JPS5850395B2 - Impedance signal transmitter/receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an impedance signal transmitting/receiving device capable of transmitting four impedance signals obtained on a transmitting side to a receiving side via a two-core cable.

For example, when reading the amount of gas or water used in each house or office in a housing complex or multi-tenant building, it is very convenient if the indicator is concentrated on one side.

In order to meet such demands, various types of flowmeters, which are referred to as remote meter types, have been considered.

These conventional remote meter flowmeters first convert the mechanical signal obtained by the flow rate detection section into an electrical signal, send this signal to a pointer section located far away from the flow rate detection section, and operate the pointer section using the signal. I have to.

However, in conventional remote measuring flow meters of this type,
For example, in the case of three digits, at least five lead wires must be used to connect the detector to the pointer, that is, the transmitter and receiver, and the distance between the two is several hundred meters. However, if there is a system in place, the installation costs would be enormous and the implementation would be complicated.

The present invention was made in view of these circumstances, and its purpose is to be able to transmit four electrical signals, that is, four impedance signals, to a remote location using a two-core cable, for example. An object of the present invention is to provide an impedance signal transmitting/receiving device that is highly effective when applied to remote flowmeters, control monitoring systems, and the like.

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

Note that the figure shows an example in which the present invention is applied to a remote measurement type flow meter.

Figure 1 shows the overall structure.This flowmeter is roughly divided into a transmitting section 1, a receiving section 2 that receives signals from the transmitting section 1, and an electrical connection between the receiving section 2 and the transmitting section 1. It consists of a two-core cable 3 that connects to.

The transmitter 1 is configured as follows.

That is, the rotating shaft of the flow rate sensor 11, which rotates at a speed proportional to the flow rate, is connected via the electromagnetic coupling 12 to the drive shaft of the counter 13, which moves mechanically.

The counter 13 has four digits of rotational needle parts 14a, 14b, 1
4c and 14a, and is configured such that the total value of each pointer corresponds to the integrated flow rate.

Rotary continuous changeover switches 15a, 15b, 15
c.

A rotating shaft 17 that drives the switching contact 16 of 15d is connected to each digit.

That is, the pointer section 14a is the lowest digit, and this pointer section 1
The shaft 4a is the rotation shaft 1 of the rotary continuous changeover switch 15a.
It is connected to 7.

The rotary continuous changeover switch 15a. 15b, 15
c, 15d is the pointer portion 14a.

Each has a total of 10 fixed contacts from 0 to 9 corresponding to the scales 14b, 14c, and 14d,
Corresponding fixed contacts are connected in common.

Resistors 18-1, 18-2, . . . , 18-9 whose values gradually increase are connected between the fixed contacts.

Note that the O-th fixed contact is connected to the output terminal A via a resistor 18-0.

On the other hand, each rotary continuous changeover switch 15a, 15b, 1
The switching contacts 16 of 5c and 15d are diodes 19a and 19b of the illustrated polarity, respectively.

Terminal 21a of changeover switch 20 via 19c and 19d
, 21b, 21c, and 21d.

The changeover switch 20 forms a part of a two-way latching relay 23, which will be described later, and has changeover contacts 22a and 22b. 22b is set to be switchably connectable to the terminals 21b and 21d.

The switching contacts 22a and 22b are connected to the output terminal B in common.
It is connected to the.

Further, between the output terminals A and B, there is a drive coil 24a for the two-way latching relay 23.

24b is a Zener diode 25a with the illustrated polarity.

They are connected in parallel via 25b.

Note that 26 in the figure indicates an arrester.

Therefore, the output terminals A and B of the transmitter 1 have two terminals for transmission.
One end of the core cable 3 is connected, and the other end of the two-core cable 3 is connected to input terminals C and D of the receiving section 2.

The receiving section 2 is configured as follows.

That is, the input terminals C and D are connected to the input terminals of the interlocking switch 31, and one output terminal 32 of the interlocking switch 31 is grounded via the switch 34, and also grounded via the switch 35 and the DC power supply 36 of the polarity shown. Then, the other output terminal 33 of the interlocking switch 31 is connected to the switch 37.
It is grounded via a switch 38 and a DC power supply 39 with the polarity shown.

In addition, the output terminal 32° 33 is connected to a constant current source 40.4 with the polarity shown.
1 and is connected to the input terminal of the voltage adder 42.

Then, the output of the voltage adder 42 is the comparator 43-0...
- Introduced to one input end of 43-10.

At the other input terminal of the comparators 43-0...43-10,
11 resistors 45-0 equal to the output of the constant current source 44...
- Voltages divided and weighted by 45-10 are introduced respectively.

Note that the constant current sources 40, 41, and 44 are obtained from the same reference power source and are configured to output the same power source.

On the other hand, the outputs of the comparators 43-0...43-9 are introduced into a voltage-to-binary signal converter 46 and converted into a binary signal, and this binary signal is provided corresponding to each digit. Latch circuits 47a, 47b, 47c.

47d.

and a latch circuit 47a. The outputs of 47b, 47c, 47d are sent to display signal converters 48a, 48b, 48c,
48d, this display signal converter 48a, 48b
, 48c.

The output of 48d is a 7 segment display 49a.

49b, 49c, and 49a.

Thus, the on/off operations of the switches 34, 35, 37, 38 and the latch circuits 47a, 47b, 47c.

The latch operation of 47d is controlled by a timing circuit 50 according to the relationship described later.

Next, the operation of the apparatus of the present invention constructed as described above will be explained.

First, when the shaft of the flow rate sensor 11 rotates, the pointers 14a and 14b of the counter 13 rotate.

14c and 14d move forward, and along with this, the rotary type changeover switches 15a, 15b, and 15c.

Each switching contact 16 of 15d also moves.

Now, at a certain point in time, the pointers 14a, 14b, 14c.

If the indicated value of 14d is 9681 from the most significant digit, the switching contact 16 of the rotary continuous changeover switch 15d becomes the 9th fixed contact, and the rotary continuous changeover switch 1
The switching contact 16 of the rotary continuous changeover switch 15a is in contact with the sixth fixed contact, and similarly the switching contact 16 of the rotary continuous changeover switch 15a is in contact with the first fixed contact.

Then, the switch 31 of the receiving section 2 is turned on, and the time point t shown in FIG. 2 is reached.

When the timing circuit 50 is brought into operation, the timing circuit 50 turns on the switch 34 and the switch 38.

When the switches 34 and 38 are turned on, the voltage across the DC power supply 39 is applied between the output terminals A and B of the transmitter 1.

If this applied voltage is higher than the Zener voltage of the Zener diode 25a, one drive coil of the bidirectional latching relay 23, for example 24a, is energized, and this energization causes the changeover contacts 22a and 22b of the changeover switch 20 to change as shown in the figure. , the switching contact 22a is switched to the terminal 21.
a, and the switching contact 22b contacts the terminal 21b.

The timing circuit 50 controls the switch 38 so as to turn it on for a very short period of time, and releases the switch 38 from the on state at time t1 shown in FIG.

When the timing circuit 50 turns off the switch 38, only the constant current source 41 is connected between the output terminals A and B of the transmitter 1, so that the constant current I is supplied to the transmitter 1.

Now, the current value is set so that even if a constant current is supplied when the impedance seen from the output terminals A and B of the transmitter 1 is maximum, the voltage between A and B will be less than the Zener voltage of the Zener diode F25a. Assuming that the supplied constant current (2) is shunted and flows through the resistors 18-0, 18-1, .

However, in this case, since the diode 19b is connected to the switching contact 16 of the rotary continuous changeover switch 15b with the opposite polarity, the supplied constant current I ends up flowing through the output terminal A.
~Resistor 18-0~Resistor 18-1~The first terminal of rotary type changeover switch 15a and changeover contact 16~Diode 19a~Output terminal B.

Therefore, assuming that the resistors 18-0 and 18-1 are each R, a voltage of 2RI will appear between the input terminals C and D of the receiving section 2, as shown in FIG. 2f.

This voltage is introduced into a group of comparators via a voltage adder 42, and then converted into a digital signal by a voltage-to-binary signal converter 46, where the converted value is 1 in decimal.

Then, the timing circuit 50 outputs the latch circuit 47 at time t2.
Give a latch signal to a.

Therefore, 1 is displayed on the display 49a.

In other words, the display is the same as the one-digit pointer 14a of the counter 13.

Next, at time t3, the timing circuit 50 turns off the switch 34 and turns on the switch 37.

In this case, the constant current source 40 is connected between the output terminals A and B of the transmitter 1, and a constant current I of the polarity flowing from the output terminal B to the output terminal A is supplied.

This constant current I flows from output terminal B to diode 19b to switching contact 16 of rotary type changeover switch 15b, and from the eighth terminal to resistor 18-8, 18-7...18-1, 1
8-0~flows through output terminal A.

Therefore, assuming that the value of each of the above-mentioned resistors is R, there is a resistance of 9R between the input terminals C2 and D of the receiving section 2 as shown in FIG. 2g.
The voltage of I will appear.

This voltage is converted into a binary signal as described above, and the exchange value at this time is 8 in decimal.

Then, the timing circuit 50 controls the latch circuit 4 at time t4.
A latch signal is given to 7b.

Therefore, the display 49b displays the number 8, that is,
The same display as the two-digit pointer section 14b of the counter 13 is made.

In this way, when the time point t5 is reached, the timing circuit 5
0 turns on switch 35 for a short period of time.

When the switch 35 is turned on, the blade terminals A and B of the transmitter 1
In between, the B side is positive and a Zener diode 25b is connected.
Since a voltage equal to or higher than the Zener voltage is applied, the other drive coil 24b of the two-way latching relay 23 is energized, and this energization holds the changeover switch 20 exactly in the state shown.

The switch 35 is turned off at time t6.

At this point, the constant current source 40 is connected between the output terminals A and B of the transmitting section 1, so the transmitting section 1 has the output terminal B, the diode 19c, the switching contact of the rotary type changeover switch 15c, and the resistor. 18-6, 115...1B
-1°18-0 ~ Constant current ■ flows through output terminal A.

Therefore, a voltage of 7RI appears between the input terminals C and D of the receiving section 2, and this voltage is converted into a binary signal as described above, and this converted value is 6 in decimal notation.

Then, the timing circuit 50 controls the latch circuit 4 at time t7.
A latch signal is given to 7c.

Therefore, the display 49c displays the number 6, that is, the same display as the three-digit pointer portion 14c of the counter 13.

Further, at time t8, the timing circuit 50 turns off the switch 37 and turns on the switch 34.

In this case, constant current source 4 is connected between output terminals A and B of transmitter 1.
1 will be connected, and the transmitter 1 will have an output terminal A.
A constant current flows through the resistor 18-0.18-1°...18-9, the ninth fixed contact and switching contact 16 of the rotary type changeover switch 15d, the diode 19d, and the output terminal B.

Therefore, between the input terminals C and D of the receiving section 2, 10R
The voltage at I appears, and this voltage is converted to a binary signal as described above, the converted value being 9 in decimal.

Then, the timing circuit 50 controls the latch circuit 4 at time t9.
A latch signal is given to 7d.

Therefore, the display 49d displays 9, that is, the same display as the four-digit pointer section 14d of the counter 13. This means that all the pointer values of each digit of the counter 13 are displayed on the receiver section 2. .

The timing circuit 50 then repeats the series of leg II described above until the switch 31 is turned off.

In this way, a two-way latching relay 2 is attached to the transmitter 1.
3 and four diodes 19a, 19b.

19c and 19d are incorporated into the above relationship to switch the holding state of the latching relay 23 and switch the polarity of the constant current I, so that the four resistances obtained in the transmitter 1, that is, the Four impedance signals can be transmitted to the receiving section 2 via the two-core cable 3.

Therefore, when the remote measurement method is adopted, the number of lead wires connecting the so-called detection part and the measurement part can be significantly reduced compared to the conventional method, so when the centralized measurement method is adopted in apartment complexes and multi-tenant buildings, equipment costs are reduced. can be significantly reduced.

Note that the present invention is not limited to remote flowmeters, but can also be applied to, for example, remote temperature measurement devices that utilize changes in resistance due to temperature, or to remotely measure disconnections in equipment.

Further, two latching relays may be combined so that they can operate in both directions.

As detailed above, according to the present invention, an impedance signal transmitting/receiving device is capable of transmitting four impedance signals to a remote location using a two-core cable, and is highly effective when applied to various remote measuring devices. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram of an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the embodiment. 1... Transmitting section, 2... Receiving section, 3...
...2-core cable, 15a, 1 sb, 1
5c, 1 scl""" Rotary continuous changeover switch that rotates according to the integrated flow rate, 1 B-0, 18-1...
・18-9...Resistance, 19a. 1 sb, 19 c, 1 9d...-
・-Diode, 23-...Two-way latching relay, 40, 41, 44... Constant current source, 3
4, 35.37.38...Power selector switch,
42... Voltage adder, 46... Voltage -
Binary signal converters, 49a, 49b, 49c. 49d... Display unit, 50... Timing circuit, A. B: Output terminal of transmitter, C, D:
Input terminal of the receiving section.

Claims (1)

[Claims] A transmitting section 1 having 12 output terminals, a receiving section 2 having two input terminals, and 2 connecting the input terminal of the receiving section 2 and the output terminal of the transmitting section 1. The transmission section 1 includes substantially four impedance elements whose one end side is commonly connected to one output terminal and whose impedance changes according to the target state quantity, and one of the above-mentioned one of the impedance elements. The drive coil is connected between the output terminal and the other output terminal, and the drive coil is energized by applying a voltage higher than the level in impedance measurement, and is commonly connected to the other output terminal during unidirectional operation. the first and second contacts 21a and 21b, and the third and fourth contacts 21c, which are commonly connected to the other output terminal when operating in the other direction;
A two-way latching relay 23 having four contacts 21d and first and fourth contacts 21a of this relay 23. 21d and the other end sides of two of the impedance elements, two diodes 19a, 19d in the same direction, and these diodes 19a,
19d, and the second and third contacts 21b
, 21c and two diodes 19b and 19c respectively connected between the other ends of the remaining two of the impedance elements, and the receiving section 2 includes:
Voltage applying means 35.36°38.39 for sequentially applying voltages of different polarities for short periods of time between the input terminals for switching the operation of the two-way latching relay 23, and a voltage applying means 35.36°38.39 for applying voltages of different polarities for a short period of time between the input terminals, and during a period when these voltages are not applied. Current supply means 34, 37, which switches and supplies currents of different polarities between the input terminals;
An impedance signal transmitting/receiving device comprising: 40° 41 and means connected between the input terminals to detect and instruct the inter-core pressure of the two-core cable 3.