JPS58195997A - Alarm circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alarm circuit, and more particularly to an improvement in an alarm circuit used in a control and monitoring device that requires alarm retention.

Conventionally, this type of alarm circuit flashes the alarm display and sounds a bell or buzzer when an alarm occurs, but since it does not have a self-holding function for the alarm, the display automatically changes when the alarm ends. It had the disadvantage that it would disappear and the history of the alarm would be lost.

Figure 1 is a circuit diagram of a conventional alarm circuit, and Figures 2 (a) to (g).
) is its operating waveform diagram. This circuit has an input terminal 51
A one-shit multivibrator 1 consisting of a two-stage 7 lip-flop 10 and 10' partially driven by an alarm input signal from a NANDu is reset by the output and is reset by the output of the inverter 5, and outputs a pel or buzzer output to the output terminal 52.
Logic that inputs the output of the flip-flop 2 and the output of the inverter 5 together with the 7 lashing signal from the input terminal 53 and outputs the display output from the output terminal 54. The circuit includes a circuit 4 and a switch 6 that resets the flip-flop 2 and stops the buzzer output.

When this circuit receives a long-term alarm signal as shown in Figure 2(a), it outputs a flashing display (Figure 2(b)
)) and the ringing output of the pel/buzzer (FIG. 2(C)) are output. By driving switch 6 (second
Figure (d)) Percent Pell/buzzer output is stopped, and display output 7 lashing is stopped.

Only the continuous display output continues until the input t*fail signal stops.

On the other hand, when a short-term alarm signal is input (Fig. 2(e)
L Flashing display output (Fig. 2 (f)) and Pell/buzzer output (Fig. 2-)) are output, but when the coma signal stops, these outputs also stop, and there is a problem that no alarm history is left. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide an alarm circuit that can solve the above-mentioned drawbacks and leave a history of alarms even after the alarms have ended.

The alarm circuit of the present invention includes a one-shot multivibrator that inputs an alarm signal and outputs a certain time width signal;
・An inverter that inputs the shaft signal and inverts the logic, a switch that controls the ringing signal of the alarm and the flashing signal of the alarm display, and the a first R-87 lipstick which is set and reset by the respective outputs of the inverter and the switch to form the ringing signal; a 20th R which is reset by the output and forms the 7 lashing signal of the alarm indicator;
-87 flip-flop, this second) T-8 flip-flop, and the above-mentioned inverter.
and a logic circuit that inputs each lashing signal and selects the display on the alarm indicator.

Below, the book@mei will be explained in detail with reference to page 1.

FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. When an alarm signal with a wide range is input to the terminal 51 (Fig. 4 (a)
)), balance eliminator-11 capacitor 12.
Inverter 13 and (J i
-S flip-flop 2 is turned off and outputs Pell/buzzer driver No. 41111 from terminal 52 (Fig. 4(b)) @ NAND game at the same time) 17. IL of cocoon 2 composed of 18 - Since the 87 lip-flop 3 is also set, the logic circuit 4 that determines whether the alarm display should be displayed continuously or flashed will output a NAN signal.
If the output of the flashing oscillator is input from the terminal 53 to the other input of the D game (D game) 19, a drive signal that causes an externally provided display device to flash 7 is output to the terminal 54 as the output of the AND game (20). Figure 4 (C)
). In this case, even if the alarm input disappears before the stop switch 6 is turned on (see Fig. 4 (Fig. 4 (f)) where the 0th alarm is self-held and the alarm history is kept), the external display The display group drive signal that causes 2 lashings is AN
The signal continues to be output from the D gate 20 via the terminal 54. However, the Pell/Buzzer output stops along with the alarm signal (see Figure 4 (
ω).

Next, by turning on the stop switch 6, the first A and the second R-8 terminals 70 and 2.3 are reset, so the alarm history disappears for the first time, and at the same time the alarm is not output from the terminal 52. The display drive output for 7 latching of the friend Pell/buzzer drive signal and terminal 54 should also be stopped.
b+c+L If the alarm signal is continuously input, a continuous display signal is output from the AND gate 20 of the logic circuit 4 (Fig. 4(b)), the inverter 5
#j, if the alarm signal is continuously input after turning on the stop switch 6, the ninth display signal is sent through all the OR gates 21 and ANDN-gates of the logic circuit 4 to cause the alarm display to display continuously. It has a function of outputting from the terminal 54 and immediately resetting the 10R-87 flip-flop 2 when the alarm signal disappears.

Note that there is a bounce eliminator #i and a multivibrator that is resistant to noise, such as the MC14490 manufactured by Motorola in the United States.

In addition, the first vibration with the multi-vibrator
And instead of setting a second T-87 flip-flop 2.3, it is also possible to set these two T-8 flip-flops from a microprocessor controlled I10 boat.

As explained in detail above, the present invention is composed of an extremely simple circuit, and the waveform of the alarm input signal is shaped by a one-shot multivibrator using a bounce eliminator. Spike noise or chuckling of mechanical contacts is eliminated, and the time width can be changed freely, so there is an advantage that it can be applied to all kinds of alarms.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional alarm circuit, and Figures 2 (a) to (g).
) is an operation timing diagram of diagram lA1. FIG. 3 is a block diagram of one embodiment of the present invention, and FIGS. 4(-) to (g) are signal timing diagrams in this embodiment. In the figure. 1°"'Wanshi Sotto Multi-by-Pure Ku, 2°3
...it-S flip-flop, 4...
7 Lashing logic circuit, 5.13 Inverter, 6 Stop switch, 10.10'
...Flip-flop, 11...Bounce eliminator -112...=+nde, sir, 14.21...OR gate, 15,161?
, 18.19...NAND gate, 20...
...AND gate, 51.52.53.54...
...Terminal.

Claims (1)

[Claims] 1. A one-shot multi-vibrator which inputs an alarm signal and outputs II#AO1 at a certain time; An inverter that inputs this alarm signal and inverts the logic, a switch that controls a ringing signal such as a bell or buzzer for alarm, and a 7 lashing signal of an alarm display, and an output of the one-switch multi-vibrator. a first R-87 lip 70 which is reset by the respective outputs of the inverter and the switch to form the ringing signal; A second H-87 flip-flop, which forms a flashing signal for the alarm indicator, inputs each output of the second H-S flip-flop, the outputs of the inverter, and an external 7 lashing signal, and generates a flashing signal for the alarm indicator. an alarm circuit including a logic circuit for selecting a display;