CN204101072U - Direct current twin wire proximity transducer failure detector circuit - Google Patents
Direct current twin wire proximity transducer failure detector circuit Download PDFInfo
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- CN204101072U CN204101072U CN201420558088.4U CN201420558088U CN204101072U CN 204101072 U CN204101072 U CN 204101072U CN 201420558088 U CN201420558088 U CN 201420558088U CN 204101072 U CN204101072 U CN 204101072U
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- proximity transducer
- twin wire
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- wire proximity
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Abstract
The utility model provides a kind of direct current twin wire proximity transducer failure detector circuit, comprising: twin wire proximity transducer S1, open detection circuit, short-circuit detecting circuit, operation level testing circuit and signal output apparatus.This circuit efficiently solves driving arrangement cannot judge sensor fault, and the output of direct current twin wire proximity transducer exists leakage current, and the residual voltage of signal causes level unstable, the problem of checkout equipment None-identified.Compared with prior art, the sensor signal after the utility model processing of circuit, without residual voltage and leakage current, compatible better.
Description
Technical field
The utility model relates to proximity transducer, and what be specifically related to is a kind of direct current twin wire proximity transducer failure detector circuit.
Background technology
Proximity transducer replaces the contact measurement modes such as limit switch, to carry out without the need to contact detection object the sensor being detected as object.Its main object detected is metal object, when the sensitive surface of object to be detected proximity switch is to operating distance, do not need Mechanical Contact and apply any pressure to make switch motion, thus drive DC electric apparatus or provide steering order to computing machine (PLC) device.The advantages such as it has reliable in action, stable performance, frequency response is fast, application life is long, antijamming capability is strong, are widely used in the industries such as lathe, metallurgy, chemical industry, light textile and printing.
Current proximity transducer can be divided into inductance type, condenser type, Hall-type etc. by principle of work; AC type and once-through type can be divided into again according to the difference of used power supply; Be divided into three-wire type and twin wire by work, power supply and the output signal of three-wire type are separated, and twin wire is powered shared with signal.For direct current twin wire proximity transducer, it exports as switching signal, when sensor or circuit open a way, short circuit time, control end cannot judge normal signal or sensor fault; And to share with signal because twin wire proximity transducer is powered, because sensor power needs certain maintenance electric current, can produce residual voltage, there will be level instability, equipment component (as PLC) None-identified significant level, causes the problem of misoperation.
Utility model content
For this reason, the purpose of this utility model is to provide a kind of direct current twin wire proximity transducer failure detector circuit, sensor fault cannot be judged to solve driving arrangement, and there is leakage current in the output of direct current twin wire proximity transducer, the residual voltage of signal causes level unstable, the problem of checkout equipment None-identified.
The purpose of this utility model is achieved through the following technical solutions.
A kind of direct current twin wire proximity transducer failure detector circuit, comprising:
Twin wire proximity transducer S1, open detection circuit, short-circuit detecting circuit, operation level testing circuit and signal output apparatus, the output terminals A point of described twin wire proximity transducer S1 is that signal exports and power supply input common terminal, and+24V source current Is outputs to A point after series diode D1, inspection leakage resistance R1;
Described open detection circuit includes voltage comparator U1A, and the negative input end B point of described voltage comparator U1A is connected between diode D1 and the R3 in parallel and inspection leakage resistance R1 connected; Positive input terminal C point is connected between the schottky diode D3 of series connection and divider resistance R6; Described voltage comparator U1A is by comparing the voltage of negative input end B point and positive input terminal C point, and when C point voltage is higher than B point, exporting as high-impedance state, is high level by resistance R7 and LED 1 pull-up, and now twin wire proximity transducer S1 is normal connection; When C point voltage is lower than B point, output low level, now twin wire proximity transducer S1 fault-signal outputs to rear class equipment through G point, and drives LED 1 to be designated as malfunction by resistance R7;
Described short-circuit detecting circuit includes voltage comparator U1B, and the negative input end D point of described voltage comparator U1B is connected between divider resistance R4, R6 of series connection; Positive input terminal E point is connected to the output terminals A point of twin wire proximity transducer S1 by resistance R2; Described voltage comparator U1B is by comparing the voltage of negative input end D point and positive input terminal E point, and when E point voltage is higher than D point, U1B exports as high-impedance state, is high level by resistance R7 and LED1 pull-up, and now twin wire proximity transducer S1 is normal connection; When D point voltage is higher than E point, U1B exports as low level, and now twin wire proximity transducer S1 fault-signal outputs to rear class equipment through G point, and drives LED 1 to be designated as malfunction by resistance R7;
Described operation level testing circuit comprises voltage comparator U1C, and negative input end and the voltage comparator U1B positive input terminal of described voltage comparator U1C share E point, and it is connected to the output terminals A point of twin wire proximity transducer S1 by resistance R2; Positive input terminal F point is connected with resistance R9 and voltage stabilizing diode D2; Described voltage comparator U1C compares the voltage of negative input end and positive input terminal F point, and when positive input terminal F point is higher than negative input end, voltage comparator U1C exports high-impedance state, and now twin wire proximity transducer S1 detects object to be detected; When positive input terminal F point voltage is lower than negative input end, voltage comparator U1C output low level, now twin wire proximity transducer S1 does not detect tested object;
Described signal output apparatus comprises triode Q1, when twin wire proximity transducer S1 does not detect tested object, when operation level detects voltage comparator U1C the 14th pin output low level, triode Q1 ends, and it is high level by pull-up resistor R8 pull-up that sensor states exports H point; When twin wire proximity transducer S1 detects tested object, when operation level detection comparator U1C exports high-impedance state, electric current flows through the base stage of triode Q1 by resistance R10, Q1 collector and emitter conducting, and sensor states exports H point output low level.
Further, when twin wire proximity transducer S1 normally connects use, the voltage of B point equals the tube voltage drop 0.7V that 24V deducts diode D1, C point voltage equals the tube voltage drop 0.3V that 24V deducts schottky diode D3, B point voltage is lower than C point voltage, now the 1st pin of U1A exports as high-impedance state, is high level by resistance R7 and LED 1 pull-up.
Further, when twin wire proximity transducer S1 opens a way, A point is unsettled over the ground, the voltage of B point equals 24V by resistance R3 pull-up, the tube voltage drop 0.3V of schottky diode D3 is deducted higher than C point voltage 24V, the 1st pin output low level of U1A, outputs to rear class equipment by G point, and drives LED 1 to be designated as malfunction by resistance R7.
Further, when twin wire proximity transducer S1 normally connects use, the voltage of E point equals 24V and subtracts sensor current Is and take advantage of R1 to subtract the tube voltage drop 0.7V of diode D1 again, D point voltage equals (24V-0.3V) * R4/(R4+R6), E point voltage is higher than D point voltage, U1B the 2nd pin exports as high-impedance state, is high level by resistance R7 and LED1 pull-up.
Further, when the S1 short circuit of twin wire proximity transducer, A point shorted to earth, the voltage of E point equals 0V, voltage (24V-0.3V) * R4/(R4+R6 lower than D point), now U1B exports the 2nd pin low level, outputs to rear class equipment by G point, and drives LED 1 to be designated as malfunction by resistance R7.
Further, when twin wire proximity transducer S1 does not detect tested object, the negative input end voltage of voltage comparator U1C equals 24V and subtracts sensor current Is and take advantage of R1 to subtract the tube voltage drop 0.7V of diode D1 again, the positive input terminal F point voltage of U1C equals the voltage of voltage regulation of voltage stabilizing diode D2, negative input end voltage is higher than positive input terminal F point voltage, and U1C the 14th pin exports as low level.
Further, when twin wire proximity transducer S1 detects object to be detected near sensor, the negative input end voltage of voltage comparator U1C equals the residual voltage 5V of A point sensor, lower than positive input terminal F point voltage, U1C the 14th pin exports high-impedance state, is high level by R10 pull-up.
Further, described triode Q1 is positive-negative-positive or NPN type triode.
Further, described voltage comparator U1A, U1B, U1C are chip LM339.
The utility model is by detecting the working current of twin wire approach switch sensor, judge the duty of sensor and open short trouble, and export corresponding signal, thus efficiently solve driving arrangement and cannot judge sensor fault, and there is leakage current in the output of direct current twin wire proximity transducer, the residual voltage of signal causes level unstable, the problem of checkout equipment None-identified.This circuit can be placed between sensor and opertaing device (as PLC), fault output signal is outputted to the equipment such as PLC or warning system, actions such as reporting to the police or stop in emergency is made to sensor fault, thus effectively can avoid the industrial accident because sensor fault causes.Compared with prior art, the sensor signal after the utility model processing of circuit, without residual voltage and leakage current, compatible better.
Accompanying drawing explanation
Fig. 1 is schematic block circuit diagram of the present utility model;
Fig. 2 is circuit theory diagrams of the present utility model.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
Refer to shown in Fig. 1, Fig. 1 is schematic block circuit diagram of the present utility model.Direct current twin wire proximity transducer failure detector circuit described in the utility model, mainly includes twin wire proximity transducer, open detection circuit, short-circuit detecting circuit, operation level testing circuit and signal output apparatus.
Wherein twin wire proximity transducer is connected with open detection circuit, short-circuit detecting circuit respectively, described open detection circuit, short-circuit detecting circuit are for detecting the electric current of twin wire proximity transducer power supply, when the wire harness of twin wire proximity transducer is cut off or sensor internal open circuit damages, open detection circuit detect sensor without working current or electric current diminish exceed normal current scope time, export fault-signal, export to realize sensor fault.
When twin wire proximity transducer signal wire shorted to earth or sensor internal short circuit, when short-circuit detecting circuit detects that sensor current change exceedes greatly normal current certain value, export fault-signal, export to realize sensor fault.
Twin wire proximity transducer is also connected with signal output apparatus by operation level testing circuit, and operation level testing circuit is mainly for detection of the level signal normally exported with distinguishing sensor; And signal output apparatus is mainly used in drive amplification, level conversion and removes the residual voltage of sensor, by the level that the level conversion that twin wire proximity transducer exports becomes rear class equipment to identify, export to realize sensor states.
As shown in Figure 2, Fig. 2 is circuit theory diagrams of the present utility model.Wherein twin wire proximity transducer S1 is twin wire metal proximity sensor, the pin (A point) of S1 is output terminal, is the power input of sensor simultaneously, and 2 pin of S1 are power supply ground input end, probe power through series diode D1, arrives A point after inspection leakage resistance R1 by 24V.
Schottky diode D3 and resistance R4, R6 are connected in series, and produce the reference voltage point C point for detecting open circuit and short circuit and D point respectively, and resistance R9 and voltage stabilizing diode D2 is composed in series operation level and detects reference voltage F point; G point and H point access PLC signal input part or other equipment.
Open detection circuit comprises voltage comparator U1A, and corresponding chip adopts LM339, the B point of comparative voltage comparer U1A and C point voltage, and B point is negative input end, and C point is positive input terminal, and when C point voltage is higher than B point, U1A exports as high-impedance state; When B point voltage is higher than C point, U1A exports as low level.
When twin wire proximity transducer S1 normally connects use, the voltage of B point equals the tube voltage drop 0.7V that 24V deducts diode D1, C point voltage equals the tube voltage drop 0.3V that 24V deducts schottky diode D3, B point voltage is lower than C point voltage, U1A the 1st pin exports as high-impedance state, is high level by resistance R7 and LED1 pull-up; When open sensor, A point is unsettled over the ground, and the voltage of B point equals 24V by resistance R3 pull-up, the tube voltage drop 0.3V of schottky diode D3 is deducted higher than C point voltage 24V, U1A the 1st pin output low level, G point output low level, and drive LED 1 to be designated as malfunction by R7.
Short-circuit detecting circuit comprises voltage comparator U1B, and its corresponding chip adopts LM339, compares the voltage of D point and E point, D point is negative input end, E point is positive input terminal, and E point voltage exports as high-impedance state higher than U1B during D point, and D point voltage exports as low level higher than U1B during E point.
When twin wire proximity transducer S1 normally connects use, the voltage of E point equals 24V and subtracts sensor current Is and take advantage of R1 to subtract the tube voltage drop 0.7V of diode D1 again, D point voltage equals (24V-0.3V) * R4/(R4+R6), E point voltage is higher than D point voltage, U1B the 2nd pin exports as high-impedance state, is high level by resistance R7 and LED1 pull-up; Work as short circuit sensor, A point shorted to earth, E point voltage equal 0V, lower than D point voltage (24V-0.3V) * R4/(R4+R6), U1B exports the 2nd pin low level, G point output low level, and by R7 drive LED 1 be designated as malfunction.
Operation level testing circuit comprises voltage comparator U1C, its corresponding employing chip LM339, negative input end and the voltage comparator U1B positive input terminal of described voltage comparator U1C share E point, the positive input terminal F point of U1C, by comparing the voltage of E point and F point, when F point voltage is higher than E point, U1C exports as high-impedance state, and E point voltage exports as low level higher than U1C during F point.
When twin wire proximity transducer S1 does not detect tested object, sensing switch output open circuit, because twin wire sensor needs to obtain working current by output terminal, sensor exports and really open circuit, but have the working current of about 1mA, i.e. Is=1mA, the voltage of E point equals 24V and subtracts sensor current Is and take advantage of R1 to subtract the tube voltage drop 0.7V of diode D1 again, be about 22.3V, F point voltage equals the voltage of voltage regulation 6.8V of voltage stabilizing diode D2, E point voltage is higher than F point voltage, and U1C the 14th pin exports as low level; When sensor detects that object to be detected is near sensor, sensing switch exports closed, and because twin wire sensor needs to obtain working current by output terminal, sensor exports and really closes, but there is the residual voltage of about 5V, what connect due to R2 is the input end of comparer, and internal resistance is infinitely great, and on resistance R2, no current flows through, E point voltage equals A point voltage 5V, lower than F point voltage, U1C the 14th pin exports high-impedance state, is high level by R10 pull-up.
Signal output apparatus forms reverse driving circuit by a NPN type triode Q1, when sensor does not detect tested object, during operation level detection comparator U1C the 14th pin output low level, triode Q1 ends, and H point is high level by pull-up R8 resistance pull-up, when sensor does not detect tested object, operation level detection comparator U1C exports high-impedance state, electric current flows through the base stage of triode Q1 by resistance R10, Q1 collector and emitter conducting, H point output low level; Q1 also according to the different needs of output driving arrangement, can be changed into positive-negative-positive and exports by output triode.
The utility model is by detecting the working current of twin wire approach switch sensor, judge the duty of sensor and open short trouble, and export corresponding signal, thus efficiently solve driving arrangement and cannot judge sensor fault, and there is leakage current in the output of direct current twin wire proximity transducer, the residual voltage of signal causes level unstable, the problem of checkout equipment None-identified.Compared with prior art, the sensor signal after the utility model processing of circuit, without residual voltage and leakage current, compatible better.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all do within spirit of the present utility model and principle any amendment, equivalent to replace and improvement etc., all should be included within protection domain of the present utility model.
Claims (3)
1. a direct current twin wire proximity transducer failure detector circuit, is characterized in that, comprising:
Twin wire proximity transducer S1, open detection circuit, short-circuit detecting circuit, operation level testing circuit and signal output apparatus, the output terminals A point of described twin wire proximity transducer S1 is that signal exports and power supply input common terminal, and+24V source current Is outputs to A point after series diode D1, inspection leakage resistance R1;
Described open detection circuit includes voltage comparator U1A, and the negative input end B point of described voltage comparator U1A is connected between diode D1 and the R3 in parallel and inspection leakage resistance R1 connected; Positive input terminal C point is connected between the schottky diode D3 of series connection and divider resistance R6; Described voltage comparator U1A is by comparing the voltage of negative input end B point and positive input terminal C point, when C point voltage is higher than B point, export as high-impedance state, be high level by resistance R7 and LED 1 pull-up, now twin wire proximity transducer S1 normally connects use; When C point voltage is lower than B point, output low level, now twin wire proximity transducer S1 fault-signal outputs to rear class equipment through G point, and drives LED 1 to be designated as malfunction by resistance R7;
Described short-circuit detecting circuit includes voltage comparator U1B, and the negative input end D point of described voltage comparator U1B is connected between divider resistance R4, R6 of series connection; Positive input terminal E point is connected to the output terminals A point of twin wire proximity transducer S1 by resistance R2; Described voltage comparator U1B is by comparing the voltage of negative input end D point and positive input terminal E point, and when E point voltage is higher than D point, U1B exports as high-impedance state, is high level by resistance R7 and LED1 pull-up, and now twin wire proximity transducer S1 is normal connection; When D point voltage is higher than E point, U1B exports as low level, and now twin wire proximity transducer S1 fault-signal outputs to rear class equipment through G point, and drives LED 1 to be designated as malfunction by resistance R7;
Described operation level testing circuit comprises voltage comparator U1C, and negative input end and the voltage comparator U1B positive input terminal of described voltage comparator U1C share E point, and it is connected to the output terminals A point of twin wire proximity transducer S1 by resistance R2; Positive input terminal F point is connected with resistance R9 and voltage stabilizing diode D2; Described voltage comparator U1C compares the voltage of negative input end and positive input terminal F point, and when positive input terminal F point is higher than negative input end, voltage comparator U1C exports high-impedance state, and now twin wire proximity transducer S1 detects object to be detected; When positive input terminal F point voltage is lower than negative input end, voltage comparator U1C output low level, now twin wire proximity transducer S1 does not detect tested object;
Described signal output apparatus comprises triode Q1, when twin wire proximity transducer S1 does not detect that tested object does not detect tested object, when operation level detects voltage comparator U1C the 14th pin output low level, triode Q1 ends, and it is high level by pull-up resistor R8 pull-up that sensor states exports H point; When twin wire proximity transducer S1 does not detect tested object, when operation level detection comparator U1C exports high-impedance state, electric current flows through the base stage of triode Q1 by resistance R10, Q1 collector and emitter conducting, and sensor states exports H point output low level.
2. direct current twin wire proximity transducer failure detector circuit as claimed in claim 1, it is characterized in that, described triode Q1 is positive-negative-positive or NPN type triode.
3. direct current twin wire proximity transducer failure detector circuit as claimed in claim 1, it is characterized in that, described voltage comparator U1A, U1B, U1C are chip LM339.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420558088.4U CN204101072U (en) | 2014-09-26 | 2014-09-26 | Direct current twin wire proximity transducer failure detector circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420558088.4U CN204101072U (en) | 2014-09-26 | 2014-09-26 | Direct current twin wire proximity transducer failure detector circuit |
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| Publication Number | Publication Date |
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| CN204101072U true CN204101072U (en) | 2015-01-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420558088.4U Withdrawn - After Issue CN204101072U (en) | 2014-09-26 | 2014-09-26 | Direct current twin wire proximity transducer failure detector circuit |
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| CN (1) | CN204101072U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266672A (en) * | 2014-09-26 | 2015-01-07 | 深圳市伊爱高新技术开发有限公司 | Direct-current two-wire type proximity sensor fault detection circuit |
-
2014
- 2014-09-26 CN CN201420558088.4U patent/CN204101072U/en not_active Withdrawn - After Issue
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266672A (en) * | 2014-09-26 | 2015-01-07 | 深圳市伊爱高新技术开发有限公司 | Direct-current two-wire type proximity sensor fault detection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20150114 Effective date of abandoning: 20161012 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |