JPH0993671A - Remote control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remote control system in which a current signal is accurately converted into a voltage signal even when the current consumption of a terminal equipment is fluctuated depending on the polarity of a voltage signal. SOLUTION: When no current signal from a terminal equipment 2 is in existence, since the current consumption of the terminal equipment 2 is stable, in this case, a changeover judgement section 11 connects a switch SW 1 to a terminal α and to set a detection level of a current detection section 11a to a level A. When the current detection section 11a detects a current signal, a changeover judgement section 11d connects the switch SW1 to a terminal βto set a detection level to a level B. Then the current detection section 11a detects the current signal based on the set detection level and provides the output of the detection signal. A conversion section 12 converts the received detection signal into plural polarity voltage signals and provides them to an output section 14. The output section 14 superimposes a power from a power supply section 13 to the terminal equipment 2 onto the conversion signal received from the conversion section 12 and provides the output of the result to a transmission line Ca.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control system capable of communicating between terminals.

[0002]

2. Description of the Related Art In a conventional remote control system, when communication is performed between terminals, one terminal sends a current signal, and a parent device processes the current signal and converts it into a voltage signal. The other terminal communicates by transmitting and receiving the voltage signal. However, in the above case,
Since the arithmetic processing unit of the master unit is necessarily involved in the communication between the terminal devices, it is impossible to communicate between the terminal devices without going through the master device.

In order to solve the above-mentioned problems, the present applicant has proposed Japanese Patent Application No. 07-241996 (prior application). 3 is an overall configuration diagram showing an example of the remote control system shown in the prior application, and FIG. 4 is a signal waveform diagram showing an example of signals input to and output from the signal converter 1 according to the earlier application. In the remote control system, a plurality of terminals 2 are connected to the signal converter 1 via a pair of transmission lines Ca.

In the remote control system of the prior application, when the terminal device 2 communicates with another terminal device 2, one terminal device 2 sends a current signal and the signal converter 1 sends the current. The signal is converted into a voltage signal and transmitted, and the other terminal device 2
Communicates by receiving the voltage signal,
The terminal device 2 itself could not convert the signal into voltage.

FIG. 5 is a flowchart showing the operation of the remote control system according to the prior application. In FIG. 5A,
When the current signal from the terminal 2 is not flowing, as shown in FIG.
As shown in (e), the voltage between the transmission lines Ca becomes Va,
The current consumption of the terminal device 2 is Ia as shown in FIG. When the current signal flows, the signal converter 1 changes the voltage between the transmission lines Ca to -Va.

[0006]

However, in the remote control system having the above-mentioned configuration, the current consumption of the terminal 2 varies depending on the polarity of the voltage between the transmission lines Ca,
If ΔI changes with respect to Ia as shown in FIG. 5B, the current on the transmission line Ca is the sum of the consumption current and the current signal, so that the current signal as shown in FIG. It will flow on the transmission line Ca.

Here, if the detection level of the detection unit for detecting the current signal of the signal converter 1 is one and the value is set as shown in FIG. 5C, the detection signal in the signal converter 1 is set. Cannot detect an accurate current signal as shown in FIG. 5D, and as a result, it cannot be converted into a voltage signal correctly as shown in FIG. There was a problem.

The present invention has been made in view of the above points, and an object thereof is to accurately convert a current signal into a voltage signal even if the current consumption of the terminal device changes depending on the polarity of the voltage signal. It is to provide a remote control system that can be converted.

[0009]

According to the first aspect of the present invention,
A plurality of terminals including a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal, a detector for detecting a current signal from the terminal and outputting it as a detection signal, and the detection A conversion unit for converting the detection signal output from the unit into a bipolar voltage signal, a power supply unit for outputting power supplied to the terminal unit, and a bipolar unit voltage signal converted by the conversion unit for the terminal unit from the power supply unit. And a signal converter having an output unit for superimposing and outputting the power supplied to the pair of transmission lines,
In the remote control system in which the current signal from the terminal device is converted into a bipolar voltage signal by the signal converter and output to the terminal device to perform communication between the terminal devices, the signal converter is A detection level setting unit that sets two detection levels of different current signals detected by the detection unit, and a switching determination unit that switches between two different detection levels set by the detection level setting unit, The detection level setting unit is set to a high detection level in advance, and when the detection unit detects a current signal, the switching determination unit switches to a lower detection level.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a signal converter 1 of a remote control system according to an embodiment of the present invention. The system configuration of the remote control system according to the present embodiment is the same as that of FIG.
Is connected to the signal converter 1 via a pair of transmission lines Ca. The signal converter 1 according to the present embodiment includes the detection unit 11
And a conversion unit 12, a power supply unit 13, and an output unit 14. The detection unit 11 detects the current signal transmitted from the terminal device 2 and outputs it as a detection signal to the conversion unit 12. The detection unit 11 includes a current signal detection unit 11a and a detection level setting unit 11b.
11c, a switching determination unit 11d, and a switch SW1. The current signal detector 11a detects the current signal transmitted from the terminal device 2 and outputs it as a detection signal. The detection level setting units 11b and 11c set the detection level of the current signal detected by the current signal detection unit 11a, and are set to the detection levels A and B, respectively. The detection level setting unit 11b is connected to the terminal α, and the detection level setting unit 11c is connected to the terminal β. In this embodiment, the detection level A>
The detection level is B. The switching determination unit 11d switches the switch S when the current signal is detected by the current signal detection unit 11a.
W1 is switched to change the detection level,
In the present embodiment, the switch SW1 is connected to the terminal α side when the current signal is not detected, and the switch SW1 is connected to the terminal β side when the current signal is detected. The conversion unit 12 converts the detection signal output from the detection unit 11 into a bipolar voltage signal and outputs the voltage signal as a conversion signal. The power supply unit 13 outputs the power supplied to the terminal device 2. The output unit 14 superimposes the power supplied from the power supply unit 13 on the converted signal output from the conversion unit 12 and outputs the superimposed power to the transmission line Ca.

The operation of this embodiment will be described below with reference to the drawings. FIG. 2 is a timing chart showing the operation of the remote control system according to this embodiment. FIG.
When there is no current signal from the terminal device 2 as shown in (a), the current consumption of the terminal device 2 is stable as shown in FIG. 2 (b). At this time, the switching determination unit 11 connects the switch SW1 to the terminal α side in advance, and the current signal detection unit 1
The detection level of 1a is set to the detection level A in advance.

When the current signal is transmitted from the terminal device 2, the current signal detector 11a detects the current signal and outputs it as a detection signal. At this time, the current signal on the transmission line is the sum of the current signal from the terminal and the consumed current, and thus has a waveform as shown in FIG. Switching determination unit 11d
When the detection signal is detected, the switch SW1 is connected to the terminal β side to set the detection level to the detection level β. By doing so, the conversion unit 12 has the configuration shown in FIG.
A detection signal as shown in is input. When the detection signal is input, the conversion unit 12 converts the detection signal into a bipolar voltage signal and outputs it as a conversion signal. The output unit 14 superimposes the power supplied from the power supply unit 13 to the terminal device 2 on the converted signal input from the conversion unit 12 and outputs the superimposed signal to the transmission line Ca.

If the detection level of the current signal detecting section is set to a low detection level in advance, the current signal for operating the relays and the like of the terminal 2 will be converted into a voltage signal. In the form, the detection level is switched.

Therefore, in the present embodiment, the terminal 2
When the current signal transmitted from the
Since the switching determination unit 11d is configured to switch the detection level of the current signal of the current signal detection unit 11a to a low detection level, the current signal is not affected by the fluctuation of the current consumption of the terminal device 2 due to the polarity of the voltage signal. It can be accurately converted into a voltage signal.

[0015]

According to the first aspect of the present invention, a plurality of terminals having a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal, and a current signal from the terminal are provided. A detection unit that detects and outputs as a detection signal, a conversion unit that converts the detection signal output from the detection unit into a bipolar voltage signal, a power supply unit that outputs power supplied to the terminal device, and a bipolar unit that is converted by the conversion unit And a signal converter having an output unit for superposing and outputting the power supplied from the power supply unit to the terminal unit to the pair of transmission lines, and converting the current signal from the terminal unit into the signal conversion unit. In a remote control system in which a voltage signal is converted into a bipolar signal by a device and output to the terminal device to perform communication between the terminal devices, the signal converter has a different current signal detected by the detector. Detection level setting to set one detection level Unit and a switching determination unit for switching between two different detection levels set by the detection level setting unit, the detection level setting unit is set to a high detection level in advance, and the current signal is detected by the detection unit. When it is detected, the switching determination unit switches to a lower detection level, so a remote control system that can accurately convert a current signal to a voltage signal even if the current consumption of the terminal device varies depending on the polarity of the voltage signal is provided. Could be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a signal converter of a remote control system according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the remote control system according to the present embodiment.

FIG. 3 is an overall configuration diagram showing an example of a remote control system according to a prior application.

FIG. 4 is a signal waveform diagram showing an example of signals input to and output from a signal converter according to the prior application.

FIG. 5 is a timing chart showing the operation of the remote control system according to the prior application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 signal converter 2 terminal device 11 detection unit 11a current signal detection unit 11b, 11c detection level setting unit 11d switching judgment unit 12 conversion unit 13 power supply unit 14 output unit Ca transmission line SW1 switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunobu Kuroda 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (1)

[Claims] 1. A plurality of terminals comprising a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal,
A detection unit that detects a current signal from the terminal and outputs it as a detection signal, a conversion unit that converts the detection signal output from the detection unit into a bipolar voltage signal, and a power supply unit that outputs power supplied to the terminal. A signal converter having an output unit for superimposing and outputting the power supplied to the terminal device from the power supply unit to the bipolar voltage signal converted by the conversion unit is connected to a pair of transmission lines, In the remote control system in which the current signal from the terminal device is converted into a bipolar voltage signal by the signal converter and output to the terminal device to perform communication between the terminal devices, the signal converter is A detection level setting unit that sets two detection levels of different current signals detected by the detection unit, and a switching determination unit that switches between two different detection levels set by the detection level setting unit, The inspection A remote control system level setting section, may be set in advance high detection level, and a current signal by the detection unit is to switch to the low detection level by the switch judgment unit to be detected.