JPH03113383A - Wire breaking detecting device - Google Patents

Abstract

PURPOSE:To detect wire breaking and compensate the current path of equipment by detecting a DC current which flows through a semiconductor element by the conduction of the element which is caused by the breaking of a lead line or by-pass line. CONSTITUTION:The breaking of lead wires LA and LB which supply electric power from a DC power source +B to the equipment is detected. At this time, by-pass lines La and Lb are provided in parallel to the lead lines LA and LB and positive and negative side wire breaking detecting circuits 3 and 5 which detect the breaking of the lines and an output circuit 7 which outputs a wire breaking detection signal at the time of the wire breaking are provided between those lines and equipment. Then when the lead lines LA and LB and by-pass lines La and Lb are all normal, all the DC current flows through the lead lines LA and LB and none of transistors (TR) Tra - Trf has a potential difference and does not turn on, so that the current flows to neither the by-pass line La nor Lb. If those lines are broken, the TRs Tra - Trf have a potential difference according to the wire breaking position and turn on, so that the current is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a disconnection detection device for detecting disconnection of a lead wire for supplying direct current to equipment.

[Conventional technology] Conventionally, tl! In mechanical equipment (e.g., proximity switches, microswitches, photoelectric switches, etc.), various detection devices are often installed. The lead wire is extended to the control panel where the equipment is housed.If this lead wire were to break for some reason, it would cause a serious problem in controlling the machine wiping device a.

Therefore, as a disconnection detection device for detecting a disconnection of a lead wire of a detection device, a device that detects a disconnection of a lead wire by detecting a fluctuation in the current flowing through the lead wire has been developed.

[Problems to be Solved by the Invention] However, although the above device can detect a break in the lead wire, it does not have a function to compensate for the current path to the detection device that is interrupted by the break.

In other words, even if a disconnection is detected, it is not possible to compensate for the operation of the detection device when the disconnection occurs, so the operation of the machinery must be stopped and the disconnection repaired. When an accident occurred, it often caused a serious failure.Of course, it is possible to install a bypass wire parallel to the lead wire, but even if this bypass wire breaks before the lead wire, the breakage will be detected. Because it is not done,
After that, when the important lead wire is disconnected, 1: the current path is not compensated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a disconnection detection device that can detect the disconnection when either the lead wire or the bypass line of the device is disconnected, and can also compensate for the current path of the device. [Means for Solving the Problems] The gist of the present invention is a disconnection detection device for detecting disconnection of a lead wire for supplying DC power to an air conditioner, comprising a bypass wire in parallel with the lead wire. A semiconductor element is provided in series with the bypass line and becomes conductive when a potential difference is generated between both ends, between the lead wire, the bypass line, and the equipment, and the semiconductor element is connected to the equipment. is provided on the opposite side, and includes grounding resistance means for connecting the bypass line and a grounding point, and current detection means for detecting a direct current flowing through the semiconductor element due to conduction of the semiconductor element. There is a disconnection detection device.

[Operation] According to the disconnection detection device of the present invention configured as described above, (
L When both the lead wire and bypass wire are normal, all DC current flows through the lead wire. No potential difference occurs in the semiconductor element. Therefore, the semiconductor element is not conductive and no current flows through the bypass line.

On the other hand, when the lead wire is disconnected, a potential difference occurs in the semiconductor element. Therefore, the semiconductor element provided in the bypass line becomes conductive, and the DC current flows through the bypass line and the semiconductor element.The current detection means detects this DC current. Therefore, the current path of the equipment is compensated by the bypass line.

Next, when the bypass line is disconnected, direct current flows through the lead wire and a potential difference is generated in the semiconductor element by the grounding resistance means. Then, the semiconductor element becomes conductive and a direct current flows from the bypass line semiconductor element to the grounding resistance means, and the current detection means detects this direct current.

In other words, when either the lead wire or the bypass wire is disconnected, the semiconductor element becomes conductive and the current detection means detects the DC current flowing through the semiconductor element, and at the same time, the DC current flows through the bypass wire or the lead wire and the current path of the device +. 1 Always guaranteed.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an electric circuit diagram showing a disconnection detection device and related equipment according to an embodiment of the present invention.

As shown in the figure, the disconnection detection device (Table 1)
, a positive side bypass wire a and a negative side lead wire provided in parallel with the positive side lead wire LA of a well-known DC two-wire proximity switch SW configured so that the flowing current increases when an object approaches. A negative side bypass line Lb is provided in parallel with LB.

Disconnection detection unit 1 (Table: Provided between the proximity switch SW and the positive lead wire LA and the negative lead wire LB,
A positive side disconnection detection circuit 3 detects a disconnection in any of the wires LA, La, LB, and Lb, and detects a disconnection in the positive lead wire LA or the positive bypass line La.
and negative electrode side lead wire 1B or negative electrode side bypass wire b
The main parts include a negative electrode side disconnection detection circuit 5 that detects a disconnection of the wire, and an output circuit 7 that outputs a disconnection detection signal to the outside when a disconnection occurs.

This disconnection detection unit 1 (↓) is sealed in a resin mold (not shown) together with the proximity switch SW, and is integrally molded into, for example, a cylindrical shape, and is attached to a part of a mechanical device (not shown).

Positive side lead wire L A (l is wired from terminal T2 to terminal P2 of connector C and terminal T2): is connected to the positive side of proximity switch SW, and the bypass wire La is wired from terminal T2 to terminal P2 of connector C. Terminal P] and terminal P2 of connector C are short-circuited with jumper wire J1, and here, positive lead wire LA and bypass wire La (relay wire L1 The photonoplastic PC inside the sequencer SEQ that controls the mechanical equipment is assembled into the control panel CNT of the mechanical equipment.
It is connected to the. Due to the in-operation of the proximity switch SW, the current flowing from the DC power source 10B to the proximity switch SW increases or decreases, thereby causing the photocoupler PC to perform an ON-OFF operation.

On the other hand, the negative electrode side lead wire L B lt is wired from the terminal T4 to the terminal P4 of the connector C, and is also connected to the negative electrode side of the proximity switch SW at the terminal T4, and the bypass wire Lb is wired from the terminal T3 to the terminal P4 of the connector C. It is wired to terminal P3. Terminals P3 and P4 of the connector are short-circuited with a jumper wire J2, and here the negative lead wire LB and the bypass wire Lb are combined into a relay wire L2 and drawn into the control panel CNT. Connected to ground terminal G.

The positive electrode side disconnection detection circuit 3 is mainly composed of two PNP type transistors Tra and Trb.

The base terminal of the transistor Tra is the proximity switch SW.
The positive electrode side 1: and the emitter terminal thereof are connected to the terminal T11:, respectively. On the other hand, the emitter terminal 1 of the transistor Trb is connected to the terminal T2 and the positive electrode side of the proximity switch SW, and the base terminal is connected to the terminal T3 via the grounding resistor R1. Also, the transistor Tra
The collector terminals of Trb and Trb are respectively connected to the base terminal of a transistor Trf, which will be described later, via a resistor R4.

Negative electrode side disconnection detection circuit 7 (upper two NPN type transistors Trc and Trd and PNP type transistor Tre)
It is composed of the main parts. The emitter terminal of the transistor Trc is connected to the terminal T3 and the base terminal (upper
It is connected to the negative electrode side of the proximity switch SW and is also connected to the terminal T4.
It is connected to the. The base terminal of the transistor Trd is connected to the terminal T1 via the grounding resistor R1, and is also connected to the terminal T3.The emitter terminal of the transistor Trd is connected to the terminal T4. Further, the collector terminal of the transistor Trc and the collector terminal of the transistor Trd are connected to the terminal T2 and the positive electrode side of the proximity switch SW via a connecting plate and a resistor R2 and a resistor R3. and,
The emitter terminal of the transistor Tre is connected to the terminal T2, and the collector thereof is connected to the base terminal of the transistor Trf via the resistor R4.The base terminal is connected to the connection point between the resistors R2 and R3. .

Output circuit 7 (consisting of an iNPN type transistor Trf and a resistor R4, the collector terminal of the transistor Trf is connected to the terminal T51, the emitter terminal is connected to the terminal T4, and the collector terminal is connected to the terminal T4. Signal line L3 is wired from terminal T5 (via terminal P5 of connector C to control panel CNT).The signal line L3 is connected to the alarm indicator light (light emitting diode) WL in control panel CNT, and transistor Trf is conductive. When the ON signal is output (oven collector output), the alarm indicator light W
It is configured so that L lights up.

Next, the operation of the disconnection detection device will be explained.

When each line LA, La, LB, Lb is normal (from the DC power supply 10B to the ground terminal G via the positive lead LA, terminal T2, proximity switch SW, terminal T4, negative lead wire LB) Since a direct current flows through the control panel CNT, each transistor Tra-Trf does not operate, and the alarm indicator light WL in the control panel CNT remains off.

When the positive side bypass line La is disconnected at the fault point x 1, a forward potential difference is generated between the emitter and the base in the transistor Trb of the positive side disconnection detection circuit 3, and a bias voltage is applied. Therefore, the current II is applied to the positive side Flows from the lead wire LA to the transistor Trb, the grounding resistor R1, and the negative bypass line Lb, as well as the transistor Trb.
is in the N state and collector current lcb flows. This collector current 1 cb is output as a bias current S to the base terminal of the transistor Trf, so the transistor Trf is turned on and the alarm lamp WL is lit. At this time, the operating current 10 of the proximity switch SW flows directly through the positive lead wire A, the proximity switch SW, and the negative lead wire LB, so the proximity switch SW operates normally.

When the positive electrode side lead wire LA is disconnected at the fault point x2, a forward potential difference is generated between the emitter and base of the transistor Tra, and a bias voltage is applied to the transistor Tra.

Therefore, when the current 12 flows from the positive side bypass line La to the negative side lead wire LB via the transistor Tra and the proximity switch SW as an operating current of 0, the transistor Tra is turned on and the collector current is 1ca.
flows. This collector current 1ca1 table transistor T
Since the bias current IS is output to the base terminal of rf, the transistor Trf is turned on and the alarm lamp WL is turned on.
lights up.

In this way, 1: Even if the positive electrode side lead wire LA is disconnected, the current 12 flows from the positive electrode side sub-lead La to the negative electrode side lead wire B via the proximity switch SW, so the proximity switch SW operates normally.

When the negative side bypass line Lb is disconnected at three fault points, the transistor Trd of the negative side disconnection detection circuit 7 has a base
A forward potential difference is generated between the emitters and a bias voltage is applied. Therefore, the current 13 flows from the positive lead wire LA to the negative lead wire LB via the grounding resistor R1 and the transistor Trd, and the transistor Tr
d is turned on, and its collector current LED flows from the positive lead LA, resistor R2, and resistor R3 to the negative lead LB. Then, a forward potential difference (a potential difference between both ends of the resistor R2) is generated between the emitter and base of the transistor Tre, and a bias voltage is applied, turning the transistor Tre into an ON state.

Therefore, the collector current Ic of the transistor Tre
e is output as a bias current IS to the base terminal of the transistor Trf. When the transistor Trb'+<ONL, the alarm lamp WL is turned on. At this time, the operating current 10 (upper) of the proximity switch SW flows as it is from the positive side lead wire LA and the proximity switch SW to the negative side node line LB, so the proximity switch SW operates normally.

When the negative electrode side lead wire LB is disconnected at the fault point x4, a forward potential difference is generated between the base and emitter of the transistor Trc, and a bias voltage is applied to the transistor Trc.

Therefore, a current 14 as the operating current 10 flows from the proximity switch SW to the negative side bypass line Lb through the transistor TrctM, and the transistor Trc is turned on, and its collector current 1cc flows through the positive side lead line Lb.
A. Flows through a path from resistor R2 and resistor R3 to negative side bypass line Lb. Then, the transistor Tre
A forward potential difference is generated between the emitter and base of the transistor, and a bias voltage is applied, resulting in a transistor Treh<ON state.

Therefore, the collector current Ice is output as a bias current 1 s to the base terminal of the transistor Trf, and when the transistor Trfh<ON L, the alarm lamp WL is turned on.

In this way, even if the negative electrode side lead wire LB is disconnected, the current 1
4 flows to the proximity switch SW and the negative side bypass line b of the transistor TrC1, so the proximity switch SW operates normally.

Note that the resistance value of the grounding resistor (R) is the same as when the positive bypass line La is disconnected, the transistor T rbl is disconnected, and when the negative bypass line Lb is disconnected, the transistor Trdl is
Each line LA, La, LB is set so that the bias current flows through each line and is sufficiently large.

When Lb is normal, the current flowing from the positive electrode side to the ground terminal G via the resistor R1 is extremely small.

Therefore, during the non-detection operation f'FE of the proximity switch SW, the DC current flowing from the DC power supply element B to the disconnection detection unit 1 via the photocoupler PC hardly increases, so the photocoupler PC does not turn on.

In addition, the resistance values of the resistor R3 and the resistor R4 are sufficiently large to compensate for the bias currents of the transistors Tre and Trf.

As mentioned above, in this embodiment (each line LA, SH, LB,
If any of Lb is disconnected, the positive electrode side disconnection detection circuit 3
Alternatively, the negative electrode side disconnection detection circuit 5 may detect the transistor Trf
Since the bias current IS is output to
Light up h<. Therefore, the occurrence of wire breakage can be immediately notified.

Furthermore, when each lead wire LA, LB is disconnected (
Transistors T ra and T rc conduct and current 2
, I4 flows through each bypass line La, Lb and the proximity switch SW as the operating current 10, so the proximity switch SW can operate normally.

On the other hand, when each of the bypass lines La and Lb is disconnected, the operating current 10 flows through the lead wires LA and LB and the proximity switch SW, so the proximity switch SW can continue its detection operation.

Although Kimoto's embodiment (Table 1) was configured so that the output signal of the output circuit 7 lights up the warning lamp WL of the control panel CNT, the wire breakage detection unit 1 is equipped with an indicator such as a light emitting diode, and each wire is It may be configured so that it lights up when any of LA, La, LB, and Lb is disconnected.This configuration (f) can be used when the control panel CNT is located far away and the alarm lamp WL is difficult to see. , it becomes possible to more reliably notify the occurrence of a disconnection accident.

[Effects of the Invention] As detailed above, according to the present invention, when the lead wire is disconnected, the semiconductor element becomes conductive and the direct current passes through the semiconductor element and the bypass line to compensate for the current path of the equipment. At the same time, the current detection means detects the DC current.On the other hand, when the bypass line is disconnected, the DC current flows through the lead wire as it is, the semiconductor element becomes conductive, and a part of the DC current is transferred from the bypass line semiconductor element to the grounding resistance means. The current detection means detects the DC current.

Therefore, it is possible to detect breakage of the lead wire (:, even if the lead wire or bypass wire is broken, the DC current path for the device can be secured. Therefore, even if the lead wire or bypass wire is broken, the device operation is compensated.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram showing a disconnection detection device and related equipment according to an embodiment. 1... Disconnection detection unit 5... Negative electrode side disconnection detection circuit LA... Positive electrode side lead wire LB... Negative electrode side lead wire Tra, Trb, Tre, Trd, T
R1...Grounding resistor

Claims (1)

[Scope of Claims] A disconnection detection device for detecting disconnection of a lead wire for supplying DC power to equipment, wherein a bypass wire is provided in parallel with the lead wire, and the lead wire, the bypass wire, and the A semiconductor element is provided in series with the bypass line between the equipment and becomes conductive when a potential difference occurs between both ends, and a semiconductor element is provided on the opposite side of the semiconductor element from the equipment, connecting the bypass line and the ground point. A disconnection detection device comprising: a grounding resistance means for connecting; and a current detection means for detecting a direct current flowing through the semiconductor element due to conduction of the semiconductor element.