opening degree priority flag to invalid (step S5). On the other hand, when neither condition in step S4 is satisfied (step S4: NO), it proceeds to step S6 described later without executing step S5.

[0036] Next, the microcomputer 18 determines whether the communication opening degree priority flag is valid (step S6). When the communication opening degree priority flag is valid (step S6: YES), the microcomputer 18 operates at the opening degree (communication instruction opening degree) included in the opening degree instruction received by the communication circuit 26 (step S7). That is, it generates a number of pulses based on the opening degree received by the communication circuit 26 and outputs them to the drive circuit 24.

[0037] On the other hand, when the communication opening degree priority flag is invalid (step S6: NO), the microcomputer 18 operates with the analog signal input from the analog input 11 (step S8). That is, it generates a number of pulses based on the digital value obtained by converting the analog signal with the A / D conversion circuit 34 and outputs them to the drive circuit 24.

[0038] Next, an operation example of the above-described pulse converter 10 will be described with reference to FIG. 5. FIG. 5 is a timing chart showing an example of the operation of the pulse converter 10. In FIG. 5, the opening degree of the electronic expansion valve 30 (expansion valve opening degree), the analog signal input from the analog input 11, the opening degree instruction (communication instruction) input from the communication port 25, and the communication opening degree priority flag (High: communication priority, Low: analog input priority) are respectively shown.

[0039] First, assume that as an initial state, the expansion valve opening degree is 0% and the communication opening degree priority flag is at the Low level (analog priority). Then, at time A, an instruction to change the opening degree to 100% is input at the analog input 11. At this time, since the communication opening degree priority flag is set to analog input priority, the pulse converter 10 treats the analog signal input from the analog input 11 as valid, outputs the number of pulses based on the instruction of 100% opening degree, and the expansion valve opening degree changes to 100%.

[0040] Next, at time B, when an instruction to change the opening degree to 50% is input at the analog input 11, since the communication opening degree priority flag is set to analog input priority, the pulse converter 10 treats the analog signal input from the analog input 11 as valid. Therefore, the pulse converter 10 outputs the number of pulses based on the instruction of 50% opening degree, and the expansion valve opening degree changes to 50%.

[0041] Next, at time C, an instruction to change the opening degree to 100% is input by the communication instruction. Then, the communication opening degree priority flag changes to High (communication priority). When the opening degree instruction is received by communication, as described in the flowchart of FIG. 4, steps S1: YES, step S2, step S4: NO, step S6: YES, and step S7 are executed, and the pulse converter 10 treats the opening degree instructed by the communication as valid. Therefore, the pulse converter 10 outputs the number of pulses based on the instruction of 100% opening degree, and the expansion valve opening degree changes to 100%.

[0042] Next, at time D, when a communication instruction to change the opening to 75% is input, the pulse converter 10 treats the received communication instruction as valid because the communication opening priority flag is set to communication priority. Therefore, the pulse converter 10 outputs the number of pulses based on the instruction for 75% opening, and the expansion valve opening changes to 75%. Note that from time C to time E (described later) the communication opening priority flag is set to communication priority, so the analog signal input from the analog input 11 is not accepted (is ignored).

[0043] Next, at time E, when a predetermined time has elapsed since time D, the communication opening priority flag changes to Low (analog input priority). Therefore, the flowchart in Fig. 4 is executed in the order of step S1: NO, step S3, step S4: YES, step S5, step S6: NO, and step S8. Therefore, the pulse converter 10 accepts the analog signal input from the analog input 11 at time E, treats it as valid, outputs the number of pulses based on the instruction for 25% opening indicated by the analog input 11 at time E, and changes the expansion valve opening to 25%.

[0044] That is, the microcomputer 18 (controller) waits for a predetermined time period after input of the opening instruction (valve opening information) to receive the opening instruction (the information) and does not accept the analog input 11 (analog signal). After the predetermined time period has elapsed, the microcomputer 18 (controller) accepts the analog input 11 (analog signal).

[0045] Next, at time F, when an instruction to change the opening to 50% is input via analog input 11, the communication opening priority flag is set to analog input priority, so the pulse converter 10 treats the analog signal input from analog input 11 as valid. Therefore, the pulse converter 10 outputs the number of pulses based on the instruction for 50% opening, and the expansion valve opening changes to 50%.

[0046] Next, at time G, an instruction to change to an opening degree of 0% is input with a communication instruction. Then, the communication opening degree priority flag changes to High. Therefore, the flowchart is executed in the same way as at time C, and the pulse converter 10 treats the received communication instruction as valid, outputs pulses to a number based on the instruction to an opening degree of 0%, and the expansion valve opening degree changes to 0%.

[0047] Next, at time H, when a priority release instruction (communication opening degree priority invalid) from communication is received, the communication opening degree priority flag changes to Low. That is, the priority release instruction functions as switching information and is switched to enable reception of an analog signal input.

[0048] Therefore, the flowchart is executed in the same way as at time E, and the pulse converter 10 treats the opening degree indicated by the analog input 11 at time H as valid. Therefore, the pulse converter 10 outputs pulses of a number based on an instruction of an opening degree of 50% of the analog input at time H, and the expansion valve opening degree changes to 50%. That is, the microcomputer 18 (control unit) switches to enable reception of the analog input 11 (analog signal) by the priority release instruction (switching information) received by the communication circuit 26 (communication unit) even within a period of a predetermined time.

[0049] According to this embodiment, the pulse converter 10 includes an analog input 11 to which an analog signal indicating the valve opening degree of the electronic expansion valve 30 is input, a communication port 25 capable of receiving an opening degree instruction from a plurality of devices by communication, a microcomputer 18 that converts the analog signal input to the analog input 11 or the opening degree instruction received by the communication port 25 into drive pulses, and a drive circuit 24 for driving the electronic expansion valve 30 based on the drive pulses. Then, the microcomputer 18 converts the opening degree instruction input from the communication port 25 into drive pulses with priority over the analog signal input from the analog input 11.

[0050] By configuring the pulse converter 10 as described above, it is not necessary to have a one-to-one connection, so a large number of wirings can be made into communication connections and aggregated into a dedicated communication line CL. Therefore, the system can be made smaller and more space-saving. Also, since the analog input 11 for which an analog signal is input is left, compatibility with a conventional system can be maintained.

[0051] Also, after receiving the opening degree instruction, the microcomputer 18 waits for the reception of a subsequent opening degree instruction for a period of a predetermined time and does not accept the analog signal input from the analog input 11. By doing so, even if communication transmission and reception are not continuously performed, communication can be preferentially handled unconditionally for a certain period. By providing a time for waiting for reception in communication for a certain period, the load on the communication processing capabilities of the microcomputer 18 and an external control device due to frequent switching between the analog input 11 and the communication port 25 can be reduced.

[0052] Also, the microcomputer 18 can accept the analog signal input from the analog input 11 after a predetermined time has elapsed. By doing so, it becomes easy to enable the analog input automatically without manual switching. Therefore, for example, when temporarily interrupting control by communication, forgetting to switch back to the analog input 11 can be prevented.

[0053] Also, even within the period of a predetermined time, the microcomputer 18 is made switchable to be able to accept the analog signal input from the analog input 11 by a priority cancellation instruction (communication opening degree priority invalid) received by the communication circuit 26. By doing so, the analog input can be enabled at an arbitrary timing. Therefore, control can be enabled by analog input at any time.

[0054] The electric valve control system 1 also includes a pulse converter 10 and a CNT20 that outputs a valve opening degree to the pulse converter 10. A plurality of pulse converters 10 are provided, and at least one or more CNT20s are provided. The communication port 25 of the pulse converter 10 is daisy-chain connected to the communication port 25 of another pulse converter 10 or the CNT20.

[0055] Since the electric valve control system 1 is configured as described above, the pulse converter 10 and the CNT20 are connected in series, so that the wiring for communication can be minimized.

[0056] In the above-described embodiment, the communication port 25 and the communication circuit 26 are mainly used for inputting instructions and the like to the pulse converter 10, but they can also be used for output from the pulse converter 10. For example, the control state such as the current valve opening degree value and various setting values may be read out and output. In this case, for example, the pulse converter 10 receives a read command or the like, and as a response, the control state may be transmitted from the communication port 25 to the party that transmitted the read command. That is, the communication port 25 (communication unit) can transmit the control state by the microcomputer 18 (control unit) to the outside.

[0057] In the above-described embodiment, the CNT20 is a temperature regulator or the like, but for example, a terminal device or the like that is temporarily added for maintenance work such as starting up the device or verifying in case of a malfunction may be inserted into the communication line CL. In this embodiment, since it is a daisy-chain connection (or a bus connection), such a temporary insertion of a terminal device is easy, and it is also possible to control a plurality of pulse converters 10 from one terminal device. Therefore, centralized control from an external device becomes possible, and the freedom of the system and control increases, such as the electric valve being arbitrarily controllable.

[0058] 1 , it is also possible to mix pulse converter 10a connected to analog input 11 with pulse converters 10b and 10c connected only via communication port 25. In this way, pulse converter 10 corresponding to important electronic expansion valves 30 can be connected via both analog input 11 and communication port 25 for redundancy, while other electronic expansion valves 30 can be configured for communication only. Furthermore, for pulse converters connected via both analog input 11 and communication port 25, connecting communication port 25 also makes it easier to perform the maintenance work described above.

[0059] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 6 and 7. Note that the same parts as those in the first embodiment described above are given the same reference numerals and the description thereof will be omitted.

[0060] 6 shows a schematic configuration diagram of a pulse converter 10A according to this embodiment. The pulse converter 10A includes an analog input 11, an I / V conversion circuit 12, an operational amplifier circuit 14, a microcomputer 18A, a power supply circuit 22, a drive circuit 24, a communication port 25, a communication circuit 26, and a DIP (Dual Inline Package) switch 44.

[0061] Of the components shown in FIG. 6, the analog input 11, the I / V conversion circuit 12, the operational amplifier circuit 14, the power supply circuit 22, the drive circuit 24, the communication port 25, and the communication circuit 26 are the same as those in FIG.

[0062] As is well known, the DIP switch 44 is a small switch used for various settings of electronic devices. In this embodiment, the DIP switch 44 functions as a switching unit that switches between a first mode and a second mode, which will be described later. Note that the physical switching means that functions as the switching unit is not limited to a DIP switch, and other types of switches, such as a push button switch or a toggle switch, may also be used. Note that in the configuration of FIG. 6, the DIP switch 44 is independent of the microcomputer 18A, but it may also be included in the microcomputer 18A. In short, it is sufficient that the DIP switch 44 is provided in the pulse converter 10A and electrically connected to the microcomputer 18A.

[0063] The microcomputer 18A includes an A / D conversion circuit 34, a CPU 36, an I / O circuit 38, a ROM 40, and a RAM 42. The microcomputer 18A has the same functional block configuration as that shown in Fig. 2, but differs in operation as described below.

[0064] Next, the communication operation in the pulse converter 10A of this embodiment will be described with reference to the flowchart of Fig. 7. The flowchart shown in Fig. 7 is executed by the microcomputer 18A.

[0065] First, the microcomputer 18A determines whether the DIP switch 44 is set to the communication-only mode (step S11). That is, it determines whether the second mode is set in which only the communication circuit (communication unit) 26 is used. The first mode will be described later.

[0066] If the DIP switch 44 is set to the communication-only mode (second mode) in step S11 (step S11: YES), the microcomputer 18A resets the elapsed time (step S12). The elapsed time indicates the time that has elapsed since the opening degree instruction was received, as explained in Fig. 4, but in this step, the elapsed time is initialized.

[0067] Next, the microcomputer 18A communicates with the opening reference destination (step S13). Then, the microcomputer 18A operates according to the opening instruction received from the communication port 25 (step S14). That is, it converts the drive pulse output from the drive circuit 24 based on the opening instruction by communication. That is, when the DIP switch 44 is switched to the second mode, the microcomputer 18A does not accept an analog signal. Here, steps S12 to S14 are executed when the second mode is set.

[0068] On the other hand, when the DIP switch 44 is not set to the communication-only mode in step S11 (step S11: NO), the microcomputer 18A determines whether it has received a command to use the opening reference destination as an analog signal (step S15). This command is the same as the command to reset the communication opening priority flag in the first embodiment. When this command is received, the analog signal input from the analog input 11 becomes valid.

[0069] Here, steps S15 and subsequent steps are executed when step S11 is determined to be NO. That is, since step S11 determines whether it is the second mode, steps S15 and subsequent steps executed when step S11 is NO mean that the first mode in which the analog input 11 (input unit) and the communication port 25 (communication unit) are used in combination is set. Note that the combined use of the analog input 11 and the communication port 25 in this embodiment does not mean using the analog input 11 and the communication port 25 simultaneously, but means making them available for mixed use in a time-division manner as shown in FIG. 5. In the case of the second mode, since the analog signal is ignored as described above, the analog signal cannot be used even in a time-division manner.

[0070] When the microcomputer 18A receives an analog signal from the analog input 11 in step S15 (step S15: YES), it resets the elapsed time (step S16). In this step, since the analog signal has become valid, the elapsed time is reset.

[0071] Next, the microcomputer 18A uses the opening reference destination as an analog signal (step S17). That is, it converts the drive pulse output from the drive circuit 24 based on the analog signal input from the analog input 11.

[0072] Next, the microcomputer 18A determines whether the opening reference destination is communication (step S18). When it is determined in step S18 that the opening reference destination is communication (step S18: YES), the microcomputer 18A operates according to the opening instruction received from the communication port 25 (step S19). On the other hand, when it is determined in step S18 that the opening reference destination is not communication (step S18: NO), the microcomputer 18A operates according to the analog signal input from the analog input 11 (step S20).

[0073] Also, when the microcomputer 18A does not receive an analog signal from the analog input 11 in step S15 (step S15: NO), it determines whether it has received an opening instruction (step S21).

[0074] When the microcomputer 18A receives an opening instruction in step S21 (step S21: YES), it resets the elapsed time (step S22). In step S21, since it has received an opening instruction, the elapsed time is reset.

[0075] Next, the microcomputer 18A uses the opening reference destination as communication (step S23). That is, it converts the drive pulse output from the drive circuit 24 based on the opening instruction input from the communication port 25.

[0076] On the other hand, when the microcomputer 18A does not receive an opening instruction in step S21 (step S21: NO), it advances the elapsed time (step S24).

[0077] Next, the microcomputer 18A determines whether the forgetting prevention function is enabled and whether a predetermined time has elapsed (step S25). The forgetting prevention function is a function that enables the analog input 11 (returns to analog) after a predetermined time has elapsed with the opening reference destination being communication in the case of the first mode which is a mode that combines communication and analog. This is a function equivalent to step S4 in the flowchart of FIG. 4, and in this embodiment, it is possible to set whether or not to enable the function of this step S4.

[0078] The forgetting prevention function is set to be enabled or disabled inside the microcomputer 18A. That is, memories, registers, etc. inside the microcomputer 18A function as a setting unit. And the setting of the forgetting prevention function may be set using communication from the communication port 25, or switching means such as a DIP switch 44 or other physical switches may be used.

[0079] If in step S25 the forgetting prevention function is enabled and a predetermined time has elapsed (step S25: YES), the microcomputer 18A resets the elapsed time (step S26) and sets the opening reference destination to an analog signal (step S27). That is, since the predetermined time has elapsed, the elapsed time is reset. Also, due to the forgetting prevention function, the analog signal becomes the opening reference destination.

[0080] Therefore, in the flowchart of FIG. 7, in the case where steps S11, S15, S21, S22, and S23 or S24, S25 are NO and it proceeds to S18, S19, there is an opening instruction by communication, and until a predetermined time (elapsed time) elapses, operation is prioritized by communication.

[0081] According to this embodiment, the pulse converter 10A includes an analog input 11 to which an analog signal indicating the valve opening of the electronic expansion valve 30 is input, and a communication port 25 capable of receiving opening instructions from multiple devices via communication. The pulse converter 10A also includes a microcomputer 18A that converts the analog signal input to the analog input 11 or the opening instruction received by the communication port 25 into a drive pulse and outputs it, and a drive circuit 24 for driving the electronic expansion valve 30 based on the drive pulse output by the microcomputer 18A. The pulse converter 10A also includes a DIP switch 44 that switches between a first mode in which both the analog input 11 and the communication port 25 are used, and a second mode in which only the communication port 25 is used.

[0082] By configuring the pulse converter 10 as described above, the second mode can be used exclusively for communication, eliminating the need for one-to-one connections, reducing wiring and enabling a more compact and space-saving system. Furthermore, the first mode allows analog signals to be used, maintaining compatibility with conventional systems. Furthermore, when control using analog signals is not required, control devices and the like can be consolidated by using communication control, enabling centralized management.

[0083] Furthermore, when the DIP switch 44 is set to the first mode, the microcomputer 18A converts the opening instruction input from the communication port 25 into a drive pulse, prioritizing it over the analog signal input from the analog input 11. This allows communication to be given priority, making it easier to manage multiple units in a unified manner.

[0084] Also, when the DIP switch 44 is switched to the first mode, a setting of a function to prevent forgetting to switch back is provided in the microcomputer 18A, which sets whether to accept the input of an analog signal after a predetermined time has elapsed after the input of the opening degree instruction. By doing so, the user can set not to automatically permit the reception of an analog signal after a predetermined time has elapsed. Therefore, it can operate only by communication until a command to use an analog signal as the opening degree reference destination is received, and can be switched at an arbitrary timing based on the user's intention.

[0085] Also, when the setting of the function to prevent forgetting to switch back is set to accept the input of an analog signal after a predetermined time has elapsed after the input of the opening degree instruction, the microcomputer 18A waits for the reception of the opening degree instruction until the predetermined time has elapsed, and accepts the analog signal after the predetermined time has elapsed. By doing so, communication can be preferentially handled unconditionally for a certain period even if communication transmission and reception are not performed. Also, it becomes easy to enable the analog input 11 automatically without manually switching.

[0086] Also, when the setting of the function to prevent forgetting to switch back is set not to accept the input of an analog signal even after a predetermined time has elapsed after the input of the opening degree instruction, the microcomputer 18A does not accept the analog signal even after the predetermined time has elapsed. By doing so, since the analog signal is not automatically accepted, the convenience of users who mainly use communication can be improved while enabling control by the analog signal.

[0087] Also, the microcomputer 18A is configured such that the communication circuit 26 can be switched to be able to accept an analog signal input from the analog input 11 by a command to use an analog signal as the opening degree reference destination even within the period of the predetermined time. By doing so, the analog input can be enabled at an arbitrary timing. Therefore, control can be enabled by the analog input at any time.

[0088] Also, when the switching unit is switched to the second mode, the microcomputer 18A does not accept an analog signal. By doing so, when using only for communication, since the input from the analog input 11 is not accepted, malfunction due to noise or the like entering from the analog input 11 can be prevented.

[0089] Note that also in this embodiment, similar to the first embodiment, the communication port 25 and the communication circuit 26 may be used for the output from the pulse converter 10.

[0090] Also, in the above-described second embodiment, the switching between the first mode and the second mode is performed by physical switching means such as the DIP switch 44, but it may be switched by receiving a command related to mode switching from the communication port 25. The setting information based on this command related to mode switching is preferably set in, for example, a non-volatile memory or the like in the microcomputer 18, and the set content is retained even when the power is turned off.

[0091] Also, the connection form of communication is not limited to wired forms such as daisy chain connection and bus connection, and may be wireless. If it is wireless, since the communication line CL becomes unnecessary, further miniaturization and the like can be achieved.

[0092] Also, the present invention is not limited to the above-described embodiments. That is, those skilled in the art can variously modify and implement it in accordance with conventionally known knowledge without departing from the gist of the present invention. As long as the configuration of the electric valve control device and the electric valve control system of the present invention is still included even by such modifications, of course, it is included in the scope of the present invention.

Explanation of Reference Numerals

[0093] 1 Electric valve control system 10, 10A Pulse converter (electric valve control device) 11 Analog input (input unit) 18, 18A Microcomputer (control unit) 20 Control device 24 Drive Circuit 25 Communication Port (Communication Unit) 30 Electronic Expansion Valve (Electric Valve) 44 DIP Switch (Switching Unit)

Claims

1. An input unit to which an analog signal indicating the valve opening degree of an electric valve is input; A communication unit capable of receiving valve opening degree information indicating the valve opening degree of the electric valve from a plurality of devices by a predetermined communication protocol; A control unit that converts the analog signal or the valve opening degree information into drive pulses and outputs them; A drive circuit that drives the electric valve based on the drive pulses output by the control unit; A switching unit that switches between a first mode in which the input unit and the communication unit are used in combination and a second mode in which only the communication unit is used; An electric valve control device comprising the above.

2. The control unit converts the valve opening degree information input from the communication unit into drive pulses with priority over the analog signal input from the input unit when the switching unit is switched to the first mode. The electric valve control device according to claim 1, characterized in that.

3. The electric valve control device according to claim 1, further comprising a setting unit that sets whether to receive the input of the analog signal after a predetermined time has elapsed after the input of the valve opening degree information when the switching unit is switched to the first mode.

4. When the setting unit is set to receive the input of the analog signal after the predetermined time has elapsed after the input of the valve opening degree information, the control unit waits for the reception of the valve opening degree information until the predetermined time has elapsed, and receives the analog signal after the predetermined time has elapsed. The electric valve control device according to claim 3, characterized in that.

5. When the setting unit is set not to receive the input of the analog signal even after the predetermined time has elapsed after the input of the valve opening degree information, the control unit does not receive the analog signal even after the predetermined time has elapsed. The electric valve control device according to claim 3, characterized in that.

6. The control unit switches to be able to receive the input of the analog signal according to the switching information received by the communication unit even within the period of the predetermined time. The electric valve control device according to claim 3, characterized in that.

7. The control unit does not receive the analog signal when the switching unit is switched to the second mode. The electric valve control device according to claim 1, characterized in that.

8. The communication unit of the electric valve control device according to claim 1, characterized in that it can transmit the control state by the control unit to the outside.

9. The electric valve control device according to any one of claims 1 to 7; An electric valve control system comprising: a control device that outputs the valve opening degree to the electric valve control device. The system includes a plurality of the electric valve control devices and at least one or more of the control devices. The communication unit of the electric valve control device is connected to the communication unit of another electric valve control device or the control device by daisy chain connection or bus connection. An electric valve control system characterized by the above.

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