JPS5916224A - Opening and closing state detector for switch - 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 [Technical Field of the Invention] The present invention relates to an open/close state detection device for a switch such as a limit switch, which detects and displays the open/close state of a switch such as a limit switch using a pulse signal, and is particularly applicable to nuclear power generation. A switch that turns a switch on and off in conjunction with the open and close states of multiple valves installed in harsh environments such as equipment, and detects and displays the open and closed state of pulp, etc. from the on and off states of this switch. The present invention relates to an opening/closing state detection device for a container.

[Technical background of the invention and its problems]

Generally, in nuclear power generation facilities, the reactor containment vessel (hereinafter referred to as
The reactor subsystem equipment such as the reactor pressure vessel and recirculation equipment is housed within the POVJ, and even if radioactive materials leak from the reactor subsystem due to an accident, this will not spread outside. It is composed of ℃. Various valves are provided within the POV.

A conventional open/close state detection device for detecting and displaying the open/close state of a valve installed under such adverse conditions is known, for example, as shown in FIG.

In Fig. 1, 1 is n valves installed in POV, and each valve 1-1.1-2°...
There are movable parts 2-1, 2-2゜ for l-n respectively.
・2-n is provided and protrudes in the direction of the arrow in FIG. 1 in response to the open state of the valve 1. When the movable part 2 protrudes, the movable parts of the limit switches 3-1, 3-2, . . . 3-n are pressed, and the contacts of each limit switch 3 are closed.

Each limit switch 3 has a signal cable 4-1.4.
-2. ...4-n and 5-1.5-2. ...5
-n are connected to each other, and a closed circuit is formed by closing the contacts of each limit switch 3. Here, the signal cables 4 and 5 are connected to connectors 6-1, 6-2.・・・
6-n, and the signal cable 5 has current dividers 8-1, 8-2. ...8-n and DC power supply 9-1.9-2. . . . g and n are connected in a row. Therefore, when the limit switch 3 is turned on, a current flows from the DC power supply 9 to the cables 4 and 5 and the needle of the ammeter 8 swings, so that the open state of the valve 1 can be detected.

However, in this type of device, as many electric circuits as there are valves 1 are required, and therefore as many connectors 6 as there are valves 1 are required. On the other hand, since the number of valves ranges from tens to hundreds, there is a drawback that connector installation work and cable connection work are complicated. Therefore, the number of connectors 6 should be minimized (
There was a need for an open/closed state detection device.

Therefore, the applicant proposed an open/close state detection device as shown in FIG. That is, valve 1-1.1-2. ...l
-n movable part 2-1.2-2. ...2-n, cable 4
-1.4-2. ... 4-n tip portion 3-1.3-2.
...3. -n is provided nearby, and the tip end 3 is configured with a switch such as a +) Mitsutswitch so that the load at the end of the cable 4 is opened and shorted by the movement of the movable part 2. A plurality of signal cables 4 corresponding to each valve 1 and one connector 6-1 inserted through the mounting plate 7 are connected at a branching portion 10 for branching the cables.

On the other hand, at the other end of the connector 6-1, there is a pulse oscillator 11 that applies pulses to the cable 4, and an echo (reflected wave) obtained when the pulses applied by the Norms oscillator 11 are reflected from the cable tip 3. A signal processing section 12 that detects positive and negative polarities and echo pulse times to determine whether each valve 1 is open or closed is connected to a display device 13 that displays the results of the signal processing section 12. The most important condition for the opening/closing state detection device configured as described above is that the cables from the branch section 10 to the valve 1 must all have different lengths.

Next, the operation of this device will be explained. First, when a pulse with a narrow pulse width is applied to the cable from the Norculus oscillator 11, this pulse is transmitted to each valve 1-1 through the branch section 10.
1-2. ...1-n, each tip 3-i, 3-2
．． ...Reflected by 3-n. At this time, when valve 1 is open, the tip 3 is open, and when valve 1 is closed, the tip 3 is open.
If the mechanism is such that the echo pulse input to the signal processing unit 12 is short-circuited, a positive pulse will be obtained when the valve 1 is open, and a positive pulse will be obtained when the valve 1 is closed in response to a positive applied pulse. Sometimes negative pulses are obtained. Also, cable 4-1.4-2. ... Since the lengths of 4-n are all different, the time it takes for the applied pulse to propagate through the cable and return (that is, one echo hour) differs depending on the length of each cable. The echo pulses obtained in this manner are individually selected, the polarity and time of each pulse are detected and measured, and each valve 1-1.1-2. ...Determine whether 1-n is open or closed.

The results are displayed on the display device 13 in various forms.

In this device, cables 4-1.4-2. ...4-n
The eco time is changed by the difference in the length of each valve 1-1, 1
Since the open/closed state of the valve 1 is detected by separating echoes corresponding to -2,...1-nVC, a high-speed pulse oscillator 11 with an extremely narrow pulse width is required, and distortion of the pulse waveform Considering external disturbances, there is a risk that the echoes will overlap unless the cable lengths differ by more than a few tens of meters.As a result, the production cost of the high-speed pulse generator increases, and as the number of pulps increases, the cables become unnecessarily long. There were problems such as what had to be done.

[Purpose of the invention]

The present invention has been developed in view of the above points, and has a small number of cables and cable connectors, and also allows the cable length to be set arbitrarily, and is suitable for use in adverse environments such as high temperature, high humidity, and high radiation. It is an object of the present invention to provide an opening/closing state detection device for a switch which is also suitable for the following applications.

[Summary of the invention]

In order to achieve this object, in the present invention, a delay circuit is provided in each cable branched into a plurality of cables by the branching section, the echo of the pulse applied by the pulse generator is delayed by the delay circuit, and the signal processing section The polarity and time of the echo are detected and measured, and the results are displayed on a display device.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a block diagram showing the structure of the opening/closing state detection device, and the same elements as in FIG. 2 are given the same reference numerals.

The difference between this device and the device shown in FIG. 2 is that each cable 4-1, 4-2, 4-2, 4-2, etc. is branched into a plurality of cables by a branching section 10. −=
4-n is a delay circuit 20-1, 20-2,...20-
For example, the point where n is inserted.

That is, in this opening/closing state detection device, each valve 1-1.1
-2. ...Signal cable compatible with 1-n 4-1.4
-2. ...4-n tip portion 3-1.3-2, ...3
-n and each signal cable 4-1.
4-2. ... 4-n is a delay circuit 20-1゜20-2.
...20-n is provided. This delay circuit 20 gives a certain delay to a signal, and is composed of an inductance L, a capacitance I10, etc., which do not include active elements such as transistors, and uses, for example, a delay line, a fixed filter, etc.

Each delay circuit 20-1. , 20-2, . . . 20-n have different delay times. In addition, since the branching section IO is installed under adverse environments such as high temperature, high humidity, and high radiation level inside the PCV, it is not reliable as a structure that only branches the cable without using electronic components such as transistors. improve.

The delay circuit 20 is connected to the connector 6-1 via the branch part 0.
connected to one end of the A pulse oscillator 11, a signal processing section 12, and a display device 13 are provided at the other end of the connector 6-1. Here, the signal processing section 12 includes a polarity detection circuit 21 that detects the positive and negative polarities of the echo pulses, an eco-hour measuring circuit 22 that measures the echo hour, and the polarity of each echo pulse and the echo hour. From each cable tip 3-1.
3-2. ... 3-n is open or closed (that is, whether each pulp 1-1.1-2...1-n is open or closed). configured.

Each of these circuits 21, 22, 23 and the pulse oscillator 11 are controlled according to a predetermined program by a control circuit 24 having a memory function, an arithmetic function, a control function, and the like. Data etc. are input to the control circuit 24 through the operation console 2.
This is done via 5.

The operation of the opening/closing state detection device configured as described above will be explained with reference to FIG. 3 and FIG. 4 showing pulse waveforms of various parts of the circuit in FIG. 3. First, based on a control command signal from the control circuit 24, a pulse (A) is applied from the pulse oscillator 11 to the cable grip. The pulse (A) is connected to the cable 4-1.4-2 corresponding to each valve 1 at the branch 10.
．． ...Branch to 4-n, delay circuit 20-1.20-2
,... 20-n to each pulp 1-1.1-2,
=・1-n is reached, and the tip portion 3-1.3-2. ...3-
reflected by n. At this time, as explained in Fig. 2 above,
When pulp 1 is open (i.e. when tip 3 is open)
When a positive echo pulse is obtained while valve 1 is closed (
That is, when the tip 3 is short-circuited) a negative pulse is obtained.

In Figure 3, since valves I-1, 1-4, ... 1-n are open, positive echo pulses (B), (E), (A are 4 (see Figure 4)), while the pulp Since 1-2.1-3 is closed, negative pulses (C, 2) are obtained (see Figure 4).Here, as shown in Figure 4, the echo pulses from each pulp 1 change over time. Delay circuit 2 to be obtained by separating the axis
The delay times Tla, Tza, . . . Tna of 0-1, 20-2, . . . 20-n are made different. In addition, THL, Tza,... in Fig. 4
・For Tna, echo pulse is connected to cable 4-1.4-2.・
...4-n propagation time, T1. T2. ...Tn
indicates the period during which the echo pulse propagates through the delay circuit 20 and the cable 4 until it returns (ie, one echo hour).

However, in this embodiment, the cable 4-1.4-2°...
The case where the lengths of 4-n are equal is described.

The echo pulse train obtained in this way is input to the polarity detection circuit 21 and the echo time measurement circuit 22 of the signal processing section 12, and these circuits 21 and 22 detect and measure the polarity and time, and the results are displayed. The signal is transmitted to the open/close state determination circuit 23. Then, in the open/closed state determination circuit 23, each pulp 1
-1.1-2. . . . The open/closed state of l-n is determined, and the result is displayed in various formats (for example, characters) on the display device 13.

Note that the eco-hour T1 r T2 + ``' Tn is 'r1'''' Tla + Tlb Tz - Tza + T21) Tn '' Tna + Tnb, so Tta >> Ttb + Tza >>
'r2b, m Tna >> TnbVC, the delay time T1. of each delay circuit 20-1.20-2°...20-n. , Tza, . . . Tna, the echo interval can be set for each cable 4-1.4-2.・・−
4-H propagation time 'rtb I T2b 1...Tn
b can be ignored. Further, the echo (first echo) reflected at the tip 3 of each cable 4 is reflected at the sending end, reaches the tip 3 again, is reflected, and is input to the signal processing section 12 as a second echo. Therefore, the delay times T1a and T2a are set so that the pulse train of the first echo and the pulse train of the second echo do not overlap.

...It is necessary to set Tna. Therefore, since twice the first eco-hour is the second eco-hour,
Each delay time T1.2T1>Tn. .

'r2a, . . . Determine Tna.

In this embodiment, the open/closed state of the pulp 1 is detected by measuring the polarity of the applied pulse, and a method is adopted in which multiple pulps are recognized using the eco-hours passed through the delay circuit 20. Therefore, not only can the number of cables and connectors be minimized, but also the echo interval can be set using the delay circuit 20, so echoes can be separated without having to make a large difference in cable length as in the prior art. Therefore, the valve open/close state can be accurately detected and displayed. In addition, the delay circuit 20 has a function of setting an eco-hour, and by appropriately selecting the impedance of each delay circuit 20-1, 20-2, . . . 20-n, the output terminal Function to correct impedance mismatch when viewed from the side (
Therefore, there is no need to provide a separate impedance matching circuit for impedance matching at the branch section 10. Moreover, this delay circuit 20 is a transistor, etc. Since it is constructed of circuits that do not include active elements, such as delay lines, it can withstand adverse environments such as high temperature, high humidity, and high radiation levels within the POV.

In addition, in the above embodiment, a method for detecting and displaying the open/closed state of the pulp 1, which is the object to be detected, has been described, but the object of the present invention is also applicable to objects to be detected other than pulp. can.

〔Effect of the invention〕

As explained above, according to the opening/closing state detection device according to the present invention, a delay circuit is provided in each signal cable branched into a plurality of cables by the branching section, and the echo of the pulse applied by the pulse transmitter is transmitted to the delay circuit. Since the echo interval can be set using the delay circuit, the echoes can be separated and the open/closed state of the switch can be determined using the minimum number of signal cables, without having to make a large difference in cable length as in the prior art. and the number of connectors can be accurately detected and displayed. In addition to the function of setting the eco time, the delay circuit has a function of correcting the impedance mismatch seen from the person at the branch and from the output terminal side by appropriately selecting the impedance of each delay circuit. Therefore, there is no need to separately provide an impedance matching circuit for impedance matting at the branch portion, and the circuit configuration can be simplified. Therefore, 1. If the device of the present invention is used to detect and display the open and closed states of a plurality of pulps, etc. installed in a bad environment, the open and close states of pulps, etc. can be detected and displayed with high accuracy. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional open/close state detection device, Fig. 2 is a block diagram of an open/close state detection device proposed earlier by the applicant, etc., and Fig. 3 is a block diagram of a conventional open/close state detection device.
The figure is a block diagram of an open/close state detection device according to an embodiment of the present invention, and FIG. 4 is a pulse waveform diagram of each part of the circuit in FIG. 3. 1.1-1.1-2. ...1-n...Valve, 2,
2-1.2-2. ...2-n... Valve moving part, 3
．． 3-1゜3-2. ...3-W-...cable tip, 4
．． 4-1.4-2. ...4-n...signal cable,
6.6-1.6-2゜...6-n...Connector, 1
0... Branch part, 11... Pulse transmitter, 12...
Signal processor, 13... Display device, 20.20-1°2
0-2. ...20-n...Delay circuit.

Claims (1)

[Claims] 1. A pulse oscillator that applies electrical pulses to an electrical signal cable provided with a switch that can electrically turn on and off the end of the cable, and a cable branch that branches the cable into a plurality of cables. and signal processing for detecting and measuring the polarity and time of the echo obtained when the applied pulse of the pulse oscillator is reflected from the tip of the cable having each of the switches to determine the on/off state of each of the switches. Department and
An open/close state detection device for a switch, comprising a display device that displays the determination result of the signal processing unit, and a delay circuit that is provided in each of the plurality of branched cables and delays the echo. 2. The switching state detection device according to claim 1, wherein the delay circuit is configured to have a function of correcting impedance mismatch at the branch portion. 3. An opening/closing state detection device for a switch according to claim 2, wherein the delay circuit is a delay line.