JP3412517B2 - Signal transmission device and signal transmission method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device for transmitting signals between at least two control units, and more particularly to a signal transmission device for depolarizing signals.

[0002]

2. Description of the Related Art Conventionally, for example, in an air conditioner, a balanced communication system using two signal lines as a signal transmission system between a remote controller (hereinafter abbreviated as "remote control"), an indoor unit and an outdoor unit. Is adopted (Japanese Patent Laid-Open No. 5-227568, etc.).

In this air conditioner, opposite polarities are assigned to each of the two signal lines. Since the polarity is often connected in the opposite direction due to incorrect connection at the time of plug connection, such polarity connection in the signal transmission device on the receiving side during communication is allowed after allowing such connection in the opposite direction. Judgment is made and the polarity of the send / receive port is automatically switched to communicate correctly.

FIG. 10 is a block diagram showing an example of a conventional signal transmission device. In this signal transmission device, the signal lines 1,
A rectifying block 3 for applying a predetermined DC voltage is connected to 2, and a signal changeover switch 5 for inverting the transmission signal is provided between the signal lines 1 and 2 and the transmission / reception block 4. Further, the polarity determination circuit 6 that outputs the different polarity signal only when the potential of the positive signal line 1 is lower than the potential of the negative signal line 2 is provided. When the polarity determination circuit 6 outputs a different polarity signal, a microcomputer (hereinafter referred to as “microcomputer”)
The signal change-over switch 5 reverses the transmission signal in accordance with the change-over signal from the change-over control unit 8 inside the switch 7.

Here, the polarity determination circuit 6 includes a pair of light emitting diodes PHD connected between the signal lines 1 and 2.
1, PHD2 and each light emitting diode PHD1, PHD2
It is composed of a pair of phototransistors PHT1 and PHT2 which respectively receive the light from the and transmit the reception result to the microcomputer 7. First light emitting diode PHD1
Emits light when the potential of the signal line 1 is higher than the potential of the signal line 2, and conversely, the second light emitting diode PHD2 is
The light is emitted when the potential of is higher than the potential of the signal line 1.

Therefore, when a transmission signal is input to the signal lines 1 and 2 through the transmission / reception ports P and N, either one of the light emitting diodes PHD1 and PHD2 emits light based on this and the light emitting state is changed to each phototransistor. PHT
The microcomputer 7 detects the signal via the PHT 1 and the PHT 2, and the changeover control unit 8 changes the port of the signal changeover switch 5 based on the detection result, so that the transmission / reception block 4 inputs / outputs a signal having a correct polarity.

[0007]

In the conventional signal transmission device, the light emitting diodes PHD1 and PHD of the polarity determination circuit 6 are used.
2 and the phototransistors PHT1 and PHT2 have failed, and these parts PHD1, PHD2, PHT1 and PH
When T2 is exchanged, when the signal transmission operation is next started in the signal transmission device, the microcomputer 7 recognizes the polarities of the transmission / reception ports P and N at the time before the last operation of the signal transmission device was completed. Of the transmission / reception ports P and N in the signal changeover switch 5 is initially defined based on the stored contents, and the signal transmission device operates (that is, the changeover operation of the signal changeover switch 5). Was going on.

When the operation of the signal transmission device is started, normal recognition is performed if the connection of the transmission / reception ports P and N is not changed before and after the failure of the polarity determination circuit 6. However, the parts PHD1, P at the time of failure
When the plugs for the transmission / reception ports P and N are also inserted and removed when the HD2, PHT1 and PHT2 are replaced,
Since it is possible that the polarities are reversed and the connection is reversed, the components PHD1, PHD2 and PH are connected as described above.
If the polarities of the transmission / reception ports P and N before replacement of T1 and PHT2 are applied as they are, it becomes difficult to recognize the transmission signal, and signal transmission between the remote controller (hereinafter abbreviated as "remote control"), the indoor unit and the outdoor unit. Will not be done correctly.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a signal transmission device which can easily correctly recognize the polarities of transmission / reception ports and easily perform automatic switching of signal changeover switches even if the conventional polarity determination circuit is omitted. To provide.

[0010]

[Means for Solving the Problems] In order to solve the above problems,
The invention according to claim 1 is a signal transmission device that transmits a signal to a predetermined external device, and includes a first signal line (L1) and a second signal line (L1) to which a pair of transmission lines are connected. Signal line (L
2) and a transmitting / receiving means (15) for connecting to one of the signal lines (L1, L2) without being inverted and for transmitting and receiving a signal by inverting to the other signal line, First signal line (L1) and second signal line (L2)
And a signal change-over switch (14) for switching between the inverted and non-inverted relations with respect to the transmission / reception means (15), giving an instruction of a transmission / reception operation of the transmission / reception block (15), and receiving at the transmission / reception block (15). A control unit (11) for instructing connection switching of the signal changeover switch (14) based on the received signal, the control unit (11) externally through the transmission line from the first signal line (L1). ) And the second signal line (L2) are given a predetermined judgment pattern, the signal changeover switch (14) directs the signal to the one signal line on the side connected without being inverted. The polarity judgment signal having the same timing and the same waveform as the judgment pattern is applied without being inverted, and is also connected to the signal of the one signal line on the side connected without being inverted. Wherein by superimposing the signal of the other signal lines and combined pattern that, the signal changeover switch only if the amplitude is less than the predetermined amplitude of the combined pattern (1
4) to instruct the first signal line (L1) and the second signal line (L2) to invert and reverse the relationship between the transmitting and receiving means (15).

According to a second aspect of the present invention, the control section (1
1) is timing adjusting means (21) for defining the timing at which the judgment pattern is given from the external predetermined device, and the polarity judgment signal through the transmission / reception block (15) in synchronization with the input of the judgment pattern. The polarity determination signal output instructing means (22) for instructing the transmission / reception block (15) to output to the one signal line on the connected side without being inverted, and the polarity determination signal output instructing means (22) An amplitude level detecting means (23) for detecting whether or not the amplitude of the combined pattern when the polarity judgment signal is output is equal to or larger than a predetermined amplitude, and the combined level of the combined pattern in the amplitude level detecting means (23) is a predetermined amplitude. When the level is not reached, the signal changeover switch (14)
Of the first signal line (L1) and the second signal line (L1
The switching control means 24 which gives an instruction to change and switch the relationship of inversion and non-inversion with respect to 2) is provided.

According to a third aspect of the present invention, the timing adjusting means (21) requests the external predetermined device to send out the determination pattern, and from the point of time of the request, the external external device continues. The signal received from a predetermined device is used as the determination pattern, and the polarity determination signal is not inverted through the transmission / reception block (15) in synchronization with the reception timing of the determination pattern, and the one signal on the connected side The transmission / reception block (1
5).

According to a fourth aspect of the present invention, when a predetermined determination pattern is given to one of the first signal line (L1) and the second signal line (L2) from the outside through the transmission line. A first step of applying a polarity determination signal having the same waveform and the same waveform as the determination pattern to the one signal line on the side connected without being inverted by the signal changeover switch (14) without inversion. In parallel with the first step, the signal of the one signal line on the side that is connected without being inverted and the signal of the other signal line that is inversely connected are superimposed to form a combined pattern, The second step of recognizing the amplitude of the combined pattern, and the signal changeover switch (1) when the amplitude of the combined pattern is equal to or larger than a predetermined amplitude.
4) The inverted and non-inverted relationship of the first signal line (L1) and the second signal line (L2) with respect to the transmitting / receiving means (15) is maintained, while the amplitude of the composite pattern is a predetermined amplitude. Signal switch (14) if less than
To the first signal line (L1) and the second signal line (L
2) The third step of mutually changing and switching the inversion and non-inversion relations with respect to the transmitting / receiving means (15).

According to a fifth aspect of the present invention, in the first step, the external predetermined device is requested to send out the determination pattern, and the external predetermined device continues after the request. The signal received from the device is used as the determination pattern, and the determination is made to the one signal line on the side connected without being inverted by the signal changeover switch (14) in synchronization with the reception timing of the determination pattern. The polarity determination signal having the same timing as the pattern and the same waveform is applied without being inverted.

[0015]

In order to solve the above-mentioned problems, in the invention described in claims 1, 2 and 4, first, the first signal line (L1) and the second signal line (L2) are externally transmitted through the transmission line. )
When a predetermined judgment pattern is given to any of
A polarity determination signal having the same waveform as the determination pattern and non-inverted (without inversion) to one signal line on the side that is connected without being inverted by the signal changeover switch (14).
give. Further, in parallel with this, the signal of one signal line on the side that is connected without being inverted and the signal of the other signal line that is inverted and connected are superimposed to form a combined pattern, and the amplitude of the combined pattern. Recognize. Then, when the amplitude of the combined pattern is equal to or larger than the predetermined amplitude, the first signal line (L1) and the second signal line (L) of the signal changeover switch (14).
While maintaining the inverted and non-inverted relation with respect to the transmitting / receiving means (15) of 2), when the amplitude of the combined pattern is less than the predetermined amplitude, the signal changeover switch (14) is provided with the first signal line (L1) and the second signal line (L1). Signal line (L2) transmission / reception means (1
The relationship between inversion and non-inversion with respect to 5) is changed and switched. That is, as a result of the superimposed reception of the determination pattern and the polarity determination signal, it is merely recognized whether or not these are canceled, and the inverted / non-inverted switching state of the signal changeover switch (14) and the external predetermined device are used. Both signal lines (L1, L2)
It is possible to easily judge the conformity / non-conformity with the polarity of the input signal to, and based on this, the switching state of the signal changeover switch (14) can be easily controlled.

In the inventions according to claims 3 and 5,
A request is sent to a predetermined external device to send a judgment pattern, and the signal received from the predetermined external device from the time of the request is used as the judgment pattern and synchronized with the reception timing of the judgment pattern. The signal changeover switch (14) applies a polarity determination signal having the same waveform and the same timing as the determination pattern to the one signal line on the connected side without inversion without inversion. This allows
The determination pattern and the polarity determination signal can be efficiently synchronized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION {First Embodiment} FIG. 1 is a diagram showing a signal transmission device according to an embodiment of the present invention. This signal transmission device is installed, for example, in an indoor unit of an air conditioner, and two transmission lines (not shown) are connected to the transmission / reception ports P and N to perform mutual signal transmission with, for example, a remote controller. When a determination pattern is given to the signal lines L1 and L2 from the outside through the transmission / reception ports P and N, a signal of the same waveform is given from the microcomputer 11 to the signal lines L1 and L2 at the same timing as the determination pattern. And the signal from the microcomputer 11 is superimposed, the superimposed signal is fed back to the microcomputer 11, and when the signals are canceled, it is determined that the reception ports P and N are erroneously connected. If they are not offset, it is determined that the connection is normal, and the receiving port P,
The transmission / reception of a signal from N to the transmission / reception block 15 is switched.

Specifically, this signal transmission device is provided with a signal changeover switch 14 for inverting and switching the connection between the signal lines L1 and L2 to which a balanced communication signal is applied and the transmission / reception block 15, and this signal changeover is performed. The switch 14 is switched by a switching signal from the microcomputer 11.

As the receiving ports P and N for connecting the signal lines L1 and L2 to the outside, it is possible to employ the same conventional receiving ports P and N which have symmetrical shapes and are indistinguishable from each other. Here, in principle, the first signal line L1 is a signal line for transmitting and receiving a pulse wave such as the positive transmission signal P1 shown in FIG. 2, whereas the second signal line L2 is in principle. Is a signal line for maintaining a pulse-free voltage for grounding like the transmission signal P2 shown in FIG.

Specifically, the positive transmission signal P1 is a reference potential Va of about 16V for supplying power to the remote controller.
With v as the reference potential, positive and negative about 5 V centered on this reference potential
It is a non-polar pulse wave having an amplitude of. On the other hand, the transmission signal P2 is maintained in the vicinity of the ground potential as a general rule, and after being input to the transmission / reception block 15, the positive and negative signs are inverted as indicated by the symbol P3 in FIG. However,
As described above and below, the two signal lines L1 and L2 are switched to each other by the switching of the signal changeover switch 14 when the external connection to the transmission / reception ports P and N is mistakenly made. The polarity is transmitted to the transmission / reception block 15. That is, in FIG. 2, the transmission signal P1
For the transmission signal P2, it is not inverted and the code P4 is obtained.
It is maintained at 2. Note that resistors R1 and R2 for preventing overcurrent are connected to the signal lines L1 and L2, respectively.

Although the signal changeover switch 14 shows an analog switch as an equivalent circuit in FIG. 1, a switch element in a logic circuit using a transistor or the like is actually used. In connection with the signal changeover switch 14 and the respective signal lines L1 and L2, as shown in FIG. 3, the transmission A port Pa1 and the reception A port P of the signal changeover switch 14 are connected.
a2 is connected to the first signal line L1, and the transmission B port Pb1 and the reception B port P of the signal changeover switch 14 are connected together.
b2 is connected to the second signal line L2 for a total of four line connections.

The transmission / reception block 15 has a positive pole to which one of the transmission A port Pa1 and the transmission B port Pb1 of the signal changeover switch 14, which is selectively changed over as the positive pole terminal by the signal changeover switch 14, is connected. The transmission A terminal Qa1 and the negative transmission B terminal Qb1 to which the other selectively switched as the negative terminal is connected
And a positive receiving A terminal Qa2 to which one of the receiving A port Pa2 and the receiving B port Pb2 of the signal changeover switch 14 which is selectively changed over as a positive electrode terminal by the signal changing switch 14 is connected, A negative receiving B terminal Qb2 to which the other selectively switched as the negative terminal is connected is formed.

Here, the signal output from the transmission / reception block 15 to the negative transmission B terminal Qb1 is an inverted signal with reference to the ground voltage, and the signal output to the positive transmission A terminal Qa1 is not inverted (non-inverted signal). Is). Also,
The signal input to the receiving block 15 from the negative receiving B terminal Qb2 is an inverted signal with reference to the ground voltage,
The signal input from the positive reception A terminal Qa2 is a non-inverted signal. Then, inside the reception block 15, signals relating to both inputs of the reception A port Qa2 and the reception B port Qb2 are superimposed and recognized as a "combined pattern".

The microcomputer 11 includes a timing adjusting means 21 for defining the timing at which a determination pattern is given as a reception signal from an external remote controller, and a dedicated signal for synchronization with this determination pattern (hereinafter referred to as "polarity determination signal"). (Referred to as “L”) through the transmission / reception block 15
1, a polarity determination signal output instruction means 22 for outputting to L2,
Amplitude level detecting means 23 for detecting whether or not the signals of both signal lines L1 and L2 obtained by outputting the polarity judgment signal are equal to or higher than a predetermined amplitude level, and in the amplitude level detecting means 23, the above-mentioned combined pattern has a predetermined amplitude level. The switching control means 24 outputs a switching signal so as to switch the signal switching switch 14 when the value is not satisfied.

The timing adjusting means 21 is specifically,
Transmission / reception block 1 when the signal transmission device starts operating
5 to give an external call signal to the transmission / reception ports P and N, and request the external remote controller to transmit the determination pattern. Incidentally, the external remote controller is adapted to transmit a judgment pattern to this signal transmission device in response to the call signal.

The polarity determination signal output instructing means 22 outputs the polarity determination signal (FIG. 5 (B)) of the same waveform as the determination pattern (FIG. 5 (A)) given from the external remote controller to the positive transmission A terminal Qa1. Send and receive block 15 to output from
To give instructions. Here, the transmission timing of the polarity determination signal (FIG. 5 (B)) is specified to be almost the same timing as the determination pattern (FIG. 5 (A)). As a result, the polarity determination signal having the same waveform as the determination pattern is input to the signal line of the signal lines L1 and L2 that is connected to the positive transmission A terminal Qa1 of the transmission / reception block 15 by the signal changeover switch 14. Become.

The amplitude level detecting means 23 detects the signal input to the transmission / reception block 15, recognizes the amplitude value of the signal, and if the amplitude value is a certain amplitude value (for example, 5 V) or more,
The switching state of the signal changeover switch 14 indicates the transmission / reception ports P, N.
While it is judged to be "compatible" with the connection polarity of
If the amplitude is less than the predetermined amplitude value, the signal changeover switch 14
It is determined that the switching state of "is incompatible" with the connection polarity of the transmission / reception ports P and N.

The changeover control means 24 outputs a changeover signal to change the changeover state of the signal changeover switch 14 only when the amplitude level detection means 23 determines that it is "incompatible".

Reference numeral 25 in FIG. 1 indicates the signal lines L1,
This is a rectification block that supplies a 16V rectification current as a power source to an external remote controller through L2 and transmission / reception ports P and N. The microcomputer 11 is a functional component that operates according to a predetermined software program in a general MPU having a ROM, a RAM and the like built therein.

The operation of the signal transmission device having the above configuration will be described with reference to the flowchart of FIG. First, at the time of turning on the power of the signal transmission device and at a predetermined periodical timing thereafter, the microcomputer 11 follows the procedure of a predetermined software program to determine whether the polarities of the signal lines L1 and L2 are undetermined at that time. The determination is made (step S01). If the judgment has already been made, the judgment processing is ended as it is. Therefore, the switching state of the signal changeover switch 14 is not changed.

On the other hand, in step S01, the signal line L
When the polarities of 1 and L2 are undetermined, the timing adjusting means 21 outputs an instruction signal to the transmission / reception block 15, and the transmission / reception block 15 outputs signal lines L1 and L2, transmission / reception ports P and N, and an external transmission line (see FIG. A transmission request for the determination pattern is issued to an external remote controller through a not shown (step S02). Then, in step S03, the process waits until the determination pattern is received from the remote controller. Here, if the determination pattern is not received at all (timeout), it is in a state in which transmission / reception cannot be performed due to a poor connection state with the remote controller, so the process is ended as it is. On the other hand, when the determination pattern is received, in step S04, the polarity determination signal output instruction means 22 of the microcomputer 11 is synchronized with the determination pattern at the timing adjusted by the timing adjustment means 21, and the positive transmission A terminal. The transmission / reception block 15 is instructed to output the polarity determination signal from Qa1.

Here, in connection with an external remote controller, a correct external connection of the transmission / reception ports P and N, that is, a positive transmission line on the positive transmission / reception port P side and a negative transmission line on the negative side transmission / reception port N. Are connected to each other (hereinafter referred to as "positive connection state"), and the switching state of the signal changeover switch 14 is in a state compatible with the polarity of the "positive connection state" (hereinafter referred to as "positive connection state"). In this case, the determination pattern (FIG. 5) given to the first signal line L1 from the external remote controller through the transmission / reception port P is used.
(A)) and the positive transmission A terminal Q of the transmission / reception block 15.
The polarity determination signal (FIG. 5 (B)) given from a1 through the signal changeover switch 14 is superimposed and input. Since the determination pattern (FIG. 5 (A)) and the polarity determination signal (FIG. 5 (B)) have exactly the same waveform as the predetermined waveform, when these are superimposed to form a composite pattern. , A waveform with a large amplitude appears as shown in FIG.

The combined pattern in the first signal line L1 is transmitted / received by the transmission / reception block 15 through the signal changeover switch 14.
Is input to the reception A terminal Qa2. In this case, the voltage level of the second signal line L2 is inverted and input to the reception B terminal Qb2, but is supplied to the second signal line L2 from the external remote controller as a voltage substantially equal to the ground voltage. The generated constant voltage state is maintained, and there is almost no effect on the combined pattern shown in FIG.

On the other hand, in connection with an external remote controller,
Contrary to the normal connection state, a state in which the transmission / reception ports P and N are externally connected (hereinafter referred to as "reverse connection state":
In this case, although the negative transmission line is connected to the positive transmission / reception port P and the positive transmission line is connected to the negative transmission / reception port N), the switching state of the signal changeover switch 14 is "Direct change state" (that is, the signal changeover switch 14
Is incompatible with the reverse connection state), the first signal line L1 is supplied with a constant voltage from the external remote controller as a voltage substantially equal to the ground voltage. The state and the polarity determination signal provided from the positive transmission A terminal Qa1 of the transmission / reception block 15 through the signal changeover switch 14 are superimposed, and a signal having a waveform as shown in FIG. 7A appears. Further, in the second signal line L2, the determination pattern similar to that shown in FIG. 7A given from the external remote controller appears as it is. Then, each signal line L
Signals 1 and L2 are transmitted through the signal changeover switch 14 to the reception A terminal Qa2 and the reception B terminal Qb2 of the transmission / reception block 15.
7A, the waveform of the first signal line L1 is maintained as the waveform of FIG. 7A as a non-inverted signal, but the waveform of the second signal line L2 is inverted and the waveform of FIG. As shown in (B), both are recognized as a combined pattern that is superimposed on each other inside the transmission / reception block 15. At this time,
The waveform of FIG. 7 (A) input non-inverted from the first signal line L1 and the waveform of FIG. 7 (B) input inverted and input from the second signal line L2 are mutually inverted waveforms. Therefore, these are canceled by each other and appear as a combined pattern having an extremely small amplitude as shown in FIG.

Further, although the external connection of the transmission / reception ports P and N is in the "normal connection state", the switching state of the signal changeover switch 14 is in a state suitable for the polarity of the "reverse connection state" ( In the case of "reverse switching state"), the first signal line L1 is provided with a determination pattern (FIG. 7) given from the external remote controller through the transmission / reception port P.
(A) only appears, and the second signal line L2 has a constant voltage state given from an external remote controller as a voltage substantially equal to the ground voltage, and the transmission / reception block 15
7 is superimposed on the polarity determination signal given from the positive transmission A terminal Qa1 through the signal changeover switch 14,
A signal having a waveform similar to that of (A) appears. Then, when inputting to the reception A terminal Qa2 and the reception B terminal Qb2 of the transmission / reception block 15 through the signal changeover switch 14, the second
The waveform of the signal line L2 of FIG. 7 is maintained as the waveform of FIG. 7 (A) as a non-inverted signal, but the waveform of the first signal line L1 is inverted and becomes as shown in FIG. 7 (B). The superimposed composite pattern is input to the reception A terminal Qa2 and the reception B terminal Qb2 of the transmission / reception block 15. These cancel each other out and appear as a composite waveform with an extremely small amplitude as shown in FIG.

Further, when the external connection of the transmission / reception ports P and N is "reverse connection state" and the switching state of the signal changeover switch 14 is "reverse switching state", the first signal line L1 is connected. , Becomes a state of a constant voltage given from an external remote controller as a voltage substantially equal to the ground voltage. In addition, a determination pattern (FIG. 5 (A)) given from the external remote controller through the transmission / reception port P to the second signal line L2,
The positive polarity transmission A terminal Qa1 of the transmission / reception block 15 and the polarity determination signal (FIG. 5 (B)) given through the signal changeover switch 14 are superimposed and input. The combined pattern in the second signal line L2 is as shown in FIG.
Appearing as a waveform with a large amplitude, the signal changeover switch 14
Is input as a non-inverted input signal to the reception A terminal Qa2 of the transmission / reception block 15. Also, the reception B terminal Qb2
In addition, the voltage level of the first signal line L1 is also inverted and input. However, in the first signal line L1, as described above, it is given from the external remote controller as a voltage substantially equal to the ground voltage. The state of constant voltage is maintained, as shown in FIG.
There is almost no effect on the synthetic pattern shown in.

FIG. 9 shows these correspondences. As shown in FIG. 9, when the transmission / reception ports P and N are in the positive connection state and the signal changeover switch 14 is in the normal changeover state, and when the transmission / reception ports P and N are in the reverse connection state and the signal changeover switch 14 is in the reverse changeover state. At this time, that is, when the switching state of the signal changeover switch 14 is in a state suitable for the connection state of the transmission / reception ports P, N, the reception terminals Qa2, Q of the transmission / reception block 15
The amplitude value of the combined pattern after being received in b2 is large. On the other hand, when the signal changeover switch 14 is in the reverse switching state despite the transmission / reception ports P and N being in the normal connection state, and when the transmission / reception ports P and N are in the reverse connection state. When the signal changeover switch 14 is in the normal changeover state, that is, when the changeover state of the signal changeover switch 14 is incompatible with the connection state of the transmission / reception ports P and N, the reception terminals Qa2 and Qb2 of the transmission / reception block 15 are selected. The amplitude value of the combined pattern after being received at is approximated to zero.

Next, in step S05 in FIG.
In step S04, the amplitude value of the combined pattern input to the transmission / reception block 15 is detected by the amplitude level detecting means 23 in the microcomputer 11. Then, if the amplitude is equal to or more than a certain amplitude value (for example, 5 V), as shown in FIG.
Either N is in the positive connection state and the signal changeover switch 14 is in the normal changeover state, or if the transmission / reception ports P and N are in the reverse connection state and the signal changeover switch 14 is in the reverse changeover state. That is, since it can be determined that the switching state of the signal changeover switch 14 is suitable for the connection state of the transmission / reception ports P and N, the changeover state of the signal changeover switch 14 is not changed by the changeover control means 24.
The polarity is maintained as it is (step S06).

On the other hand, as a result of the judgment of the amplitude level detecting means 23 in step S05, a constant amplitude value (for example, 5
If it is less than V), as shown in FIG. 9, the transmission / reception ports P, N are in the positive connection state and the signal changeover switch 14 is in the reverse switching state, or the transmission / reception ports P, N are in the reverse connection state. When the signal changeover switch 14 is in the normal changeover state, that is, the signal changeover switch 14
Since it can be determined that the switching state of is incompatible with the connection state of the transmission / reception ports P and N, a switching signal is transmitted from the switching control means 24 to the signal switching switch 14, and the switching state of the signal switching switch 14 is changed. Then, the polarity is inverted (step S07).

In this way, the polarity is determined (step S
08), and the process ends. After that, a transmission signal may be transmitted between the indoor unit and the remote controller through this signal transmission device to perform a predetermined control operation.

As described above, in the signal transmission device according to this embodiment, the predetermined judgment pattern and the polarity judgment signal are collated at the time of start-up and at every predetermined cycle thereafter, and the amplitude value of the combined pattern is detected. By simply doing so, it is possible to easily make a polarity determination signal as to whether or not the switching state of the signal changeover switch 14 is suitable for the connection state of the transmission / reception ports P, N. The signal changeover switch 1 can be easily performed without using an expensive signal detection circuit using PHT1, PHT2).
It is possible to perform the switching control automatically by judging the suitability of No. 4. In particular, by omitting the polarity determination circuit, there is a great advantage that it is no longer necessary to consider the response to the polarity determination circuit itself when it fails.

In the above embodiment, the signal transmission device has been described as being installed in the indoor unit for transmitting / receiving the transmission signal to / from the remote controller. It may be applied to transmitting / receiving the transmission signal of the above, or for transmitting / receiving the transmission signal to / from the indoor unit installed in the outdoor unit. In particular, when a plurality of indoor units are connected to a single or a plurality of outdoor units through a predetermined network, it is effective to apply the signal transmission between these outdoor units and the indoor units.

[0043]

According to the inventions of claims 1, 2 and 4, first, a predetermined judgment pattern is applied to either the first signal line or the second signal line from the outside through the receiving port. Is applied to the one signal line on the connected side without being inverted by the signal changeover switch, the polarity determination signal having the same waveform and the same waveform as the determination pattern is non-inverted, and in parallel with this. Then, the signal of one signal line on the connected side without being inverted and the signal of the other signal line connected on the other side are superimposed to form a combined pattern, and the amplitude of the combined pattern is recognized and combined. When the amplitude of the pattern is equal to or larger than the predetermined amplitude, the inverted and non-inverted relations of the first signal line and the second signal line of the signal changeover switch with respect to the transmitting / receiving means are maintained, while the amplitude of the combined pattern is predetermined. amplitude The signal changeover switch in the case of the full first
Since the inverted and non-inverted relations of the signal line and the second signal line with respect to the transmission / reception means are mutually changed and switched, as a result of the superposition reception of the determination pattern and the polarity determination signal, these are canceled out? Only by recognizing whether or not the inverted / non-inverted switching state of the signal changeover switch and the polarity of the input signal from the external prescribed device to both signal lines can be easily judged, and therefore the conventional The switching state of the signal changeover switch can be easily controlled without using a special polarity determination circuit using a light emitting diode and a phototransistor.

In the invention described in claims 3 and 5,
A request is sent to a predetermined external device to send a judgment pattern, and the signal received from the predetermined external device from the time of the request is used as the judgment pattern and synchronized with the reception timing of the judgment pattern. , The polarity determination signal having the same waveform and the same waveform as the determination pattern is non-inverted to the one signal line on the connected side without being inverted by the signal changeover switch. The effect is that it can be efficiently synchronized with.

[Brief description of drawings]

FIG. 1 is a block diagram showing a signal transmission device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a signal waveform according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a connection relationship in the embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the signal transmission device according to the embodiment of the present invention.

FIG. 5 is a waveform diagram showing a state before combining the signals applied to the reception terminals of the transmission / reception block according to the embodiment of the present invention.

FIG. 6 is a waveform diagram showing a state after combining the signals applied to the reception terminals of the transmission / reception block according to the embodiment of the present invention.

FIG. 7 is a waveform diagram showing a state before combining the signals applied to the reception terminals of the transmission / reception block according to the embodiment of the present invention.

FIG. 8 is a waveform diagram showing a state after combining the signals applied to the reception terminals of the transmission / reception block in the embodiment of the present invention.

FIG. 9 is a diagram showing an operation of the embodiment of the present invention.

FIG. 10 is a block diagram showing a conventional signal transmission device.

[Explanation of symbols]

11 microcomputer, 12 signal detection unit, 14 signal changeover switch, 15 transmission / reception block, 16 changeover control unit, 2
DESCRIPTION OF SYMBOLS 1 timing adjusting means, 22 polarity judgment signal output instructing means, 23 amplitude level detecting means, 24 switching control means, P, N transmission / reception port, L1 first signal line, L2
Second signal line

Continuation of front page (56) Reference JP-A-8-251670 (JP, A) JP-A-6-216947 (JP, A) JP-A-8-14635 (JP, A) JP-A-1-288133 (JP , A) JP-A-2-276337 (JP, A) JP-A 2000-22763 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F24F 11/00-11/02 H03J 9 / 00-9/06 H04Q 9/00-9/16

Claims (5)

(57) [Claims] 1. A signal transmission device for transmitting a signal to a predetermined external device, comprising a first signal line (L1) and a second signal line (L2) to which a pair of transmission lines are connected. ), And a transmitting / receiving unit (15) that is connected to one of the two signal lines (L1, L2) without being inverted and that is inverted to the other signal line to transmit / receive a signal. 1 signal line (L1) and the second signal line (L1)
2) A signal changeover switch (14) for switching between the inverted and non-inverted relations with respect to the transmitting / receiving means (15), giving an instruction of a transmitting / receiving operation of the transmitting / receiving block (15), and the transmitting / receiving block (15) And a control unit (11) for instructing connection switching of the signal changeover switch (14) based on the received signal received by the first signal line from the outside through the transmission line. (L1) and the second signal line (L2) when a predetermined judgment pattern is given, the one signal line on the side connected without being inverted by the signal changeover switch (14) A polarity determination signal having the same timing and the same waveform as that of the determination pattern is given without being inverted, and the signal of the one signal line on the side connected without being inverted is inverted and connected. The signal of the other signal line that is being used is superimposed to form a combined pattern, and the first signal line (L1) is applied to the signal changeover switch (14) only when the amplitude of the combined pattern is less than a predetermined amplitude. And the second
The signal transmission device is characterized by instructing to mutually change and switch the inversion and non-inversion relations of the signal line (L2) with respect to the transmitting / receiving means (15). 2. The signal transmission device according to claim 1, wherein the control unit (11) defines a timing adjusting unit (21) that defines a timing at which the determination pattern is given from the external predetermined device.
And instructing the transmission / reception block (15) to output the polarity determination signal to the one signal line on the connected side without being inverted through the transmission / reception block (15) in synchronization with the input of the determination pattern. A polarity determination signal output instructing means (22) and an amplitude level for detecting whether or not the amplitude of the combined pattern when the polarity determination signal output instructing means (22) outputs the polarity determination signal is not less than a predetermined amplitude. Detection means (23), and the first signal line (L1) and the second signal line of the signal changeover switch (14) when the combined pattern does not reach a predetermined amplitude level in the amplitude level detection means (23). Switching control means 2 for giving an instruction to change and switch the inversion and non-inversion relations with respect to the signal line (L2).
4. A signal transmission device, characterized in that 3. The signal transmission device according to claim 2, wherein the timing adjusting means (21) requests the external predetermined device to transmit the determination pattern,
The polarity determination signal is not inverted through the transmission / reception block (15) in synchronization with the reception timing of the determination pattern, using the signal received from the external predetermined device after the request time as the determination pattern. A signal transmission device characterized by instructing the transmission / reception block (15) to output to the one signal line on the side connected to. 4. When a predetermined judgment pattern is given to either the first signal line (L1) or the second signal line (L2) from the outside through a transmission line, it is inverted by a signal changeover switch (14). Without applying a polarity determination signal having the same timing and the same waveform as the determination pattern to one of the signal lines on the side that is not connected, and in parallel with the first step, Second step of recognizing the amplitude of the composite pattern by superimposing the signal of the one signal line on the side that is connected without being inverted and the signal of the other signal line that is connected in reverse And a transmitting / receiving means (15) for the first signal line (L1) and the second signal line (L2) of the signal changeover switch (14) when the amplitude of the combined pattern is equal to or larger than a predetermined amplitude. The inversion and non-inversion relation to While lifting, the first signal line the on signal changeover switch (14) when the amplitude of the combined pattern is less than a predetermined amplitude (L
1) and a third step of mutually changing and switching the inversion and non-inversion relations of the second signal line (L2) with respect to the transmitting / receiving means (15). 5. The signal transmission method according to claim 4, wherein the first step requests the external predetermined device to transmit the determination pattern, and continues from the request time. The signal received from the external predetermined device is used as the determination pattern, and the one of the side connected without being inverted by the signal changeover switch (14) in synchronization with the reception timing of the determination pattern. The signal transmission device is characterized in that a polarity determination signal having the same timing and the same waveform as the determination pattern is applied to the signal line of FIG.