CN111650494B - Safety loop detection device and detection method thereof - Google Patents
Safety loop detection device and detection method thereof Download PDFInfo
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- CN111650494B CN111650494B CN202010463402.0A CN202010463402A CN111650494B CN 111650494 B CN111650494 B CN 111650494B CN 202010463402 A CN202010463402 A CN 202010463402A CN 111650494 B CN111650494 B CN 111650494B
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- threshold value
- pwm signal
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/2832—Specific tests of electronic circuits not provided for elsewhere
- G01R31/2836—Fault-finding or characterising
- G01R31/2843—In-circuit-testing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
- B66B5/00—Applications of checking, fault-correcting, or safety devices in elevators
- B66B5/0006—Monitoring devices or performance analysers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/02—Measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time or duration
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/54—Testing for continuity
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Elevator Control (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
A safety loop detection device comprising: the conversion circuit is used for converting the alternating current output voltage of the safety loop into a PWM signal; and the input end of the controller is connected with the output end of the conversion circuit and is used for judging the state of the safety loop according to the duty ratio of the PWM signal. The invention also provides a safety loop detection method. The invention can detect the working state of the safety loop, and has high reliability of the detection result and high detection speed.
Description
Technical Field
The invention relates to an elevator control technology.
Background
In order to ensure the safety and the reliability of the operation of the elevator, a plurality of safety components are installed in the elevator system, each safety component is provided with a safety switch, and all the safety switches are connected in series to form a safety loop. Only if all safety parts are normal and the safety loop is conducted, the elevator can work normally.
Present safety circuit detection mode adopts opto-coupler and electric capacity sampling at the safety circuit end, directly judges whether safety circuit switches on with the break-make of opto-coupler, but this kind of detection mode exists not enough in two respects: one is the slower reaction time. Because the false alarm when the voltage in an alternating current period tends to 0 must be avoided, a capacitor is generally adopted for filtering, so that the detection has time delay; secondly, in the elevator use process, the switch contact of each safety component is exposed in the air, and the possibility of oxidation exists, resulting in the voltage drop at the tail end of the safety circuit, and when the voltage drop is reduced to a certain degree, the detection of the safety circuit is caused to be problematic.
Disclosure of Invention
The invention aims to provide a safety loop detection device and a detection method thereof, which can detect the working state of a safety loop, and has high reliability of detection results and high detection speed.
The embodiment of the invention provides a safety loop detection device, which comprises: the conversion circuit is used for converting the alternating current output voltage of the safety loop into a PWM signal; and the input end of the controller is connected with the output end of the conversion circuit and is used for judging the state of the safety circuit according to the duty ratio of the PWM signal.
In the above safety circuit detection device, the controller is configured to determine that the safety circuit is in an off state when a duty ratio of the PWM signal is smaller than a preset first threshold L1, determine that the safety circuit is in an on state when the duty ratio of the PWM signal is greater than or equal to a preset second threshold H1, and determine that the safety circuit is in an under-voltage state when the duty ratio of the PWM signal is greater than or equal to the preset first threshold L1 and smaller than a preset third threshold H2; wherein H2> H1> L1.
In the above safety circuit detecting device, the controller is configured to determine the state of the safety circuit every time a half period of the PWM signal elapses.
The invention also provides a safety loop detection method, which comprises the following steps:
converting the alternating current output voltage of the safety loop into a PWM signal;
and judging the state of the safety loop according to the duty ratio of the PWM signal.
The invention has at least the following advantages:
1. the safety loop detection device of the embodiment of the invention judges the state of the safety loop by measuring the duty ratio of the PWM signal, and can monitor the voltage state of the safety loop, so that an elevator system can take further measures to make up the voltage at the tail end of the safety loop or eliminate an oxide film existing on a contact of a safety switch, and the reliability of the detection result is improved;
2. the embodiment of the invention can carry out duty ratio analysis on the PWM signal of each half period by utilizing the symmetrical characteristic of the converted PWM wave, thereby improving the detection speed of the safety loop.
Drawings
Fig. 1 shows a schematic circuit diagram of a safety loop detection device according to an embodiment of the invention.
Fig. 2 shows a circuit schematic of a conversion circuit according to an embodiment of the invention.
Fig. 3 shows a signal waveform diagram of a conversion circuit according to an embodiment of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
Fig. 1 shows a schematic circuit diagram of a safety loop detection device according to an embodiment of the invention. Referring to fig. 1, a safety loop detection apparatus 100 according to an embodiment of the invention includes a conversion circuit 1 and a controller 2.
The conversion circuit 1 is used for converting the alternating current output voltage of the safety loop 9 into a PWM signal; the input terminal of the controller 2 is connected to the output terminal of the switching circuit 1, and is configured to determine the state of the safety circuit 9 according to the duty ratio of the PWM signal.
Further, the controller 2 is configured to determine that the safety circuit 9 is in an off state when the duty ratio of the PWM signal is smaller than a preset first threshold L1, determine that the safety circuit 9 is in an on state when the duty ratio of the PWM signal is greater than or equal to a preset second threshold H1, and determine that the safety circuit 9 is in an under-voltage state when the duty ratio of the PWM signal is greater than or equal to the preset first threshold L1 and smaller than a preset third threshold H2; wherein H2> H1> L1. H1 is a voltage for ensuring that the safety relay 8 or the safety contactor 8 connected to the end of the safety circuit can normally operate.
Under the condition that the safety loop 9 is completely normal, the duty ratio of the PWM signal received by the controller 2 is greater than or equal to the third threshold H2, when the resistance is increased due to oxidation of the safety switch contact in the safety loop and the duty ratio of the PWM signal received by the controller 2 is reduced to a value between the third threshold H2 and the second threshold H1, it is indicated that the safety loop 9 has entered an undervoltage state and the voltage needs to be increased, and at this time, the safety loop 9 can still work normally because the safety loop 9 is still maintained in a conducting state. If the duty ratio of the PWM signal received by the controller 2 is greater than or equal to the first threshold L1 and less than the second threshold H1, it indicates that the safety circuit 9 is in an undervoltage state and is not turned on, and at this time, the safety circuit 9 cannot work normally.
Further, a first output of the controller 2 is coupled to an input of the motor drive 3, and an output of the motor drive 3 is coupled to an input of the elevator drive motor 4; the controller 2 is used for sending a disconnection signal to the motor driving device 3 when judging that the safety circuit 9 is in a disconnection state, and the motor driving device 3 is used for controlling the elevator driving motor 4 to stop running when receiving the disconnection signal. Alternatively, the motor drive 3 is a frequency converter, which upon receiving a switch-off signal will cut off the current supplied to the elevator drive motor 4 (i.e. the elevator machine) and stop the elevator, so as to ensure the safety of the operation of the elevator.
Further, a second output of the controller 2 is coupled to an input of the adjustable power supply 5, and a power supply output of the adjustable power supply 5 is coupled to a power supply input of the safety loop 9; the controller 2 is configured to send an under-voltage signal to the adjustable power supply 5 when it is determined that the safety circuit is in an under-voltage state, and the adjustable power supply 5 is configured to increase an output voltage or output a peak high voltage when receiving the under-voltage signal, so as to remove an oxide film of a safety switch contact in the safety circuit 9. When the oxide film is removed by applying a high peak voltage, the adjustable power supply 5 may have a voltage limiting or current limiting device to prevent damage to personnel or equipment.
Fig. 2 shows a circuit schematic of a conversion circuit according to an embodiment of the invention. In the present embodiment, the conversion circuit 1 includes a full-wave rectification circuit 11 and an optical coupler 12; the output end of the full-wave rectification circuit 11 is connected with the input end of the optical coupler 12, and the output end of the optical coupler 12 is coupled with the input end of the controller 2.
Please refer to fig. 3. The uppermost original waveform in fig. 3 is 50Hz alternating current output by the safety loop 9; the full-wave rectifying circuit 11 can convert 50Hz alternating current into 100Hz electrical signal, as shown in the middle waveform of fig. 3, and then convert the electrical signal into 100Hz PWM wave, as shown in the lowest waveform of fig. 3, by switching the optical coupler 12. According to the even symmetry characteristic of the transformed PWM wave, the controller can judge the state of the safety loop once every half period of the PWM signal (in the figure, 0 to 5ms are the first half period, and 5 to 10ms are the second half period), so that the reaction speed can be increased to 5ms (namely, the monitoring frequency is 200 Hz). When the duty ratio is lower than a first threshold value L1, the safety circuit is judged to be in a disconnected state, when the duty ratio is larger than or equal to a second threshold value H1, the safety circuit is judged to be in a connected state, and when the duty ratio is larger than or equal to a preset first threshold value L1 and smaller than a preset third threshold value H2, the possible resistance value is considered to be overlarge, and the safety circuit is in an undervoltage state. In one specific embodiment, the first threshold L1 is 10%, the second threshold H1 is 40%, and the third threshold is 60%.
In this embodiment, the controller 2 is a single chip microcomputer.
In other embodiments, the conversion circuit 1 is formed by a bidirectional optical coupler, and an output terminal of the bidirectional optical coupler is coupled to an input terminal of the controller 2. The 50Hz alternating current output by the safety loop 9 is directly changed into a PWM signal through the on-off of the bidirectional optical coupler, and the frequency of the PWM signal is changed into 100Hz.
The invention also provides a safety loop detection method, which comprises the following steps:
converting the alternating current output voltage of the safety loop into a PWM signal;
and judging the state of the safety loop according to the duty ratio of the PWM signal.
The safety loop detection device provided by the embodiment of the invention can convert 50Hz alternating current into 100Hz PWM waveform, and can detect the duty ratio of a PWM signal by using 200Hz monitoring frequency according to the even symmetry of the waveform. When the duty ratio is lower than a first threshold value L1, the controller judges that the safety loop is disconnected, the elevator stops running, and meanwhile, the motor driving device can be informed to cut off the current of the host; when the duty ratio is higher than a second threshold value H1, the controller judges that the safety loop is conducted, and the elevator normally runs; when the duty ratio is lower than the third threshold H2 but greater than or equal to the first threshold L1, the controller determines that the resistance value may be increased due to oxidation of the contact of the safety switch, the safety loop is in an undervoltage state, and the controller may notify the adjustable power supply to increase the output voltage or output a peak high voltage for removing an oxide layer of the contact of the safety switch.
Claims (9)
1. A safety circuit detection device, comprising:
the conversion circuit is used for converting the alternating current output voltage of the safety loop into a PWM signal;
the input end of the controller is connected with the output end of the conversion circuit and used for judging the state of the safety loop according to the duty ratio of the PWM signal; the controller is used for judging that the safety circuit is in a disconnected state when the duty ratio of the PWM signal is smaller than a preset first threshold value L1, judging that the safety circuit is in a connected state when the duty ratio of the PWM signal is larger than or equal to a preset second threshold value H1, and judging that the safety circuit is in an undervoltage state when the duty ratio of the PWM signal is larger than or equal to the preset first threshold value L1 and smaller than a preset third threshold value H2;
wherein, H2> H1> L1; the second threshold value H1 is the voltage for ensuring that a safety relay or a safety contactor connected with the tail end of the safety loop can work normally; under the condition that the safety loop is completely normal, the duty ratio of a PWM signal received by the controller is larger than or equal to a third threshold value H2, when the resistance is increased due to oxidation of a safety switch contact in the safety loop and the duty ratio of the PWM signal received by the controller is reduced to a value between the third threshold value H2 and a second threshold value H1, the safety loop is indicated to enter an undervoltage state, the voltage needs to be increased, and the safety loop can still normally work at the moment because the safety loop is still kept in a conducting state; if the duty ratio of the PWM signal received by the controller is greater than or equal to the first threshold value L1 and smaller than the second threshold value H1, the safety circuit is in an undervoltage state and is not conducted, and at the moment, the safety circuit cannot work normally.
2. The safety loop detection device of claim 1, wherein the first output of the controller is coupled to an input of a motor drive, the output of the motor drive being coupled to an input of an elevator drive motor; the controller is used for sending a disconnection signal to the motor driving device when the safety loop is judged to be in a disconnection state, and the motor driving device is used for controlling the elevator driving motor to stop running when receiving the disconnection signal.
3. The safety loop detection device of claim 2, wherein the motor drive is a frequency converter.
4. The safety loop detection device of claim 1, wherein the second output of the controller is coupled to an input of an adjustable power supply, a power supply output of the adjustable power supply being coupled to a power supply input of the safety loop; the controller is used for sending an undervoltage signal to the adjustable power supply when the safety loop is judged to be in an undervoltage state, and the adjustable power supply is used for increasing output voltage or outputting a peak high voltage when receiving the undervoltage signal so as to remove an oxide film of a safety switch contact in the safety loop.
5. The safety loop detection device of claim 1, wherein the controller is configured to determine the state of the safety loop once every half cycle of the PWM signal.
6. The safety loop detection device of claim 1, wherein the conversion circuit comprises a full wave rectifier circuit and an optocoupler; the output end of the full-wave rectification circuit is connected with the input end of the optical coupler, and the output end of the optical coupler is coupled with the input end of the controller.
7. The safety loop detection device of claim 1, wherein the conversion circuit comprises a bidirectional optocoupler, an output of the bidirectional optocoupler coupled to an input of the controller.
8. The safety loop detection device of claim 1, wherein the controller is a single chip microcomputer.
9. A safety loop detection method, comprising the steps of:
converting the alternating current output voltage of the safety loop into a PWM signal;
judging the state of the safety loop according to the duty ratio of the PWM signal; when the duty ratio of the PWM signal is smaller than a preset first threshold value L1, judging that the safety circuit is in a disconnected state, when the duty ratio of the PWM signal is larger than or equal to a preset second threshold value H1, judging that the safety circuit is in a connected state, and when the duty ratio of the PWM signal is larger than or equal to the preset first threshold value L1 and smaller than a preset third threshold value H2, judging that the safety circuit is in an undervoltage state;
wherein, H2> H1> L1; the second threshold value H1 is the voltage for ensuring that a safety relay or a safety contactor connected with the tail end of the safety loop can work normally; under the condition that the safety circuit is completely normal, the duty ratio of the PWM signal received by the controller is more than or equal to a third threshold value H2, when the resistance is increased due to the oxidation of a safety switch contact in the safety circuit and the duty ratio of the PWM signal received by the controller is reduced to be between the third threshold value H2 and a second threshold value H1, the safety circuit is indicated to enter an undervoltage state, the voltage needs to be increased, and the safety circuit can still normally work at the moment because the safety circuit is still kept in a conducting state; if the duty ratio of the PWM signal received by the controller is greater than or equal to the first threshold value L1 and smaller than the second threshold value H1, the safety circuit is in an undervoltage state and is not conducted, and at the moment, the safety circuit cannot work normally.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010463402.0A CN111650494B (en) | 2020-05-27 | 2020-05-27 | Safety loop detection device and detection method thereof |
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| CN202010463402.0A CN111650494B (en) | 2020-05-27 | 2020-05-27 | Safety loop detection device and detection method thereof |
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| CN111650494A CN111650494A (en) | 2020-09-11 |
| CN111650494B true CN111650494B (en) | 2023-02-14 |
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| CN112707301B (en) * | 2021-01-06 | 2022-08-19 | 上海新时达电气股份有限公司 | Switch detection method, device, electronic equipment and storage medium |
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| CN108092405A (en) * | 2017-12-29 | 2018-05-29 | 上海新时达机器人有限公司 | Electric power controller and robot control system |
| CN109387694A (en) * | 2017-08-04 | 2019-02-26 | 兄弟工业株式会社 | Electric voltage exception detection device |
| CN209427900U (en) * | 2018-08-16 | 2019-09-24 | 西继迅达（许昌）电梯有限公司 | A kind of elevator high pressure detection protection circuit |
| CN110562811A (en) * | 2019-09-12 | 2019-12-13 | 苏州汇川技术有限公司 | Safety loop state detection device and elevator system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203652973U (en) * | 2013-11-29 | 2014-06-18 | 广州日滨科技发展有限公司 | Elevator hall car door lock contact oxidation detecting device |
| CN105280439B (en) * | 2015-10-30 | 2017-10-31 | 林肯电梯(中国)有限公司 | High-reliability safety loop |
| CN106586755A (en) * | 2017-02-06 | 2017-04-26 | 上海峰景移动科技有限公司 | Detection device and method for contact of elevator door lock in elevator safety circuit |
| CN108445386A (en) * | 2018-05-24 | 2018-08-24 | 顺科新能源技术股份有限公司 | A kind of electric vehicle power relay fault detection system and its method |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109387694A (en) * | 2017-08-04 | 2019-02-26 | 兄弟工业株式会社 | Electric voltage exception detection device |
| CN108092405A (en) * | 2017-12-29 | 2018-05-29 | 上海新时达机器人有限公司 | Electric power controller and robot control system |
| CN209427900U (en) * | 2018-08-16 | 2019-09-24 | 西继迅达（许昌）电梯有限公司 | A kind of elevator high pressure detection protection circuit |
| CN110562811A (en) * | 2019-09-12 | 2019-12-13 | 苏州汇川技术有限公司 | Safety loop state detection device and elevator system |
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