JP4393142B2 - Defrosting control device for cooling system - Google Patents

Description

  The present invention relates to an evaporator that cools the interior by supplying refrigerant, a compressor that pumps the refrigerant to the evaporator, a cooling device that includes defrosting means that removes frost attached to the evaporator, and the compressor and defrost. The invention relates to a cooling system having first and second cooling units each comprising an electrical control device for controlling the operation of the means.

Conventionally, a large storage is cooled by using a plurality of cooling units each provided with a cooling device having an evaporator, a compressor and defrosting means, and an electric control device for controlling the operation of the compressor and defrosting means. It is done. In such a large storage, it is not preferable to operate the defrost during the business hours of users who frequently open and close the door to remove the frost adhering to the evaporator. Defrosting by frost means is performed outside the business hours of the user. In order to satisfy such a requirement, in the defrosting control device for a cooling system shown in Patent Document 1 below, a plurality of cooling units are synchronously controlled so that a plurality of cooling units simultaneously perform a defrosting operation. .
Japanese Patent Publication No.7-18637

  However, in the above-described conventional apparatus, if a plurality of cooling units are simultaneously switched to the defrosting operation, the power consumption accompanying the simultaneous defrosting operation becomes excessive, which may cause a problem. In particular, when a cooling unit of a type that removes frost adhering to the evaporator using a heater that superheats the evaporator by energization is used as the defrosting means, the excessive power consumption becomes a problem. .

  The present invention has been made to address this problem of power consumption, and its purpose is to attach an evaporator that cools the interior of the warehouse by supplying refrigerant, a compressor that pumps the refrigerant to the evaporator, and an evaporator. In a cooling system having first and second cooling units each having a cooling device having a defrosting means for removing the generated frost and an electric control device for controlling the operation of the compressor and the defrosting means, first, excessive electric power An object of the present invention is to provide a defrosting control device for a cooling system capable of defrosting an evaporator as quickly as possible outside the business hours of a user while avoiding consumption.

  In order to achieve the above object, the present invention is characterized in that both electrical control devices of the first and second cooling units are electrically connected to each other from the electrical control device of the first cooling unit to the electrical control device of the second cooling unit. And a signal indicating the end of defrosting by the defrosting means of the first cooling unit provided in the electric control device of the first cooling unit to the electric control device of the second cooling unit. The defrosting end notification means sent via the communication line and the defrosting means by the defrosting means of the second cooling unit in response to the signal indicating the end of the defrosting provided in the electric control device of the second cooling unit. A defrosting start control means for starting frost is provided. In this case, the defrosting means is a heater that heats the evaporator by energization.

  In such a feature of the present invention, the defrosting in the second cooling unit is always performed immediately after the defrosting in the first cooling unit is performed by the action of the defrosting end notification unit and the defrosting start control unit. Is called. That is, the defrosting in the 1st cooling unit and the defrosting in the 2nd cooling unit are performed continuously in order. In general, it is not necessary to frequently perform defrosting, and it is sufficient to perform defrosting after elapse of a predetermined time from the end of defrosting or within a predetermined time outside the business hours of the user. According to the feature, defrosting in the first and second cooling units can be performed periodically after avoiding simultaneous operation of both defrosting means in the first and second cooling units. Thereby, even if both defrosting of a 1st and 2nd cooling unit is performed regularly, excessive power consumption can be prevented. In addition, since the defrosting is continuously performed in the first and second cooling units as described above, the total defrosting time of the first and second cooling units can be relatively shortened, and the first The time from the start of the defrosting of the first cooling unit to the end of the defrosting of the second cooling unit can be shortened, and the defrosting can be prevented from being performed within the business hours of the user.

  Another feature of the present invention is that the electric control devices of the first and second cooling units are electrically connected to each other and transmitted from the electric control device of the first cooling unit to the electric control device of the second cooling unit. And a defrost signal that is provided in the electric control device of the first cooling unit and that indicates the defrost control state by the electric control device of the first cooling unit is communicated to the electric control device of the second cooling unit. The defrosting notification means by the defrosting means of the second cooling unit when receiving the signal indicating the defrosting control state provided in the electric control device of the second cooling unit and the defrosting control state sent through the line. The defrosting prohibition control means for prohibiting the defrosting and the defrosting means by the defrosting means of the second cooling unit at the end of reception of the signal indicating the sent defrosting control state provided in the electric control device of the second cooling unit. Defrost opening to start And a start control means. Also in this case, the defrosting means is a heater that heats the evaporator by energization. In addition, the defrosting prohibition control unit includes, for example, a stopping unit that stops the defrosting operation by the defrosting unit when the defrosting unit of the second cooling unit is performing the defrosting operation.

  Also according to the other features of the present invention, the defrosting in the first cooling unit and the defrosting in the second cooling unit are successively performed in order by the action of the defrost notification means and the defrost start control means. Therefore, also in this case, the same effect as the feature of the present invention can be expected. Further, in another feature of the present invention, the defrosting inhibition control means is provided in the electric control device of the second cooling unit and receives the second cooling when receiving the signal indicating the defrosting control state sent thereto. Since the defrosting operation by the defrosting means of the unit is prohibited, it is possible to reliably avoid the simultaneous defrosting in the first and second cooling units. Therefore, according to the other feature of the present invention, the above-described effect of the present invention can be expected more reliably.

  In addition, another feature of the present invention is that the defrosting means of the first cooling unit is further provided after the elapse of a predetermined time from the time of transmission of the signal indicating the defrost control state provided in the electric control device of the first cooling unit. A defrosting start timing control means for starting frost is provided.

  In another aspect of the present invention, even if defrosting is performed in the second cooling unit at the start of defrosting in the first cooling unit, the defrosting by the first cooling unit is performed by the defrosting start timing control means. While the start is delayed by a predetermined time from the transmission of the signal indicating the defrost control state, the defrost prohibition control means stops the defrosting of the second cooling unit. As a result, according to the other feature of the present invention, it is possible to more reliably avoid simultaneous defrosting in the first and second cooling units, and further, the effect of the present invention described above can be expected with certainty. It becomes like this.

  Another feature of the present invention is that the defrosting notification means sends a pulse train signal having a different duty ratio to the communication line in the defrosting control state by the electric control device and in other states, Further, in the electric control device of the two cooling units, there is further provided an abnormality determining means for checking the presence of the pulse train signal to be sent and determining a communication line abnormality when the pulse train signal is absent.

  In another aspect of the present invention, when an abnormality due to a short circuit or disconnection occurs in the communication line, a signal sent from the electric control device of the first cooling unit to the electric control device of the second cooling unit is The power source potential or the ground potential is a constant potential. Therefore, the abnormality determination means can determine the abnormality of the communication line by examining the presence of the pulse train signal to be sent. Even if the signal indicating the defrost control state is a signal composed of a high level and a low level, it is possible to determine a communication line abnormality by the absence of the high level or low level signal. Since frost is not frequently performed, determination of an abnormality in the communication line is delayed. On the other hand, by using the pulse train signal as in the other feature of the present invention, it becomes possible to perform the abnormality of the communication line within a short time from the occurrence of the abnormality, and the abnormality can be dealt with quickly. It becomes like this.

  Another feature of the present invention is that the communication line connecting the electric control devices of the first and second cooling units is connected to the electric control device of the first cooling unit and the electric control device of the second cooling unit. The signal indicating the defrosting by the defrosting means of the first cooling unit is provided in the electric control device of the first cooling unit via the communication line to the electric control device of the second cooling unit. A first defrosting notification means for sending and a signal indicating that defrosting is being performed by the defrosting means of the second cooling unit provided in the electric control device of the second cooling unit is connected to the electric control device of the first cooling unit. The second defrosting notification means sent via the first cooling unit and the first cooling unit at the time of receiving the signal representing the defrosting sent from the electric control device of the second cooling unit. By defrosting means The first defrosting prohibition control means for prohibiting the defrosting operation and the first defrosting prohibition control means provided in the electric control device of the second cooling unit and receiving a signal representing the defrosting sent from the electric control device of the first cooling unit. 2nd defrost prohibition control means for prohibiting the defrosting operation by the defrosting means of the 2 cooling unit, and the defrost sent from the electrical control device of the first cooling unit provided in the electrical control device of the 2nd cooling unit And defrosting start control means for starting defrosting by the defrosting means of the second cooling unit at the end of reception of the signal representing the inside. Also in this case, the defrosting means is a heater that heats the evaporator by energization, for example.

  In such another feature of the present invention, the defrosting in the second cooling unit is prohibited and controlled during the defrosting operation in the first cooling unit by the action of the first defrosting notification unit and the second defrosting prohibition control unit. The On the other hand, the defrosting in the first cooling unit is prohibited and controlled during the defrosting operation in the second cooling unit by the action of the second defrosting notification unit and the first defrosting prohibition control unit. And by the effect | action of a defrost start control means, the defrost in a 2nd cooling unit is started at the end of the defrost in a 1st cooling unit. Therefore, according to the other feature of the present invention, it is possible to more reliably avoid the simultaneous defrosting in the first and second cooling units, and the defrosting in the first cooling unit and the second cooling unit. Defrosting is performed continuously in order. Accordingly, excessive power consumption can be prevented also in the other feature of the present invention. Further, the total defrosting time of the first and second cooling units can be relatively shortened, and the time from the start of defrosting of the first cooling unit to the end of defrosting of the second cooling unit is shortened. It is possible to prevent defrosting during the business hours of the user.

  In addition, another feature of the present invention is that the first and second defrosting notification means respectively send pulse train signals having different duty ratios to the communication line in the defrosting control state by the electric control device and in other states. Abnormality in which the presence of the pulse train signal to be sent is further checked in each of the electric control devices of the first and second cooling units to determine a communication line abnormality when the pulse train signal is absent. The determination means is provided.

  In such other features of the present invention, as in the case described above, it is possible to detect a communication line abnormality within a short time from the occurrence of the abnormality so that the abnormality can be dealt with quickly. Become.

a, 1st Embodiment Hereinafter, if 1st Embodiment of this invention is described using drawing, FIG. 1 is a schematic block diagram which shows the whole cooling system which concerns on the same embodiment. This cooling system includes a master cooling unit MUNT and a slave cooling unit SUNT for cooling the inside of a refrigerator or a freezer. The master cooling unit MUNT includes a cooling device 10 for cooling the interior of the cabinet and an electric control device 20 for electrically controlling the cooling device 10. The 2nd cooling unit SUNT consists of the cooling device 30 for cooling the inside of a store | warehouse | chamber, and the electric control apparatus 40 for controlling the cooling device 30 electrically.

  The cooling device 10 includes an electric compressor 11, a condenser 12, a throttle 13, and an evaporator 14. The refrigerant is circulated when the electric compressor 11 is operated, and the inside of the refrigerator is cooled by the evaporator 14. The evaporator 14 is assembled with a defrost heater 15 and a defrost thermo switch 16. The defrost heater 15 superheats the evaporator 14 when energized to remove frost attached to the evaporator 14. The defrosting thermo switch 16 is a temperature sensitive element that is kept in an on state below a predetermined temperature and switched to an off state when the temperature exceeds a predetermined temperature, and is in an on state during normal times (during cooling and defrosting). It changes to the off state only at the end of defrosting. The cooling device 10 also includes an internal temperature sensor 17 that detects the internal temperature.

  The electric control device 20 includes a microcomputer 21, a display 22, and a communication control unit 23. The microcomputer 21 includes a computer main body portion including a CPU, a ROM, a RAM, and a timer connected to a bus, and peripheral circuits thereof. The microcomputer 21 repeatedly executes the master control program of FIG. 2 (including the defrost start control routine of FIG. 3 and the defrost stop control routine of FIG. 4) every predetermined short time, and the cooling device 10 and the display 22 and the communication with the slave cooling unit SUN. Indicator 22 consists of a light emitting diode or a liquid crystal indicator, and displays the internal temperature, the operating state of cooling device 10, etc. The communication control unit 23 includes an NPN transistor TR1 and transmits information to the electric control device 40 of the slave cooling unit SUN. The collector of the transistor TR1 is connected to the terminal T21, its emitter is connected to the terminal T22, and its base is connected to the microcomputer 21.

  The cooling device 30 of the slave cooling unit SUNT is configured in the same manner as the cooling device 30 of the master cooling unit MUNT, and includes an electric compressor 31, a condenser 32, a throttle 33, an evaporator 34, a defrost heater 35, and a defrost thermo switch 36. And an internal temperature sensor 37 is provided. The electric control device 40 of the slave cooling unit SUN also includes a microcomputer 41, a display 42, and a communication control unit 43. The microcomputer 41 is configured in the same manner as the microcomputer 21 described above, and executes the slave control program of FIG. 5 (including the defrost start control routine of FIG. 6 and the defrost stop control routine of FIG. 7) for a predetermined short time. Each time, the cooling device 30 and the display 42 are controlled. The display device 42 is configured in the same manner as the display device 22. The communication control unit 43 is connected to the DC power source + V at one end and includes a resistor R1 having the other end connected to the terminal T41 and the microcomputer 41, and receives information from the electric control device 20 of the master cooling unit MUNT. . The terminal T42 is grounded.

  The electric control device 20 of the master cooling unit MUNT and the electric control device 40 of the slave cooling unit SUNT are a communication line 51 connected between the terminal T21 and the terminal T41, and a communication line connected between the terminal T22 and the terminal T42. 52, the electric control device 20 is connected to the electric control device 40 so that one-way communication is possible.

  Next, the operation of the cooling system configured as described above will be described with reference to the flowcharts of FIGS. With the start of the operation of the master cooling unit MUNT, the microcomputer 21 starts to repeatedly execute the master control program of FIG. 2 every predetermined short time. The execution of the master control program is started in step M10, and it is determined in step M12 whether or not the defrost flag DF1 is “0”. This defrost flag DF1 indicates that the cooling device 10 is in the cooling operation by “0”, and “1” indicates that the cooling device 10 is in the defrosting operation, and is initially set to “0” by executing an initial program (not shown). Has been. Immediately after the start of the operation of the cooling system, the defrost flag DF1 is set to “0”. Therefore, “Yes” is determined in Step M12, and the process proceeds to Step M14.

  In step M14, it is determined whether the timer count value TM1 is equal to or greater than a predetermined time value TM10. This timer count value TM1 is counted up as time elapses by executing a program (not shown), and measures the time from the start of the previous defrosting operation to the start of the next defrosting operation. Is initially set to “0”. The predetermined time value TM10 is set by the user by executing a program (not shown), and is usually set to a value representing a time interval at which the defrosting control is executed every time outside the business hours of the user. Therefore, the operation start of the cooling system is started from the outside of the business start of the user, or the first defrost start time is set and a value indicating the time interval of the defrost operation after the first time is set as the predetermined time value TM10. Good. Immediately after the start of the operation of the cooling system, the timer count value TM1 is less than the predetermined time value TM10. Therefore, “No” is determined in Step M14, and the cooling operation control routine of Step M16 is executed.

  In this cooling operation control routine, the microcomputer 21 inputs the internal temperature detected by the internal temperature sensor 17 and continues to operate the electric compressor 11 until the internal temperature becomes a predetermined lower limit temperature or less. The refrigerant is pumped by the operation of the electric compressor 11, and the refrigerant continues to circulate through the condenser 12, the throttle 13, the evaporator 14, and the electric compressor 11. During the circulation of the refrigerant, the evaporator 14 cools the inside of the refrigerator. Thereby, the internal temperature falls.

  When the internal temperature becomes equal to or lower than the predetermined lower limit temperature, the microcomputer 21 stops the operation of the electric compressor 11. Thereby, the circulation of the refrigerant in the electric compressor 11, the condenser 12, the throttle 13, and the evaporator 14 described above is stopped, and the internal cooling by the evaporator 14 is stopped, so that the internal temperature gradually increases. When the internal temperature becomes equal to or higher than a predetermined upper limit temperature (a temperature higher than the lower limit temperature) due to this temperature increase, the microcomputer 21 starts the operation of the electric compressor 11. Therefore, the internal temperature begins to decrease again due to the cooling of the evaporator 14. As a result, the interior temperature is maintained within a predetermined temperature range while the interior temperature changes between the lower limit temperature and the upper limit temperature. Further, the internal temperature is displayed on the display 12 by the execution of the cooling operation control routine of step M16.

  On the other hand, when the cooling system is started, the microcomputer 41 of the slave cooling unit SUN also starts executing the slave control program shown in FIG. 5 repeatedly every predetermined short time. The execution of the slave control program is started in step S10, and it is determined in step S12 whether or not the defrost flag DF2 is “0”. The defrost flag DF2 indicates that the cooling device 30 is in the cooling operation by “0”, and “1” indicates that the cooling device 30 is in the defrosting operation, and is initially set to “0” by executing an initial program (not shown). Has been. Immediately after the start of the operation of the cooling system, the defrost flag DF2 is set to “0”. Therefore, “Yes” is determined in step S12, and the process proceeds to steps S14 and S16.

  In step S14, it is determined whether or not the defrost input (the potential of the terminal T41) input from the communication control unit 43 has changed from the high level “1” to the low level “0”. In step S16, it is determined whether or not the defrost input is at a high level. This defrost input is controlled by the electric control device 20 of the master cooling unit MUNT. As will be described in detail later, while the cooling device 10 of the master cooling unit MUNT is kept at the low level during the cooling operation, the same cooling is performed. When the device 10 enters the defrosting control operation, it is changed to a high level. Therefore, immediately after the start of the operation of the cooling system, it is determined “No” in steps S14 and S16, and the process proceeds to step S18.

  In step S18, it is determined whether timer count value TM2 is equal to or greater than predetermined time value TM20. This timer count value TM2 is counted up as time elapses by executing a program (not shown), and measures the time from the start of the previous defrosting operation to the start of the next defrosting operation. Is initially set to “0”. The predetermined time value TM20 is set by the user by executing a program (not shown), and normally, as in the case of the master cooling unit MUNT, the defrosting control is executed every time outside the user's business hours. It is set to a value that represents a simple time interval. However, in this cooling system, it is assumed that after the defrost control of the master cooling unit MUNT is performed first, the defrost control of the slave cooling unit SUN is continuously performed, so the defrosting of the slave cooling unit SUNT is performed. It is good to set the value which represents the time interval of the defrost operation after the first time as predetermined time value TM20 while setting the first defrost start time so that the defrost control of slave cooling unit SUN may be performed after control. . Also in the case of the slave cooling unit SUN, immediately after the start of the operation of the cooling system, the timer count value TM2 is less than the predetermined time value TM20. A cooling operation control routine is executed.

  Also in this cooling operation control routine, as in the case of the master cooling unit MUNT described above, the microcomputer 41 sets the internal temperature below the predetermined lower limit temperature based on the internal temperature detected by the internal temperature sensor 37. The electric compressor 11 is operated until the temperature reaches the predetermined value, and the operation of the electric compressor 11 is stopped when the internal temperature becomes a predetermined lower limit temperature or less. When the internal temperature reaches or exceeds a predetermined upper limit temperature (a temperature higher than the lower limit temperature), the microcomputer 41 starts the operation of the electric compressor 11. Therefore, by cooling the evaporator 34, the interior temperature is maintained within a predetermined temperature range while the interior temperature changes between the lower limit temperature and the upper limit temperature. That is, the slave cooling unit SUN cools the interior together with the master cooling unit MUNT. Also in this case, the internal temperature is displayed on the display 42.

  When the timer count value TM1 becomes equal to or greater than the predetermined time value TM10 during the cooling operation described above, it is determined as “Yes” in step M14 of FIG. 2, and the process proceeds to the defrosting start control routine of step M14. This defrosting start control routine is shown in detail in FIG. 3, and its execution is started in step M30, and the defrost output is set to a high level in step M32 (see defrost output in FIG. 8). Specifically, the potential of the communication line 51 is kept at a high level by outputting a low level signal to the base of the transistor TR1 of the communication control unit 23 to turn off the transistor TR1. The high level of the communication line 51 is maintained until the next processing for setting the defrost output to the low level is executed. After the process of step M32, the timer count value TM1 is cleared to “0” in step M33.

  Next, in step M34, the timer count value STM1 is cleared to “0”. The timer count value STM1 is counted up as time elapses by executing a program (not shown), and measures the time from when the defrost output is set to a high level to when the defrosting operation is actually started. Next, in step M36, it is determined as “No” until the timer count value STM1 becomes equal to or greater than the predetermined time value STM10, and the program is stopped. The predetermined time value STM10 is a relatively short time, for example, about 10 seconds. Then, when the time represented by the predetermined time value STM10 has elapsed from the process of step M34, it is determined as “Yes” in step M36, and the processes after step M38 are executed.

  In step M38, the cooling operation is stopped. Specifically, when the electric compressor 11 is operating, the operation of the electric compressor 11 is stopped. If the electric compressor 11 is not operating, the state is maintained. Next, by energizing the defrost heater 15 in step M40, the evaporator 14 starts to be overheated (see the master side defrost heater in FIG. 8). In step M42, the display state of the display 22 is switched from the internal temperature display to the defrost display. In the defrost display state, for example, the characters “DF” are displayed on the display 22. After the processing in step M42, the defrost flag DF1 is set to “1” in step M44, and the execution of the defrosting start control routine is ended in step M46.

  When the defrost flag DF1 is set to “1”, when the master control program of FIG. 2 is executed next, “No” is determined in step M12, and the defrosting stop control routine in step M20 is executed. Start running. As long as the defrost flag DF1 is kept at “1”, the defrosting stop control routine continues to be executed. This defrosting stop control routine is shown in detail in FIG. 4, and its execution is started in step M50, and it is determined in step M52 whether or not the defrosting thermo switch 16 is in the OFF state. The defrost thermo switch 16 is in an ON state when frost is attached to the evaporator 14 and the temperature of the evaporator 14 is still low. Therefore, it determines with "No" in step M52, and complete | finishes execution of a defrost stop control routine in step M62. As long as the defrost thermo switch 16 is in the ON state, it is determined as “No” in step M52, so the defrost heater 15 is maintained in the energized state.

  By maintaining the energization of the defrost heater 15, the temperature of the evaporator 14 gradually increases, and frost attached to the evaporator 14 is removed. When the temperature of the evaporator 14 is increased and frost is removed and the defrost thermoswitch 16 is switched to the OFF state, it is determined as “Yes” in Step M52, and the processes after Step M54 are executed. . In step M54, the defrosting heater 15 is de-energized, and in step M56, the display 22 is switched to the display state of the internal temperature. Next, in step M58, the defrost output is set to low level "0". Specifically, the potential of the communication line 51 is kept at a low level by outputting a high level to the base of the transistor TR1 of the communication control unit 23 and turning on the transistor TR1. The low level of the communication line 51 is maintained until the next processing for setting the defrost output to the high level is executed. Thereby, the defrosting operation in the master cooling unit MUNT is completed.

  After the process of step M58, the defrost flag DF1 is changed to “0” in step M60, and the execution of the defrosting stop control routine is ended in step M62. When the defrost flag DF1 is set to “0”, both are determined “No” in step M12 of the master control program of FIG. 2, and the process proceeds to step M14. In step M14, as described above, the timer count value TM1 is compared with the predetermined time value TM10, but this timer count value TM1 is cleared to “0” just before the start of the defrosting and is still a small value. , “No” is determined, and the cooling operation control routine of Step M16 is started to be executed.

  On the other hand, as described above, when the defrost output in the master cooling unit MUNT changes from the high level to the low level, the microcomputer 41 in the slave cooling unit SUN determines “Yes” in step S14 of the slave control program of FIG. Then, the execution of the defrosting start control routine in step S22 is started.

  This defrosting start control routine is shown in detail in FIG. 6, and its execution is started in step S30, and the cooling operation is stopped in step S32. Specifically, when the electric compressor 31 is operating, the operation of the electric compressor 31 is stopped. If the electric compressor 31 is not operating, the state is maintained. After the process of step S32, the timer count value TM2 is cleared to “0” in step S33. Next, by supplying power to the defrost heater 35 in step S34, the evaporator 34 starts to be overheated (see the slave side defrost heater in FIG. 8). In step S36, the display state of the display 42 is switched from the internal temperature display to the defrost display. In the defrost display state, for example, the character “DF” is displayed on the display 42. After the processing in step S36, the defrost flag DF2 is set to “1” in step S38, and the execution of the defrosting start control routine is ended in step S40.

  When the defrost flag DF2 is set to “1”, when the slave control program in FIG. 5 is executed next, “No” is determined in step S12, and the defrosting stop control routine in step S24 is executed. Start running. As long as the defrost flag DF2 is maintained at “1”, the defrosting stop control routine continues to be executed. This defrost stop control routine is shown in detail in FIG. 7, and its execution is started in step S50, and it is determined in step S52 whether or not the defrost input is at a high level. If the defrost input is not at the high level, “No” is determined in step S52, and the processing from step S54 onward is executed.

  In step S54, it is determined whether or not the defrost thermo switch 36 is in an OFF state. As in the case of the defrost thermo switch 16, the defrost thermo switch 36 is in the on state when frost is attached to the evaporator 34 and the temperature of the evaporator 34 is still low. Therefore, first, it determines with "No" in step S54, and complete | finishes execution of a defrost stop control routine in step S62. As long as the defrost thermo switch 36 is in the on state, it is determined “No” in step S52, so the defrost heater 35 is maintained in the energized state.

  Also in the case of this slave cooling unit SUN, when the temperature of the evaporator 34 is raised and frost is removed and the defrosting thermo switch 36 is switched to the OFF state, it is determined as “Yes” in step S54, and the step The processing after S56 is executed. In step S56, the defrosting heater 35 is de-energized, and in step S58, the display 42 is switched to the display state of the internal temperature. Thereby, the defrosting operation in the slave cooling unit SUN is completed. After the process of step S58, the defrost flag DF2 is changed to “0” in step S60, and the execution of this defrosting stop control routine is ended in step S62. When the defrost flag DF2 is set to “0”, as described above, both of the steps “S12” and “S18” in the slave control program of FIG. It is determined as “No” and the cooling operation control routine of step S16 is continued to be executed.

  Actually, the predetermined time value TM20 is set to substantially the same value as the predetermined time value TM10, the defrosting of the slave cooling unit SUN is always executed after the defrosting of the master cooling unit MUNT, and the timer count value TM2 is Since the defrosting of the slave cooling unit SUN is cleared to “0”, the timer count value TM2 is not counted up to the predetermined time value TM20.

  Next, the case where the defrosting of the master cooling unit MUNT is started during the defrosting operation of the slave cooling unit SUN for some reason will be described. In this case, since the defrost input is at the high level, it is determined as “Yes” in step S52 of FIG. 7, and the processes of steps S56 to S60 described above are executed. Therefore, in this case, the defrosting operation in the slave cooling unit SUN is forcibly terminated. On the other hand, in the master cooling unit MUNT, as described above, when the timer count value TM1 reaches the predetermined time value TM10 by the processing of steps M34 and M36 in FIG. Since it shifts to defrosting operation after STM10, master cooling unit MUNT and slave cooling unit SUN do not defrost simultaneously.

  Furthermore, when the master cooling unit MUNT is performing a defrosting operation, the defrost input of the slave cooling unit SUNT is at a high level. Therefore, in this case, it is always determined “Yes” in step S16 of FIG. 5, and the cooling operation control routine of step S20 is executed. In other words, since the determination process of step S18 is not executed, the defrosting operation is not started in the slave cooling unit SUNT.

  As described above, according to the first embodiment, since the defrosting operation is not performed simultaneously in both the cooling units MUNT and SUN, simultaneous energization to both the defrosting heaters 15 and 35 of both the cooling units MUNT and SUN is performed. This avoids excessive power consumption. In addition, since the defrosting of the slave cooling unit SUNT is started following the completion of the defrosting of the master cooling unit MUNT by the processing of Step M58 of FIG. 4 and Step S14 of FIG. 5, both cooling units MUNT, The total defrosting time of each SUN can be made relatively short, and the time from the start of defrosting of the master cooling unit MUNT to the end of defrosting of the slave cooling unit SUN can be shortened. It is good to be able to prevent defrosting in time.

b. Second Embodiment Next, a cooling system according to a second embodiment obtained by modifying a part of the first embodiment will be described. As shown in FIG. 9, this cooling system deforms the communication control units 23 and 43 in the electric control devices 20 and 40 of the master cooling unit MUNT and the slave cooling unit SUN, and also has an alarm device in the electric control device 40. 44.

  In the communication control unit 23, a pulse train generator 23a, inverter circuits INV1, INV2, AND circuits AND1, AND2, and an OR circuit OR1 are added to the configuration of the communication control unit 23 of the first embodiment. The pulse train generator 23a outputs a pulse train signal having a duty ratio shorter than the low level time, that is, a duty ratio smaller than at least 50%, as shown in FIG. When the microcomputer 21 outputs a low level signal, the inverter circuit INV1 and the AND circuit AND1 supply the pulse train signal shown in FIG. 12B to the base of the transistor TR1 via the OR circuit OR1. In this case, the potential change of the terminal T21, the communication line 51, and the terminal T41 is a pulse train signal having a high level time longer than the low level time, that is, a duty ratio larger than at least 50%, as shown in FIG. It becomes. The inverter circuit INV2 and the AND circuit AND2 supply the pulse train signal shown in FIG. 12A to the base of the transistor TR1 through the OR circuit OR1 when the microcomputer 21 outputs a high level signal. In this case, potential changes at the terminal T21, the communication line 51, and the terminal T41 are pulse train signals as shown in FIG.

  The communication control unit 43 adds a pulse waveform converter 43b to the configuration of the communication control unit 43 of the first embodiment. The pulse waveform converter 43b converts a pulse train signal having a different duty ratio into a high level signal and a low level signal and outputs the converted signal. The pulse train signal shown in FIG. 12A having a large duty ratio is converted into a high level signal. Output. Further, the pulse train signal shown in FIG. 12B having a small duty ratio is converted into a low level signal and output. Such a pulse waveform converter 43b includes, for example, an integrator and a comparator. In this case, the output of the pulse waveform converter 43b is input to the microcomputer 41 as a signal indicating defrosting of the master cooling unit MUNT in the first embodiment. On the other hand, the signal at the terminal T41 is also directly supplied to the microcomputer 41. This signal is used for detecting an abnormality in the communication lines 51 and 52. The alarm device 44 notifies the user of an abnormality in the communication line by voice or display. Instead of or in addition to the alarm device 44, the display device 42 may notify the user of an abnormality in the communication line.

  Further, in the second embodiment, the microcomputer 21 of the master cooling unit MUNT is similar to the master control program of FIG. 2 (the defrosting start control program of FIG. 3 and the defrosting stop of FIG. 4) similar to the first embodiment. Control program). However, the slave cooling unit SUN executes the slave control program of FIG. However, this slave control program is obtained by inserting steps S02 to S06 between steps S10 and S12 of the slave control program of FIG. 5 as in the first embodiment. As the defrosting start control program and the defrosting stop control program that are respectively executed at, the defrosting start control program of FIG. 6 and the defrosting stop control program of FIG. 7 similar to those of the first embodiment are used. The other points are the same as those in the first embodiment, so the same reference numerals as those in the first embodiment are given and the description thereof is omitted.

  Next, the operation of the second embodiment configured as described above will be described. In the second embodiment, information from the master cooling unit MUNT is sent to the slave cooling unit SUN via the communication line 51. In this case, a pulse train signal shown in FIG. 12A, that is, a pulse train signal having a large duty ratio is employed as a signal representing the defrosting control state of the master cooling unit MUNT. In other cases, the pulse train signal shown in FIG. 12B, that is, a pulse train signal having a small duty ratio is employed.

  That is, at the time of switching from the defrost control state to the cooling operation state in the master cooling unit MUNT, when the microcomputer 21 outputs a high level signal as in the first embodiment in step M58 of FIG. 4, the inverter circuit INV2 As a result, the AND circuit AND2 supplies the pulse train signal shown in FIG. 12A to the base of the transistor TR1 via the OR circuit OR1. Therefore, the signal on the communication line 51 has a small duty ratio as shown in FIG. On the other hand, at the time of switching from the cooling operation state to the defrosting control state in the master cooling unit MUNT, when the microcomputer 21 outputs a low level signal as in the first embodiment in step M32 of FIG. 3, the inverter circuit INV1 As a result, the AND circuit AND1 supplies the pulse train signal shown in FIG. 12B to the base of the transistor TR1 via the OR circuit OR1. Therefore, the signal on the communication line 51 has a large duty ratio as shown in FIG. Signals on the communication line 51 representing the cooling operation state and the defrost control state are shown as defrost output physical values (defrost input physical values) in FIG.

  This signal is supplied to the pulse waveform converter 43b of the slave cooling unit SUNT. The pulse waveform converter 43b converts the signal on the communication line 51 into a high level signal or a low level signal and supplies it to the microcomputer 41. . In this case, the pulse waveform converter 43b converts a signal having a small duty ratio into a low level signal and converts a signal having a large duty ratio into a high level signal. Therefore, the microcomputer 41 has the same defrost control state of the master cooling unit MUNT as shown in FIG. 11 as the defrost output logic value (defrost input logic value), which is the same as in the first embodiment. A signal is supplied. As a result, the master cooling unit MUNT and the slave cooling unit SUNT perform the cooling operation and the defrosting operation as in the first embodiment.

  However, the microcomputer 41 of the slave cooling unit SUN executes a process different from that of the first embodiment only in steps S02 to S06 in FIG. In step S02, a signal on the communication line 51 is directly input from the terminal T41, and a pulse train signal input determination process is executed. In this pulse train signal input determination process, it is determined whether the input signal changes between a high level and a low level within a predetermined short time. This determination process is performed as long as the communication lines 51 and 52 are not short-circuited or disconnected, whether the master cooling unit MUNT is in the cooling operation or in the defrosting operation. The change between high level and low level within a short time is utilized. Therefore, if the input signal changes between a high level and a low level within a predetermined short time, it is determined that the communication lines 51 and 52 are normal. On the other hand, if a short circuit abnormality has occurred in the communication lines 51 and 52, the potential of the terminal T41 is kept at the ground potential, that is, the low level. If a disconnection abnormality has occurred in the communication lines 51 and 52, the potential of the terminal T41 is kept at the power supply potential + V, that is, the high level. Therefore, if the input signal does not change between the high level and the low level within a predetermined short time and continues to be maintained at the low level or the high level, an abnormality in the communication lines 51 and 52 is determined. .

  If it is determined by the determination process that the communication lines 51 and 52 are normal, “No” is determined in step S04, and the process proceeds to step S12. On the other hand, if it is determined by the determination process that the communication lines 51 and 52 are abnormal, “Yes” is determined in step S04, and the alarm device 44 is activated in step S06 to issue an alarm. Then, the process after step S12 mentioned above is performed.

  Also in the second embodiment that operates as described above, the master cooling unit MUNT and the slave cooling unit SUN operate in the same manner as in the first embodiment with respect to the cooling operation and the defrosting operation. The same effect as the form can be expected. In addition, the processing of steps S02 to S06 in FIG. 10 determines whether the communication lines 51 and 52 are abnormal in a short time corresponding to one cycle of the pulse train signal generated from the pulse train generator 23a. Since the alarm is generated by the user 44, the user can quickly cope with the abnormality. Instead of the alarm device 44, the display device 42 may display an abnormality in the communication lines 51 and 52.

c. Third Embodiment Next, a cooling system according to a third embodiment obtained by modifying a part of the first embodiment will be described. In this cooling system, as shown in FIG. 13, the communication control units 23 and 43 in the electric control devices 20 and 40 of the master cooling unit MUNT and the slave cooling unit SUN are modified so that the electric control devices 20 and 40 are connected. It is possible to communicate with each other.

  The communication control unit 43 further includes an NPN transistor TR2 in addition to the case of the first embodiment, and transmits information to the electric control device 20 of the master cooling unit MUNT. The collector of the transistor TR is connected to the terminal T43, its emitter is connected to the terminal T44, and its base is connected to the microcomputer 41. In addition to the case of the first embodiment, the communication control unit 23 further includes a resistor R2 that is connected to the DC power source + V at one end and connected to the terminal T23 and the microcomputer 21 at the other end. Information from the SUN electric control device 40 is received. The terminal T24 is grounded. Further, the terminal T23 and the terminal T43 are connected by a communication line 53, and the terminal T44 and the terminal T24 are connected by a communication line 54.

  Furthermore, in the third embodiment, the microcomputer 21 of the master cooling unit MUNT executes the master control program shown in FIG. In this master control program, the defrosting stop control routine of FIG. 4 similar to that of the first embodiment is executed, but the defrosting start control of FIG. 15 is different from the first embodiment regarding the defrosting start control routine. Run the routine. Further, the microcomputer 41 of the slave cooling unit SUN executes the slave control program of FIG. 5 similar to the first embodiment. However, in this slave control program, the defrosting start control routine of FIG. 16 and the defrosting start control routine of FIG. 17 different from the first embodiment are executed. Since the other points are the same as those in the first embodiment, the same reference numerals as those in the first embodiment are given and the description thereof is omitted.

  Next, the operation of the third embodiment configured as described above will be described. In the third embodiment, similarly to the first embodiment, the slave cooling unit SUN enters the defrosting operation immediately after the defrosting of the master cooling unit MUNT is the same. However, in the third embodiment, since transmission from the slave cooling unit SUNT to the master cooling unit MUNT is also possible, the start of the defrosting operation in the master cooling unit MUNT is prohibited during the defrosting operation of the slave cooling unit SUNT. Is done. Further, in order to prohibit the start of the defrosting operation in the master cooling unit MUNT, it is unnecessary to perform the defrosting operation stop control during the defrosting operation of the slave cooling unit SUNT and the delay control of the defrosting operation in the master cooling unit MUNT. Become.

  For such an operation, in the microcomputer 41 of the slave cooling unit SUN, in the defrost start control routine of FIG. 16 executed by the defrost control program of FIG. 5 similar to the first embodiment, The process of step S42 is inserted between both processes of S30 and S32 so that the defrost output signal is set to a high level. Specifically, the microcomputer 41 inputs a low level signal to the base of the transistor TR2, and sets the communication line 53 to a high level. Further, in the defrost stop control routine of FIG. 17 executed by the defrost control program of FIG. 5, the process of step S64 is inserted between the processes of steps S58 and S60, and the defrost output signal is set to the low level. It has come to be. Specifically, the microcomputer 41 inputs a high level signal to the base of the transistor TR2, and sets the communication line 53 to a low level.

  Further, in order to prohibit the defrosting operation in the master cooling unit MUNT during the defrosting operation of the slave cooling unit SUNT, in the master control program of FIG. 14, the defrost input (communication line 53) is performed between the processes of steps M12 and M14. ) Is at a high level, the determination process for proceeding to the cooling operation in step M16 is inserted without executing the determination process for starting defrosting in step M14. Furthermore, in the defrosting start control routine of FIG. 15 executed by this master control program, a step for delaying the defrosting start is compared with the defrosting start control routine (FIG. 3) of the first embodiment. The processing of M34 and M36 is omitted. FIG. 18 is a time flowchart showing both defrost output signals (defrost input signals) on the communication lines 51 and 52 and the state of the defrosting heaters in both cooling units MUNT and SUNT.

  Also in the third embodiment that operates as described above, the defrosting operation of the master cooling unit MUNT and the slave cooling unit SUN is not performed simultaneously and is performed continuously, and thus the same effect as in the first embodiment. Can be expected. In the third embodiment, bidirectional communication between the master cooling unit MUNT and the slave cooling unit SUN is possible, and the defrosting operation in the master cooling unit MUNT is started when the slave cooling unit SUN is defrosting. Since it is prohibited and the defrosting operation stop control during the defrosting operation of the slave cooling unit SUN and the delay control of the defrosting operation in the master cooling unit MUNT are unnecessary, the cooling of the master cooling unit MUNT and the slave cooling unit SUNT is unnecessary. The control mode of operation and defrosting operation can be simplified.

d. Fourth Embodiment Next, in the third embodiment that enables bidirectional communication between the master cooling unit MUNT and the slave cooling unit SUNT, the communication using the pulse train signal described in the second embodiment is performed for the bidirectional communication. A cooling system according to the applied fourth embodiment will be described. As shown in FIG. 19, this cooling system deforms the communication control units 23 and 43 in the electric control devices 20 and 40 of the master cooling unit MUNT and the slave cooling unit SUN of the third embodiment and performs electric control. Alarm devices 24 and 44 are provided in the devices 20 and 40.

  In the communication control unit 23, a pulse train generator 23a, inverter circuits INV1, INV2, and AND circuits AND1, AND2 similar to the communication control unit 23 of the second embodiment are compared with the communication control device 23 of the third embodiment. And OR circuit OR1 is added. The alarm device 44 connected to the microcomputer 41 is the same as that of the second embodiment. In the communication controller 43, the pulse train generator 43a, the inverter circuits INV3 and INV4, the AND circuit AND3, which function in the same manner as the pulse train generator 23a, the inverter circuits INV1 and INV2, the AND circuits AND1 and AND2, and the OR circuit OR1, respectively. AND4 and OR circuit OR2 are added. The alarm device 24 connected to the microcomputer 21 has the same function as the alarm device 44.

  Also in this case, the output of the pulse waveform converter 43b is input to the microcomputer 41 as a signal indicating defrosting of the master cooling unit MUNT in the third embodiment. On the other hand, a signal at the terminal T41 is also supplied to the microcomputer 41. This signal is used for detecting an abnormality in the communication lines 51 and 52. The output of the pulse waveform converter 23b is input to the microcomputer 21 as a signal representing defrosting of the slave cooling unit SUN in the third embodiment. On the other hand, a signal at the terminal T21 is also supplied to the microcomputer 21, and this signal is used for detecting an abnormality in the communication lines 53 and 54.

  Furthermore, in the fourth embodiment, the microcomputer 21 of the master cooling unit MUNT executes the master control program shown in FIG. However, the defrosting start control routine and the defrosting stop control routine of this master control program are the same as the defrosting start control routine of FIG. 15 and the defrosting stop control routine of FIG. 4 similar to the third embodiment. The slave cooling unit SUNT executes the slave control program of FIG. 10 (including the defrosting start control routine of FIG. 16 and the defrosting stop control routine of FIG. 17) similar to the third embodiment. Since the other points are the same as those of the third embodiment, the same reference numerals as those of the third embodiment are given and the description thereof is omitted.

  Next, the operation of the fourth embodiment configured as described above will be described. In 4th Embodiment, the information from the master cooling unit MUNT is supplied to the slave cooling unit SUN via the communication line 51, and is shown to FIG. 12 (A) as a signal showing defrosting of the master cooling unit MUNT. A pulse train signal, that is, a pulse train signal having a large duty ratio is employed. In other cases, the pulse train signal shown in FIG. 12B, that is, a pulse train signal having a small duty ratio is employed. Regarding the information supplied from the slave cooling unit SUNT to the master cooling unit MUNT via the communication line 53, that is, the signals indicating the defrosting and other states, two types of pulse train signals having different duty ratios are the same as described above. Used.

  Therefore, also in the fourth embodiment, similarly to the third embodiment, the cooling operation and the defrosting operation in the master cooling unit MUNT and the slave cooling unit SUN are controlled. FIG. 21 shows the defrost output logical value, the defrost output physical value, and the control state of the defrost heater 15 by the master cooling unit MUNT, and also the defrost output logical value, the defrost output physical value, and the defrost heater 35 by the slave cooling unit SUNT. Indicates the control state. Further, in the slave cooling unit SUN, the processing of steps S02 to S06 of the slave control program of FIG. 10 described above detects the short circuit and disconnection of the communication line 51 in the same manner as in the second embodiment, and also provides an alarm. Processing is done.

  On the other hand, in the master cooling unit MUNT, the microcomputer 21 executes the master control program of FIG. This master control program is obtained by adding the processes of steps M02 to M06 between the processes of steps M10 and M12 of the master control program of FIG. 14 of the third embodiment. And the process of step M02-M06 respond | corresponds to the process of step S02-S06 of the slave control program of FIG. 10 of the said 2nd Embodiment. However, in this case, since the microcomputer 21 executes the pulse train signal input process based on the signal at the terminal T23, the short circuit and the disconnection of the communication lines 53 and 54 are detected. The user is alerted.

  Therefore, in the fourth embodiment, the master cooling unit MUNT and the slave cooling unit SUN operate in the same manner as in the third embodiment with respect to the cooling operation and the defrosting operation. Can be expected. Further, the processing of steps S02 to S06 in FIG. 10 and steps M02 to M06 in FIG. 20 determines the abnormality of the communication lines 51 to 54 in a short time, and an alarm is generated by the alarm devices 24 and 44 when the abnormality is determined. Therefore, the user can quickly cope with the abnormality. In this case as well, an abnormality in the communication lines 51 to 54 may be displayed on the display devices 22 and 42 instead of or in addition to the alarm devices 24 and 44.

  The first to fourth embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the object of the present invention. is there.

  For example, in each of the above embodiments, the microcomputer 41 of the slave cooling unit SUN also executes the time counting process for starting the defrosting operation independently of the master cooling unit MUNT. However, unless an abnormality occurs on the master cooling unit MUNT side, the defrosting operation of the slave cooling unit SUN is instructed by the microcomputer 21 of the master cooling unit MUNT at the end of the defrosting operation by the master cooling unit MUNT. Therefore, the time counting process for the defrosting operation by the microcomputer 41 of the slave cooling unit SUN can be omitted. In this case, the process in step S18 in FIGS. 5 and 10 and the process in step S33 in FIGS. 6 and 16 may be omitted.

It is a schematic block diagram which shows the whole cooling system which concerns on 1st Embodiment of this invention. It is a flowchart which shows the master control program which concerns on 1st and 2nd embodiment of this invention, and is performed by the microcomputer of the master cooling unit of FIG. 1 and FIG. 3 is a flowchart showing details of a defrosting start control routine in the master control program of FIG. 2 according to the first and second embodiments of the present invention. It is a flowchart which shows the detail of the defrost stop control routine in each master control program of FIG.2, FIG.14 and FIG.20 regarding 1st thru | or 4th embodiment of this invention. 14 is a flowchart showing a slave control program executed by the microcomputer of the slave cooling unit of FIGS. 1 and 13 according to the first and third embodiments of the present invention. FIG. 11 is a flowchart showing details of a defrosting start control routine in each slave control program of FIGS. 5 and 10 according to the first and second embodiments of the present invention. 11 is a flowchart showing details of a defrosting stop control routine in each slave control program of FIGS. 5 and 10 according to the first and second embodiments of the present invention. It is a time chart which concerns on 1st Embodiment of this invention and shows the state of the defrost heater in a defrost output by a master cooling unit, a master cooling unit, and a slave cooling unit. It is a schematic block diagram which shows the whole cooling system which concerns on 2nd Embodiment of this invention. 10 is a flowchart showing a slave control program executed by the microcomputer of the slave cooling unit of FIG. 9 according to the second and fourth embodiments of the present invention. It is a time chart which concerns on 2nd Embodiment of this invention and shows the state of the defrost heater in a defrost output logic value and defrost output physical value by a master cooling unit, and both the cooling units. It is an enlarged view of the A part and the B part of the defrost output physical value of FIG. It is a schematic block diagram which shows the whole cooling system which concerns on 3rd Embodiment of this invention. It is a flowchart which shows the master control program which concerns on 3rd Embodiment of this invention and is performed by the microcomputer of the master cooling unit of FIG. It is a flowchart which shows the detail of the defrost start control routine in each master control program of FIG. 14 and FIG. 20 concerning 3rd and 4th embodiment of this invention. FIG. 11 is a flowchart showing details of a defrosting start control routine in each slave control program of FIGS. 5 and 10 according to the third and fourth embodiments of the present invention. 11 is a flowchart showing details of a defrosting stop control routine in each slave control program of FIGS. 5 and 10 according to the third and fourth embodiments of the present invention. It is a time chart which concerns on 3rd Embodiment of invention and represents the state of each defrost output by both cooling units, and the defrost heater in both the cooling units. It is a schematic block diagram which shows the whole cooling system which concerns on 4th Embodiment of this invention. FIG. 20 is a flowchart illustrating a master control program executed by the microcomputer of the master cooling unit in FIG. 19 according to the fourth embodiment of the present invention. It is a time chart which concerns on 4th Embodiment of this invention, and shows the state of each defrost output logic value and each defrost output physical value by both cooling units, and the defrost heater in both the cooling units.

Explanation of symbols

MUNT: Master cooling unit, SUN: Slave cooling unit, 10, 30 ... Cooling device, 11, 31 ... Electric compressor, 12, 32 ... Condenser, 13, 33 ... Throttling, 14, 34 ... Evaporator, 15, 35 Defrosting heater, 16, 36 ... Defrosting thermoswitch, 20, 40 ... Electric control device, 21, 41 ... Microcomputer, 23, 43 ... Communication control unit, 23a, 43a ... Pulse train generator, 23b, 43b ... Pulse Waveform converter, 51-54 ... Communication line

Claims (8)

An evaporator that cools the interior by supplying refrigerant, a compressor that pumps the refrigerant to the evaporator, a cooling device that has defrosting means for removing frost attached to the evaporator, and the compressor and defrosting means A cooling system having first and second cooling units each comprising an electric control device for controlling the operation of
A communication line that electrically connects both electrical control devices of the first and second cooling units to enable transmission from the electrical control device of the first cooling unit to the electrical control device of the second cooling unit; ,
A signal provided in the electric control device of the first cooling unit to send a signal indicating the end of defrosting by the defrosting means of the first cooling unit to the electric control device of the second cooling unit via the communication line. Frost end notification means;
A defrosting start control means provided in the electric control device of the second cooling unit and starting defrosting by the defrosting means of the second cooling unit in response to the sent signal indicating the end of the defrosting. A defrost control device for a cooling system, comprising: An evaporator that cools the interior by supplying refrigerant, a compressor that pumps the refrigerant to the evaporator, a cooling device that has defrosting means for removing frost attached to the evaporator, and the compressor and defrosting means A cooling system having first and second cooling units each comprising an electric control device for controlling the operation of
A communication line that electrically connects both electrical control devices of the first and second cooling units to enable transmission from the electrical control device of the first cooling unit to the electrical control device of the second cooling unit; ,
A defrost signal provided in the electric control device of the first cooling unit and indicating a defrost control state by the electric control device of the first cooling unit is sent to the electric control device of the second cooling unit via the communication line. Defrost notification means to send;
A defrosting prohibition control means for prohibiting the defrosting operation by the defrosting means of the second cooling unit when receiving a signal representing the sent defrosting control state provided in the electric control device of the second cooling unit; ,
A defrosting start control means that is provided in the electric control device of the second cooling unit and starts defrosting by the defrosting means of the second cooling unit at the end of reception of the signal indicating the sent defrosting control state; A defrosting control device for a cooling system, comprising: In the cooling system defrost control device according to claim 2, further comprising:
Defrosting start timing control that is provided in the electric control device of the first cooling unit and starts defrosting by the defrosting means of the first cooling unit after elapse of a predetermined time from the time of transmission of the signal indicating the defrosting control state. A defrosting control device for a cooling system, characterized in that means is provided.   The defrosting prohibition control unit includes a stopping unit that stops the defrosting operation by the defrosting unit when the defrosting unit of the second cooling unit is performing a defrosting operation. Or the defrost control apparatus of the cooling system described in 3. In the defrost control device for a cooling system according to any one of claims 2 to 4,
The defrost notification means sends a pulse train signal having a different duty ratio to the communication line in the defrost control state and other states by the electric control device,
In the electric control device of the second cooling unit, there is further provided an abnormality determining means for checking the presence of the pulse train signal to be sent and determining the abnormality of the communication line when the pulse train signal is absent. A defrosting control device for a cooling system. An evaporator that cools the interior by supplying refrigerant, a compressor that pumps the refrigerant to the evaporator, a cooling device that has defrosting means for removing frost attached to the evaporator, and the compressor and defrosting means A cooling system having first and second cooling units each comprising an electric control device for controlling the operation of
A communication line that electrically connects the electric control devices of the first and second cooling units to enable mutual communication between the electric control device of the first cooling unit and the electric control device of the second cooling unit. When,
A first signal provided in the electric control device of the first cooling unit and indicating a defrosting by the defrosting means of the first cooling unit is sent to the electric control device of the second cooling unit via the communication line. Defrost notification means;
A second signal that is provided in the electric control device of the second cooling unit and sends a signal indicating defrosting by the defrosting means of the second cooling unit to the electric control device of the first cooling unit via the communication line. Defrost notification means;
A defrosting operation by the defrosting means of the first cooling unit is received at the time of receiving a signal indicating that the defrosting is being sent from the electric control device of the second cooling unit provided in the electric control device of the first cooling unit. First defrosting prohibiting control means for prohibiting;
A defrosting operation by the defrosting means of the second cooling unit is received when receiving a signal indicating that the defrosting is in progress and is sent from the electric control device of the first cooling unit. A second defrosting prohibiting control means for prohibiting;
Defrosting by the defrosting means of the second cooling unit at the end of reception of a signal provided in the electric control device of the second cooling unit and indicating the defrosting sent from the electric control device of the first cooling unit. A defrosting control device for a cooling system, comprising: a defrosting start control means for starting. In the defrost control apparatus of the cooling system according to claim 6,
The first and second defrosting notification means respectively send pulse train signals having different duty ratios to the communication line in the defrosting control state by the electric control device and in other states,
In each of the electric control devices of the first and second cooling units, an abnormality determining means for checking the presence of the pulse train signal to be sent and determining the abnormality of the communication line when the pulse train signal is absent. A defrosting control device for a cooling system, characterized in that each is provided. The defrosting control device for a cooling system according to any one of claims 1 to 7, wherein the defrosting means is a heater that heats the evaporator by energization.

Images