JPS58144997A - Bypass apparatus for alarm - 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 a bypass device used in the testing of process quantity alarms used in nuclear couplants and the like, whose performance must be regularly checked.

A conventional device of this type is shown in FIG.

In the figure, (L) is an alarm, (2) is a comparator, and (3) is a transistor that is turned ON or I/10 by the output of comparator (2).
It is said to be yp. (5) is a load relay and one end is a power supply (4)
, the other end is connected to the transistor (3) via the diode (7) in the bypass device (ψ (8) Fi
The bypass switch is normally turned to side B, and turned to a@ when bypassed. (9) is a process amount human power line, and (10) is a signal changeover switch which is normally turned to side a and turned to b1111 during testing. (13) is a testing device for an alarm device, which is composed of an output detector (11) of the alarm device (L) and a test signal generator (12).

Next, the operation will be explained. Under normal conditions, the process amount is input manually to the comparator (2) via the human power line (9) and the a contact of the signal changeover switch (10). is turned on, so the power supply (4) is applied to the load relay (5), keeping it in an excited state.On the other hand, if the process amount is abnormal, the comparator (2) turns off the transistor (3), so the load relay Relay (5
) is considered de-energized.

When testing the alarm (1), first turn down the bypass switch (8) to 5 LINK.
) Even if the power is OIF F, the power supply (
4) is applied. Next, the signal selection switch (
A variable signal from the test signal generator (12) is input to the comparator (2)' to measure the trip point.
The switching of N-〇FF or OF If'-, ON is detected, the human power level of the comparator (2) at this time is measured, and it is tested whether this value satisfies the required value. The diode (η is for electrically insulating the bypass switch (8) and the transistor (3).

Since the conventional bypass device is configured as described above, it is necessary to use a diode (7), and as shown at point A in Fig. 2, the diode (η) and the load relay (5) are There was a drawback that even if a grounding accident occurred, it could not be detected by the test.

In other words, the grounding accident is equivalent to being bypassed all the time, and causes the alarm device (2) to lose its function.

This invention was made in order to eliminate the shortcomings of the above-mentioned devices.The bypass device interrupts the excitation current supplied to the load relay, thereby detecting a ground fault in the wiring during the trip point test of the alarm. The purpose is to provide equipment.

An embodiment of the present invention will be described below with reference to the drawings. Third
In the figure, (14) t''jj bypass device pass switch (8), drive circuit (15), ) transistor (16)
).

Normal bypass switch (8) Fil) l1111
be defeated by At this time, drive circuit (15) #:l transistor (16) is set to OF'F. On the other hand, during testing, turn the bypass switch (8) to aill. At this time, the drive circuit (1
5) #Li) Transistor (16) as shown in Figure 4 (O
Generate a test signal to make N, 0IPF! ! A variable signal from (12) is manually applied to the comparator (2), and the manual power level of the comparator (2) when the transistor (3) switches from ON to FF to ON is measured and the trip point is reached. seek.

If the transistor (3) is ON now, the output detector (11) has a human input logic "Ll" as shown in Fig. 4.Next, when the transistor (3) becomes 0IIF, the output detection II (
11) Human power becomes a pulse signal that repeats logic 1H1 and 1L1, that is, by detecting the presence or absence of this pulse signal, the state of 0FF10N of transistor (3) can be known, so compare! ! (2) The trip point can be measured.

Also, if a grounding accident occurs in the dark wiring between the alarm (υ) and the relay (5), it is equivalent to the transistor (3) being ON, and the transistor (3) is ON and OFF'F.
Output detection 1 regardless! (11) No pulse signal appears in human power. Therefore, it appears that the trip point of the comparator (2) deviates from the required value, prompting the tester to investigate the cause.

The selection is made so that the load relay (5) can continue to be energized when the transistor (15) remains ON, OF, and F when the +11R) range switch (3) becomes 01P'IP.

As described above, according to the present invention, it is possible to detect a wiring grounding fault when testing the trip point of the alarm, thereby providing a highly safe 11F function.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an alarm using a conventional bypass device, Fig. 2 is a circuit diagram showing a grounding accident of an alarm using a conventional bypass device, and Fig. 3 is according to an embodiment of the present invention. Circuit diagram showing an IFlli device using a bypass device, No. 4
The figure is an operation waveform diagram.In the figure, (1)...
Alarm, (5) Load relay, (14) Bypass device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno -1 Figure 1 and Figure 2- Figure 3 Figure 4

Claims (1)

[Claims] Monitoring the process amount and controlling the load relay - When the equipment is normal, the load relay is energized, and when the equipment is abnormal, the operation of the alarm device, which has characteristics characteristic of the load relay, is selectively disabled and the load relay is always energized. A bypass device that maintains the load relay in an excited state regardless of the output of the alarm by connecting it in parallel with the alarm and supplying the excitation current of the load relay, wherein the excitation current is an intermittent current. An alarm bypass device characterized by using.