JPS6054565B2 - Signal transmission device for air conditioners - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal transmission device between indoor and outdoor units of an air conditioner configured with an indoor unit and an outdoor unit.

More specifically, by using a multiplex transmission method for transmission between indoor and outdoor units, one, one, A, --IP'
Stand ^, Le = Nail L &-& Jlt Ga゛,,,''l Yu1
It is ^. In recent years, as LSIs such as microcomputers have become available at relatively low prices, these devices have been introduced into air conditioner control devices, and there has been a shift from conventional electromechanical control to so-called electronic control. be.

An example of an electric circuit of an air conditioner using such a so-called electronic control device is shown in FIG. In FIG. 1, 1 is an indoor unit, which includes an operation switch 101 and a blower fan motor 10.
2. The speed of the auxiliary heating heater 103 and the blower fan motor 102, and the on/off of the auxiliary heating heater 103 are controlled on and off according to the operating mode via the on/off contacts 111 and 112. For the outdoor unit controller 210, the compressor motor 20
1, a blower fan motor 202, and a four-way valve 203.

The controller 110 includes sensors such as a room temperature detector and an indoor unit status detector (heat exchanger temperature sensor and outlet temperature sensor), operation switches such as a cooling/heating switch operated by the user, and a room temperature setting device, and stores information on these sensors. and mode determining means such as a microcomputer for determining the operating mode of the air conditioner based on information from the outdoor unit controller 210. Reference numeral 2 denotes an outdoor unit, which includes a compressor motor 201, a blower fan motor 202, and a four-way valve 203 for switching between cooling and heating, and is turned on and off by contacts 211, 212, and 213 controlled by an outdoor unit controller 210.

The outdoor unit controller 210 is the indoor unit controller 11
Based on the information sent from 0, contacts 211 and 212
It includes a logic circuit that controls on/off of the contact 213 and a de-icer that controls the contact 213. 3 is a commercial power source.

S1-4 are signal transmission lines, for example, S1 is for turning on and off the compressor motor 201, S2 is for turning on and off the four-way valve, S3 is for defrosting operation, and S4 is for common potential.

The deaiser takes the configuration shown in FIG. 2, for example.

This de-icer is a standby type de-icer, and the thermostat 2 includes the outdoor unit heat exchanger temperature detection thermistor 215H.
15, a first timer 216, a second timer 217, a logic circuit 218, and a relay 213C. If heating operation is started, a heating signal is transmitted from the indoor unit controller 110 to the outdoor unit controller 210 using S2.

This signal causes the outdoor unit controller 210 to
is closed, the four-way valve 203 is turned on, and the refrigeration cycle becomes a heating cycle. Simultaneously with the start of heating in the heating cycle, the first timer 216 of the de-Isa starts operating, and prohibits the operation of the thermostat 215 for a certain period of time Ti. When the outdoor heat exchanger temperature decreases due to frost formation due to heating operation being continued for more than t1, this causes the thermistor 215
Detected by H, thermostat! 215 operates, energizing the relay coil 213C through the control circuit 218, the contact 213 turns off, the four-way valve 203 turns off, and switches to the cooling cycle, and the outdoor fan motor 202 stops and defrosting operation starts. Enter. At the same time, through S3, room! The information is transmitted to the indoor unit controller 110, and the fan motor 102 is controlled to the lowest speed and the heater 10 is
3 is forced on. At the start of the defrosting operation, the de-icer control circuit 2184 raises the reference level of the thermostat to the return level and triggers the second timer 21D.
Defrosting is completed when the heat exchanger temperature detected by thermistor 215H rises to the elevated reference level of the thermostat, or the time TL set by the second timer, whichever is earlier. When defrosting is completed, the control circuit 218
The energization of the relay coil 213C is stopped, the contact 213 is closed, and the normal heating cycle is resumed, and the indoor unit controller 110 cancels the defrosting operation of the fan motor 102 and the heater 103. The advantage of such a configuration is that since the outdoor unit 2 is provided with a relay that controls the contacts 211 and 212, the space for the controller 110 of the indoor unit 1 can be reduced, and therefore the indoor unit 1 itself can be made smaller. It is possible to do this.

However, for this reason, the number of electric wires connected between the indoor and outdoor units 1 and 2 is six, which increases cost and deteriorates workability. In other words, since there are many connections, it becomes cumbersome and connection errors tend to occur frequently. FIG. 3 is an electrical circuit diagram of an air conditioner according to an embodiment of the present invention.

The same numbers as in FIGS. 1 and 2 indicate the same items. Reference numeral 120 denotes a microcomputer, which sets its output terminal n1 to "Hi" when the air conditioner is on, N7 when the heating is off, and N3 when the heating is on; otherwise, each output terminal becomes "b".

These signals are transferred to inverters 121, 123, 125,
A converter consisting of resistors 122, 124, 126 and 220 is used to convert the signal into a discrete DC signal S, and the signal is transmitted to the outdoor unit controller 210 via the transmission μSD. For example, when the air conditioner is on, VS=V2.

Here, R2 is the resistance value of the resistor 122, RO is the resistance value of the resistor 220, and Vcc is the DC power supply voltage of the outdoor unit controller 210.

The level V of S with heating off and the same level V4 with copper on is given below. However, R4 and R6 are resistors 124 and 126
resistance value. Also, 01 to 03 all correspond to "b", which corresponds to cooling off, and in this case ■S=V1 becomes Vcc. Vs levels V1 to 4 correspond to cooling off, cooling on, heating off, and heating on, respectively. This discrete DC level V
s are comparators 225 to 227, AND gate 22
9, an inverter 228, an 0R gate 230, and a resistor network 221 to 224, and the outdoor unit controller 210 demodulates the signal to obtain an outdoor unit control signal. Vs at the inverting inputs of comparators 225 to 227
is applied. Level of Vs ■ Size relationship of 1 to V4 ■
1>■2>V3>V4. Comparator 225-2
27 is applied with voltages El, E2, and E3 obtained by dividing Vcc by resistors 221 to 224. Here,■
The magnitude relationship with the level of S is V1>E1>V2>E2>V
3>E3>V4. First, when the air conditioner is off, ■S=V1, and all outputs of the comparators 225 to 227 become inverted input>non-inverted input, and become ゜゜b゛.

Therefore, the AND gate 229 output becomes "fat",
The σR gate 230 output also becomes “゜L0゛”, and the driver 2
31 output becomes ゜゜Hi゛, the relay coil 211C is not energized, and the compressor motor 201 is stopped. Since the comparator 226 output is 61♂3, the driver 232 output becomes '6Hi'2, the relay coil 212C is not energized, and the four-way valve 203 is turned off.

When the air conditioner is on, VS=V2, and since E1>■2·E2, only the output of the comparator 225 becomes "Hi" and the outputs of the other comparators 226 and 227 remain at "°L♂3".

The inverter 228 output becomes 6"Hi'5, the AND gate output becomes "゜Hi'', the '0R gate output also becomes "゜Hi", the relay coil 211C is energized, and the compressor motor 201 is operated.The four-way valve 203 remains off, so cooling operation is performed.When heating is off, VS=
becomes V2, becomes E2〉■3〉E3, and comparator 2
The outputs 25 and 226 become "Hi", and the output 227 remains at "L0".

Since the output of the comparator 22 is '6Hi', the output of the inverter 228 becomes 'L0', the output of the AND gate 229 becomes 'LO', and the compressor motor 201 is turned off.Meanwhile, the relay coil 212C is energized via the driver 232, The four-way valve 203 is turned on, and the refrigeration cycle becomes a heating cycle.When heating is on, VS=V4, and E3>V
4, and the outputs of the comparators 225 to 227 all become ゜゜H1゛.

The output power of the R gate 230 becomes "Hi", the compressor motor 201 operates, and the heating operation is started.
This is a deaiser with the configuration shown in the figure.

Other configurations of the de-icer include a temperature difference type, a timer type, etc., but any of these may be used. 215H is a thermistor that detects the heat exchanger temperature, and divides Vcc with the resistor 241, converts the temperature into the resistance value, and converts the voltage into the de-Icer 240.
is input.

The output of deaiser 240 is input to a pulse generator described below. A first differential circuit composed of a capacitor 246 and a resistor 247, an inverter 242, and a capacitor 2
43 and a resistor 245, and the output of each differentiator circuit is input to the R gate for a period of 248. The 0R gate 248 output is input to a positive edge triggered monostable multivibrator 249.

66Hi'1 pulse time of monostable multivibrator■
is determined by an external capacitor 250 and an external resistor 251. The monostable multivibrator 249 is easily available as an IC, for example, SN74l2 for TT'L.
2. For C-MOS, there is MC-14528B. The monostable multivibrator 249 output is applied to the transmission line SD via a diode 253 and a resistor 257 and to the non-inverting input of the converter 227 via a diode 252. The output of the de-icer 240 is further connected to the driver 23
3 and drives the relay coil 213C.The level V of the transmission line SD is applied to the comparator 12.
7. Input to a level detector composed of resistors 128-129.

The output voltage V of the output terminal N3 of the microcomputer 120 is applied to the non-inverting input of the comparator 127, and the inverting input thereof receives the output voltage V of the output terminal N3 of the microcomputer 120. Voltage E obtained by dividing 3 by resistors 129 and 130
D is applied.

If the ED when N3 is “Hi” is E4, then E4=E
The resistance values of the resistors 129 and 130 are selected to be as low as 3. The output of comparator 127 is an open collector type, and its output is pulled up to N3 via resistor 128. The output of the comparator 227 becomes the input of the ()R gate and the input of the inverter 254, and the output of the inverter 254 is applied to the input of the de-icer 240 via the diode 256.

Next, the operation of the above circuit will be explained with reference to the timing chart of FIG. In Figure 4, A is the signal level Vs, port is the output of the comparator 127, C is the temperature of the outdoor unit heat exchanger detected by the thermistor 215H, second is the output of the de-icer 240, and E is the monostable multivibrator. 249 output, h shows the on/off state of the compressor motor 201, v shows the on/off state of the four-way valve 203, and h shows the on/off state of the relay contact 213. Masu time tφ
When heating operation is started, the transmission level becomes V3 or V4 depending on whether the operation is on or off. Compressor motor 20
1 is off when V3 is on, and on when V4 is on. Four-way valve 20
3 turns on when V3 or V4. Consequently, heating operation begins.

When the transmission level Vs is V3, the comparator 227
The output of is “゜b゛”, and the inverter 254 output power is “H”.
i゛, the input voltage of the de-icer 240 increases,
The resistance value of the thermistor 215H is small, which is equivalent to a high temperature of the heat exchanger, and the output of the de-icer 240 is ゜゜Hi゛, that is, the defrosting operation is prohibited. By continuing the heating operation, the heat exchanger temperature θ gradually decreases. At time t1, Vs becomes V4, heating is turned on, and in this state, when the heat exchanger temperature θ reaches the low temperature level θL due to the progress of frost formation on the heat exchanger, the comparator 227 outputs because the heating is on. is '6Hi'5, the output of the inverter 254 is "L0", and the voltage corresponding to the heat exchanger temperature 0 is applied to the input of the de-icer 240, so the output is set to "Hi" and the defrosting operation is started. I'm here. That is,
The relay contact 213 is turned off, the four-way valve 203 and the blower fan motor 202 are stopped, and defrosting operation is started. At the same time, the output of the de-icer 240 changes from "゜Fat" to "゜Hi", which is detected by the first differentiating circuit of the capacitor 246 and resistor 247, and triggers the monostable multivibrator 249 via the 0R gate 248. , the output of the monostable multivibrator 249 becomes TH゜“Hi” for a certain period of time. The transmission level ■S thereby increases from ■4 to V3. That is, the output of the monostable multivibrator 24
If the output ゜゜Hi15 voltage of 9 is approximately equal to Vcc, then Vs at this time will be approximately as shown below, so R7 should be selected so that Vs at this time is equal to 3. Here, R7 is the resistance value of the resistor 257. On the other hand, since the monostable multivibrator 249 output is also applied to the non-inverting input of the comparator 227, E3 rises to Vcc. This allows other comparators 225, 226
Since the non-inverted input of
This allows the heating to remain on. When the transmission level Vs rises to V3, comparator 1
27 is larger than the inverting input E4, so the comparator 12
7 output becomes “゜Hi゛”.

At this time, the heating is on, so the N3 output is at Hi, and this is the operation. When the heating is off, the N3 output voltage is L055, so the comparator 127 output is always 'TOl'. When TH elapses from time T2 (time T3), the output of the monostable multivibrator 249 becomes "゜L0゛" again, and therefore V
s also returns from ■3 to V4, and the output of the comparator 127 also becomes ゜"b".

In this manner, the microcomputer 120 can recognize that the defrosting operation has started when the output of the comparator 127 becomes "Hi" for the first time when the heating is on, that is, when the n'3 output is in the "Hi" state.

As a result, the operation mode on the indoor unit 1 side is changed to defrost rotation (
The blower fan motor 102 is forced to operate at the lowest speed, and the auxiliary heater 103 is forced on. As the outdoor heat exchanger is defrosted by the defrosting operation, its temperature θ increases,
When defrosting is completed at time T4 and the high temperature level θH is reached, the output of the de-icer 240 becomes “Hi” to complete the defrosting operation.
Changes from ゛ to ゜゜b゛.

As a result, the relay contact 213 is turned on again, and the four-way valve 2
03 turns on and returns to the refrigeration cycle, and at the same time, the outdoor ventilation fan motor 202 turns on and returns to heating operation. The output change of the de-icer 240 is caused by the inverter 242 and the capacitor 2.
43, a positive pulse is generated in the second differentiator circuit of resistor 245,
Trigger the monostable multivibrator 249 via the '0R gate 248. Monostable multivibrator 24
9 maintains IllTl'HlHi'3 for a certain period of time. The operation at this time is the same as that at the start of the defrosting operation described above.
As a result, the microcomputer 120 receives the second "Hi" signal input, and from this,
The completion of the defrosting operation is recognized, the defrosting operation on the indoor unit 1 side is canceled, and the normal heating operation mode is returned. Thereafter, the above-described operation is repeated, and the heating operation and defrosting operation are repeated.

If the defrosting operation time (T2 to T4 in Fig. 4) is always longer than TH, the method of the above-mentioned embodiment may be used, but if the defrosting operation time is sometimes shorter than TH, Fifth
Inconveniences as shown in the figure occur.

At time T5, O reaches θL and in order to enter the defrosting operation, the output of the de-icer 240 becomes Hi, and at the same time, the output of the monostable multivibrator 249 becomes Hi.However, the output of the monostable multivibrator 249 becomes Hi. θ reaches θH within the time TH during which ゛ is maintained, and time T
6, the de-icer 240 output power becomes ゜L0゛. Therefore, the monostable multivibrator 249 output is “゜H
While maintaining i', it becomes "LO" at time T7. In the method described above, when starting and ending defrosting operation, the monostable multivibrator 249 output is 44Hi99+4.
The series t09941Hi99 is required, and 64
For H199+46H199444L0, it is 7. Even if the computer 120 can recognize the start of defrosting, it cannot recognize the end. On the outdoor unit 2 side, heating operation is performed after time T6, but on the indoor unit 1 side, defrosting operation is performed. Further, in the early hours of the day, θ becomes 0L or less again, and when the time set in the first timer 216 in FIG.
゜Hi55, the monostable multivibrator 249 output also becomes “゜Hi”, and after a certain period of time, at time T9, it becomes “LO”.
Become ゛. This is the second ゜゜Hi゛ for the microcomputer 120.
is recognized as the completion of defrosting operation. Accordingly, after the time period,
The outdoor unit 2 is in defrosting operation, and the indoor unit 1 is in normal operation. When 0 reaches 0H at time TlO, the output of the de-icer 240 becomes "LO", and the output of the monostable multivibrator 249 becomes "Hi" at a certain time again. For the microcomputer 120, this is the first ゜゜Hi゛ signal during normal operation, so it recognizes it as the start of defrosting operation.
Starts defrosting operation. That is, after time TlO, the outdoor unit 2 is in heating operation, and the indoor unit 1 is in defrosting operation. In order to solve the above-mentioned disadvantages, it is necessary to provide an appropriate ゜゜b゛ period between the first pulse for starting the defrosting operation and the second pulse for completing the defrosting operation.

An embodiment of the present invention that takes such measures is shown in FIG.
The timing chart is shown in FIG. The circuit in Figure 6 is a monostable multivibrator 258 in addition to the circuit in Figure 3.
, time setting capacitors 260 and 259, and an inverter (open collector output) are added. 7th
In the timing chart in the figure, the same symbols as in FIG. 4 indicate the same states. 2 shows the output of the monostable multivibrator 258. "゜Hi" of monostable multivibrator 258 output
゛Time TH2 is the first monostable multivibrator 24
It is set longer than the "Hi2" time TH of 9. First, at time Tl2, θ reaches 0L, and the output of the de-icer 240 becomes "Hi" as soon as possible to enter the defrosting operation, and at the same time, the monostable multivibrator 249, 258 output also becomes 66Hi'2.

Therefore, the inverter 261 output becomes "L0" and the resistor 241 is short-circuited, so the de-icer 240 input voltage becomes almost zero V, which is equivalent to a state in which the resistance value of the thermistor 215H is extremely large, that is, the heat exchanger temperature is extremely low. . The first monostable multivibrator 249 output is ゜“
Even if O rises to 0H at time Tl3 during Hi゛, the input voltage to the de-icer 240 is zero, so the de-icer 240
Maintain the output power “Hi” and continue defrosting operation. Time T
TH elapses at time T14, and the output of the first monostable multivibrator 249 becomes "LO". TH2 elapses at time Tl5, and the output of the monostable multivibrator 258 becomes "LO".
F'', the inverter 261 output becomes "Hi",
The short state of the resistor 241 is released, and the de-iser 240
In and, a voltage corresponding to the heat exchanger temperature is input. At this point, 0 is greater than θH, so the deicer 240 output is “
The state becomes LO, the defrosting operation of the outdoor unit 2 is completed, the output of the first monostable multivibrator 249 becomes "Hi", and the microcomputer 120 becomes "Hi" for the second time.
It receives the signal, recognizes that defrosting is complete, and completes the defrosting operation of the indoor unit 1. Thereafter, the above-described operation is repeated, and the heating and defrosting operation is repeated. Since the transmission paths SD and S4 are relatively long, noise may enter from the outside and change the transmission level Vs, resulting in malfunction.

In order to prevent this, as a simple method, as shown in FIG.
62 is provided.

In this case, 66 of the monostable multivibrator 249 output
Delay in transmission level Vs when changing from L0'' to ゜゜Hi゛ or vice versa, microcomputer 1
20, a delay occurs when changing the transmission level Vs. Capacitors 263 and 132 are provided to prevent malfunctions due to such delays.

In particular, in the capacitor 263, Vs changes relatively slowly from V3 to V4 from the time the N3 output becomes "Hi", but when the inverting input of the comparator 127 immediately rises to E4, the comparator 127 output changes to "Hi". In order to eliminate this, the inverting input is smoothly raised from zero to E4, and Vs changes from V3 to V4.
This generates a delay such that the signal reaches E4V after moving to . This is a microcomputer 120
If the internal processing alone is as follows, the capacitor 13
2 may be omitted. In other words, after setting the N3 output to "Hi", it is sufficient to ignore the input signal for the time t required for Vs to change from V3 to V4.In the above example, the transmission level ■3 of S Assign heating off,
The transmission level of the pulses at the start and end of defrosting was set to ■3. However, by modifying the present invention, the person concerned can allocate V3 to heating on, set the above-mentioned pulse level to ■3, change the assignment of transmission νVel, etc. without changing the gist of the present invention. be. In addition, at the start and end of defrosting, pulses are sent to the indoor unit 1 from the outdoor unit 2.
Although the transmission is performed using a specific level for h, it is clear that if the start and end of defrosting can be determined on the indoor unit 1 side by other means, only one of h may be used.

According to the present invention, not only can the number of wires connected between indoor and outdoor units be reduced by multiplexing signals, but also the defrosting signal can be
Since specific transmission levels are used, the difference between the levels can be made large, which increases the noise margin of each transmission level and improves transmission reliability.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram of a conventional air conditioner, FIG. 2 is a configuration diagram of the same de-icer, FIG. 3 is an electrical circuit diagram of an embodiment of the present invention, and FIG. 4 is a timing chart diagram of FIG. 3. 5 is a timing chart diagram for a special case of FIG. 3, FIG. 6 is an electric circuit diagram of another embodiment of the present invention, FIG. 7 is a timing chart diagram of FIG. 6, and FIG. 8 is a diagram of the present invention. FIG. 3 is an electrical circuit diagram of another embodiment of the invention. 1...Indoor unit, 2...Outdoor unit, SD...Transmission line, 121, 123, 1
25... Inverter, 127, 225-227
...Comparator, 228-230,254...
...Gate, 240...Deaisa, 243
, 249, 258... Monostable multivibrator.

Claims (1)

[Scope of Claims] 1. A converter that converts a control signal to be transmitted from the indoor unit to the outdoor unit into a discrete DC signal in signal transmission between the indoor and outdoor units of an air conditioner consisting of an indoor unit and an outdoor unit; a transmission line for transmitting the discrete DC signal; a demodulator for receiving the discrete DC signal as input and outputting an outdoor unit control signal; For an air conditioner, comprising: a pulse generator that maintains the level of the discrete DC signal at a specific level for a predetermined time at the start or end; and a level detector installed in an indoor unit that detects the discrete DC signal at the specific level. Signal transmission equipment. 2. The pulse generator is configured to maintain the level of the discrete DC signal for a predetermined time at the same level as the level corresponding to heating on or heating off at the start or end of the defrosting operation. The signal transmission device for an air conditioner according to item 1.