JPH01202674A - System for detecting opening/closing state of no-voltage contact - Google Patents

Abstract

PURPOSE:To detect the opening/closing state of a contact by reduced power consumption, by intermittently repeating the supply and stop of the voltage from a power supply when the state of the connection part of a no-voltage contact and a current limiting resistor is changed by the closure of the no-voltage contact. CONSTITUTION:The control signal output part 100d of a detector 3 receives the signals from both of a judge part 100b and a timer 100c to preset such a state that voltage is supplied to a no-voltage contact 7A from a power source 104 through a current limiting resistor 103 at first. Thereafter, when the contact 7A is closed by person's operation, the state of the connection part of the contact 7A and the resistor 103 is changed and the output signal SEN of an inverter 102 is detected by a detector 100a and, when it is judged that the level thereof is changed from 0 to 1, the supply of voltage to the contact 7A from the power supply 104 is stopped. Thereafter, control signals *SEN, SW are outputted to an inverter 101 so that the supply/stop of voltage to the contact 7A from the power supply 104 is intermittently repeated until the open state of the contact 7A (the change of the output logic of the inverter 102 from 1 to 0) is detected.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial application field Prior art (Figures 5 to 7) Means for solving the problem to be solved by the invention (Figure 1) Effect (Figure 1) Figure 1) Embodiment (Figures 2 to 4) Effects of the invention [Summary] Open/close state/detection method of a non-voltage contact for detecting the open/close state of a non-voltage contact such as an external push button switch in an LP gas automatic meter reading system, for example. The purpose of this technology is to detect the open/closed state of a non-voltage contact with low power consumption by supplying current from a finite battery to an external non-voltage contact via a resistor. In a voltage-free contact open/close state detection method that detects the open/close state of the voltage-free contact by detecting the state of the connection with a resistor, first, voltage from the finite battery is supplied to the voltage-free contact via the resistor. Then, when the non-voltage contact closes and the state of the connection between the non-voltage contact and the resistor changes, the supply of voltage from the finite battery is stopped. The configuration is such that supply and stop of voltage from the finite battery are intermittently repeated until the open state of the non-voltage contact is detected.

[Industrial Field of Application] The present invention relates to a method for detecting the open/close state of a voltage-free contact, such as an external push button switch in an LP gas automatic meter reading system.

[Prior Art] Fig. 5 is an overall configuration diagram showing an LP gas automatic meter reading system. In Fig. 5, 1 indicates an LP gas consumer, 2
is an information processing center.

First, the LP gas consumer 1 is equipped with an automatic meter reading terminal device 3, and this automatic meter reading terminal device 3 includes a centrally monitored microcomputer meter 4. Gas leak alarm 5. Seismic sensor6.
Reset switch 7, automatic switching regulator 8. A telephone 9 is connected. In addition.

A backup alarm 10 can also be connected to this automatic meter reading terminal device 3.

Furthermore, the LP gas consumer 1 and the information processing center 2 are
The information processing center 2 is connected via a subscriber telephone line 12, and is provided with a communication control adapter 13, to which a processing device 14 such as a personal computer is connected. . Note that this processing device 1
4 is connected to a printer 15, and an even larger host computer 16 is also connected thereto.

In addition, in FIG. 5, 17 is an LP gas cylinder.

By the way, the relationship between the automatic meter reading terminal device 3 and the reset switch 7 is shown in FIG.

That is, the automatic meter reading terminal device 3 has a reset switch 7
In terms of the relationship with
9, voltage can be supplied to the voltage-free contact 7A of the reset switch 7.

Further, an inverting circuit (inverter) 20 as a digital interface is connected to the connection between the non-voltage contact 7A and the current limiting resistor 19.
The output side of the inverter 2o is connected to a detection circuit 21 that detects the output logic (output level) of the inverter 2o.

With this configuration, the voltage from the power supply 18 is constantly supplied to the non-voltage contact 7A via the current limiting resistor 19, so when the non-voltage contact 7A is open, the output logic of the inverter 20 is It consists of 0. After that, for example, when a person presses the reset switch 7 and the non-voltage contact 7A closes, the input level of the inverter 20 decreases and the output logic of the inverter 2o changes to 1. This change is detected by the detection circuit 21. By this detection, it is detected that the voltage-free contact 7A is closed.

[Problems to be Solved by the Invention] However, in such a conventional open/close state detection method of a voltage-free contact, the voltage-free contact 7A changes from open to closed.
Even after the detection circuit 21 detects that the output logic of the inverter 20 changes from 0 to 1,
As shown in b), while the voltageless contact 7A is closed, the current limited by the current limiting resistor 19 continues to flow, resulting in an increase in current consumption. Such problems are particularly acute considering the use of finite batteries as a power source.

Therefore, it is conceivable to use a large battery in consideration of the above current consumption, but this does not allow for miniaturization and cost reduction of the device.

Therefore, an object of the present invention is to provide a method for detecting the open/close state of a voltage-free contact, which can detect the open/close state of a voltage-free contact with low power consumption.

[Means to solve the problem] FIG. 1 shows a block diagram of the principle of the present invention.

In Fig. 1, D is a no-voltage contact opening/closing state detection device, and S
is an external sensor section, and this sensor section S is.

It has a non-voltage contact SW.

In addition, the control circuit 10 is a non-voltage contact opening/closing state detection device.
0. Inversion circuits (inverters) 101, 102 as digital interfaces. It has a current limiting resistor 103 and a power source 104 consisting of a finite battery.

Here, the control signals $SEN, SW from the control circuit 100
is supplied to the current limiting resistor 103 via the inverter 101, and the current limiting resistor 103 is connected to the non-voltage contact SW. In addition, an inverter 1 is connected to the connection between the current limiting resistor 103 and the non-voltage contact SW.
02 is connected, and the output signal SEN of this inverter 102 is input to the control circuit 100.

Note that the power supply 104 is connected to the control circuit 100,
The electric power is supplied to the current limiting resistor 10 through the control circuit 100.
It is possible to supply to 3 sides.

By the way, the control circuit 100 initially has a current limiting resistor 1.
The voltage from the power source 104 is supplied to the non-voltage contact SW via the voltage-free contact SW 03, and then the voltage-free contact SW is closed.
When the state of the connection with 03, that is, the output logic of the inverter 102 changes, the voltage supply from the power supply 104 is stopped, and thereafter, the voltage from the power supply 104 is stopped until the open state of the non-voltage contact SW is detected. A control signal rate SEN, S is sent to the inverter 101 so that the supply and stop of the
It is now possible to output W.

[Function] With such a configuration, the non-voltage contact switching state detection device initially detects the non-voltage contact SW via the current limiting resistor 103.
When the voltage from the power source 104 is supplied to the terminal, and then the voltage-free contact SW is closed by human operation, the state of the connection between the voltage-free contact SW and the current limiting resistor 103 changes. , the voltage-free contact open/close state detection device stops the voltage supply from the power supply 104, and then intermittently supplies and stops the voltage from the power supply 104 until the open state of the voltage-free contact SW is detected. Repeat.

In this way, the outflow current flows only intermittently during the time when the voltage-free contact SW changes from opening to closing and then to opening again, so that the power source 104 is less consumed.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

This embodiment relates to the LP gas automatic meter reading system shown in Fig. 5, but in the following example, the relationship between the automatic meter reading terminal device and the reset switch, which are related to the present invention, in this system will be explained. explain in detail.

Now, FIG. 2 is a block diagram showing one embodiment of the present invention, and in this FIG. 2, 3 is an automatic meter reading terminal device as a non-voltage contact opening/closing state detection device in the above-mentioned LP gas automatic meter reading system; is a reset switch as an external sensor part in the same LP gas automatic meter reading system, and this reset switch 7 has a non-voltage contact 7A that can be opened and closed by a person.

Also, automatic meter reading terminal bag! 23 is an inversion circuit (inverter) as a control circuit 100° digital interface
101, 102. It has a current limiting resistor 103 and a power source 104 consisting of a finite battery.

Here, the control signal rate SEN, SW from the control circuit 100 is
is supplied to the current limiting resistor 103 via the inverter 101, and the current limiting resistor 103 is connected to the non-voltage contact SW. In addition, an inverter 1 is connected to the connection between the current limiting resistor 103 and the non-voltage contact SW.
02 is connected, and the output signal SEN of this inverter 102 is input to the control circuit 100.

Note that the power supply 104 is connected to the control circuit 100,
The electric power is supplied to the current limiting resistor 10 through the control circuit 100.
It is possible to supply to 3 sides.

By the way, the control circuit 100 includes a level detection section 10Qa, a determination section 100b, a timer 100c, and a control signal output section 10.
0d, the determination unit 100b and the timer 100c
, the control signal output section 100d is functionally provided within the CPU.

Here, the level detection section 100a receives the signal SEN from the inverter 102 and detects the signal level, and the determination section 100b determines the signal level based on the detection signal from the level detection section 100a.

Further, the timer 100c uses the signal SE in the determination unit 100b.
N level ranges from O (low level; L) to 1 (high level;
When it is determined that the signal SEN has changed to H), it is triggered and the level of the control signal SEN and SW is intermittently changed to L or H, and then the determination unit 100b changes the level of the signal SEN from H to L. If it is determined that this is the case, it is reset and outputs a signal for setting the SEN and SW levels of the control signals to L to the control signal output section 100d.

Further, the control signal output unit 100d receives each signal from the determination unit 100b and the timer 100c, and initially connects the power supply 104 to the voltage-free contact 7A via the current limiting resistor 103.
After that, by closing the voltage-free contact 7A, the state of the connection between the voltage-free contact 7A and the current limiting resistor 103 changes, and the output logic of the inverter 102 changes. When the voltage changes from O to 1, the supply of voltage from the power supply 104 to the no-voltage contact 7A is stopped, and thereafter, the voltage supply from the power supply 104 to the no-voltage contact 7A is stopped until the open state of the no-voltage contact 7A is detected. Control signals l5EN and SW are output to the inverter 101 so that supply and stop are intermittently repeated.

That is, the operational flow of the CPU including this control signal output section 100d is shown in FIG. 3.

In this flow, first in step a1, the signal SEN is set to 1.
(H level) is determined, and if YES,
At step a2, the control signal SEN.

SW is set to 1 (H level), and after the required time determined by the timer 1000, the control signal l5ENISW is set to 0 (
After that, in step a5, it is determined whether the output logic of the inverter 102 is O (L level). If NO, return to step a2, and perform steps a3 and 4. After the processing, the process proceeds to step a5. In step a5, if the output logic of the inverter 102 has changed to 1 (H level), the YES route is taken and the process ends.

With the above configuration, for example, at a certain time t, the fourth
As shown in FIG. 4(a), when the non-voltage contact 7A is in an open state, the control signals SEN and SW from the control circuit 100 at this time are at L level as shown in FIG. 4(Q). (0). As a result, the voltage from the power source 104 is supplied to the non-voltage contact 7A via the current limiting resistor 103.

Thereafter, at time t1, the non-voltage contact 7A is closed, thereby connecting the non-voltage contact 7A and the current limiting resistor 103.
The state of the connection with the inverter 102, that is, the output signal S of the inverter 102
When EN changes from 0 to 1 (from L level to H level) [see Figure 4(b)], after the required time delay (time t2
As shown in FIG. 4(C), the control circuit 100 sets the control signals SEN and SW to H level (1) at the time (time point).

As a result, the output level of the inverter 101 is set to L level (
0), and the supply of voltage from the power supply 104 to the non-voltage contact 7A is stopped. Therefore, the outflow current flowing out through the current limiting resistor 103 is as shown in FIG. 4(d).
It flows only from time t to t2.

After that, until the open state of the no-voltage contact 7A is detected,
The control circuit 100 repeatedly changes the output levels of the control signals SEN and SW from H(1) to L(0) or vice versa. That is, at time t, the control signals are zero SEN, SW.
falls to L(0), and then returns to H(1) at time t4.
), and also brought down to L(0) at time 1s,
Further, at subsequent time t6, the voltage is raised to H(1) again, and at one time t, the voltage is lowered to L(0). This allows the power supply 104
The supply and stop of voltage from to the voltage-free contact 7A is repeated intermittently.

In this example, since the non-voltage contact 7A is open at time t7, which is earlier than time t, the control signal skewer SEN
, when SW is turned off at time t, the inverter 10
Since the output of 2 also goes to L level (0) at the same time, the control circuit 100 detects that the non-voltage contact 7A has become open from this state, and from then on, the control signals SEN and SW are set to L level.
Fixed at level (0). This returns to the initial state in which the voltage from the power source 104 is supplied to the non-voltage contact 7A via the current limiting resistor 103 again.

In this way, the voltageless contact 7A changes from open to closed.

The outflow current until it becomes further open is as shown in FIG. 4(d), between times t31 and t4 and at time tstt6.
Since the power supply 104 only lasts for a while, consumption of the power supply 104 is small. As a result, the open/closed state of the voltage-free contact can be detected with low power consumption, thereby making it possible to sufficiently reduce the size and cost of the device.

[Effects of the Invention] As detailed above, according to the method for detecting the open/closed state of a voltage-free contact of the present invention, the outflow current during the period from when the voltage-free contact changes from open to closed until it becomes further open is intermittently Since only a certain amount of current flows, the open/closed state of the voltage-free contact can be detected with low power consumption, which has the advantage that the device can be made smaller and lower in cost.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a flowchart explaining the operation of an embodiment of the invention, and Fig. 4 is a block diagram of the principle of the invention. FIG. 5 is an overall configuration diagram of an LP gas automatic meter reading system. FIG. 6 is a block diagram of a conventional example. FIG. 7 is a time chart explaining the operation of a conventional example. be. In the figure, 3 is an automatic meter reading terminal device as a non-voltage contact open/close state detection device. 7 is a reset switch as a sensor section, 7A is a non-voltage contact, and 100 is a control circuit. 100a is a level detection section. 100b is a determination unit, 100c is a timer, 100d is a control signal output unit, 101.102 is an inverter, 103 is a current limiting resistor, 104 is a power source (finite battery), D is a no-voltage contact opening/closing state detection device, S is a sensor Department. SW is a voltageless contact.

Claims (1)

[Claims] By supplying current from the finite battery (104) to the external non-voltage contact (SW, 7A) via the resistor (103), the non-voltage contact (SW, 7A) and the resistor (103) ) In the open/close state detection method of the no-voltage contact (SW, 7A), the open/close state of the no-voltage contact (SW, 7A) is detected by detecting the state of the connection with the no-voltage contact (SW, 7A). SW
, 7A) is supplied with voltage from the finite battery (104), and then the voltage-free contact (SW, 7A) is closed, thereby causing the voltage-free contact (SW, 7A) and the resistor (SW, 7A) to be connected to each other. 103), the voltage supply from the finite battery (104) is stopped, and thereafter, the finite battery (104) stops supplying voltage until the open state of the non-voltage contact (SW, 7A) is detected. Supplying voltage from the battery (104)
An open/close state detection method for voltage-free contacts that is characterized by intermittent repeated stops.