JPS5825312B2 - remote reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for remotely reading the readings of a scale.

For example, there are various methods of electrically reading the indicated value of a meter for electricity, gas, water, etc.

Among them, there is a reading system in which an encoder is added to these measuring instruments.

As this encoder, a rotary switch having a mechanical contact that operates in response to a multi-digit instruction value of three or four digits is generally used, and the output is often taken out as a contact output.

In this case, the indicated value is “0” to “9” as it is displayed in decimal notation.
It is customary to use a rotary switch with 10 contacts for each digit.

In this case, remote reading is often installed in apartment complexes with the purpose of meter reading in one place and meter reading in each unit. The biggest issue is how to read it properly.

Therefore, it is most convenient to simplify the wiring work by minimizing the number of output lines from the encoder.

In this case, the conditions are that the prices of scales and encoders do not increase, that the central reading device is not expensive compared to the size of the system, and that it is highly reliable.

The circuits of FIGS. 1 and 2 are illustrative of previously provided remote reading systems that meet the above requirements.

First, the method shown in Figure 1 is from 0 to 9 corresponding to the reading on the measuring instrument.
A total of 14 lines, including 10 data lines up to and four digit lines for each digit C1 to C4, are led out from the encoder, and a plurality of these lines are read at one location.

This is a shift register S according to the output of the oscillator O8C.
R switches the digit lines C1 to C4 and accordingly switches the digits of the display DP, while the decimal signals on the output lines 0 to 9 are converted into BCD codes by the first code converter CC1, and then the digits of the display DP are changed. Display D by code converter CC2 of 2
However, in this method, the number of connection cable cores per weighing scale is 14, which means that the cable must be drawn over a long distance. It is unsuitable for applications in turning or complicated wiring systems, or for concentrating many machines.

Furthermore, in the method shown in FIG. 2, the numerical values of the contacts corresponding to the indicated values of the measuring instrument are connected in common, and r is connected between the contacts.

By arranging 10 equivalent resistors −r9, ro
to γ9 are connected in series, and a supply voltage E is applied across them.

In the case of this figure 2, the number of lead lines from the encoder can be reduced by deriving three digit lines of 1 m3゜10 m3.100 m'' and reading the divided voltage of each digit with the circuit configuration shown. .

For example, if the supply voltage E is 10■,
The reading of the voltmeter connected to the m3 digit is 7■, which can be recognized as a reading of 7.

In this case, the number of lead-out lines from the encoder may be 2+n (n is the number of digits), and the number of lines is quite small.

However, five wires were still required to read a three-digit number, and there was a high risk of wiring errors during wiring work.

The present invention was made as part of the development of such a remote reading device, and it is possible to read the indicated value of a measuring instrument with at least three digits or more with fewer lead wires, using the same number of signal wires as the number of digits. Moreover, it is an object of the present invention to provide a remote reading device with a simple structure.

To achieve this objective, in the present invention, rectifying element groups are connected in opposite directions between both ends of the impedance element row of the measuring instrument and the terminals of each digit to which the signal line is connected, and the rectifying elements are connected in opposite directions to correspond to the movable contacts of the encoder. A measuring instrument is constructed by connecting an impedance element between the terminals, and when a signal line of one digit is selected for reading any one digit, a voltage is applied to signal lines of at least two other digits. A remote reading device is constructed that includes a reader having a changeover switch for simultaneous selection and a device for detecting the amount of electricity obtained from one selected digit.

An embodiment of the present invention will be described below with reference to FIG. 3 ayb.

FIG. 3a shows an embodiment of the present invention, in which a measuring instrument ME is configured to display three digits and perform measurement.

E C1t E C2 and EC3 are, for example, 10°,
It is an encoder for each digit of 101 and 102, and the movable contacts M C1t M C2t M C
3 rotates and comes into contact with any of the fixed contacts 0 to 9.

Normally, this encoder is linked to the display character wheel.
A contact rotary switch is used.

Fixed contacts of each digit encoder EC1, EC2 and EC3 are connected in common to those having the same value, and an equal value resistor r, which is a common impedance element, is connected between adjacent contacts.

-r8 are connected to each other, and one end of a resistor γ9 which is an impedance element is connected to the fixed contact 9, thereby forming a resistor array which is an impedance element array.

A signal line A is connected to both ends of this resistor string via diodes D1 to D3 and D4 to D6, which have the same number as the number of digits to be read.

Connect to B and C.

The diodes D1 to D3 are connected in the same direction,
Furthermore, the diodes D4 to D6 are also connected in the same direction.

However, diodes D1-D3 and diodes D4-D6 are connected in opposite directions.

These diodes constitute a rectifying element group.

As a result, the resistor array forms a closed circuit that conducts directional current through the diode.

In addition, resistors R1e R2e R3, which are impedance elements, are connected to the terminals of the measuring instrument connected to the signal lines A, B, and C.
Each movable liquid of encoders EC1 to EC3, individual cI
~MC3 is connected.

Here, what about the resistances R1 to R3? ”0-1 for r9 <
It is in the relationship of R.

Note that γ=γ0+rl+...+r.

Signal lines A, B, and C are connected to a reader MS.

The reader MS consists of a power source E, a display S forming an electrical quantity detection device and displaying measured values, and a three-position three-circuit switch SW.

The switch SW has switches SWa, SWb, and SWc that operate in three positions (10° and 101.10" in FIG. 3a) for each of the signal lines A, B, and C, and
By switching these simultaneously, it is possible to display 10° on display S.
, 101, and 102 digits are displayed.

FIG. 3 shows how the signal lines A, B, and C are connected by switching the switch SW in FIG. 3a.

Then, turn switch SW to 10°. By switching to the three positions of 101 and 102, signal lines A, B, and C have R9+,
- three polar voltages appear in a predetermined order.

The reading verification procedure is, for example, to read a 10 degree digit, supply a positive voltage to B and a negative voltage to C among the three signal lines A, B, and C, and extract the corresponding voltage from A. Make it.

In circuit terms, the positive voltage applied to the signal line B via the switch sb at the 10° position passes through the diode D2, reaches the resistor r9, and passes through the resistor string to the resistor r.

One closed circuit returns from the negative side of the power supply to the switch SWc at 10° via diode D6 and signal line C, and from the negative side of the power supply to diode D8, indicator S1 and diode D7.
, the switch S W a , the signal line A1 resistor R1, and further the resistor r through the contact "2" between the resistors r1 and r2.

, diode D6 and another closed circuit returning to switch SWc located 10° from signal line C, with the latter closed circuit measuring the divided voltage.

10 by operating the changeover switch SW in the same manner.
Can measure 1 digit and 102 digits.

In the circuit of FIG. 3a, diodes D7. inserted on both sides of the display S. D8 is inserted to compensate for errors due to voltage drops in the diodes D1 to D6 on the encoder side.

Further, the resistors R1 to R3 are set at γ so that the voltage to be applied to both ends of the resistor string is not bypassed by the line from the movable contact.

It is necessary to make it sufficiently large compared to the total resistance value from to r9.

Furthermore, the display S should ultimately indicate the number of times from 0 to 9.For this, the technology of a digital voltmeter or the like can be used, and a digital display may be provided.

Further, the changeover switch SW does not necessarily have to be a mechanical switch, but can also display three digits simultaneously by performing high-speed switching using a shift register for digit switching.

Furthermore, the present invention is capable of not only reading three digits using three signal lines, but also reading a zero digit (where n is a natural number, n≧3) using n signal lines.

In this case, the number of rectifying elements, such as diodes, connected to both ends of the impedance element array on one side is n.

As described above, the present invention connects a group of rectifying elements in opposite directions between both ends of an impedance element row of a measuring instrument and terminals of each digit to which signal lines are connected, and the terminals corresponding to movable contacts of an encoder. A measuring instrument is constructed by connecting an impedance element between them, and when selecting the signal line of one digit to read any one digit, simultaneously selecting the signal lines of at least two other digits to which a voltage is applied. Since the reader has a changeover switch that detects the amount of electricity obtained from one selected digit, it is possible to remotely read multi-digit measured values with a small number of connection lines, that is, a zero-digit meter. It can be read using n signal lines and can contribute to solving the biggest problem of this type of device.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams of a conventional remote reading device,
FIGS. 3a and 3b are circuit diagrams showing an embodiment of the present invention, and diagrams showing connections of leader lines accompanying switching operations in the embodiment. ro-r9. R1-R3...Resistance, E C...Encoder, MC1-MC3...Movable contact, ME...Measuring device, MS...Reader, SW...Choice switch, S
... Electrical quantity detection device.

Claims (1)

[Scope of Claims] 1. In a device for reading the indicated value of a measuring instrument having an encoder of at least three digits or more by a reader at a remote location via the same number of signal lines as the number of digits, the measuring instrument has the following functions: An impedance element array formed by connecting common impedance elements between the fixed contacts of the digit encoder that are commonly connected for each numerical value,
(2) a first rectifying element group whose respective cathodes are connected to one end of the impedance element Ta and whose respective anodes are connected to the signal line of the corresponding digit;
) a second rectifying element group whose respective anodes are connected to the other ends of the impedance element arrays and whose respective cathodes are connected to the signal lines of the corresponding digits; and a number of impedance elements corresponding to the number of digits inserted in the path between the movable contacts of the encoder of each digit and the signal line corresponding to these movable contacts. The reader includes (5) a power source for applying a voltage between both ends of the impedance element array, and (6) a signal line connected between a signal output terminal of the changeover switch described later and a negative electrode of the power source. (7) a quantity of electricity detection device that detects the quantity of electricity obtained from the above; a selector switch that selectively connects the signal line corresponding to the selected digit to the signal output terminal and selectively connects the power source between two signal lines other than the signal line corresponding to the selected digit; A remote reading device comprising: