JPS5825311B2 - remote reader - Google Patents

Description

[Detailed description of the invention] The present invention relates to remote reading devices.

By the way, there are various ways to electrically read the pointer values of electricity, gas, water meters, etc. at a location far from the measurement location, but we will explain the case where an encoder is attached to the meter itself and the digital value corresponding to the pointer value is read. do.

The output of the encoder attached to such a meter is generally taken out as a contact output by a rotary switch mechanism having mechanical contacts that operate in response to a multi-digit indication value such as 3 or 4 digits. Since the indicated value itself is based on a decimal value from "0" to "19", it is normal that the low-return switch mechanism has 10 contacts for each digit.

However, remote reading itself is often carried out in apartment complexes, where meters are installed in each house and meter reading is done at one location. The biggest challenge is how to transmit and concentrate the information in one place and read the guideline values.

To this end, the first step is to simplify the wiring work by minimizing the number of output lines from the encoder, but this must not make the meter or encoder expensive, and the meter or encoder must not become expensive. encoder,
Even if the construction cost is low, the device for centralized reading must not be expensive compared to the size of the system or be unreliable.

For this reason, remote reading devices as shown in FIGS. 1 and 2 have been developed.

In other words, the device shown in Fig. 1 has 10 contacts from ``0'' to ``9'' that have the same numeric values connected in common for the 4-digit numbers ``0'' to ``9'' corresponding to the meter readings. A total of 14 lines, including the data line DL and the four digit lines KL for each digit C1 to C4, are derived from the encoder of each meter,
This is a method for reading a plurality of these meters at one location.

In the figure, 1 is the decimal data from the encoder
Code converter for converting to CD code, 2 is B
This code converter converts a CD code into a 7-segment code for lighting on an LED (light emitting diode) display device 5.

On the other hand, the four digit lines KL are sequentially selected by the shift register 3 based on the signal from the oscillator 4.
Dot the four digits in sequence.

In this way, the LED display device 5 can sequentially display four digits corresponding to the instruction value of the encoder.

Here, by increasing the output frequency of the oscillator 4, display can be performed almost continuously.

However, with this device, the number of connection cables for construction work was as high as 14 cores per meter, and in order to concentrate reading at one location, there was a lot of loss during construction due to complicated wiring and long distance multi-core wiring. .

On the other hand, the device shown in FIG. 2 connects the numerical values of the contacts corresponding to the meter readings in common, and connects each contact with r.

r by arranging 10 equivalent resistances −r9.

This is done by connecting in series from r9 to r9 and applying voltage E to both ends to obtain divided voltages.

Thus, in the example shown, 1m8t"77Z8s
The number of lead lines from the encoder can be reduced by leading three digit lines of the three digits of "Om" from the encoder and reading the divided voltage of each digit with a meter checker.

For example, if the voltage E is IOV, the voltmeter of the meter reading checker corresponding to the 1 mB digit shown in the figure will show 7. From this, it can be known that the indicated value of the meter is "7".

According to this device, the number of lead-out lines from the encoder is only five, and if n is the number of digits, then (n+2) is sufficient, which is economical.

However, in the case of an n-core wire, this method can only read n digits, and a more economical device is desired.

In this way, in conventional remote reading devices, the contact output from each meter is concentrated in one place using multi-core cables, so there is a risk of incorrect wiring during construction and the cost is high. Ta.

Therefore, an object of the present invention is to provide a remote reading device that also satisfies such requirements.

An embodiment of the present invention will be described below with reference to the drawings.

An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, 1 m" + "Om8 of the measuring instrument 16
゜When reading the 4-digit measurement value of 1007713 and 1000m3 by sending it to the reader using a 3-core signal line, 11 to 14
is the encoder for each digit.

For example, movable contacts 11a to 14a that interlock with display character wheels
The contacts corresponding to the same scale of each rotary switch are commonly connected for each scale, and the equivalent resistance r, which is a common impedance element, is established between these commonly connected items.

-r9 is connected to form an impedance element array 15.

One end r9 side of the impedance element array 15 is a diode D.
The anodes of these diodes are connected to the signal lines A, B, and C of the reader 10, respectively.

Also, the other end r of the impedance element array 15. The sides are connected to the anodes of diodes D4-D6, and the cathodes of these diodes are connected to signal lines A, B, C.

That is, the two rectifying element groups are connected between the impedance element array 15 and the reader 10 in opposite directions.

The movable contact 11a of the 1 m 3-digit encoder is connected to a terminal to which the signal line A from the reader 10 is connected via a resistor R1 and a light emitting element such as a phototransistor PT1.
Similarly, the movable contact 12a of the m'fF encoder has a resistance R.
2. It is connected to the terminal to which the signal line A from the reader 10 is connected via the phototransistor PT2.

Also, 100m3゜1000771 buttock movable contact 13a
, 14a are connected to the signal lines B, 14a through resistors R3 and R4, respectively.
Connected to C.

Note that the resistance value of each of the resistors R1 to R4 is resistance r. - Make it larger than the sum of the resistance values of r9.

Furthermore, a light emitting diode LD1. LD2 is connected, and the phototransistor PTl transfers the light from the light emitting diode LD1 to the phototransistor PT2.
is configured to receive light.

Phototransistor PT1 is a switching element controlled by light emitting diode LD1.

Also, phototransistor PT2, light emitting diode LD1
The same is true.

The movable contacts 11a and 12a are phototransistors P Tl
The reason why they are connected to the same signal line A via ePT2 is to interrupt and read the movable contact 12a, that is, the value in the 10 m3 digit, when obtaining the divided voltage from the movable contact 11a, as will be described later.

The same applies when obtaining the divided voltage from the movable contact 12a.

The reader 10 to which signal lines A, B, and C are connected has signal lines A,
Changeover switch S with movable contacts connected to B and C respectively
It has WA, SWB, and SWC, and these changeover switches SW
A, SWB, and SWC have four fixed contacts (a and b, respectively).
, c, d).

These changeover switches are usually composed of a 3-circuit, 4-contact type changeover switch SW, and the width of 1m3゜107713,
It is provided to display 4 digits of 07713 and 1000m3.

The voltmeter S, which is an electric quantity detection device, displays the measured value of the desired selected digit, and the diodes D7 and D8 inserted on both sides of the voltmeter S are connected to the diodes D1 to D inside the measuring instrument 16.
It is inserted to compensate for errors due to voltage drop at 6.

In such a configuration, if the changeover switches 5WA-8WC, which operate in conjunction with each other, are now in the a position shown in the figure,
Signal line B becomes a positive voltage, and signal line C becomes a negative voltage.

Therefore, the light emitting diode LD1 of the photocoupler P1
is forward biased and emits light, which turns on the phototransistor PT1, but the photocoupler P
Since the second light emitting diode LD2 is biased in the reverse direction, the phototransistor PT2 remains in the off state.

Thus, the indicated value voltage of 1 m1v is transmitted to the signal line A via the resistor R1 and the phototransistor PT1, and the indicated value can be read by the voltmeter S via the contact a1 of the changeover switch SWA and the diode D6.

When the changeover switches 5WA-8WC are switched to the b position, the signal line B is biased to a negative voltage and the signal line C is biased to a positive voltage.

Therefore, the photodiode P of photocoupler P2'
T2 is turned on by light emission from the light emitting diode LD2, and the phototransistor PT1 is turned off.

As a result, the indicated value voltage of 10 m3 digits is transmitted to the signal line A via the resistor R2 and the phototransistor PT2, and the indicated value can be read by the voltmeter S via the contact b1 of the changeover switch SWA and the diode D8.

Further, by switching the changeover switch 5WA-8WC to the C position, it is possible to read an indicated value of 100 m%, and by switching it to the d position, it is possible to read an indicated value of 1000 m''.

Here, if the respective positions of the changeover switches 5WA-8WC and the respective states of the signal lines A-C are summarized in a table, the following Table 1 will be obtained.

Note that R indicates a measurement end.

As described above, according to one embodiment of the present invention, three signal lines can generate four digits, and further 100772. ”digit and 1000rrL
By similarly providing a photocoupler for the third digit, it is possible to read up to six digits with three signal lines, which is extremely economical.

In the above embodiment, the case of a 3-core transmission line was described, but if the number of digits to be read is further increased, the number of rectifying element groups on both sides is increased to n.
is a natural number, n≧3), and in this case a maximum of 2n digits can be read.

Further, although an example has been described in which a photocoupler is used as a means for detecting the bias state of a transmission line, the configuration can also be made using other switching elements such as rectifying elements or relays.

[Brief explanation of drawings]

FIGS. 1 and 2 are circuit diagrams showing examples of conventional remote reading devices, respectively, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. 1.2... Code converter, 3... Shift register, 4... Oscillator, 5... LED display device, 10...
...Reader, 11-14...Encoder, 11a-1
4a... Movable contact, 16... Measuring instrument, ro-r9.
R1-R4...Resistor, P1-P2...Photocoupler, LDl, LD2...Light emitting diode, PTl, PT
2...Phototransistor, D1-D8...diode, SW...changeover switch, S...voltmeter.

Claims (1)

[Scope of Claims] 1. A reading device for reading the indicated value of a measuring instrument having an encoder of at least three digits or more via at least three signal lines with a reader located at a remote location, the measuring instrument comprising: (1) ) an impedance element array formed by connecting common impedance elements between the fixed contacts of the encoder of each digit that are commonly connected for each numerical value;
(2) a first rectifying element group whose respective cathodes are connected to one end of this impedance element array and whose respective anodes are connected to the signal line of the corresponding digit; (3)
(4) a second rectifying element group whose respective anodes are connected to the other end of the impedance element array and whose respective cathodes are connected to the signal line of the corresponding digit; (5) a number of impedance elements corresponding to the number of digits each having an impedance corresponding to the number of digits, one end of which is connected to the movable contact of the encoder of each digit; and (5) two impedance elements among the impedance elements are commonly connected. signal line and the above 2
It consists of two switching elements connected to the paths between each of the impedance elements, and the switching control voltage input terminal of each switching element is connected to a predetermined line other than the signal line to which the two impedance elements are connected. When the voltage applied to this switching control voltage input terminal has one polarity, one switching element closes and the other switching element opens, and the applied voltage The reader has at least one set of a pair of switching elements in which one switching element is open and the other switching element is closed when is the other polarity, and the reader has (6) @ impedance element array. (7) a power supply for applying a voltage across both ends of the switch and supplying a voltage for controlling the switching element; A quantity of electricity detection device that detects the quantity of electricity that is generated;
8) Connected to each of the at least three signal lines, the contacts for each digit can be switched according to an arbitrarily selected digit, and the movable contacts of the encoder of the digit corresponding to the selected digit are connected to the at least three signal lines. Connect the connected signal line to the signal output terminal, and selectively connect the positive and negative poles of the power source with the selected polarity between the two predetermined signal lines other than the signal line corresponding to the selected digit. A remote reading device characterized in that it has a changeover switch that allows it to read up to twice the number of digits as the signal line.