Device for acquiring switching value by using optocoupler

Abstract

The device comprises a photoelectric coupler and a signal acquisition unit, one input pin of the photoelectric coupler is connected with a first direct-current power supply, the other input pin of the photoelectric coupler is connected with a device to be acquired, one output pin of the photoelectric coupler is connected with a second direct-current power supply through a first pull-up resistor, and the signal acquisition unit is connected with the second direct-current power supply through a second pull-up resistor. The other output pin of the photoelectric coupler is grounded, and the signal acquisition unit acquires a level signal from the output pin, connected with the first pull-up resistor, of the photoelectric coupler. The utility model has the advantages of high sensitivity and high electrical safety, can avoid burnout caused by electromagnetic interference and short circuit, and can perform energy absorption on reverse voltage and instantaneous large voltage.

Description

Technical Field

[0001] The utility model relates to the field of switch quantity acquisition devices, in particular to a device which utilizes an optical coupler to acquire switch quantities. Background Art

[0002] In industrial automation control, we often encounter various concepts, such as switch quantity, digital quantity, analog quantity, pulse quantity, etc., and the digital quantity acquisition module is used to collect digital quantity. Generally speaking, digital quantity is a signal type composed of 0 and 1, usually a regular signal after encoding. In industrial production, industrial control for the acquisition of switch quantity as protection, control, feedback regulation and other applications is common, is the most indispensable part of industrial control design.

[0003] The acquisition of switch quantity is an indispensable part in the industrial control industry. Common switch quantity acquisition mostly uses the acquisition of switch quantity status. For example, general switch quantity devices directly output the switch quantity through the attraction and release of the internal relay coil. The 0 / 1 acquisition of the switch quantity is to input a voltage through the acquisition end, and the output end reads whether there is a voltage value feedback to determine the state of the switch quantity. Although the principle of this type of switch quantity acquisition is relatively simple, it has been found in long-term use that this method has the problem that the acquisition result is easily interfered with, and the safety problem of failing to protect the signal acquisition circuit. The most common problem of judging the state only by the feedback of the voltage value is false alarm. When inductive voltage interference occurs in the circuit, the acquisition circuit is inductively charged, which is very likely to misreport the switch quantity state. The industrial control use environment determines that the equipment works in a working area with dense electromagnetic interference for a long time, and it is not uncommon for the acquisition voltage to be interfered. In addition, when a short circuit and reverse voltage appear in the circuit, the voltage impacts the entire device, and the signal acquisition unit is often damaged by the impact due to the lack of isolation protection. Utility Model Content

[0004] The utility model provides a device for acquiring switch quantity by using an optical coupler, and solves the problems of easy interference and poor safety of acquisition results in the prior art of switch quantity acquisition by performing electrical-optical-electrical conversion on the switch quantity voltage.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A device for collecting switch quantities using an optical coupler comprises a photoelectric coupler and a signal collection unit, wherein the anode input pin of the light emitting diode of the photoelectric coupler is connected to a first DC power supply, the cathode input pin of the light emitting diode of the photoelectric coupler is connected to a device to be collected, the transistor collector output pin of the photoelectric coupler is connected to a second DC power supply via a first pull-up resistor, the transistor emitter output pin of the photoelectric coupler is grounded, and the signal collection unit collects a level signal from the transistor collector output pin of the photoelectric coupler.

[0007] Furthermore, a second pull-up resistor is connected between the anode input terminal and the cathode input terminal of the light emitting diode of the photoelectric coupler, and the cathode input terminal of the light emitting diode of the photoelectric coupler is clamped at a high level through the second pull-up resistor.

[0008] Furthermore, a Schottky light emitting diode is connected between the anode input terminal and the cathode input terminal of the light emitting diode of the photocoupler, and the large reverse voltage is absorbed by the Schottky light emitting diode.

[0009] Furthermore, an indicator light is connected in parallel to the first pull-up resistor.

[0010] In the utility model, when the device to be collected on the input side of the photoelectric coupler light emitting diode is disconnected, the collector on the output side of the photoelectric coupler triode is pulled up to a high potential by the first pull-up resistor, and the signal collection unit collects a high-level signal. When the device to be collected on the input side of the photoelectric coupler light emitting diode is closed, the collector and emitter on the output side of the photoelectric coupler triode are connected, and the collector potential on the output side of the photoelectric coupler triode is pulled down, and the signal collection unit collects a low-level signal.

[0011] Normally, interference signals will cause the switching voltage generated by the device to be collected to fluctuate, but generally will not cause the device to be collected to change directly from disconnected to closed or from closed to disconnected. In the present invention, as long as the device to be collected is disconnected, the signal acquisition unit must collect a high level, and as long as the device to be collected is closed, the signal acquisition unit must collect a low level. It can be seen that the results collected by the signal acquisition unit of the present invention are less affected by interference signals. In addition, through the isolation effect of the photoelectric coupler, when there is a problem with the device to be collected, the signal acquisition unit can be isolated and protected.

[0012] In the utility model, the cathode input terminal of the light emitting diode of the photoelectric coupler is clamped at a high level through the second pull-up resistor, thereby improving the accuracy and safety of signal collection and avoiding false fault alarms.

[0013] In the utility model, a Schottky light emitting diode is arranged between the anode input terminal and the cathode input terminal of the light emitting diode of the photoelectric coupler, so that a large reverse voltage can be absorbed and the impact of the large reverse voltage on the circuit can be prevented.

[0014] In the utility model, by connecting an indicator light in parallel with the first pull-up resistor, the closing and opening status of the device to be collected can be intuitively reflected, so that the user can intuitively judge the switch value.

[0015] In summary, the utility model changes the voltage value collection into the level state collection of photoelectric conversion, uses the photoelectric coupler as a medium, and utilizes the conversion of electric-optical-electrical signals to realize the switch quantity collection. The utility model has the advantages of high sensitivity and high electrical safety. The level of the input and output ends of the photoelectric coupler is pulled up to avoid burning caused by electromagnetic interference and short circuit; the Schottky light emitting diode is used as a protective energy absorption device to absorb reverse voltage and instantaneous large voltage. By optimizing the collection principle, the utility model can effectively avoid false alarms caused by electromagnetic interference and improve the safety and reliability of collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit schematic diagram of an embodiment of the utility model.

[0017] Figure 2 It is a circuit structure diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0018] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0019] like Figure 1 , Figure 2 As shown, this embodiment discloses a device for collecting switch quantities using an optocoupler, including a photocoupler 5 and a signal collection unit 10. The anode input pin of the light emitting diode of the photocoupler 5 is connected to the first DC power supply 1 through a first voltage divider resistor 2, and the cathode input pin of the light emitting diode of the photocoupler 5 is connected to the device to be collected. A second pull-up resistor 3 is connected between the anode input pin and the cathode input pin of the light emitting diode of the photocoupler 5, and a Schottky light emitting diode 4 is also provided between the anode input pin and the cathode input pin of the light emitting diode of the photocoupler 5, the cathode of the Schottky light emitting diode 4 is connected to the anode input pin of the light emitting diode of the photocoupler 5, and the anode of the Schottky light emitting diode 4 is connected to the cathode input pin of the light emitting diode of the photocoupler 5.

[0020] The transistor collector output pin of the photoelectric coupler 5 is connected to the second DC power supply 7 through the first pull-up resistor 6, and the first pull-up resistor 6 is connected in parallel with a series branch consisting of a second voltage-dividing resistor 8 and an indicator light 9, and the transistor emitter output pin of the photoelectric coupler 5 is grounded GND. The level acquisition end of the signal acquisition unit is connected to the transistor collector output pin of the photoelectric coupler 5, so that the signal acquisition unit collects the level signal from the transistor collector output pin of the photoelectric coupler 5.

[0021] In this embodiment, the terminal socket 11 is taken as an example of the device to be collected, and the first DC power supply 1 of 24VDC, the first voltage-dividing resistor 2 of 5.1KΩ, the second pull-up resistor 3 of 10KΩ, the Schottky light-emitting diode 4 of model 1N5819, the optocoupler 5 of model TLP785GB-S, the first pull-up resistor 6 of 10KΩ, the second DC power supply 7 of 3.3VDC, the second voltage-dividing resistor 8 of 10KΩ, the LED indicator light 9, and the MCU collection unit as the signal collection unit 10 are taken as examples to illustrate the principle of this embodiment.

[0022] Depend on Figure 2 It can be known that when the terminal socket 11 is disconnected, the voltage at the first DC power supply 1 is placed at the anode input pin of the light-emitting diode of the photocoupler 5 along the circuit, and the voltage is from the anode input pin of the light-emitting diode of the photocoupler 5 to the cathode input pin of the light-emitting diode. Because the terminal socket 11 is disconnected, when the voltage reaches one terminal of the terminal socket 11, it cannot be connected to the other terminal of the terminal socket 11, that is, the ground GND, so this circuit cannot form a loop conduction. At this time, the transistor collector output pin and emitter output pin of the photocoupler 5 are not turned on, and the second DC power supply 7 pulls up the potential of the transistor collector output pin of the photocoupler 5 through the first pull-up resistor 6. At this time, the level collected at the IO point of the MCU acquisition unit 10 is a high level, then it is judged that the terminal socket 11 state is disconnected, that is, the corresponding switch quantity is in the disconnected state at this time.

[0023] When the terminal socket 11 is in the conducting state, that is, the heating protection switch corresponding to the two terminals of the terminal socket 11 is closed. At this time, the voltage at the first DC power supply 1 is placed along the circuit to the anode input pin of the light-emitting diode of the photocoupler 5, and the conduction voltage drop of the light-emitting diode input side of the photocoupler 5 is about 1 to 1.5V, and the current range of the light-emitting diode input side of the photocoupler 5 is 2 to 20mA, which is generally used below 5mA in most cases. For 24V input, the voltage drop on the light-emitting diode input side of the photocoupler 5 is 1.3V, and the residual voltage is 22.7V. For the resistor at the first voltage divider resistor 2, the light-emitting diode input side of the photocoupler 5 is about 4.45mA, which meets its requirements. Then the anode input pin and cathode input pin of the light-emitting diode of the photocoupler 5 are turned on, and the voltage goes along the circuit to one terminal of the terminal socket 11 and enters the other terminal, namely the ground GND, to achieve circuit return to zero, that is, at this time, the light-emitting diode input side of the photocoupler 5 is turned on. The input electrical signal drives the light emitting diode inside the photocoupler 5, causing it to emit light of a certain wavelength, which is received by the photodetector inside the photocoupler 5 to generate a photocurrent, which is then further amplified and output. When the photocurrent of the photocoupler 5 is amplified and enters the base of the triode output side of the photocoupler 5, the collector and emitter of the triode output side of the photocoupler 5 are turned on. At this time, according to the conduction characteristics of the triode, the collector potential will be pulled down, and the collector state will be converted from a high level to a low level. At this time, the level collected at the IO point of the MCU acquisition unit 10 is a low level, and it is judged that the terminal socket 11 is closed, that is, the corresponding switch quantity is in a closed state at this time.

[0024] The Schottky light emitting diode 4 has the characteristic of low forward conduction voltage (0.4V). Under the same current, its forward voltage drop is much smaller than that of ordinary light emitting diodes and its recovery time is short. The Schottky light emitting diode 4 mainly plays a role in preventing the impact of reverse voltage on the circuit. When the output side of the light emitting diode of the photocoupler 5 enters a large reverse voltage, the output end of the Schottky light emitting diode 4 can be equivalent to the reverse input voltage end, and the reverse voltage can be absorbed to prevent direct impact on the power supply and equipment.

[0025] The second pull-up resistor 3 can pull up the potential of the cathode input pin of the light-emitting diode of the photocoupler 5 to prevent interference (such as a small negative voltage) from the terminal socket 11. The second pull-up resistor 3 can be regarded as being powered by 24V, and the first voltage-dividing resistor 2 and the second pull-up resistor 3 are equivalent to a 15.1KΩ pull-up resistor, which always clamps the cathode input pin of the light-emitting diode of the photocoupler 5 at a high level. Through this design, the accuracy and safety of signal acquisition can be improved, and false fault alarms can be avoided.

[0026] Because it is not easy to visually judge the high and low potentials, an LED indicator 9 is connected in parallel to the first pull-up resistor 6. When the terminal socket 11 is disconnected, the collector output pin of the transistor of the photocoupler 5 is not conductive with the emitter output pin, and the voltage distributed to the LED indicator 9 from the second DC power supply 7 cannot form a loop with the GND connected to the emitter output pin of the photocoupler 5, and the LED indicator 9 cannot be lit. When the terminal socket 11 is closed, the collector output pin of the transistor of the photocoupler 5 is conductive with the emitter output pin, and ICE (collector-emitter current) can flow to GND. At this time, the LED indicator 9 can form a loop and the LED indicator 9 is lit. When the switch quantity acquisition state is disconnected, the on and off of the LED indicator 9 can be used to reversely infer whether the switch quantity is in a closed state.

[0027] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. The embodiments described in the present invention are merely descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. The various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. Such combinations should also be regarded as the contents disclosed in the present disclosure as long as they do not violate the concept of the present invention. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0028] The present invention is not limited to the specific details in the above-mentioned embodiments. Within the technical concept of the present invention and without departing from the design concept of the present invention, various modifications and improvements made to the technical solution of the present invention by technical personnel in this field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A device for collecting switch quantities using an optical coupler, characterized in that: It includes a photoelectric coupler and a signal acquisition unit. The anode input pin of the light-emitting diode of the photoelectric coupler is connected to a first DC power supply, the cathode input pin of the light-emitting diode of the photoelectric coupler is connected to a device to be collected, the transistor collector output pin of the photoelectric coupler is connected to a second DC power supply through a first pull-up resistor, the transistor emitter output pin of the photoelectric coupler is grounded, and the signal acquisition unit collects a level signal from the transistor collector output pin of the photoelectric coupler.

2. The device for acquiring switch quantity using an optical coupler according to claim 1, characterized in that: A second pull-up resistor is connected between the anode input terminal and the cathode input terminal of the light emitting diode of the photoelectric coupler, and the cathode input terminal of the light emitting diode of the photoelectric coupler is clamped at a high level through the second pull-up resistor.

3. The device for acquiring switch quantity using an optical coupler according to claim 1, characterized in that: A Schottky light emitting diode is connected between the anode input terminal and the cathode input terminal of the light emitting diode of the photocoupler, and a large reverse voltage is absorbed by the Schottky light emitting diode.

4. The device for acquiring switch quantity using an optical coupler according to claim 1, characterized in that: The first pull-up resistor is connected in parallel with an indicator light.

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