Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
2001-03-29
2004-08-10
Horabik, Michael (Department: 2635)
Communications: electrical
Continuously variable indicating
With meter reading
C340S693100, C340S315000
Reexamination Certificate
active
06774812
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-206819, field Jul. 7, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device which is used, for example, in a remote data control system and to-be-controlled device, in which transmission/reception of power and data communication between the control device and one or more devices to be controlled, are carried out via two power lines (we refer to the display device as a two-wire type display device, hereinafter). The two-wire type display device is used as a stock display device and price display device, which may be attached to, for example, a display shelf on which various types of sales products are displayed.
2. Description of the Related Art
There are conventionally several types of methods each known as a technique for carrying out data and electric transmission/reception communication which is conducted with use of two power lines. One (called the first method here) is that a high-frequency signal is superimposed on a power line in a transmitter side, and transmitted, and only the high-frequency signal is extracted by means of a band-pass filter on a receiver device side. Another one (called the second method here) is that a pulse signal whose phase is modulated is superimposed on two-wire type DC power lines and then transmitted on the transmitter side. Still another one is that a DC power is transformed into a pulse by periodically disconnecting or short-circuiting one of the two DC power lines, and transmitted on the transmitter side and such a pulse signal is separated with use of a pulse transformer on the receptor device.
With the first method, it is not easy to clear the problem of leakage which is innately entailed to a high-frequency signal or its anti-noise property. For this method, a complicated circuit structure or circuit parts having particularly high characteristics must be employed for modulation, and therefore the production cost becomes remarkably high. The second method requires phase separation and therefore it has a certain limitation in the transmission speed. The third method can simplify the circuit structure, but entails the problem of noise in any way. In any of the above-described cases, it is very difficult to use a great number of receiver devices if the transmission efficiency is taken into consideration.
As a solution to the above-described drawback of the conventional techniques, the applicant of the present invention proposed before a two-wire type data and electric transmission/reception communication technique capable of high-speed and high anti-noise mutual communications between transmitter and receiver, as well as using a plurality of receiver devices, without having leakage of a transmitted power (Japanese Patent No. 2787976).
According to this technique, to summarize, a transmitter-side device is structured such as to make power levels on two power lines into equivalent pulse-like power on the basis of pulse group data containing the address and instruction data of a receiver-side device. Further, the receiver-side device is structured such as to rectify the equivalent pulse-like power received from the two power lines and store it, and to make power levels on the two power lines into equivalent pulse-like power on the basis of pulse group data containing the address of the self device and the data addressed to the transmitter-side device. In each side, the power supply is stopped while receiving power.
However, the above-described two-wire type data and electric transmission/reception communication technique still entails a drawback to be solved.
More specifically, in the case where the transmission and reception of power and data communication are conducted through the two-wire type device, there is a possibility of misjudging the polarity of data when pulse group data flow in time-series. The judgment of the polarity of data has an influence on the contents of the pulse group data after they are recognized by the receiver-side device. Therefore, it is extremely importance to accurately judge the polarity, for example, in the case where a power receiver device is remotely controlled by a power transmitter device.
In most of the cases, a receiver device can be set on or removed from the power line while the line is in an active state (that is, it can be replaced while current is being carried through the line). However, in order to accurately judge the polarity of data, it is necessary to turn off the entire system including the transmitter-side device when a receiver device is set on (into a state where current is not carried). Therefore, in the case of such a system that involves a great number of receiver devices, the operation of these devices is greatly influenced.
Data stored in a receiver device is usually utilized independently within the device itself, and therefore it is not possible to write arbitrary data therein from the receiver side or to read such data at an arbitrary time. If such writing or reading of data can be performed flexibly, it is expected to facilitate the remote control of the receiver-side device by the transmitter-side device while the transmitter device monitoring the receiver device.
Since the receiver device uses the stored power as its power source, it is important for it to reduce the power consumption as much as possible. Therefore, there must create here an inventive idea to maintain the best possible performance in function while keeping the structure of the hardware which consumes the power should be limited to the minimum necessary level. Especially when the receiver-side device includes display means, the power consumption by the display device cannot be neglected.
SUMMARY OF THE INVENTION
The present invention has been proposed to solve the above-described drawback of the conventional technique, and its main object is to provide a two-wire type remote control system which can accurately judge the polarity of data on a receiver side.
Another object of the present invention is to provide a two-wire type remote control system of a general usage of a wide variety, having so various functions and yet suppressed power consumption.
According to a first aspect of the present invention, there is provided a two-wire type remote control system comprising: a wiring case including two power lines; a control device comprising: a generator for generating pulse group data representing an assigned address of a target device to be controlled and control data addressed to the target device; and a power controller for converting DC power into power in equilibrium pulse waveform according to the generated pulse group data, and supplying the converted power to the two power lines; and at least one device to be controlled which is removably attached to the wiring case such that the control device ant the at least one to-be-controlled device are electrically connected to each other via the two power lines, comprising: a charger for rectifying the converted power received from the two power lines, to be charged therein; a polarity identifying circuit for detecting continuation of a logical level of the pulse group data included in the received power for a certain period of time, and identifying a polarity of the pulse group data; a data processor for determining whether or not the assigned address of the self device is included in the received power according to the identified polarity, extracting control data from the pulse group data when the assigned address of the self device is included in the received power, and executing data processing according to the extracted control data; and a display for displaying a result of the data processing by the data processor.
It may be arranged that the at least one to-be-controlled device further comprises: a data generator for generating another pulse group data representing the assigned address
AIOI Systems Co., Ltd.
Bachman & LaPointe P.C.
Horabik Michael
Nguyen Nam V
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