JPS6239796B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention detects the operation of a slave unit such as a fire transmitter or theft transmitter connected to a signal line from a receiver by detecting the value of a specific resistance assigned in advance to each slave unit. The present invention relates to an alarm device that can be identified and displayed.

Conventionally, a device for identifying and displaying slave devices activated by the value of resistivity on the receiver side has a resistor between the signal lines 2 and 2' from the receiver 1, as shown in Figure 1. Child devices 3a, 3 having R ₁ , R ₂ , R ₃ ,...R _o
b, 3c,..., 3n are connected and, for example, when slave unit 3a operates, a voltage whose magnitude depends on its specific resistance R ₁ is generated, so by knowing the line voltage at this time, the specific resistance R Find the value of ₁ , and
The operation of a is displayed.

As described above, devices using specific resistance are used in many security devices and fire detection devices because the principle is simple and the circuits are not complicated and are very inexpensive.

By the way, in order to accurately measure the value of resistivity in the above device, it is necessary to keep the line insulation resistance R _Y at a sufficiently large value so as not to affect the detection of resistivity. Even if a sufficiently large line-to-line insulation resistance _R In this case, the specific resistance of the slave unit measured by the receiver also decreases, and there is a risk that the activated slave unit may be mistakenly identified.

In addition, in the above equipment, from the receiver 1 to each slave device 3a
The line resistance up to ~3n is added to the specific resistance R ₁ ~ _Ro when measured, so if the line is made too long, the line resistance will increase and the specific resistance cannot be measured accurately, making it difficult for the line to be laid. There is a problem with the length being limited.

The present invention has been made in view of the above, and it is possible to accurately determine the specific resistance of a slave unit without being affected by changes in line-to-line insulation resistance or the magnitude of line resistance, and to display identification of activated slave units. The purpose of the present invention is to provide an alarm device that can reliably perform the following.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention. First, to explain the configuration, a pair of signal lines 5, 5' are led out from the receiver 4, and between the signal lines 5, 5', a plurality of slave units 6a, . . . having specific resistances R ₁ to R _o are connected. , 6n are connected. still,
The line insulation resistance is shown as R _Y and the line resistance is shown as R _X.

On the other hand, the receiver 4 includes a constant current circuit 7 that supplies voltage so that a constant current flows through the signal lines 5 and 5'.
and an A/D converter 8 that detects the line voltage V _L between the lines 5 and 5' on the receiver side and converts it into a digital value, and inputs the digital value converted by the A/D converter 8 at a predetermined timing. the input/output interface 9, the CPU (central processing unit), RAM (random access memory), and ROM (read-on memory) that calculates the specific resistance of the activated slave unit.
A computer unit 10 consisting of a
A display 12 is provided for identifying and displaying the slave unit activated by the output.

FIG. 3 shows an example of a child device used in the embodiment shown in FIG. 2, in which terminals 13 and 13' are connected to signal lines 5 and 5', and a resistor R _o and also has a thyristor S2 for shorting the lines 5, 5'. The thyristors S1 and S2 are turned on and off by the trigger signals e ₁ and e ₂ of the trigger circuit 14 that are activated when the non-lock pushbutton switch SW is closed.The trigger circuit 14 consists of a high resistance R _K and a diode. Power is supplied by capacitor C which is being charged via D.

Thyristors S1 and S by this trigger circuit 14
As shown in FIG. 4, when the pushbutton switch SW is closed, the trigger signal _e1 is first generated, the thyristor S1 is turned on, and the resistor _Ro is connected between the lines. Then, after a predetermined time τ, a trigger signal e ₂ is generated to turn on the thyristor S2 and short-circuit the resistor R _o , that is, short-circuit the lines.

Next, the operation will be explained.

First, the line 5 at the lead-out end of the receiver 1,
Since the constant current circuit 7 causes a constant current to flow, the line voltage V _L between the terminals 5' and 5' is proportional to the value of the line resistance Z as seen from the receiver side.
Therefore, the voltage value V _L converted by the A/D converter 8 can be treated as the resistance value Z as is.

Assuming that none of the slave units is currently operating, the computer unit 10 of the receiver 1 reads the output of the A/D converter 8 into a predetermined address in the RAM via the input/output interface 9 at predetermined intervals. There is. The line resistance Z ₁ temporarily stored in the RAM by such reading is the line insulation resistance R _Y shown in FIG. 5, and Z ₁ =R _Y.

Next, when the child device 6a is activated, as is clear from FIG. 3, the thyristor S1 is first turned on and its resistor _R1 is connected between the lines 5 and 5'.

At this time, the line resistance Z ₂ read into a predetermined address of the RAM of the computer unit 10 is a composite resistance of the line insulation resistance R _Y , the line resistance R _X , and the specific resistance R ₁ , and Z ₂ =R _Y ( R ₁ +R _x ).

Furthermore, when the time τ has elapsed, the thyristor S2 turns on and short-circuits the lines 5 and 5', and at this time the computer unit 10 increases the line resistance R.
The combined resistance of _X and line insulation resistance R _Y is read as line resistance Z ₃ , and Z ₃ =R _{X RY} .

Organizing the above line resistances Z ₁ , Z ₂ , and Z ₃ , Z ₁ = R _Y Z ₂ = R _Y (R ₁ + R _X ) = R _Y (R ₁ + R _X )/(R _Y + R _X + R ₁ ) Z _{3 = R X RY = R}

After reading Z ₁ , Z ₂ , and Z ₃ in this manner, the computer unit 10 executes an operation to calculate the specific resistance R ₁ of the activated child device 6a from the above-mentioned Z ₁ to Z ₃ .

That is, R ₁ =Z ₁・Z ₂ /Z ₁ −Z ₂ −Z ₁・Z ₃ /Z ₁ −Z
The value of the specific resistance R ₁ is determined by the calculation in step ₃ .

When the value of the specific resistance R ₁ is determined, select the display number of the slave unit corresponding to this value from the ROM, etc., and display the slave unit 6 on the display 12 via the input/output interface 11.
Display the operation of a.

FIG. 6 shows a computer unit 10 of the present invention.
This shows another example of the equivalent circuit used to calculate the specific resistance in Figure 6. Using the equivalent circuit in Figure 6, R ₁ = (Z ₁ - Z ₃ ) (Z ₃ - Z ₂ )/Z ₂ −Z Calculate the specific resistance by calculating ₁ .

It has been confirmed that with either the equivalent circuit in Figure 5 or Figure 6, the calculated resistivity value for the actual resistivity value has an error of no more than ±1.0Ω. There is.

FIG. 7 shows another embodiment of the present invention,
Relay contacts la, lb, lc, etc., which open when slave units 6a, 6b, 6c, ... are activated, are provided on one track 5, so that even if multiple slave units operate at the same time, , the slave devices closest to the receiver 4 are identified and displayed in order.

For example, if slave units 6a and 6b operate at the same time, the operation of slave unit 6a opens contact la and disconnects connected slave units 6b, 6c,..., and the above-mentioned line resistance Z ₁ ~ Find the value of specific resistance R ₁ by reading and calculating Z ₃ and display the operation of slave unit 6a,
After the calculation processing time has elapsed, the child device 6a recovers by itself and closes its contact la, so that the lines 5 and 5'
The sub unit 6b which is in operation is connected to the sub unit 6b, its specific resistance _R2 is determined in the same way, and the operation of the sub unit 6b is displayed. In order to perform the above-mentioned sequential connection, when multiple slave units operate simultaneously in the slave unit circuit shown in Figure 3, the downstream slave unit must wait until the slave unit closest to the receiver completes its operation. Since it is necessary to hold the operation input of the device, for example, the push button switch SW needs to be a lock type, and the thyristor S1,
A timer reset circuit is provided to turn S2 back off.

In the above embodiment, a slave device activated by a switch operation was used as an example, but it goes without saying that a fire detector or the like activated by detecting heat or smoke caused by a fire may also be used. In addition, in the above example,
Although the resistor is first connected during operation and then the line is short-circuited, another embodiment is such that the line is short-circuited during operation, and then the short-circuit is released before connecting the resistor. You can also do it.

As explained above, according to the present invention, when the slave device is activated, the resistor is first connected to the line, and then the line is short-circuited, while in the receiver, a constant current is caused to flow through the line. This makes it possible to detect changes in line resistance using line voltage, and detects the line resistance when the slave unit is not operating, the line resistance when the slave unit connects a specific resistance, and the line resistance when the slave unit is connected to the line resistance. The system detects each line resistance when a short circuit is made between lines, calculates the specific resistance of the operated slave unit from these line resistances, and displays the slave unit number corresponding to the calculated specific resistance. , it is possible to determine the specific resistance of the activated slave unit regardless of the values of the line-to-line insulation resistance and line resistance of the signal line, and even if the insulation resistance has decreased due to long-term use, the slave unit number will be displayed incorrectly. In addition, line resistance can be ignored, so there are no practical restrictions on line length.
A highly reliable device that operates stably can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional device using specific resistance, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is an embodiment of a child device used in the present invention. 4 is a time chart showing the operation of the slave device, FIGS. 5 and 6 are equivalent circuits for determining the specific resistance, and FIG. 7 is a block diagram showing another embodiment of the present invention. It is a diagram. 1, 4... Receiver, 2, 2', 5, 5'... Signal line, 3a to 3n, 6a to 6n... Slave device, 7... Constant current circuit, 8... A/D converter, 9, 11... Input/output Interface, 10... Computer unit, 12... Display, 13, 13'... Terminal, 14...
Trigger circuit, R ₁ to R _o ... specific resistance, R _X ... line resistance, R _Y ... line insulation resistance, R _K ... high resistance, S1, S
2...thyristor, SW...push button switch, la~
ln...Relay contact.

Claims (1)

[Claims] 1. In a device for connecting a plurality of slave units to a pair of signal lines led out from a receiver and identifying and displaying an activated slave unit on the receiver, the slave unit is provided with a predetermined signal when activated. A connection control circuit is provided that alternately connects a specific resistance of a predetermined value between the signal lines and short-circuits the signal lines, and the receiver supplies a constant current to the signal lines. A constant current circuit, a voltage detection circuit that detects the line voltage on the receiver side of the signal line receiving constant current supply from the constant current circuit, and a slave device is operated by the detected voltage of the voltage detection circuit. The slave unit operates from each line resistance by detecting the line resistance when the slave unit is not connected, the line resistance when the slave unit connects a specific resistance, and the line resistance when the slave unit shorts the lines. What is claimed is: 1. An alarm device comprising: an arithmetic circuit for determining the specific resistance of the arithmetic unit; and a display circuit for identifying and displaying the operation of the handset corresponding to the specific resistance determined by the arithmetic circuit.