CN202797945U - Industrial control system signal circuit overvoltage protective device - Google Patents
Industrial control system signal circuit overvoltage protective device Download PDFInfo
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- CN202797945U CN202797945U CN 201220468904 CN201220468904U CN202797945U CN 202797945 U CN202797945 U CN 202797945U CN 201220468904 CN201220468904 CN 201220468904 CN 201220468904 U CN201220468904 U CN 201220468904U CN 202797945 U CN202797945 U CN 202797945U
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- transient voltage
- protective device
- overvoltage
- voltage suppressor
- suppressor diode
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Abstract
The utility model relates to an industrial control system signal circuit overvoltage protective device. High-power transient voltage is utilized to restrain a nanosecond level extremely fast response speed character of overvoltage at two ends of a transient voltage suppressor (TVS); by parameter matching with an overcurrent electric protective element of a polymeric positive temperature coefficient (PPTC) to form a protective circuit, lightning stroke overvoltage and other various forms of accident overvoltage are suppressed within a safety voltage range which cannot damage downstream end devices, and then accident overvoltage are blocked outside the protective device through the PPTC overcurrent electric protective element capable of bearing power frequency emergency power supply voltage. The overvoltage protective device has good restraining function on lightning stroke overvoltage occurred at industrial production sites, and even a 220V alternating current (AC) power frequency power supply is wrongly and directly connected with an input end of the protective device for a plurality of days, the protective device cannot be damaged, and downstream end devices connected with an output end of the protective device cannot be damaged.
Description
Technical field
The utility model relates to analog input (AI), the simulation output (AO) of Distributed Control System (DCS), the Programmable Logic Controller (PLC) of industrial processes, the anti-lightning strike anti-overvoltage protective device of switching value input (DI) two-wire system signal line.
Background technology
At present; on the domestic and international market take anti-lightning strike as purpose two-wire system signal line overvoltage protection; substantially be to adopt piezo-resistance; discharge tube; the various composite sets that transient voltage suppressor diode (TVS) carries out; these overvoltage protections have inhibitory action for the overvoltage that causes because of thunderbolt; but the abnormal overvoltage for the industrial production scene; the signal line fault that for example in the Installation and Debugging process, occurs; wrong line particularly; mistake is with the phase line of 220VAC power frequency supply; or the 220VAC power frequency supply directly is linked into Distributed Control System (DCS); the accident in the dc low-voltage signal loop of Programmable Logic Controller (PLC) happens occasionally; this accident is in case generation causes Distributed Control System (DCS); the serious accident of Programmable Logic Controller (PLC) input card moment damage.In this case, even present anti-lightning strike overvoltage protection on the market has been installed, can not protect the safety of its downstream equipment, and can these protective devices self be damaged in moment equally.
On the other hand, Lightning Over-voltage is that a kind of voltage magnitude is very high, but the duration is lacked again the overvoltage of (generally in tens to hundreds of μ s) very much.Power-frequency overvoltage then is very long a kind of abnormal overvoltage of duration, although the amplitude of voltage unlike Lightning Over-voltage so up to several KV
P-P, but 220VAC power frequency supply voltage compares with 24VDC direct current signal loop, its extent of injury even surpass Lightning Over-voltage once mistake occurs, must cause downstream equipment moment 100% to damage, and may give you any error correcting chance again! Therefore, research and solve the various Over-voltage Protection that may occur of industrial process control system signal line prevention, have important Technological Economy and be worth.
Summary of the invention
The purpose of this utility model provides a kind of industrial control system signal line overvoltage protection; not only the on-the-spot Lightning Over-voltage that occurs of industrial production had good inhibitory action; even with input time a couple of days that directly is linked into protective device of the power frequency supply mistake of 220VAC; not only protective device self can not cause damage, and the downstream equipment of its output can not cause damage too.
The utility model utilizes the characteristics of the response speed that is exceedingly fast of the nanosecond that high-power transient voltage suppressor diode (TVS) has the overvoltage at its two ends; by with (PPTC) the overcurrent Electronic Protection element of (PolyerPositiveTemperature Coefficent) protective circuit of carrying out parameter matching and consisting of of a kind of being called " resettable fuse "; Lightning Over-voltage and other various forms of abnormal overvoltages are clamped down in the safe voltage scope that can not damage downstream equipment, by the PPTC overcurrent Electronic Protection element that can bear power frequency emergency power supply voltage abnormal overvoltage is blocked outside this protective device again.Concrete technical scheme is:
The circuit of this overvoltage protection constitutes: input is made of binding post IN+ and IN-respectively, the output of protective device is respectively by binding post OUT+, OUT-and earth terminal GND consist of, resettable fuse PPTC1 is with after glass tube fuse FUS1 connects, the other end of resettable fuse PPTC1 is connected with input wires terminal IN+, the other end of glass tube fuse FUS1 respectively with the end of transient voltage suppressor diode TVS1, the end of transient voltage suppressor diode TVS2, the end of filtering capacitor C1, the end of filtering capacitor C2, output wiring terminal OUT+ is connected; Resettable fuse PPTC2 is with after glass tube fuse FUS2 connects, and the other end of resettable fuse PPTC2 is connected with input wires terminal IN-; The other end of glass tube fuse FUS2 is connected with the other end, the end of transient voltage suppressor diode TVS3, the other end of filtering capacitor C1, the end of filtering capacitor C3, the output wiring terminal OUT-of transient voltage suppressor diode TVS1 respectively; The other end of the other end of the other end of the other end of transient voltage suppressor diode TVS2, filtering capacitor C2, transient voltage suppressor diode TVS3, filtering capacitor C3 is connected with ground wire GND respectively; Rectifier diode D1 is with after LED 1, current-limiting resistance R1, transient voltage suppressor diode TVS4 connect, the other end of rectifier diode D1 is connected with input wires terminal IN+, and the other end of transient voltage suppressor diode TVS4 is connected with earth terminal GND; Rectifier diode D2 is with after LED 2, current-limiting resistance R2, transient voltage suppressor diode TVS5 connect, the other end of rectifier diode D2 is connected with input wires terminal IN-, and the other end of transient voltage suppressor diode TVS5 is connected with earth terminal GND.
The input direct-current resistance of this overvoltage protection self (the direct short circuit of output is measured) is at 8-22 ohm.This overvoltage protection is to be installed in series in the middle of signal line, thereby realizes the defencive function to the input and output fastener of downstream expensive instrument instrument, sophisticated electronics, DCS system.If this protective device has been installed, just be equivalent in original measurement circuitry, increase the line resistance of 8-22 ohm in signal line.Such resistance value can not have any impact to the normal operation in original observing and controlling loop.
After overvoltage protection of the present utility model is linked into 24VDC measurement and control signal loop; the leakage current of himself is generally at 1-5 μ A; this leakage current is compared with the direct current signal of 4～20mA, can the normal operation in original observing and controlling loop not had any impact equally.The response speed of this overvoltage protection be exceedingly fast (nanosecond); industrial control system signal line over-voltage protection function is comprehensive; it is safe and reliable that the industry control message line thunder protection hits the defencive function of anti-overvoltage, and electronic devices and components type selecting and configuration are rationally used non-maintaining for a long time.
Overvoltage protection of the present utility model; not only the on-the-spot Lightning Over-voltage that occurs of industrial production had good inhibitory action; even with input time a couple of days that directly is linked into protective device of the power frequency supply mistake of 220VAC; not only protective device self can not cause damage, and the downstream equipment of its output can not cause damage too.Simultaneously, which root is the phase line that accident voltage occurs by 2 LED light-emitting diode measurements be, thereby can search as early as possible targetedly and get rid of line fault.As long as got rid of line fault, protective device can automatically restore to normal operating conditions again.
Description of drawings
Fig. 1 is overvoltage protection circuit theory diagrams of the present utility model.
Embodiment
As shown in Figure 1, overvoltage protection circuit of the present utility model constitutes: input is made of binding post IN+ and IN-respectively, the output of protective device is respectively by binding post OUT+, OUT-and earth terminal GND consist of, resettable fuse PPTC1 is with after glass tube fuse FUS1 connects, the other end of resettable fuse PPTC1 is connected with input wires terminal IN+, the other end of glass tube fuse FUS1 respectively with the end of transient voltage suppressor diode TVS1, the end of transient voltage suppressor diode TVS2, the end of filtering capacitor C1, the end of filtering capacitor C2, output wiring terminal OUT+ is connected; Resettable fuse PPTC2 is with after glass tube fuse FUS2 connects, and the other end of resettable fuse PPTC2 is connected with input wires terminal IN-; The other end of glass tube fuse FUS2 is connected with the other end, the end of transient voltage suppressor diode TVS3, the other end of filtering capacitor C1, the end of filtering capacitor C3, the output wiring terminal OUT-of transient voltage suppressor diode TVS1 respectively; The other end of the other end of the other end of the other end of transient voltage suppressor diode TVS2, filtering capacitor C2, transient voltage suppressor diode TVS3, filtering capacitor C3 is connected with ground wire GND respectively; Rectifier diode D1 is with after LED 1, current-limiting resistance R1, transient voltage suppressor diode TVS4 connect, the other end of rectifier diode D1 is connected with input wires terminal IN+, and the other end of transient voltage suppressor diode TVS4 is connected with earth terminal GND; Rectifier diode D2 is with after LED 2, current-limiting resistance R2, transient voltage suppressor diode TVS5 connect, the other end of rectifier diode D2 is connected with input wires terminal IN-, and the other end of transient voltage suppressor diode TVS5 is connected with earth terminal GND.
Operation principle:
Input IN+, the IN-of protective device with the on-the-spot end of overvoltage may occur and be connected, output OUT+, the OUT-of protective device is connected with protected two-wire system instrument and meter, sophisticated electronics.Under normal operation, protective device can not affect and change the original operating state of measuring control loop because of line resistance very little (IN+ is to 4～10 ohm of the D.C. resistances between the OUT+, and IN-is to 4～10 ohm of the D.C. resistances between the OUT-).On the other hand; under normal operation; between the input IN+ of protective device and the IN-and the electronic devices and components between output OUT+ and the OUT-have very high impedance, even directly access 24VDC at the two ends of OUT+ and OUT-, the leakage current of this protective device also only has 1～5 μ A.But when any type of overvoltage occurring between the input IN+ of protective device and the IN-; transient voltage suppressor diode TVS1, TVS2, TVS3 will the rapid conductings with the response speed of nanosecond, and output OUT+ and OUT-two ends, OUT+ and ground end, the OUT-of protective device held with ground and clamp down on respectively in a safe voltage scope.Simultaneously owing to the electric current that flows through resettable fuse PPTC1 and PPTC2 increases rapidly; when this electric current greatly to above PPTC1 and the maximum rated operating current of PPTC2 " overcurrent protection electronic devices and components " time; PPTC1 and PPTC2 overcurrent protection electronic component will generate heat because of overcurrent; thereby cause PPTC1 and PPTC2 resistance value to increase rapidly, the overvoltage of circuit appearance is dropped to the two ends of PPTC1 and PPTC2 overcurrent protection electronic component.On the other hand, the increase of PPTC1 and PPTC2 resistance causes again its electric current to reduce rapidly, be multiply by by the voltage at PPTC1 and PPTC2 two ends at last that heat that the electric current that flows through PPTC1 and PPTC2 produces is kept PPTC1 and PPTC2 is in a kind of high impedance status.
The basic connected mode of the Distributed Control System of this overvoltage protection and industrial processes:
1. when this protective device is installed in central control room; adopt series system that two-wire system analog input (AI), simulation output (AO) and the switching value input (DI) at industrial production scene accessed first the input (IN+ and IN –) of this protective device, the output of protective device (OUT+ and OUT-) is connected with the signal terminal that Distributed Control System (DCS), the various two-wire system analog inputs (AI) of Programmable Logic Controller (PLC), simulation output (AO), the switching value of central control room are inputted (DI) again.Like this; when being linked into protective device input signal circuit two ends from the scene and any type of overvoltage occurs; protective device just can be clamped down on these abnormal overvoltages in the voltage range of a safety rapidly, just can guarantee that protective device downstream sophisticated electronics, device, module exempt from the damage that various abnormal overvoltages cause.
2. when this overvoltage protection is installed in the scene, adopt series system that the input (IN+ and IN –) of this protective device is connected with the signal line that central control room comes, the output of protective device (OUT+ and OUT-) is connected with the various two-wire system instrument and meters at industrial production scene again; Like this; when being linked into protective device input signal circuit two ends from the scene and any type of overvoltage occurs; protective device just can be clamped down on these abnormal overvoltages in the voltage range of a safety rapidly, just can guarantee that the instrument and meter of protective device downstream exempts from the damage that various abnormal overvoltages cause.
Claims (1)
1. industrial control system signal line overvoltage protection, it is characterized in that this overvoltage protection circuit constitutes: input is made of binding post IN+ and IN-respectively, the output of protective device is respectively by binding post OUT+, OUT-and earth terminal GND consist of, resettable fuse PPTC1 is with after glass tube fuse FUS1 connects, the other end of resettable fuse PPTC1 is connected with input wires terminal IN+, the other end of glass tube fuse FUS1 respectively with the end of transient voltage suppressor diode TVS1, the end of transient voltage suppressor diode TVS2, the end of filtering capacitor C1, the end of filtering capacitor C2, output wiring terminal OUT+ is connected; Resettable fuse PPTC2 is with after glass tube fuse FUS2 connects, and the other end of resettable fuse PPTC2 is connected with input wires terminal IN-; The other end of glass tube fuse FUS2 is connected with the other end, the end of transient voltage suppressor diode TVS3, the other end of filtering capacitor C1, the end of filtering capacitor C3, the output wiring terminal OUT-of transient voltage suppressor diode TVS1 respectively; The other end of the other end of the other end of the other end of transient voltage suppressor diode TVS2, filtering capacitor C2, transient voltage suppressor diode TVS3, filtering capacitor C3 is connected with ground wire GND respectively; Rectifier diode D1 is with after LED 1, current-limiting resistance R1, transient voltage suppressor diode TVS4 connect, the other end of rectifier diode D1 is connected with input wires terminal IN+, and the other end of transient voltage suppressor diode TVS4 is connected with earth terminal GND; Rectifier diode D2 is with after LED 2, current-limiting resistance R2, transient voltage suppressor diode TVS5 connect, the other end of rectifier diode D2 is connected with input wires terminal IN-, and the other end of transient voltage suppressor diode TVS5 is connected with earth terminal GND.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220468904 CN202797945U (en) | 2012-09-14 | 2012-09-14 | Industrial control system signal circuit overvoltage protective device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220468904 CN202797945U (en) | 2012-09-14 | 2012-09-14 | Industrial control system signal circuit overvoltage protective device |
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| Publication Number | Publication Date |
|---|---|
| CN202797945U true CN202797945U (en) | 2013-03-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201220468904 Expired - Fee Related CN202797945U (en) | 2012-09-14 | 2012-09-14 | Industrial control system signal circuit overvoltage protective device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109921377A (en) * | 2019-03-25 | 2019-06-21 | 珠海格力电器股份有限公司 | Wiring protection circuit, wiring board and air conditioning system |
| CN110086142A (en) * | 2019-04-25 | 2019-08-02 | 瑞纳智能设备股份有限公司 | A kind of protective device based on MBUS node cluster |
-
2012
- 2012-09-14 CN CN 201220468904 patent/CN202797945U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109921377A (en) * | 2019-03-25 | 2019-06-21 | 珠海格力电器股份有限公司 | Wiring protection circuit, wiring board and air conditioning system |
| CN110086142A (en) * | 2019-04-25 | 2019-08-02 | 瑞纳智能设备股份有限公司 | A kind of protective device based on MBUS node cluster |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130313 Termination date: 20140914 |
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| EXPY | Termination of patent right or utility model |