CN203313150U - Switching value signal interface circuit for two-wire system sensor - Google Patents
Switching value signal interface circuit for two-wire system sensor Download PDFInfo
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- CN203313150U CN203313150U CN2012203612190U CN201220361219U CN203313150U CN 203313150 U CN203313150 U CN 203313150U CN 2012203612190 U CN2012203612190 U CN 2012203612190U CN 201220361219 U CN201220361219 U CN 201220361219U CN 203313150 U CN203313150 U CN 203313150U
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Abstract
The utility model discloses a switching value signal interface circuit for a two-wire system sensor. The switching value signal interface circuit is composed of a signal source, an initial loop, a voltage stabilizing circuit, a relay loop and an output terminal. A signal conversion circuit is additionally arranged between the two-wire system sensor and the output terminal for eliminating static state leakage current. When there are no input signals, an initial starting current forms a loop via the signal conversion circuit so that the starting current exerts no influence on an electromagnetic relay loop; and when there are input signals, an initial circuit is cut off, the signals of the sensor form a loop via an electromagnetic relay so that sufficient power is ensured for driving the working of the electromagnetic relay. The provided switching value signal interface circuit helps to solve problems that the electromagnetic relay cannot be released reliably due to the existence of leakage current when a conventional two-wire system sensor outputs digital value switch signals, the stability of a controller can be better guaranteed, and the device service life can be prolonged.
Description
Technical field
The present invention relates to signal interface circuit, relate in particular to and using the two-wire system transducer as the interface circuit of switching value signal, belong to automatic electronic control technology field.
Background technology
In electric-automation control system, the switching value input comprises two classes: a class is the contact of auxiliary contact and the relevant relay of equipment, to detect the operating state folding of these equipment; Another kind of is some contacts of intelligent controlling device itself, as the contact of output relay and the diverter switch on the device panel.By the closed or disconnection of switch, with the form of level, reflect the situation of equipment.The input circuit of this switch state is a most basic link of electric control system Shen, and its reliability and electrical characteristic directly affect performance and the structure of control system.
The two-wire system transducer that current digital quantity input signal adopts, wherein a core cable is holding wire, an other core is power line, when transducer detects monitored physical quantity and changes, on holding wire, there will be the output of high-low level signal, the high-low level that rear class equipment can the collection signal line is known the state of physical quantity.When the two-wire system transducer directly accesses the loop of electromagnetic relay, transducer is when having signal to be input to the conversion of no signal input, there will be the insecure situation of release that causes electromagnetic relay because of the existence of quiescent current, caused the bust this of signal.In addition, often to use push-button switch, toggle switch, multi-position switch, contactor, relay etc.They are usually the input sources of switching value.Because this class switch is mostly mechanical switch, when switch contact is closed, can produce of short duration shake reaching before stable, the time of spring shake generally can reach several milliseconds.
Therefore, level, transfer rate, the load mode of input/output signal had to requirement usually, external signal, if do not met these requirements, just needs interface, in order to obtain coordination with microsystem.In addition, interface can help to solve interference problem, when signal is input to interface, signal useless, mistake is intercepted outside or is distinguished.Only have the choose reasonable microcomputer interface circuit, Control System of Microcomputer is worked safely and reliably.
Summary of the invention
The object of the invention is to overcome the above problem that prior art exists, a kind of switching value signal interface circuit of two-wire system transducer is proposed, adopt signaling conversion circuit to eliminate the mode of static leakage current, solve the two-wire system transducer when output digital quantity switching signal, because transducer is not having under input condition, need starting current to maintain the normal operation of transducer; Due to the existence that leakage current is arranged, the collection signal mistake, while especially driving electromagnetic relay, the problem that can cause electromagnetic relay reliably not discharge; Can guarantee preferably the stability of controller, the useful life of prolongation device.
Above-mentioned purpose of the present utility model will be achieved by the following technical programs:
A kind of switching value signal interface circuit of two-wire system transducer, it is characterized in that: by signal source S1, initial loop, voltage stabilizing circuit, relay circuit, output forms, signal source S1 connects two inputs of initial loop, two outputs of initial loop connect voltage stabilizing didoe D1 two ends, the input of relay K 1 connects the resistance R 3 of initial loop output, the two ends of light-emitting diode B2 and sustained diode 1, described initial loop is by power switch pipe Q1, power switch pipe Q2, resistance R 1, resistance R 2, resistance R 4, resistance R 5, resistance (R6) forms, described power switch pipe Q1, the input of power switch pipe Q2 connects voltage stabilizing circuit, the positive input of signal source S1 forward voltage access power switching tube Q1, the reverse input end of reverse voltage access power switching tube Q1, the reverse input end of power switch pipe Q1 is connected with the positive input of power switch pipe Q2 and the positive input of cut-in relay, and the output of power switch pipe Q1, power switch pipe Q2 connects in relay circuit.
Further; initial loop is the preposition circuits for triggering of switching value; in its reverse input end access signal source; after signal source S1 place in circuit; by resistance R 1, resistance R 2, resistance R 4, resistance R 5, resistance R 6, power switch pipe Q1, power switch pipe Q2, formed the initial loop of transducer; resistance R 6 provides the quiescent operation condition with voltage stabilizing didoe ZD1 for Q1, and protection diode D2 has protected the reverse surge voltage of power switch pipe Q1.Resistance R 2 and voltage stabilizing didoe ZD2 provide the quiescent operation condition for power switch pipe Q2, and protection diode D3 has protected the reverse surge voltage of power switch pipe Q2.At transducer during without input signal, power switch pipe Q1, power switch pipe Q2 are in conducting state, the static starting current of transducer is got back to power-via power switch pipe Q2, and now V1 is near 0V, and now electromagnetic relay is because operating voltage can't adhesive lower than operation voltage.
Power switch pipe Q1 in initial loop, power switch pipe Q2 is the power switch pipe of circuits for triggering, has certain thresholding starting resistor, threshold voltage by power supply through resistance R 1, resistance R 2, resistance R 4, resistance R 5, resistance R 6 dividing potential drops obtain, the positive input of its forward voltage access power switching tube Q1, the reverse input end of reverse voltage access power switching tube Q1, the reverse input end of power switch pipe Q1 is connected with the positive input of power switch pipe Q2 and the positive input of cut-in relay, switching tube power switch pipe Q1, in the connected also cut-in relay loop of the output of power switch pipe Q2.
Further, described relay circuit is served as reasons and is positioned at initial loop resistance R 3, light-emitting diode B2 and sustained diode 1 composition afterwards, because the voltage on relay can not suddenly change, sustained diode 1 discharges the residual current energy in the electromagnetic relay circuit, thereby make the voltage can be with the closing of contact or the shake while disconnecting and sharply changing, eliminated shaking interference.When secondly signal source provided normal running conditions, drive current can maintain light-emitting diode B2 through resistance R 3 and show, makes operating state as can be known.
The application implementation of the switching value signal interface circuit of the utility model transducer, its effect shows as:
This scheme adopts the isolation technology design, and signal source and output are isolated fully on electric, and antijamming capability is strong.This switching value signal interface circuit has been realized the collection of the conversion of switching value high-low level and open-circuit condition signal, adopts switching value previous state restore circuit to guarantee the accuracy of each collection signal, thereby meets various safety standard-requireds.In addition, compatible good, stability and reliability are high, solve electromagnetic relay in the situation that loop current is arranged, and because of the existence of static leakage current, cause the problem of the unreliable release of signal transmission, and interface circuit turn-offs, and signal transmission loop is not exerted an influence.
The accompanying drawing explanation
Fig. 1 is the theory diagram of the switching value signal interface circuit of this practical transducer;
Embodiment
Following constipation closes the embodiment accompanying drawing, embodiment of the present utility model is described in further detail, so that technical solutions of the utility model are easier to understand.
As shown in Figure 1, the switching value signal interface circuit product of the transducer that this technical scheme proposes, taked the isolation technology design, this interface circuit mainly comprises following part, by signal source, initial loop, voltage stabilizing circuit, relay circuit, output forms, between two-wire system input pickup and output, increased signaling conversion circuit, adopt signaling conversion circuit to eliminate the mode of static leakage current, behind two-wire system transducer access loop, while there is no input signal, initial starting current forms loop via signaling conversion circuit, guarantee starting current on the electromagnetic relay loop without any impact, the reliability of the signal transmission improved.Having under the signal input state, initial circuit will turn-off, and the signal of transducer forms loop via electromagnetic relay, ensure the work of enough power drive electromagnetic relays.
Further, this initial loop forms circuits for triggering by being positioned at signal source S1 resistance R 1, resistance R 2, resistance R 4, resistance R 5, resistance R 6, voltage stabilizing didoe ZD1, voltage stabilizing didoe ZD2 and power switch pipe Q1, power switch pipe Q2 afterwards, the line voltage distribution of signal source is converted to a suitable level and by the pin of relay K 1, is detected; The effect of Schottky type voltage stabilizing didoe ZD1 and voltage stabilizing didoe ZD2 is: when the voltage step-down on power switch pipe Q1, power switch pipe Q2, maintain the voltage on it, make power switch pipe Q1, the power switch pipe Q2 can normal running, bear the effect of burning voltage.Between the two-stage of power switch pipe Q1, power switch pipe Q2, also increase Schottky type protection diode D2, protection diode D3, prevent that the reverse surge voltage of switching tube is too high, the breakdown switch pipe.
Further, when signal source S1 has input signal, the voltage that V1 is ordered rises near supply voltage, now because the voltage of voltage stabilizing didoe ZD2 higher than the voltage of voltage stabilizing didoe ZD1, power switch pipe Q1 will turn-off rapidly, because the shutoff of power switch pipe Q1, power switch pipe Q2 can't make On current is provided power switch pipe Q2 also turn-off rapidly; Interface circuit will quit work like this, due to the voltage rising of V1, reach the operation voltage of electromagnetic relay, and now electromagnetic relay adhesive, realized the transmission of digital quantity switching signal.
When signal source S1 does not have input signal again, now the V1 voltage of ordering falls back near 0V, now voltage stabilizing didoe ZD2 both end voltage is lower than the thresholding burning voltage, make the turn-on condition of power switch pipe Q1 meet and work rapidly, after power switch pipe Q1 conducting, Q2 provides On current for power switch pipe, and power switch pipe Q2 is conducting rapidly also, now the quiescent current of transducer mainly forms loop by power switch pipe Q2 and gets back to power-, no longer by relay K 1, forms loop; Now relay K 1 can not occur because quiescent current is arranged that the situation that can't discharge reliably occurs again; Because relay K 1 belongs to inductive load, after relay K 1 coil instant power-down, will form damping circuit by sustained diode 1; energy in release coil; sustained diode 1 plays the overvoltage protection effect, in case the relay misoperation work, for circuit provides the reliable guarantee of work.
In the switching value signal interface circuit of described transducer, also comprise a show circuit circuit, be comprised of resistance R 3 and light-emitting diode B2, be used for the driving LED luminous tube, show circuit is by the correct transmission of display.
Certainly, above is only concrete exemplary applications of the present invention, and protection scope of the present invention is not constituted any limitation.All employing equivalents or equivalence are replaced and the technical scheme of formation, within all dropping on rights protection scope of the present invention.
Claims (2)
1. the switching value signal interface circuit of a two-wire system transducer, it is characterized in that: by signal source S1, initial loop, voltage stabilizing circuit, relay circuit, output forms, signal source S1 connects two inputs of initial loop, two outputs of initial loop connect voltage stabilizing didoe D1 two ends, the input of relay K 1 connects the resistance R 3 of initial loop output, the two ends of light-emitting diode B2 and sustained diode 1, described initial loop is by power switch pipe Q1, power switch pipe Q2, resistance R 1, resistance R 2, resistance R 4, resistance R 5, resistance R 6 forms, described power switch pipe Q1, the input of power switch pipe Q2 connects voltage stabilizing circuit, the positive input of signal source S1 forward voltage access power switching tube Q1, the reverse input end of reverse voltage access power switching tube Q1, the reverse input end of power switch pipe Q1 is connected with the positive input of power switch pipe Q2 and the positive input of cut-in relay, and the output of power switch pipe Q1, power switch pipe Q2 connects in relay circuit.
2. the switching value signal interface circuit of two-wire system transducer according to claim 1, is characterized in that: between the two-stage of described power switch pipe Q1, power switch pipe Q2, also increase Schottky type protection diode D2, protection diode D3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203612190U CN203313150U (en) | 2012-07-25 | 2012-07-25 | Switching value signal interface circuit for two-wire system sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203612190U CN203313150U (en) | 2012-07-25 | 2012-07-25 | Switching value signal interface circuit for two-wire system sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203313150U true CN203313150U (en) | 2013-11-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012203612190U Expired - Fee Related CN203313150U (en) | 2012-07-25 | 2012-07-25 | Switching value signal interface circuit for two-wire system sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203313150U (en) |
-
2012
- 2012-07-25 CN CN2012203612190U patent/CN203313150U/en not_active Expired - Fee Related
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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: 20131127 Termination date: 20140725 |
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| EXPY | Termination of patent right or utility model |