An elevator door lock detection circuit

Abstract

The present invention discloses an elevator door lock detection circuit, comprising a front-end circuit located on one side of the door lock switch and a back-end circuit located on the other side of the door lock switch: the front-end circuit comprises a series circuit connected in series by a first resistor and a rectifier circuit, one side of the door lock switch is connected to one end of the series circuit, and the other end of the series circuit is grounded through a second resistor, the front-end circuit also comprises a power supply circuit, a comparator and an active detection circuit, the power supply circuit is connected between the series circuit and one side of the door lock switch, the first end of the comparator is connected to a reference voltage, the second end of the comparator is connected between the rectifier circuit and the second resistor, and the output end of the comparator is connected to the active detection circuit; the back-end circuit is connected to the ground through a third resistor. The detection circuit of the present invention is small in size, occupies less space, has no limitation on the life of the electrical switch, can be used for a long time in theory, and reduces the maintenance cost of the elevator.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to an elevator door lock detection circuit. Background Art

[0002] There are two common methods for detecting whether a door lock is bypassed or a through-door lock. One is to introduce 220VAC or 110VAC strong electricity through a relay or a contactor for detection and judgment. The other is to claim that detection and judgment can be performed by introducing a DC power supply.

[0003] In the first solution of detection through relays, ordinary relays are basically used. Ordinary relays have a disadvantage that their electrical switching life is generally only about 100,000 times. If calculated based on normal switching 100 times a day, the service life will not exceed 5 years. If safety relays or contactors are used, the life will be more ideal, but there are problems of high cost and large size of contactors.

[0004] The second method of testing by introducing a DC power supply is still in the theoretical stage and there is no specific implementation plan. In addition, the use of a DC power supply easily introduces the risk of accidentally bypassing the door lock. Summary of the invention

[0005] The invention provides an elevator door lock detection circuit, which is used to solve the problems of short life, high cost and large volume of a traditional elevator door lock detection method.

[0006] An embodiment of the present invention provides an elevator door lock detection circuit, comprising a front-end circuit located on one side of a door lock switch and a back-end circuit located on the other side of the door lock switch:

[0007] The front-end circuit includes a series circuit composed of a first resistor and a rectifier circuit connected in series, one side of the door lock switch is connected to one end of the series circuit, and the other end of the series circuit is grounded through a second resistor. The front-end circuit also includes a power supply circuit, a comparator and an active detection circuit. The power supply circuit is connected between the series circuit and one side of the door lock switch. The first end of the comparator is connected to a reference voltage, the second end of the comparator is connected between the rectifier circuit and the second resistor, and the output end of the comparator is connected to the active detection circuit;

[0008] The back-end circuit is connected to the ground via a third resistor.

[0009] Furthermore, the first end of the first resistor is connected to the front end of the door lock switch, the second end of the first resistor is connected to the rectifier circuit, the rectifier circuit is grounded through the second resistor, the power supply circuit includes a DC power supply circuit and a fourth resistor, and the DC power supply circuit is connected to the first end of the first resistor through the fourth resistor.

[0010] Furthermore, the active detection circuit includes a first photocoupler, the output end of the comparator is connected to the light emitter of the first photocoupler, and the collector of the light receiver of the first photocoupler is connected to the control system of the elevator.

[0011] Furthermore, the output end of the rectifier circuit is also grounded through a first filter capacitor.

[0012] Furthermore, the first resistor, the third resistor and the fourth resistor are isolation resistors, and the second resistor is a bias resistor.

[0013] Furthermore, the rectifier circuit is a rectifier diode, the anode of the rectifier diode is connected to the first resistor, and the cathode of the rectifier diode is connected to the second resistor.

[0014] Furthermore, the DC power supply circuit includes a voltage converter, an input end of the voltage converter is connected to the DC power supply of the elevator system, and an output end of the voltage converter is connected to the fourth resistor.

[0015] Furthermore, the other side of the door lock switch is also connected to a passive detection circuit, and the passive detection circuit includes a second optical coupler.

[0016] Furthermore, the positive electrode of the light emitter of the second optocoupler is connected to the other side of the door lock switch, the negative electrode of the light emitter of the second optocoupler is connected to the neutral line through a current limiting resistor, and the collector of the light receiver of the second optocoupler is connected to the collector of the light receiver of the first optocoupler.

[0017] Furthermore, the positive electrode of the light emitter of the second optical coupler is connected to the other side of the door lock switch through a second filter capacitor, and the negative electrode of the light emitter of the second optical coupler is connected to the neutral line through a current limiting resistor.

[0018] The embodiment of the present invention sets a front-end circuit on one side of the door lock switch and sets a back-end circuit on the other side of the door lock switch. The front-end circuit cooperates with the back-end circuit to detect the state of the door lock switch. Since the voltage of the second output terminal of the comparator is different when the door lock switch is closed and disconnected, when the reference voltage is set between the voltages of the two different states (closed and disconnected), the input signal of the active detection circuit can be different, thereby achieving the purpose of actively detecting the state of the door lock, so that the elevator door lock detection circuit of the present invention does not need to pass through a relay or a contactor, and the embodiment of the present invention uses active and passive electronic components, which are small in size, occupy less space, and have no restrictions on the life of the electrical switch. In theory, it can be used for a long time, reducing the maintenance cost of the elevator. At the same time, the power supply circuit provided in this embodiment can provide detection power when there is a lack of power on both sides of the door lock switch. Similarly, the purpose of judging the state of the door lock switch is achieved by different input signals of the active detection circuit, which greatly improves the applicability and reliability of the detection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a circuit schematic diagram of the elevator door lock detection circuit of the present invention;

[0021] Figure 2 It is a block diagram of the structural relationship between the elevator door lock detection circuit and the elevator system of the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] When the embodiments of the present invention mention ordinal numbers such as "first" and "second", unless they do express the meaning of order according to the context, they should be understood as being merely for the purpose of distinction.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Please refer to Figure 1 As shown, an embodiment of the present invention provides an elevator door lock detection circuit, including a front-end circuit located on one side of the door lock switch and a back-end circuit located on the other side of the door lock switch:

[0026] The front-end circuit includes a series circuit consisting of a first resistor 1 and a rectifier circuit, one side of the door lock switch is connected to one end of the series circuit, and the other end of the series circuit is grounded through a second resistor R1. The front-end circuit also includes a power supply circuit, a comparator and an active detection circuit. The power supply circuit is connected between the series circuit and one side of the door lock switch. The first end of the comparator is connected to a reference voltage Vref, the second end of the comparator is connected between the rectifier circuit and the second resistor R1, and the output end of the comparator is connected to the active detection circuit;

[0027] The back-end circuit is connected to the ground via the third resistor 2 .

[0028] As a specific solution but not limitation, the first end of the first resistor 1 is connected to the front end of the door lock switch, the second end of the first resistor 1 is connected to the rectifier circuit, the rectifier circuit is grounded through the second resistor R1, the power supply circuit includes a DC power supply circuit and a fourth resistor 3, and the DC power supply circuit is connected to the first end of the first resistor 1 through the fourth resistor 3.

[0029] As a specific solution but not limitation, the active detection circuit includes a first photocoupler U1, the output end of the comparator is connected to the light emitter of the first photocoupler U1, and the collector of the light receiver of the first photocoupler U1 is connected to the control system of the elevator. Using a photocoupler as the input end of the active detection circuit can effectively avoid crosstalk between the front and rear ends of the signal, and can effectively improve the reliability of the detection circuit.

[0030] As an improvement to the embodiment of the present invention, the output end of the rectifier circuit is also grounded via a first filter capacitor C1. The first filter capacitor C1 can filter out the AC component of the series circuit, thereby improving the reliability of the detection circuit.

[0031] Specifically, the first resistor 1, the third resistor 2 and the fourth resistor 3 are isolation resistors, and the second resistor R1 is a bias resistor. In this embodiment, the first resistor 1, the third resistor 2 and the fourth resistor 3 are composed of three 200 kilo-ohm resistors connected in series, so that the door lock switch can be prevented from being bypassed after some components of the detection circuit fail, thereby improving the reliability of the detection circuit of the present invention. The second resistor R1 is used to provide a suitable bias voltage for the second end of the comparator.

[0032] As a specific solution but not limitation, the rectifier circuit is a rectifier diode D1, the anode of the rectifier diode D1 is connected to the first resistor 1, and the cathode of the rectifier diode D1 is connected to the second resistor R1.

[0033] As an improvement of the power supply circuit, the DC power supply circuit includes a voltage converter 4, the input end of the voltage converter 4 is connected to the DC power supply of the elevator system, and the output end of the voltage converter 4 is connected to the fourth resistor 3. In this embodiment, the DC power supply of the elevator system is 24V, which is converted into 20V DC through DC-DC conversion. The power supply circuit can realize power supply for the detection circuit under the premise that the door lock switch has no 220VAC power supply, which can ensure that the detection circuit of the present invention can actively detect the door lock under all-day conditions, greatly improving the applicability and reliability of the detection circuit. At the same time, the DC-DC power supply can meet the enhanced isolation conditions, ensuring that the door lock detection circuit has a good isolation effect with the 24V of the elevator system.

[0034] As an improvement but not limitation, the other side of the door lock switch is further connected to a passive detection circuit 5, and the passive detection circuit 5 includes a second optical coupler.

[0035] Specifically, the positive electrode of the light emitter of the second optocoupler U2 is connected to the other side of the door lock switch, the negative electrode of the light emitter of the second optocoupler is connected to the neutral line through a current limiting resistor, and the collector of the light receiver of the second optocoupler is connected to the collector of the light receiver of the first optocoupler.

[0036] The passive detection circuit can detect the door lock state when the door lock switch is connected to 220VAC, which is a supplementary solution for active detection to maximize the reliability of the present invention.

[0037] As a specific solution but not limitation, the positive electrode of the light emitter of the second optical coupler U2 is connected to the other side of the door lock switch through the second filter capacitor C2, and the negative electrode of the light emitter of the second optical coupler U2 is connected to the neutral line through the current limiting resistor R2.

[0038] Principle description: When the door lock switch JK2 is closed and the door lock switch JK2 is connected to 220VAC, the voltages of the front-end circuit input terminal S1 and the back-end circuit input terminal S0 are the same, and the second input terminal of the comparator is affected by the bias resistor R1 to obtain the first voltage U1', Uref<U1', and the comparator outputs a low level, the first optical coupler U1 is turned on, and the collector signal FB of the light receiver of the first optical coupler U1 is a low level. When FB is detected to be a low level, the elevator system determines that the door lock switch JK2 has been closed; at the same time, the passive detection circuit obtains power to turn on the second optical coupler U2, and the collector signal FB of the light receiver of the second optical coupler U2 is also a low level. It can be seen from the above description that this embodiment can simultaneously realize active and passive detection of the door lock switch JK2 in the closed state when connected to 220VAC.

[0039] When the door lock switch JK2 is disconnected and the door lock switch JK2 is connected to 220VAC, the voltage of the front-end circuit input terminal S1 is higher than the voltage of the back-end circuit input terminal S0, and the second input terminal of the comparator is affected by the bias resistor R1 to obtain a second voltage U2', Uref>U2', and the comparator outputs a high level, the first optical coupler U1 is cut off, and the collector signal FB of the light receiver of the first photocoupler U1 is a high level; when FB is detected to be a high level, the elevator system determines that the door lock switch JK2 has been disconnected. At the same time, the second photocoupler U2 of the passive detection circuit is cut off due to no power supply, and the collector signal FB of the light receiver of the second photocoupler U2 is also a high level. It can be seen from the above description that this embodiment can simultaneously realize active and passive detection of the door lock switch JK2 in the disconnected state when connected to 220VAC.

[0040] In addition, the embodiment of the present invention can realize power supply for the detection circuit under the premise that the door lock switch JK2 has no 220VAC power supply. The principle is the same as the above principle, and this embodiment will not be traced back.

[0041] It should be noted that this is a preferred solution rather than a limitation. Figure 2 As shown, the collector signal FB of the light receiver of the first photocoupler U1 or the second photocoupler U2 of this embodiment can be connected to the elevator system through the elevator call. In this embodiment, the detection circuit and the door lock switch are in a one-to-one correspondence.

[0042] The embodiment of the present invention sets a front-end circuit on one side of the door lock switch and sets a back-end circuit on the other side of the door lock switch. The front-end circuit cooperates with the back-end circuit to detect the state of the door lock switch. Since the voltage of the second output terminal of the comparator is different when the door lock switch is closed and disconnected, when the reference voltage is set between the voltages of the two different states (closed and disconnected), the input signal of the active detection circuit can be different, thereby achieving the purpose of actively detecting the state of the door lock, so that the elevator door lock detection circuit of the present invention does not need to pass through a relay or a contactor, and the embodiment of the present invention uses active and passive electronic components, which are small in size, occupy less space, and are not limited by the life of the electrical switch. In theory, it can be used for a long time, reducing the maintenance cost of the elevator. At the same time, the power supply circuit provided in this embodiment can provide detection power when there is a lack of power on both sides of the door lock switch, and the purpose of judging the state of the door lock switch is also achieved by the different input signals of the active detection circuit.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For example, the input end of the active detection circuit is not limited to the use of photocouplers, but can also use the cooperation of switching circuits such as triodes, thyristors or thyristors with peripheral circuits. The judgment scheme of the present invention is not limited to the contents disclosed in the principle description, etc. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An elevator door lock detection circuit, characterized in that: It includes the front-end circuit on one side of the door lock switch and the back-end circuit on the other side of the door lock switch: The front-end circuit includes a series circuit composed of a first resistor and a rectifier circuit connected in series, one side of the door lock switch is connected to one end of the series circuit, and the other end of the series circuit is grounded through a second resistor. The front-end circuit also includes a power supply circuit, a comparator and an active detection circuit. The power supply circuit is connected between the series circuit and one side of the door lock switch. The first end of the comparator is connected to a reference voltage, the second end of the comparator is connected between the rectifier circuit and the second resistor, and the output end of the comparator is connected to the active detection circuit; The back-end circuit is connected to the ground via a third resistor; The first resistor, the third resistor and the fourth resistor are each composed of three 200 kilo-ohm resistors connected in series; The first end of the first resistor is connected to the front end of the door lock switch, the second end of the first resistor is connected to the rectifier circuit, the rectifier circuit is grounded through the second resistor, the power supply circuit includes a DC power supply circuit and a fourth resistor, and the DC power supply circuit is connected to the first end of the first resistor through the fourth resistor; The active detection circuit comprises a first photoelectric coupler, the output end of the comparator is connected to the light emitter of the first photoelectric coupler, and the collector of the light receiver of the first photoelectric coupler is connected to the control system of the elevator; The output end of the rectifier circuit is also grounded via a first filter capacitor; The first resistor, the third resistor and the fourth resistor are isolation resistors, and the second resistor is a bias resistor; The rectifier circuit is a rectifier diode, the anode of the rectifier diode is connected to the first resistor, and the cathode of the rectifier diode is connected to the second resistor.

2. The elevator door lock detection circuit according to claim 1, characterized in that: The DC power supply circuit comprises a voltage converter, an input end of the voltage converter is connected to a DC power supply of the elevator system, and an output end of the voltage converter is connected to a fourth resistor.

3. The elevator door lock detection circuit according to any one of claims 1 to 2, characterized in that: The other side of the door lock switch is also connected to a passive detection circuit, and the passive detection circuit includes a second optical coupler.

4. The elevator door lock detection circuit as claimed in claim 3, characterized in that: The positive electrode of the light emitter of the second optocoupler is connected to the other side of the door lock switch, the negative electrode of the light emitter of the second optocoupler is connected to the neutral line through a current limiting resistor, and the collector of the light receiver of the second optocoupler is connected to the collector of the light receiver of the first optocoupler.

5. The elevator door lock detection circuit according to claim 4, characterized in that: The positive electrode of the light emitter of the second optical coupler is connected to the other side of the door lock switch through a second filter capacitor.

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