Electric valve control device and electric 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 a motor-operated valve control device that controls the valve opening of a motor-operated valve such as an electronic expansion valve, and to a motor-operated valve control system including the motor-operated valve control device. [[BACKGROUND ART]]

[0002] For example, motor-operated valves such as electronic expansion valves are used in refrigerating machines, chillers for semiconductor manufacturing apparatuses, and the like. This type of motor-operated valve can perform precise opening / closing control by using a stepping motor.

[0003] Such a motor-operated 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 driving 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]] Japanese Unexamined Patent Application Publication No. 2011-220451 [[SUMMARY OF THE INVENTION]] [[Problem to be Solved by the Invention]]

[0005] In the case of the configuration described in Patent Document 1, one pulse driving device and one control device are required for one motor-operated valve. Therefore, when a plurality of motor-operated valves are required, for example, due to a plurality of temperature adjustment points, a plurality of pulse driving devices and control devices are required, which complicates wiring processing and increases the size of the system.

[0006] Furthermore, when a plurality of pulse driving devices are used, if each is to be individually controlled by an analog signal, it becomes difficult to control timing between the plurality of pulse driving devices and motor-operated valves, and there has been a demand for centralized management independent of analog signals.

[0007] Therefore, the present invention aims to enable miniaturization and space saving of the system, while also allowing for centralized management and maintaining compatibility with conventional systems. [Means for solving the problem]

[0008] The invention made to solve the above problem is the valve opening degree of an electric valve. Instructions for changes An input section to which an analog signal indicating the valve opening degree of the electric valve is input, and the valve opening degree of the electric valve. Includes an opening degree instruction, which is an instruction for a change. Valve opening information Send multiple control device from , the valve opening information A communication unit capable of receiving signals via a predetermined communication protocol, and a control unit that converts the analog signal or the valve opening information into a drive pulse and outputs it. ,before The device is characterized by comprising: a drive circuit that drives the electric valve based on a recorded drive pulse; and a switching unit that switches between a first mode in which the input unit and the communication unit are used together, and a second mode in which only the communication unit is used. [Effects of the Invention]

[0009] According to the present invention, the second mode can be dedicated to communication, eliminating the need for one-to-one connections, reducing wiring, and enabling system miniaturization and space saving. Furthermore, by using the first mode, analog signals can also be used, maintaining compatibility with conventional systems. In addition, control via communication allows for the consolidation of control devices and other components, enabling centralized management. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an electric valve control system equipped with an electric valve control device according to a first embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of the electric valve control device. [Figure 3] This diagram shows the output patterns of an electric valve driven by a 1-2 phase excitation method, with the output waveforms corresponding to the output patterns in the table. [Figure 4]Figure 2 is a flowchart illustrating the communication operation of the pulse converter. [Figure 5] Figure 2 is a timing chart showing an example of the operation of the pulse converter. [Figure 6] This is a schematic diagram of an electric valve control device according to a second embodiment of the present invention. [Figure 7] Figure 6 is a flowchart of the communication operation of the pulse converter shown. [Modes for carrying out the invention]

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

[0012] The electric valve control system 1 shown in Figure 1 comprises a pulse converter 10, a control device (CNT) 20, and an electronic expansion valve 30. In the example in Figure 1, there are three pulse converters 10 (code 10a-10c), three CNTs 20 (code 20a-20c), and three electronic expansion valves 30 (code 30a-30c), but the number of each device is not limited to three. The pulse converter 10 functions as the electric valve control device according to this embodiment.

[0013] The pulse converters 10a to 10c and the CNTs 20a to 20c are connected by a communication line CL. In this embodiment, a daisy-chain connection is used, in which CNTs 20a, 20b, 20c and pulse converters 10c, 10b, and 10a are connected in that order. Communication standards such as RS485 or RS422 can be used for the daisy-chain connection. Bus connections or ring connections may also be used. These connection configurations do not involve a one-to-one correspondence between the pulse converters 10 and CNTs 20, thus reducing the amount of wiring required for communication.

[0014] Alternatively, the pulse converter 10 and the CNT 20 may be connected via an analog signal line AL. In Fig. 1, the pulse converter 10a and the CNT 20a can be connected via an analog signal line AL1, the pulse converter 10b and the CNT 20b can be connected via an analog signal line AL2, and the pulse converter 10c and the CNT 20c can be connected via an 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 a signal current relating to the opening degree of a motor-operated valve (valve opening signal) input from the analog input 11 into a voltage, and outputs the voltage to the operational amplifier circuit 14. This valve opening signal current is output from the CNT 20 as, for example, a current of 4 to 20 mA. The analog signal line AL is connected to the analog input 11, and the valve opening signal current output from the CNT 20, that is, an analog signal, is input to the analog input 11. That is, the analog input 11 functions as an input unit to which an analog signal indicating the valve opening degree of an electronic expansion valve 30 (motor-operated valve) is input.

[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 the converted voltage value 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 into a digital signal.

[0020] The CPU 36 converts the valve opening signal, which has been converted into a digital signal by the A / D conversion circuit 34, or the opening instruction input from the communication circuit 26 (described later), into drive pulses to drive the electronic expansion valve 30. The CPU 36 then controls the valve opening of the electronic expansion valve 30 via the I / O circuit 38 and the drive circuit 24 using the converted drive pulses. Furthermore, as will be described later, the CPU 36 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.

[0021] In other words, the CPU 36 functions as a control unit that converts a valve opening signal (analog signal) or 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, prioritizing it 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 programs such as those for converting valve opening signals and opening instructions into drive pulses, and the communication control programs mentioned above. The RAM 42 is used as temporary storage necessary for the CPU 36 to execute programs that have been pre-written to the ROM 40.

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

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

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

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

[0027] CNT20 is a control device that controls the pulse converter 10. CNT20 can be configured as a temperature controller that outputs a control signal based on the temperature measured at a predetermined location, such as a refrigerator or a chiller for semiconductor manufacturing equipment. CNT20 can also be configured as a PLC (Programmable Logic Controller), for example.

[0028] The electronic expansion valve 30 is a form of electric valve in this embodiment. The electronic expansion valve 30 is installed in refrigerators, chillers for semiconductor manufacturing equipment, and the like. As described above, the electronic expansion valve 30 has a stepping motor and is opened and closed by the pulse converter 10.

[0029] Next, the communication operation of the pulse converter 10 with the above configuration will be explained with reference to the flowchart in Figure 4. The flowchart shown in Figure 4 is operated by the microcomputer 18.

[0030] First, the microcomputer 18 determines whether it has received an opening degree instruction via communication (step S1). Receipt of an opening degree instruction via communication can be determined by whether or not an opening degree instruction has been input from the communication line CL to 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] If an opening degree instruction is received via communication in step S1 (step S1: YES), the microcomputer 18 resets the elapsed time and sets the communication opening degree priority flag to enabled (step S2). The elapsed time refers to the time elapsed since the opening degree instruction was received. In step S2, the elapsed time is reset because an opening degree instruction was received in step S1. In this embodiment, the elapsed time is set to, for example, 1 to 3 minutes so that control does not immediately switch to analog.

[0032] The communication opening priority flag indicates that an opening instruction received from communication port 25 takes precedence over an analog signal input from analog input 11. This flag is set to be active when an opening instruction is received. When the communication opening priority flag is set to be active, the opening instruction takes precedence, and any analog signals input from analog input 11 during the valid period are ignored. In other words, analog signals are not accepted while the communication opening priority flag is active.

[0033] On the other hand, if no opening instruction is received via communication in step S1 (step S1: NO), the microcomputer 18 advances the elapsed time and proceeds to step S4, which will be described later (step S3).

[0034] Next, the microcomputer 18 determines whether a predetermined time has elapsed or whether it has received a command to reset the communication opening priority flag (step S4). The command to reset the communication opening priority flag is a type of command input from the communication line CL via the communication port 25 and the communication circuit 26. Upon receiving this command, the communication opening priority flag is reset, and the analog signal input from the analog input 11 becomes valid. In other words, the command to reset the communication opening priority flag functions as switching information that switches the input of the analog signal to be accepted.

[0035] In step S4, if a predetermined time has elapsed or a command is received to disable the communication opening priority flag (step S4: YES), the microcomputer 18 resets the communication opening priority flag to disabled (step S5). On the other hand, if none of the conditions in step S4 are met (step S4: NO), the process proceeds to step S6, which will be described later, without executing step S5.

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

[0037] On the other hand, if the communication opening priority flag is invalid (step S6: NO), the microcomputer 18 operates on 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 by the A / D conversion circuit 34 and outputs them to the drive circuit 24.

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

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

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

[0041] Next, at time C, a communication instruction is received to change the opening to 100%. The communication opening priority flag then changes to High (communication priority). Upon receiving the opening instruction via communication, as explained in the flowchart in Figure 4, steps S1: YES, S2, S4: NO, S6: YES, and S7 are executed, and the pulse converter 10 treats the opening instruction given in that communication as valid. Therefore, the pulse converter 10 outputs a number of pulses corresponding to the instruction for a 100% opening, and the expansion valve opening changes to 100%.

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

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

[0044] In other words, the microcomputer 18 (control unit) waits for a predetermined period of time after receiving the opening degree instruction (valve opening degree information) and does not accept the analog input 11 (analog signal). After the predetermined period of time has elapsed, the microcomputer 18 (control unit) 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 pulse converter 10 treats the analog signal input from analog input 11 as valid because the communication opening priority flag is set to analog input priority. Therefore, the pulse converter 10 outputs a number of pulses based on the instruction to change the opening to 50%, and the expansion valve opening changes to 50%.

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

[0047] Next, at time H, when a priority cancellation instruction (communication opening priority disabled) is received from the communication, the communication opening priority flag changes to Low. In other words, the priority cancellation instruction functions as switching information, and the system is switched to accept analog signal input.

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

[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 opening degree instructions from multiple devices via 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 a drive pulse, and a drive circuit 24 for driving the electronic expansion valve 30 based on the drive pulse. The microcomputer 18 converts the opening degree instruction input from the communication port 25 into a drive pulse with priority over the analog signal input from the analog input 11.

[0050] By configuring the pulse converter 10 as described above, there is no need for one-to-one connections, and numerous wires can be consolidated into a dedicated communication line CL using communication connections. Therefore, the system can be miniaturized and space-saving. In addition, since the analog input 11 for receiving analog signals is retained, compatibility with conventional systems can be maintained.

[0051] Furthermore, after receiving an opening degree instruction, the microcomputer 18 waits for a predetermined period of time before accepting subsequent opening degree instructions and does not accept analog signals input from the analog input 11. In this way, even if communication transmission and reception do not occur continuously, communication can be given priority unconditionally for a certain period of time. By setting a time for waiting for communication reception, the load on the communication processing capacity of the microcomputer 18 and the external control device caused by frequent switching between the analog input 11 and the communication port 25 can be reduced.

[0052] Furthermore, the microcomputer 18 can accept an analog signal input from the analog input 11 after a predetermined time has elapsed. This makes it easy to automatically enable the analog input without manual switching. Therefore, for example, when temporarily interrupting control by communication, it is possible to prevent forgetting to switch back to the analog input 11.

[0053] Furthermore, the microcomputer 18 is configured to allow the acceptance of analog signals input from the analog input 11 even within a predetermined time period, based on a priority cancellation instruction (disable communication opening priority) received by the communication circuit 26. In this way, the analog input can be enabled at any time. Therefore, control can be made possible by analog input at any time.

[0054] Furthermore, the electric valve control system 1 includes a pulse converter 10 and a CNT 20 that outputs the valve opening degree to the pulse converter 10. The system includes multiple pulse converters 10 and at least one CNT 20. The communication port 25 of the pulse converter 10 is daisy-chained with the communication ports 25 of other pulse converters 10 or CNT 20.

[0055] With the electric valve control system 1 configured as described above, the pulse converter 10 and the CNT 20 are connected in a daisy-chain configuration, thus minimizing the amount of wiring required for communication.

[0056] In the embodiment described above, the communication port 25 and communication circuit 26 were mainly used for inputting instructions to the pulse converter 10, but they can also be used for output from the pulse converter 10. For example, the control status, such as the current valve opening value or various setting values, may be read out and output. In this case, for example, the pulse converter 10 can receive a read command and, in response, send the control status from the communication port 25 to the party that sent the read command. In other words, the communication port 25 (communication unit) can transmit the control status from the microcomputer 18 (control unit) to the outside.

[0057] Furthermore, in the embodiment described above, the CNT20 was a temperature controller or the like, but terminal devices that are temporarily added for maintenance work such as starting up the device or verifying malfunctions may also be inserted into the communication line CL. In this embodiment, since it is a daisy-chain connection (or bus connection), it is easy to temporarily insert such terminal devices, and it is also possible to control multiple pulse converters 10 from a single terminal device. Therefore, centralized control from external devices becomes possible, and the motorized valves can be controlled arbitrarily, increasing the flexibility of the system and control.

[0058] Furthermore, it is possible to mix pulse converters 10a connected to the analog input 11 and pulse converters 10b and 10c connected only to the communication port 25, as in the configuration shown in Figure 1, where CNT20b and 20c are omitted. In this way, pulse converters 10 corresponding to important electronic expansion valves 30 can be made redundant by connecting them to both the analog input 11 and the communication port 25, while other electronic expansion valves 30 can be made to communicate only. In addition, pulse converters connected to both the analog input 11 and the communication port 25 can be made easier to maintain by connecting them to the communication port 25 as described above.

[0059] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 6 and 7. Parts identical to those in the first embodiment described above are denoted by the same reference numerals and their descriptions are omitted.

[0060] Figure 6 shows a schematic configuration diagram of the 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 configurations shown in Figure 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 Figure 2.

[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 the first mode and the second mode, which will be described later. Note that the physical switching means for functioning as a switching unit is not limited to a DIP switch; other types of switches such as push-button switches or toggle switches may also be used. In the configuration of Figure 6, the DIP switch 44 is independent of the microcomputer 18A, but it may be included in the microcomputer 18A. In short, the DIP switch 44 only needs to be provided by 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 functional block configuration of the microcomputer 18A is the same as in Figure 2, but its operation, as described below, is different.

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

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

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

[0067] Next, the microcomputer 18A uses communication as the reference for the opening degree (step S13). Then, the microcomputer 18A operates according to the opening degree instruction received from the communication port 25 (step S14). In other words, it converts the drive pulse output from the drive circuit 24 based on the opening degree instruction received via communication. That is, the microcomputer 18A does not accept analog signals when the DIP switch 44 is switched to the second mode. Steps S12 to S14 are executed when the system is set to the second mode.

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

[0069] Here, steps S15 and beyond are executed only if step S11 is determined to be NO. In other words, since step S11 determines whether it is the second mode, steps S15 and beyond, which are executed when step S11 is NO, mean that the system is set to the first mode, in which the analog input 11 (input section) and communication port 25 (communication section) are used in combination. Note that in this embodiment, using the analog input 11 and communication port 25 in combination does not mean using the analog input 11 and communication port 25 simultaneously, but rather making them usable by mixing them in time division, as shown in Figure 5. In the case of the second mode, as described above, analog signals are ignored, so analog signals cannot be used even in time division.

[0070] If an analog signal is received from the analog input 11 in step S15 (step S15: YES), the microcomputer 18A resets the elapsed time (step S16). In this step, the elapsed time is reset because the analog signal has become active.

[0071] Next, the microcomputer 18A uses an analog signal as the reference point for the opening degree (step S17). In other words, 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 degree reference is for communication or not (step S18). If it is determined in step S18 that the opening degree reference is for communication (step S18: YES), the microcomputer 18A operates according to the opening degree instruction received from the communication port 25 (step S19). On the other hand, if it is determined in step S18 that the opening degree reference is not for communication (step S18: NO), the microcomputer 18A operates according to the analog signal input from the analog input 11 (step S20).

[0073] Furthermore, if no analog signal is received from the analog input 11 in step S15 (step S15: NO), the microcomputer 18A determines whether an opening instruction has been received (step S21).

[0074] If an opening degree instruction is received in step S21 (step S21: YES), the microcomputer 18A resets the elapsed time (step S22). In step S21, the elapsed time is reset because an opening degree instruction was received.

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

[0076] On the other hand, if no opening instruction is received in step S21 (step S21: NO), the microcomputer 18A advances the elapsed time (step S24).

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

[0078] The function to prevent forgetting to return the device is enabled or disabled within the microcomputer 18A. That is, the memory and registers within the microcomputer 18A function as the setting unit. The setting of the function to prevent forgetting to return the device may be configured using communication via the communication port 25, or by using a DIP switch 44 or other physical switch or other switching means.

[0079] In step S25, if the return-retention 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 degree reference to an analog signal (step S27). In other words, the elapsed time is reset because the predetermined time has elapsed. Also, the return-retention prevention function causes the analog signal to become the opening degree reference.

[0080] Therefore, in the flowchart of Figure 7, if steps S11, S15, S21, S22, and S23 or S24, S25 proceed to NO, S18, and S19, there is an opening degree instruction via communication, and the system will operate prioritizing communication until a predetermined time (elapsed time) has elapsed.

[0081] According to this embodiment, the pulse converter 10A includes an analog input 11 to which an analog signal indicating the valve opening degree of the electronic expansion valve 30 is input, and a communication port 25 capable of receiving opening degree 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 degree 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. Furthermore, the pulse converter 10A includes a DIP switch 44 that switches between a first mode that uses both the analog input 11 and the communication port 25, and a second mode that uses only the communication port 25.

[0082] By configuring the pulse converter 10 as described above, it can be dedicated to communication in second mode, eliminating the need for one-to-one connections, reducing wiring, and enabling system miniaturization and space saving. Furthermore, by using first mode, analog signals can also be used, maintaining compatibility with conventional systems. When control by analog signals is not required, control devices can be consolidated through communication control, enabling centralized management.

[0083] Furthermore, when the DIP switch 44 is switched to the first mode, the microcomputer 18A prioritizes converting the opening degree instruction input from the communication port 25 into a drive pulse over the analog signal input from the analog input 11. This allows communication to be given priority. Therefore, it becomes easier to centrally manage multiple units.

[0084] Furthermore, the microcomputer 18A includes a setting to prevent forgetting to switch back, which, when the DIP switch 44 is switched to the first mode, sets whether or not to accept an analog signal input after a predetermined time has elapsed since the input of the opening degree instruction. In this way, the user can set it so that the acceptance of analog signals is not automatically permitted after the predetermined time has elapsed. Therefore, it can operate using only communication until a command is received to set the opening degree reference to an analog signal, and the user can switch at any timing based on their will.

[0085] Furthermore, if the setting for the return-to-back prevention function is configured to accept an analog signal input after a predetermined time has elapsed since 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 then accepts the analog signal. In this way, communication can be given priority unconditionally for a certain period of time even if no transmission or reception is taking place via communication. In addition, it becomes easy to automatically enable the analog input 11 without manual switching.

[0086] Furthermore, if the setting for the return-to-back prevention function is configured to not accept analog signal input even after a predetermined time has elapsed since the input of the opening degree instruction, the microcomputer 18A will not accept analog signal even after the predetermined time has elapsed. By doing so, it is possible to prevent the system from automatically accepting analog signals, thereby enabling control using analog signals while improving convenience for users who primarily use communication.

[0087] Furthermore, the microcomputer 18A is configured to allow the communication circuit 26 to switch to accepting analog signals from the analog input 11, even within a predetermined time period, by a command to set the opening degree reference to an analog signal. In this way, the analog input can be enabled at any time. Therefore, control can be made possible by analog input at any time.

[0088] Furthermore, the microcomputer 18A is configured not to accept analog signals when the switching unit is switched to the second mode. By doing so, when used only for communication, it does not accept input from the analog input 11, thereby preventing malfunctions caused by noise entering from the analog input 11.

[0089] In this embodiment as well, the communication port 25 and communication circuit 26 may be used as outputs from the pulse converter 10, similar to the first embodiment.

[0090] Furthermore, in the second embodiment described above, the switching between the first mode and the second mode was performed by a physical switching means such as a DIP switch 44, but the switching may also be performed by receiving a command for mode switching from the communication port 25. Preferably, the setting information from this command for mode switching is set in, for example, a non-volatile memory in the microcomputer 18, so that the set content is retained even when the power is turned off.

[0091] Furthermore, the communication connection method is not limited to wired connections such as daisy-chain or bus connections; it can also be wireless. Wireless connections eliminate the need for communication cables (CLs), allowing for further miniaturization.

[0092] Furthermore, the present invention is not limited to the embodiments described above. That is, those skilled in the art can implement the invention in various ways without departing from the core principles, in accordance with prior art knowledge. As long as such modifications still possess the configuration of the electric valve control device and electric valve control system of the present invention, they are of course included within the scope of the present invention. [Explanation of symbols]

[0093] 1. Electric Valve Control System 10, 10A pulse converter (motorized valve control device) 11. Analog input (input section) 18, 18A Microcomputer (Control Unit) 20 Control device 24 Drive Circuit 25. Communication Port (Communication Section) 30 Electronic expansion valve (electric valve) 44 DIP switches (selection section)

Claims

1. An input section into which an analog signal indicating an instruction to change the valve opening of an electric valve is input, A communication unit capable of receiving valve opening information, including an opening instruction which is an instruction to change the valve opening of the electric valve, from a plurality of control devices, via a predetermined communication protocol, A control unit that converts the analog signal or the valve opening information into a drive pulse and outputs it, A drive circuit that drives the electric valve based on the drive pulse, A switching unit that switches between a first mode in which the input unit and the communication unit are used together, and a second mode in which only the communication unit is used. An electric valve control device characterized by comprising the following:

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

3. The electric valve control device according to claim 1, further comprising a setting unit that, when the switching unit is switched to the first mode, sets whether or not to accept the input of the analog signal after a predetermined time has elapsed since the input of the valve opening information.

4. The electric valve control device according to claim 3, wherein if the setting unit is set to accept the input of the analog signal after a predetermined time has elapsed since the input of the valve opening information, the control unit waits to receive the valve opening information until the predetermined time has elapsed, and accepts the analog signal after the predetermined time has elapsed.

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

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

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

8. The electric valve control device according to claim 1, characterized in that the communication unit is capable of transmitting the control state by the control unit to an external source.

9. An 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 analog signal to the electric valve control device and transmits the valve opening degree information to the electric valve control device, The system comprises multiple electric valve control devices, and at least one of the control devices. The communication unit of the electric valve control device is connected to the communication unit or control device of another electric valve control device by daisy-chain connection or bus connection. An electric valve control system characterized by the following:

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