JPH0545043A - Device for controlling indication of malfunction in thermoregulatory machine - Google Patents

Abstract

PURPOSE:To enable easily discovering the cause, when a thermoregulatory machine malfunctions, by a method wherein the detected data describing the malfunction in classified details are written in the sequence of the occurrence of the details in a memory and the data of the malfunction are read out and shown in the sequence. CONSTITUTION:A thermoregulatory machine maintains the temperature of a storage space at a prescribed point by using a microcomputer 20 which controls, on the basis of the storage-space temperature detected by a temperature sensor 23, the intermittent operation of a cooling apparatus comprising an electric compressor 11, condenser 12, throttle 13, and evaporator 16. The microcomputer 20 is capable of detecting malfunctioning of the thermoregulatory machine, such as shutoff of an overload relay 17, activation of a thermometal cutout 25 for a casing, and abnormal temperature in the storage space. Error codes denoting the kinds of such details of malfunction are stored in a RAM 20d in the sequence of their occurrence. The error codes thus stored are read out in the sequence of their occurrence by manipulating an indication- shifting switch 31, up switch 33, and down switch 34 and shown on a storage space- temperature indicator 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant temperature machine such as a refrigerator or a freezer in which the temperature inside the refrigerator is maintained between an upper limit temperature and a lower limit temperature by repeatedly operating and stopping a cooling device. The present invention relates to an abnormality display control device for a thermostatic machine, which controls the display of the abnormality when an abnormality occurs.

[0002]

2. Description of the Related Art Conventionally, as a device of this type, as shown in, for example, Japanese Patent Laid-Open No. 226578/1988, a lamp is extinguished when no abnormality is detected in the thermostatic chamber. It is well known that a lamp is turned on when an abnormality is detected to inform the user of the abnormality of the incubator.

[0003]

However, in the above-mentioned conventional device, the type of abnormality that has occurred is not clear, and after the abnormality has occurred, this abnormality is cured for various reasons and the abnormality is detected. When it disappears, the lamp is turned off, so if one or more failures lead to many abnormalities in a chain, and if some of these abnormalities are healed naturally, past abnormalities will occur. There was a problem that it was difficult to determine the cause of the abnormality because the occurrence state was unknown. The present invention has been made to solve the above problems, and an object thereof is to provide an abnormality display control device for a thermostatic machine that enables easy investigation of the cause even when a plurality of abnormalities occur in a chain. To provide.

[0004]

In order to achieve the above object, the structural features of the invention according to claim 1 are: a temperature sensor for detecting the temperature inside the refrigerator; a cooling device for cooling the inside of the refrigerator; Cooling control means for repeatedly controlling the operation and stop of the cooling device based on the temperature inside the chamber detected by the temperature sensor to maintain the temperature inside the chamber between a predetermined upper limit temperature and a lower limit temperature, and a temperature sensor In a constant temperature machine equipped with a display means for displaying the temperature inside the refrigerator, an abnormality detection means for detecting each of a plurality of types of abnormalities occurring in the constant temperature machine,
The writable storage means, the writing means for writing the abnormality data indicating the type of abnormality in the storage means in the order of occurrence of the abnormality in response to the abnormality detection by the abnormality detection means, and the internal temperature display state of the display means to the abnormal display state A display switching operation switch for switching, a stepping operation switch for advancing a read address to the storage means, and an address stepped by the stepping operation switch when the display state of the display means is switched to the abnormal display state by the switching operation switch Based on the above, there is provided a reading means for sequentially reading each abnormal data in the storage means in the order of occurrence and supplying it to the display means to display the type of abnormality corresponding to the abnormal data on the display means.

Further, the structural feature of the invention according to claim 2 is that in the structure of the invention according to claim 1, a clear operation switch for clearing abnormal data in the storage means in response to an operation is further provided. It is in the provision.

[0006]

In the invention according to claim 1 configured as described above, when an abnormality occurs in the thermostat, the abnormality detecting means detects this abnormality, and the writing means indicates the type of abnormality. Since the data is written in the storage unit in the order of occurrence of the abnormality, when a plurality of abnormalities occur in the thermostat, the storage unit stores the abnormality data representing each of the plurality of abnormalities in the order of occurrence of the abnormality. On the other hand, in this state, when the changeover operation switch is operated to change the display state of the display means to the abnormal display, each abnormal data stored in the storage means is read by the reading means every time the step operation switch is operated, The plurality of abnormalities are sequentially displayed on the display means while being sequentially read out in the order of occurrence and supplied to the display means.

As a result, according to the invention of claim 1, a plurality of abnormalities once generated in the thermostat are generated in the display means each time the stepping operation switch is operated, even if the abnormalities are cured. Since it is displayed in order, even if multiple abnormalities occur in a chain from one or more failures, the user,
A repair person or the like can easily find the essential cause of the abnormality by looking at the types of abnormalities that have occurred in a chain. Moreover,
According to the present invention, since the display means used for displaying the temperature inside the refrigerator is also used for displaying the abnormality, the number of display means can be reduced and the entire apparatus can be configured easily.

According to the invention of claim 2, in addition to the operation of the invention of claim 1, operating the clear operation switch clears the abnormal data stored in the storage means. It

As a result, according to the invention of claim 2, if the cause of the abnormality is investigated, the thermostat is repaired if necessary, and the clear operation switch is operated, the following chain is generated. Since the abnormality will be stored in the storage means,
In addition to the effect of the invention according to the first aspect, it becomes possible to deal with the next abnormality occurrence by a simple operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an entire thermostatic machine such as a refrigerator and a freezer by a block diagram.

This thermostat is an electric compressor 1 provided outside the refrigerator.
1, a condenser 12, a throttle 13, and an evaporator 1 provided in the refrigerator
4 is provided, the refrigerant sent under pressure from the electric compressor 11 is circulated in the above order, and the inside of the refrigerator is cooled by the evaporator 14. Electric power is supplied from the AC power supply 15 to the electric compressor 11 via the normally open contacts x ₁₁ and x _{12 of the} relay 16 and the overload relay 17. The normally open contacts x ₁₁ and x ₁₂ are adapted to be turned on / off by energizing / de-energizing the coil X _{1 of the} relay 16. The overload relay 17 is normally in the on state, and is turned off to interrupt the circuit when an abnormally large current flows.

The discharge port of the electric compressor 11 and the evaporator 1
4, an electromagnetic valve 18 is provided between the upstream side and the upstream side of 4, and hot gas from the electric compressor 11 is supplied to the evaporator 14 when the valve 18 is in conduction. The electromagnetic valve 18 is connected to the AC power source 15 via the normally open contacts x ₂₁ and x ₂₂ of the relay 19, and is set to a conductive state when power is supplied and a non-conductive state when power is not supplied. .. Normally open contacts x _21, x ₂₂ of the relay 19, the relay 1
The ninth coil X ₂ is turned on / off by energizing / de-energizing.

The energization / de-energization of these coils X ₁ and X ₂ is performed by the microcomputer 20 which constitutes an electric control device.
It is controlled by. A DC voltage is supplied to the microcomputer 20 from a power supply circuit 22 connected to the AC power supply 15 via a transformer 21, and the computer 20 operates by the supply of the DC voltage. The DC voltage is also supplied to a display control circuit 26, a display 27, various switches 31 to 35, etc., which will be described later.

The microcomputer 20 has a bus 20a.
ROM20b, CPU20c, R respectively connected to
It is composed of an AM 20d, a timer 20e, and an I / O 20f. The ROM 20b stores a program corresponding to the flowcharts of FIGS.
20c is for executing the above-mentioned program, and is a RAM
Reference numeral 20d temporarily stores variables necessary for executing the program, and in particular, a plurality of storage areas EMEM (i) for storing error codes EC _{1 to} EC ₆ indicating an abnormality type of the thermostat.
An abnormal data memory EMEM (i is about 1 to 20) is provided. The timer 20e measures time, and a predetermined time,
For example, a timer interrupt signal is output every 1 millisecond. The I / O 20f exchanges signals with the outside,
In the same I / O 20f, the coils X _{1 of the} relays 16 and 19 are
X ₂ is connected, and the overload relay 17, the internal temperature sensor 23, the defrost thermo switch 24, the case thermo switch 25, the display control circuit 26, the display 27, the display changeover switch 31, the temperature setting switch 32, and the up switch. Switch 33, down switch 34, and clear switch 35
Are connected.

The inside temperature sensor 23 is provided in the inside of the refrigerator or the freezer, and detects the inside temperature and outputs a detection signal indicating the detected temperature T. The defrost thermoswitch 24 is composed of a temperature-sensitive switch attached to the evaporator 14, and is normally in the ON state (when the cooling device is repeatedly operated and stopped), and the evaporator 14 completes defrosting. It is turned off for the first time when the temperature rises to a certain temperature, and a signal indicating this on / off state is output. The case thermo switch 25 is composed of a temperature sensitive switch attached to the case of the compressor 11, and is normally in an on state, and is turned off when the case becomes abnormally hot. A signal indicating the on / off state. Is output. The display 27 is composed of a liquid crystal display or the like for displaying alphanumeric characters, and is controlled by the display control circuit 26. Further, the overload relay 17 outputs a signal indicating ON / OFF.

The display changeover switch 31 is a display 27.
Is a switch for switching the in-compartment temperature display state to the abnormal display state. The temperature setting switch 32 is a switch for switching the thermostat to an in-compartment temperature setting mode in which the set temperature T _S inside the _refrigerator is arbitrarily changed. The up switch 33 and the down switch 34 are switches used to raise and lower the set temperature T _S in the inside temperature setting mode, and at the same time, the address of the abnormal data memory EMEM is displayed in the abnormal display state of the display 27. It is a switch used to move up and down. The clear switch 35 is a switch for clearing all the stored contents of the abnormal data memory EMEM with one operation.

Next, the operation of the embodiment configured as described above will be described. When a power switch (not shown) is turned on, the CPU 20c starts executing the program in step 100 of FIG. 2, and in step 101 various variables DFTM, D.
CTM, ERRN, I, various flags COLF, DEFF, ERF (1) to ERF (6) and all data stored in the abnormal data memory EMEM are cleared to "0" and the variable J is initialized to "1". After initially setting the set temperature T _S to the standard temperature T ₀ (−3 ° C. for a refrigerator, −18 ° C. for a freezer), step 10
The circulation process consisting of 2 to 114 is repeatedly executed. In the circulation process, the CPU 20c first deenergizes the coil X ₂ of the relay 19 in step 102.
Not energized coil X _2, since the normally open contacts x _21, x ₂₂ of the relay 19 is turned off, the electromagnetic valve 18 is set to a non-conducting state, the hot gas is not supplied to the upstream of the evaporator 14 in this state ..

After the processing of step 102, the CPU 20
c is the defrost timer count value DF at step 103
Whether TM has counted up, that is, the same count value
It is determined whether DFTM has reached a predetermined value (for example, a value representing about 6 to 8 hours). In this case, since the defrost timer count value DFTM has just been initialized to "0", it is determined to be "NO" in step 103, and the CPU 20c sets the defrost flag DEFF to "0" in step 104. Step 10 through the program
Go to 5 or later.

First, various abnormalities have not occurred in the thermostat, and abnormality flags ERF (1) to ER which respectively indicate various abnormalities.
The case where F (6) is set to "0" will be described. In this case, both of the steps 105 and 106 are determined as "YES", and the CPU 20c determines that the step 107
At step 108, it is determined to be "YES" based on the cooling flag COLF initially set to "0", and at step 108, a detection signal indicating the detected temperature T is input from the internal temperature sensor 23,
The same temperature T is 1 degree higher than the set temperature T _S. Upper limit temperature T _S +1
It is determined whether or not (T ≧ T _S +1) or more. In the thermostat, since the internal temperature (detected temperature T) is equal to or higher than the upper limit temperature T _S +1 immediately after the power switch is turned on, the CPU 20c determines “YES” in step 108.
And the coil X _{1 of the} relay 16 is determined in step 109.
Power on, and in step 110, set the cooling flag COLF to "1".
Change to. As a result, the normally open contact x ₁₁ ,
x ₁₂ is set to the ON state, electric power is supplied from the AC power supply 15 to the electric compressor 11, the compressor 11 starts operating, and cold refrigerant is supplied to the evaporator 14 to cool the inside of the refrigerator. Start being done.

Next, the CPU 20c returns the program to step 103, and after the processing of steps 103 to 106, it is judged "NO" based on the cooling flag COLF changed to "1" in step 107, Step 11
The detected temperature T detected by the temperature sensor 23 in 1 is less than the lower limit temperature T _S −1 that is 1 degree lower than the set temperature T _S (T <T
_S −1). In this case, the inside of the refrigerator is immediately after being cooled, and the detected temperature T is the lower limit temperature T _S.
Since it is -1 or more, the CPU 20c causes the step 1
When it is judged to be "NO" in step 11, the program is step 1
Return to 03. After that, the circulation process including steps 103 to 107 and 111 is repeatedly executed. During this circulation process, the coil X _{1 of the} relay 16 is continuously energized, so that the inside of the cold storage is continuously cooled by the evaporator 14, and the internal cold storage temperature (detected temperature T) gradually drops.

In this way, when the detected temperature T falls and becomes lower than the lower limit temperature T _S -1, the CPU 20c causes the step 1
When it is determined to be “YES” in 11, the power supply to the coil X ₁ of the relay 16 is released in step 112, and the cooling flag CFLG is changed to “0” in step 113. As a result, the normally open contacts x ₁₁ and x ₁₂ of the relay 16 are set to the off state,
Since the supply of electric power from the AC power supply 15 to the electric compressor 11 is stopped and the compressor 11 is stopped, the cooling of the inside of the refrigerator by the evaporator 14 is stopped and the detected temperature T starts to rise. Next, the program is returned to step 103, and after the processing of steps 103 to 106, based on the cooling flag COLF set to "0", "YES" in step 107.
Since it is determined that the detected temperature T until equal to or larger than the upper limit temperature T _S +1, CPU 20 c repeatedly executes circulating processing consisting of steps 103-108. Then, when the detected temperature T becomes equal to or higher than the upper limit temperature T _S +1, the CPU 20c determines “YES” in step 108, and starts cooling the inside of the refrigerator by the processes of steps 109 and 110 described above. By the circulation processing including such steps 103 to 113, the operation and stop of the cooling device are repeatedly controlled, and the internal cold storage temperature is maintained between the lower limit temperature T _S −1 and the upper limit temperature T _S +1.

On the other hand, during the circulation processing consisting of the above steps 103 to 113, the CPU 2 is executed every predetermined time (about 1 millisecond).
0c interrupts and executes the "timer interrupt program" consisting of steps 300 to 312 in FIG. In this "timer interrupt program", the display switching timer count value DCTM is incremented by "1" at step 301 every time it is executed, and the display switching switch 3
1 and the temperature setting switch 32 are not turned on and both are judged as "NO" in steps 303 and 304, the display switching timer count value DCTM is set to the predetermined value CT ₂ (about 1) in step 305. Time corresponding to seconds)
If it is determined that the count value DCTM is greater than or equal to the predetermined value CT _{2 in} step 305, "YE
It is determined to be "S", and the "first display routine" of step 307 is executed. The execution of this "first display routine" is started in step 600 of FIG. 9, and the processing of step 613 causes the display switching timer count value DC
Since TM is cleared to "0", this "first display routine" is executed about every 1 second.

In the "first display routine", the abnormality flags ERF (1) to
Since the ERF (6) is still initialized to "0", the variable I is always changed to "0" by the processing of steps 604 to 607 even if the variable I is not "0", and the program step Proceed to 608. Then, in this case, during the circulation process including the steps 103 to 113 (FIG. 2), the defrost flag DE is determined by the process of step 104.
Since FF is continuously set to "0", the above step 608 is performed.
In step 609, the display data indicating the detected temperature T detected by the temperature sensor 23 is output to the display control circuit 26. Then, the display control circuit 26 controls the display 27 based on the display control signal, and the display 27 numerically displays the detected temperature T (for example, “−1.5 ° C.”). This results in step 103
When the operation of the cooling device and the stop of the cooling device are repeatedly controlled by the circulation processing consisting of ~ 113, the temperature inside the refrigerator is displayed in characters on the display 27.

On the other hand, during the circulation processing consisting of steps 103 to 113, the "timer interrupt program"
When the defrost timer count value DETM becomes equal to or larger than the predetermined value CT ₁ (corresponding to about 6 to 8 hours) by the processing of step 301 of FIG. 4 (corresponding to about 6 to 8 hours), the CPU 20c determines “YES” in step 103, Defrost routine "is executed. In this "defrost routine", the defrost flag DE is determined in step 201 of FIG.
After FF is set to "1", step 2 is performed based on the abnormality flags ERF (1) and ERF (2) initially set to "0".
Since YES is determined in both 02 and 203, as long as the defrost thermoswitch 24 is in the ON state, the circulation process including steps 202 to 205 is executed, and the coil of the relay 16 is processed in step 204. Power is continuously applied to X ₁ and the coil X _{2 of the} relay 19. As a result, the normally open contacts x ₁₁ and x ₁₂ of the relay 16 are set to the ON state, and the normally open contacts x ₂₁ and x _{22 of the} relay 19 are also set to the ON state, so that the electric compressor 11 and the electromagnetic valve. Power is supplied from the AC power supply 15 to the compressor 18, and the compressor 1
Hot gas from the evaporator 1 via the electromagnetic valve 17
4 upstream. As a result, the temperature of the evaporator 14 starts to rise.

During the circulation process consisting of steps 202 to 205, as described above, a predetermined time (about 1 millisecond)
The "timer interrupt program" of FIG. 4 is interrupted every time, and at the same time every predetermined time (about 1 second).
“Display control routine” is executed. Then, in this case, the defrost flag DEFF is set in the step 201.
Since it is set to "1" by the processing of (FIG. 3), it is determined to be "NO" in step 608, and step 61
With the processing of 0, display data for displaying that defrosting is being performed is output to the display control circuit 26. As a result, the display control circuit 26 controls the display device 27 based on the display data, and the display device 27 displays the fact that defrosting is in progress (for example, "dF").

By controlling the supply of hot gas to the evaporator 14, the temperature of the evaporator 14 rises and the evaporator 1
The frost adhering to 4 starts to be gradually removed. When the temperature of the evaporator 14 rises to the extent that the defrosting of the evaporator 14 is completed, the defrosting thermoswitch 24 is turned off. At this time, during the circulation processing consisting of 202 to 205, the CPU 20c determines “YES” in step 205, and determines the defrost timer count value in step 206.
DFTM is initialized to "0", and the execution of this "defrost routine" is ended in step 207. Upon completion of the "defrost routine", the CPU 20c returns the program to step 102 of FIG. 2 and again starts repeatedly controlling the operation and stop of the cooling device by the circulation process including steps 103 to 113 described above.

Next, the case of changing the set temperature T _S will be described. In this case, the user sets the temperature setting switch 3
2 is turned on, and in this turned-on state, the up switch 33 or the down switch 34 is turned on a desired number of times. When the temperature setting switch 32 is turned on,
Step 30 of the "timer interrupt program"
It is determined to be "YES" in 3 and the "temperature setting routine" is executed in step 306.

The execution of this "temperature setting routine" is started in step 500 of FIG.
At, it is determined whether the up switch 33 or the down switch 34 has been turned on. In this case, when both the up switch 33 and the down switch 34 are not turned on, both of the steps 501 and 502 are “NO”.
Is determined, the display data representing the set temperature T _S is output to the display control circuit 26 in step 505, and step 50
At 6, the execution of this "temperature setting routine" is completed. As a result, in this case, the set temperature T _S is displayed on the display 27 instead of the internal temperature (detected temperature T).

On the other hand, as described above, the temperature setting switch 3
When the up switch 33 is turned on while 2 is turned on, it is determined to be “YES” in step 501, and “1” is added to the set temperature T _S in step 503, and in step 505. The display data representing the set temperature T _S that has been added is output to the display control circuit 26. If the down switch 34 is turned on while the temperature setting switch 33 is turned on, step 50
It is determined to be “YES” in step 2, and “1” is subtracted from the set temperature T _{S in} step 504, and display data representing the subtracted set temperature T _S is displayed in the display control circuit 26 in step 505. Is output to. In this way, the set temperature T _S is set to the temperature setting switch 32 and the up switch 3.
3 and the down switch 34 are operated, and the changed set temperature T _S is displayed on the display 27.

When the ON operation of the temperature setting switch 32 is released, it is judged as "NO" at the step 303 of the "timer interrupt program" of FIG.
The "temperature setting routine" of step 306 (FIG. 8) is no longer executed. Further, in the repeated operation of the operation and stop of the cooling device, due to the change of the set temperature T _S , the temperature inside the refrigerator rises above and below the changed set temperature T _S by the processing of steps 108 and 111 of FIG. It is kept between the lower limit temperature T _S −1 and the upper limit temperature T _S +1 which are separated by 1 degree.

Next, the case where an abnormality occurs in the thermostat will be described. This abnormality detection is detected by the "abnormality detection routine" in step 302 of the "timer interrupt program" in FIG. First, a case where an excessive current flows through the compressor 11 and the overload relay 17 is turned off will be described.

As described above, when the overload relay 17 is turned off, the "abnormality detection routine" is executed in step 400 of FIG.
The CPU 20c that has started execution of the step determines YES in step 401, and determines NO in step 402 based on the abnormality flag ERF (1) that was previously 0.
In step 403, add "1" to the error occurrence number ERRN,
In step 404, the error code EC ₁ indicating that the overload relay 17 is turned off is written in the abnormal data memory EMEM (ERRN), and in step 405, the abnormal flag ERF (1) is set to “1”.
Set to. In this case, if the error is the first time, the error occurrence number ERRN is set to "1", and the error code EC
₁ is written to the first address EMEM (1) of the abnormal data memory EMEM. In addition, if the above-mentioned abnormality is the second time including other abnormalities to be described later, the number of abnormality occurrences ERRN is “2”.
Error code EC ₁ is set to abnormal data memory E
It will be written to the second address EMEM (2) of MEM.
In this way, the error code EC ₁ is sequentially written in the abnormal data memory EMEM. Then, as long as this abnormality continues, it is determined to be “YES” in both steps 401 and 402, and the program proceeds to step 411.

When the case thermo switch 25 is turned off due to the high temperature of the compressor 11, the CPU 20c makes a "YES" determination at step 411 and the previous "0" at step 412 as in the above case. Abnormal flag that was
Based on the ERF (2) determines "NO", "1" is added to the abnormality generation number ERRN at step 413, the abnormal data Erakodo EC ₂ indicating that the case thermoswitch 25 is turned off at step 414 Write to the memory EMEM (ERRN),
In step 415, the error flag ERF (2) is set to "1". And as long as this abnormality continues, steps 411, 4
Both are determined to be “YES” at 12, and the program proceeds to step 421.

In this way, the overload relay 17 is turned off and the abnormality flag ERF (1) is set to "1", or the compressor 11 becomes hot and the abnormality flag ERF (2) is set to "1". If it is, during the intermittent operation of the compressor 11 by the circulation processing of steps 103 to 113 in FIG.
When it is determined to be “NO” in 06, the energization of the coil X ₁ of the relay 16 is released by the process of step 112.
Further, during the defrosting control by the circulation processing of steps 202 to 205 of FIG. 3, the abnormality flags ERF (1), ERF are set as described above.
When (2) is set to "1", steps 202 and 203
Is determined to be “NO”, and the coil X _{1 of the} relay 16 and the coil X ₁ of the relay 19 are processed by the process of step 208.
The energization of ₂ is released. As a result, when the overload relay 17 is turned off or the temperature of the compressor 11 becomes high, the operation of the thermostat is stopped.

Further, due to the intermittent operation of operating and stopping the cooling device by the circulation processing consisting of the above steps 103 to 113, the detected temperature T is originally set to a temperature between the lower limit temperature T _S -1 and the upper limit temperature T _S +1. It should be kept.
However, for some reason, or becomes 5 degrees above the upper abnormal temperature T _S +5 or higher than the detected temperature T is the set temperature T _S, or become five degrees lower than the lower abnormal temperature T _S -5 than the set temperature T _S Then, these abnormalities are detected in step 4 of FIG.
21 to 425 and steps 431 to 435 are detected, "1" is added to the number of abnormal occurrences ERRN, and an abnormal high temperature is detected in the address EMEM (ERRN) of the abnormal data memory EMEM specified by the number of abnormal occurrences ERRN. Error codes EC ₃ and EC ₄ indicating abnormal low temperature are written, and abnormal flag ER
F (3) and ERF (4) are set to "1".

Further, when the temperature sensor 23 is disconnected, the sensor 23 outputs a value representing + 70 ° C., and when the temperature sensor 23 is short-circuited, the sensor 2
3 outputs a detection signal indicating −40 ° C. Therefore, when the temperature sensor 23 is disconnected or short-circuited, the disconnection or short-circuit is detected by the processing of steps 441 to 445 or steps 451 to 455 in FIG. 7, and "1" is added to the number of abnormal occurrences ERRN. , Error code EC indicating disconnection or short circuit of the temperature sensor 23 at the address EMEM (ERRN) of the abnormal data memory EMEM
_5, EC ₆ is written, the abnormality flag ERF (5), ERF (6 ) is set to "1".

When various kinds of abnormalities occur in the thermostat in this way, the contents of these abnormalities, together with the internal temperature (detected temperature T or during defrosting), are included in the "first timer interrupt program" step 307 of FIG. It is displayed on the display 27 by the processing of the "display routine". This "display control routine" (FIG. 9) is executed approximately every 1 second as described above, and by the processing of steps 601, 602 and 612,
The variable I repeatedly changes by "1" from "0" to "6" corresponding to the number of types of abnormality detection about every one second. While the variable I is changing, it is determined in step 603 whether or not the variable I is "0". If the variable I is "0", the defrost flag is determined by the determination process in step 608 as described above. Depending on the value of DEFF, the display 27 displays the detected temperature T or "dF" during defrosting.

On the other hand, if the variable I is not "0", it is determined to be "NO" in step 603, and steps 604 to
Through the circulation processing of 606, the variable I is sequentially incremented by "1" from the current value until the variable I whose abnormal flag ERF (I) is "1" is found. When abnormality flag ERF (I) is found variable I is "1", it is determined as "NO", the display data representing the error code EC _I corresponding to the variable I in step 611 displayed in step 604 Control circuit 26
Is output to. The display control circuit 26 controls the error display “EC _I ” (where I is 1, 2, 3, ...) On the display 27 according to the display data. Step 61
After the processing of 1, the variable I is incremented by "1" in step 612, and the incremented variable I is used when the next "first display routine" is executed. In this case, FIGS.
Steps 405, 415, 425, 435, 445
By the processing of 455, the error code EC _{1 to} E is sent to the thermostat.
If the abnormality corresponding to C ₆ occurs, the error code EC
With ₁ ～EC ₆ abnormality flag ERF corresponding to (1) ~ERF (6) it is set to "1" and the process of the "first display routine" is performed every about 1 second as described above Therefore, the indicator 27
Indicates that the internal temperature (detected temperature T) or the character “dF” indicating defrosting and the error codes EC _{1 to} EC ₆ indicating the type of abnormality occurring in the thermostat are automatically displayed about every 1 second. Are sequentially switched and displayed.

The case where the above-mentioned various abnormalities of the thermostatic machine are eliminated will be described. In this case, FIGS.
Steps 401, 411, 421, 431, 441 of
It is determined to be "NO" in step 451 and steps 406 and 4 are executed.
By the processing of 16,426,436,446,456,
The corresponding abnormality flags ERF (1) to ERF (6) are changed to "0". As described above, when the abnormality flags ERF (1) to ERF (6) are changed to "0", "YES" is determined in step 604 of the "first display routine" of FIG. Therefore, the error code previously displayed on the display 27
EC _{1 to} EC ₆ are also no longer displayed, and only the error codes EC _{1 to} EC ₆ relating to the currently occurring abnormality are sequentially and repeatedly displayed together with the internal temperature (detected temperature T).

Next, the operation and operation for observing the error codes EC _{1 to} EC ₆ stored in the abnormal data memory EMEM will be described.

When the user turns on the display changeover switch 31, it is determined to be "YES" in step 304 of the "timer interrupt program" of FIG. 4, and the processing of the "second display routine" is executed in step 308. To be done. The execution of this "second display routine" is started in step 700 and then executed in step 70, as shown in FIG.
1, 702, it is determined whether the up switch 33 or the down switch 34 has been turned on. in this case,
If both the switches 33 and 34 have not been turned on, it is determined as "NO" in both the steps 701 and 702, and the address position EMEM (J) in the abnormal data memory EMEM designated by the variable J is set. The display data representing the error codes EC _{1 to} EC ₆ stored in is output to the display control circuit 26, and the control circuit 26 controls the display 27 to display the error codes EC _{1 to} EC ₆ .

On the other hand, when the up switch 33 is turned on while the display changeover switch 31 is turned on,
It is determined as “YES” in Step 701, and Step 7
At 03, the variable J is incremented by "1", and by the processing of the step 709, the error codes EC _{1 to} EC ₆ stored in the address position EMEM (J) designated by the incremented variable J are changed. It is displayed on the display 27. By repeating this operation, the variable J is increased by "1" and the address position specified by the increased variable J is increased.
The error codes EC _{1 to} EC ₆ stored in EMEM (J) are sequentially displayed on the display 27. When the variable J becomes larger than the number of abnormal occurrences ERRN due to the increase of the variable J, it is determined to be “YES” in step 704, and step 70
Since the variable J is returned to the abnormal occurrence number ERRN in step 5, even if the up switch 33 is further turned on, the variable J does not become larger than the abnormal occurrence number ERRN.

When the down switch 34 is turned on while the display changeover switch 31 is turned on,
It is determined as “YES” in Step 702, and Step 7
At 06, the variable J is decreased by "1", and by the processing of the step 709, the error codes EC _{1 to} EC ₆ stored in the address position EMEM (J) designated by the decreased variable J are changed. It is displayed on the display 27. By repeating this operation, the variable J is decreased by "1" and the address position specified by the decreased variable J is also decreased.
The error codes EC _{1 to} EC ₆ stored in EMEM (J) are sequentially displayed on the display 27. When the variable J becomes smaller than "1" due to the decrease of the variable J, step 7
Since it is determined to be "YES" at 07 and the variable J is returned to "1" at step 708, the variable J will not become smaller than "1" even if the down switch 34 is further turned on.

In this way, the display changeover switch 31,
By turning on the up switch 33 and the down switch 34, each address EMEM (1) to EMEM of the abnormal data memory EMEM
The error codes EC _{1 to} EC ₆ stored in MEM (ERRN) are sequentially read and displayed on the display 27. The addresses EMEM (1) to EMEM (ERRN) are assigned to the addresses shown in FIG.
By the processing of the "abnormality detection routine" of to 7, error codes EC _{1 to} EC ₆ representing the types of the abnormalities are written in the order of occurrence of the abnormalities. In this case, even if the abnormalities disappear automatically. Since the error codes EC _{1 to} EC ₆ written in the respective addresses EMEM (1) to EMEM (ERRN) are not deleted and remain, the sequential display causes all of the errors generated from the start of operation to the present. The abnormality types will be displayed in sequence.
As a result, it is possible to confirm a plurality of anomalies that have occurred in a chain due to one or a plurality of failures in the thermostat in the order in which they occur, and it becomes easy to find the essential cause of the anomaly.

Further, in the thermostat, all error codes stored in the abnormal data memory EMEM are
It is also possible to clear EC _{1 to} EC ₆ . In this case, the user turns on the clear switch 35. By this ON operation, the switch 309 of the "timer interrupt program" of FIG.
By the processing of 10, all the error codes EC _{1 to} EC ₆ stored in the abnormal data memory EMEM are cleared. Also,
In this case, the number of error occurrences ER
RN is also set to "0" at the same time. As a result, all error codes EC ₁ to ₁ stored in the abnormal data memory EMEM
You can easily clear EC ₆ and prepare for the next anomaly detection.

[Brief description of drawings]

FIG. 1 is an overall schematic block diagram of a thermostatic machine showing an embodiment of the present invention.

2 is a flowchart of a main program executed by the microcomputer of FIG.

FIG. 3 is a detailed flowchart of the defrost routine of FIG.

4 is a flowchart of a timer interrupt program executed by the microcomputer of FIG.

5 is a part of a detailed flowchart of the abnormality detection routine of FIG.

FIG. 6 is a part of a detailed flowchart of the abnormality detection routine of FIG.

7 is a part of a detailed flowchart of the abnormality detection routine of FIG.

FIG. 8 is a detailed flowchart of the temperature setting routine of FIG.

FIG. 9 is a detailed flowchart of the first display routine of FIG.

10 is a detailed flowchart of the second display routine of FIG.

[Explanation of symbols]

11 ... Electric compressor, 12 ... Condenser, 13 ... Throttle, 14 ...
Evaporator, 16, 19 ... Relay, 17 ... Overload relay, 1
8 ... Electromagnetic valve, 20 ... Microcomputer, 23 ...
Inside temperature sensor, 24 ... Defrosting thermo switch, 25 ... Case thermo switch, 27 ... Indicator, 31 ... Display change switch, 32 ... Temperature setting switch, 33 ... Up switch, 34 ... Down switch, 35 ... Clear switch.

Claims (2)

[Claims] 1. A temperature sensor that detects a temperature inside the refrigerator, a cooling device that cools the inside of the refrigerator, and a refrigerator that repeatedly controls operation and stop of the cooling device based on the temperature inside the refrigerator detected by the temperature sensor. In a thermostatic machine provided with a cooling control means for maintaining the internal temperature between a predetermined upper limit temperature and a lower limit temperature, and a display means for displaying the internal temperature detected by the temperature sensor, the constant temperature machine generates the constant temperature. Abnormality detecting means for respectively detecting a plurality of types of abnormalities, writable storage means, and writing means for writing abnormal data representing types of abnormalities in the storage means in the order of occurrence of abnormalities in response to the abnormality detection by the abnormality detecting means And a display switching operation switch for switching the inside temperature display state of the display means to an abnormal display state, and a step operation for advancing a read address to the storage means. When the display state of the switch and the display means is switched to the abnormal display state by the switching operation switch, each abnormal data in the storage means is sequentially arranged in the order of occurrence based on the address stepped by the step operation switch. An abnormality display control device for a thermostatic machine, comprising reading means for reading and supplying to the display means to display an abnormality type corresponding to the abnormality data on the display means. 2. The thermostat abnormality display control device according to claim 1, further comprising a clear operation switch for clearing the abnormality data in the storage means in response to an operation. Machine abnormality display control device