CN201392358Y

CN201392358Y - Passive power distribution isolator and 0-20mA signal passive isolator

Info

Publication number: CN201392358Y
Application number: CN200920137306U
Authority: CN
Inventors: 张惠益
Original assignee: FUJIAN SHANGRUN PRECISION INSTRUMENT Co Ltd
Current assignee: FUJIAN SHANGRUN PRECISION INSTRUMENT Co Ltd
Priority date: 2009-03-30
Filing date: 2009-03-30
Publication date: 2010-01-27
Anticipated expiration: 2019-03-30

Abstract

The utility model discloses a passive power distribution isolator and a 0-20mA signal passive isolator, and belongs to a passive isolator used in electric control line products. The utility model provides the passive power distribution isolator and the 0-20mA signal passive isolator which use a complementary symmetrical emitter output circuit and a high-frequency transformer to realize the transmission of Hart communication digital signals. The utility model belongs to an automatization technical tool which can be applied in industrial automatization instruments and systems for realizing obtaining, transferring, conversion and processing of production process information, and usually the passive isolator is added between an on-site sensor and a control room device during the obtaining and the transferring processes of information, which can improve the reliability and the stability of information obtaining. The utility model relates to an innovative current mutual inductance self-oscillation signal transmission lossless magnetic isolation technology through improving the circuit and the high-frequency transformer, and solves the problem that the transmission efficiency is affected because of self change of signals and load.

Description

Passive power distribution isolator and 0～20mA signal passive isolator

Technical field

The utility model relates to the passive isolator that uses in the electric control series of products, a kind of specifically passive power distribution isolator and 0～20mA passive signal isolator.

Background technology

Along with the emerge in multitude of industrial automation product and extensively universal, electronic equipment, Switching Power Supply, computing machine and Programmable Logic Controller PLC etc., when industrial automation is brought convenience, it promptly is the object of noise, it is again a noise source, the noise of particularly transition character, its climbing speed is fast, duration is short, voltage amplitude is big, randomness is strong, and automated system realizes obtaining of production process information, transmit, transfer process is when signal circuit two ends all during ground connection, because there is potential difference (PD) in the place, two ends, will form the vagabond current loop, vagabond current becomes interference voltage through signal wire resistance, and metering circuit is caused interference.Therefore in industrial automation control system, between pulpit, computer house PLC and on-the-spot electronic measuring instrument, sensor according to the different common adjunction passive power distribution isolator and the passive signal isolator of control method, can filter extraneous interference, can avoid again sending out noise and string mould, common mode interference all being played inhibiting effect, to improve electronic measuring instrument, sensor, the antijamming capability of PLC and the reliability of system to the external world.

In a word, in passive isolator, all adopt the magnetic isolation mode of electric current mutual inductance at present both at home and abroad, the dc current signal of its transmission, the communication digital signal, antidamping, bringing onto load, signal linear index etc. all are subjected to the very big restriction of employed separation principle.

Show patents such as the enterprise of existing many production passive isolators, and " realizing passive 4～20mA isolator " 200720008536.3 at present from the interrelated data retrieval that comprises Chinese patent with constant current source and high-frequency transformer.And the product that present product mainly is provided with signal, audio frequency etc., it is strong to have a unicity, does not have defectives such as versatility.

The utility model content

In order to overcome the deficiencies in the prior art, the purpose of this utility model is that passive power distribution isolator and the 0～20mA passive signal isolator of realizing transmitting Hart communication digital signal with complementary symmetrical expression emitter output circuit and high-frequency transformer will be provided.

The technical scheme that its technical matters that solves the utility model adopts is: a kind of passive power distribution isolator and 0～20mA signal passive isolator, it is characterized in that: the circuit of forming by output of complementary symmetrical expression emitter-base bandgap grading and high-frequency transformer: Vi+end and-hold input end to be connected to source device for isolator, Vo+end with-hold output terminal into isolator; One end of resistance R 1 with an end of the collector of triode T1 and capacitor C 3 be connected to Vi+end; One end of the negative terminal of the other end of resistance R 1 and diode D1, capacitor C 1 and the base stage of triode T1 connect; One end of the other end of the negative terminal of the anode of diode D1 and diode D2, capacitor C 1, capacitor C 2 and the end of coil resistance r1 connect; The other end of resistance r1 is connected with an end of inductance L 1; One end of the emitter of the emitter of the other end of inductance L 1 and triode T1, triode T2 and inductance L 2 connects; The other end of inductance L 2 is connected with an end of inductance L 3; One end of the other end of the other end of inductance L 3 and capacitor C 3 and capacitor C 4 connects; The base stage of one end of the anode of diode D2 and resistance R 2, the other end of capacitor C 2 and triode T2 connects; The other end of resistance R 2 with the other end of the collector of triode T2 and capacitor C 4 be connected to Vi-end; The negative terminal of one end of inductance L 4 and the anode of diode D3 and diode D4 connects; One end of the other end of inductance L 4 and capacitor C 5 and an end of capacitor C 6 connect; The negative terminal of diode D3 with an end of the other end of capacitor C 5 and capacitor C 7 be connected to Vo+end; The anode of diode D4 with the other end of the other end of capacitor C 6 and capacitor C 7 be connected to Vo-end.

R1, R2 are the identical resistance of resistance in the described circuit, and D1, D2 are the diode of same model, and T1 is a NPN type triode, and T2 is the positive-negative-positive triode.

C1, C2 are the alternating voltage shunt capacitance in the described circuit, r1, L1, L2 are step-up transformer, r1 is a transformer secondary coil resistance, L1 is a transformer secondary coil inductance, and the induced voltage that the connection between them makes L1 is connected to input end as the input signal of complementary symmetrical expression emitter output circuit through C1, C2.

L2 is a transformer polar curve circle inductance just in the described circuit, first very for a short time the ignoring of polar curve circle resistance, C3, C4 electric capacity rises and cuts off that the direct current conducting exchanges the source of doing and the appearance value equates, the L3 inductance value is greater than L2, L3, L4 is a mutual inductor polar curve circle inductance just for current transformer L3, L4 is a mutual inductor secondary coil inductance, the load that connects to form complementary symmetrical expression emitter output circuit between them, they and triode T1, T2 connects to form modulation-demodulation circuit, when circuit is used for Signal Spacing, circuit can be modulated into square wave current signal with dc current signal, and when circuit was used for the distribution isolation, circuit can be demodulated to dc current signal with square wave current signal.

D3, D4 are the diode of same model in the described circuit, C5, C6, C7 are electric capacity, connect to form between they and the L4, also be modulation-demodulation circuit simultaneously, when circuit is used for the distribution isolation, circuit can be modulated into square wave current signal with dc current signal again, and when circuit was used for Signal Spacing, circuit can be demodulated to dc current signal with square wave current signal.

Its principle of work is to make distribution when circuit to isolate the time spent, Vi connects 24 volts of power supplys of direct current, because C3, the dividing potential drop effect B point voltage of C4 is 12 volts, and the bias line that is provided with at this moment triode T1 saturation conduction e point voltage be 24 volts, the T1 collector current is through L2, L3 flows to the B point by the e point, because of the electric current that flows through inductance can not suddenly change, L2 generation induced voltage A point voltage after L1 boosts is higher than the e point ends the further saturated T2 of T1, along with reducing the e point voltage gradually, the transient process L1 ends A point voltage of induced voltage raises gradually, triode T1 ends when voltage e point is higher than the A point, T2 conducting at this moment e point voltage is 0 volt, the T2 collector current is through L3, L2 flows to the e point by the A point, L2 generation induced voltage e point voltage after L1 boosts is higher than the A point ends the further saturated T1 of T2, along with the transient process L1 ends A point voltage of the induced voltage e point voltage that raises gradually reduces gradually, triode T2 ends when voltage e point is lower than the A point, the such T1 of T1 conducting, the upset repeatedly of T2 conducting cut-off state, above-mentioned schematic diagram has just been formed complementary symmetrical expression emitter-base bandgap grading output multivibrator circuit, and the L3 two ends also just form its frequency of square-wave signal that amplitude is about 24 volts and are about L1,0.7 times the inverse of two transit times of r1.Because L3, L4 is current transformer ratio 1: 1, L4 two ends square-wave signal is through D3, D4, C5, produce 24 volts of power supplys of direct current of isolation after the C6 rectification C7 filtering when spot sensor is powered, sensor generates the 4～20mA Constant Direct Current electric current that changes with the in-site measurement value, become square wave current signal by L3 through the two ends of D4 and L4 square-wave frequency modulation again, T1, T2 is demodulated to 4～20mA Constant Direct Current electric current of changing with the in-site measurement value and is flowed out by the input negative terminal and deliver to the pulpit and regulate or control, when the scene is intelligence sensor, the isolator component parameter is selected, circuit is very little to the Hart 1.2KHz ~ 2KHz numerical frequency signal impedance of communicating by letter, can transmit the Hart signal of communication when therefore the realization of this circuit is isolated on-the-spot distribution, and realize the loss of direct supply isolation processes noenergy, so this circuit realizes that Signal Spacing signal transduction process good linearity carrying load ability is strong.Make 0～20mA dc current signal when this circuit and isolate the time spent, input end inserts current signal, the voltage of signal itself makes the circuit resonance current be modulated into square wave current signal through T1, T2, L3, be demodulated to flow out through D3 with the corresponding 0～20mA dc current signal of input signal by L4, D3, D4, C5, C6 again and be used for control or regulate, this sample circuit has just been realized the function of passive isolated DC current signal.

Passive power distribution isolator can play by the pulpit active equipment when spot sensor provides the direct supply effect of isolation, 4～20mA the dc current signal with the variation of in-site measurement value that reception is produced by sensor is delivered to the pulpit active equipment and is used for control and adjusting, and can transmit Hart communication digital signal synchronously.Be used as the passive signal isolator time spent, can play 0～20mA dc current signal effect that isolation was controlled or regulated by pulpit active equipment and instrument, instrument being used to of sending.

The beneficial effects of the utility model are: the utility model can be widely applied to the automation equipment that obtains, transmits, changes, handles of industrial automation instrument and system's realization production process information, obtain in information, sensor and pulpit equipment room add this passive isolator, the reliability and stability that obtains with raising information to transmittance process at the scene usually.The utility model by to circuit Ji electric current mutual inductance, self-sustained oscillation, signal that the improvement of Gao Frequency transformer is innovated transmit lossless magnetic isolation technology, solved because of signal self and changed and the load size influences the transmission efficiency problem.

Description of drawings

Below in conjunction with drawings and Examples the utility model is further described.

Fig. 1 is a circuit diagram of the present utility model.

Fig. 2 is an isolation module work synoptic diagram of the present utility model.

1 is (resource loop are arranged) such as pulpit instrument or computing machines among Fig. 2, and 2 is the HART digital signal, and 3 is spot sensor.

When expression is isolated among Fig. 2, module makes complementary symmetrical expression emitter output circuit high-frequency transformer generation multi-harmonic-oscillations frequency 100KHz make isolation module work from there being resource loop to obtain voltage signal, output provides the power supply of isolation to spot sensor with rectifier system, and 4～20mA signal that receiving sensor produces passes back to the pulpit, and can transmit Hart communication digital signal synchronously.As resource loop is that 0～20mA can improve behind isolation module and anti-interferencely can be used for control or regulate.

Embodiment

Embodiment 1:

See also the circuit that Fig. 1 and Fig. 2 are made up of output of complementary symmetrical expression emitter-base bandgap grading and high-frequency transformer: Vi+end and-hold input end to be connected to source device for isolator, Vo+end with-hold output terminal into isolator; One end of resistance R 1 with an end of the collector of triode T1 and capacitor C 3 be connected to Vi+end; One end of the negative terminal of the other end of resistance R 1 and diode D1, capacitor C 1 and the base stage of triode T1 connect; One end of the other end of the negative terminal of the anode of diode D1 and diode D2, capacitor C 1, capacitor C 2 and the end of coil resistance r1 connect; The other end of resistance r1 is connected with an end of inductance L 1; One end of the emitter of the emitter of the other end of inductance L 1 and triode T1, triode T2 and inductance L 2 connects; The other end of inductance L 2 is connected with an end of inductance L 3; One end of the other end of the other end of inductance L 3 and capacitor C 3 and capacitor C 4 connects; The base stage of one end of the anode of diode D2 and resistance R 2, the other end of capacitor C 2 and triode T2 connects; The other end of resistance R 2 with the other end of the collector of triode T2 and capacitor C 4 be connected to Vi-end; The negative terminal of one end of inductance L 4 and the anode of diode D3 and diode D4 connects; One end of the other end of inductance L 4 and capacitor C 5 and an end of capacitor C 6 connect; The negative terminal of diode D3 with an end of the other end of capacitor C 5 and capacitor C 7 be connected to Vo+end; The anode of diode D4 with the other end of the other end of capacitor C 6 and capacitor C 7 be connected to Vo-end.

The present embodiment isolator can play by the pulpit active equipment when spot sensor provides the direct supply effect of isolation, 4～20mA the dc current signal with the variation of in-site measurement value that reception is produced by sensor is delivered to the pulpit active equipment and is used for control and adjusting, and can transmit Hart communication digital signal synchronously.Be used as the passive signal isolator time spent, can play 0～20mA dc current signal effect that isolation was controlled or regulated by pulpit active equipment and instrument, instrument being used to of sending.

Claims

1, a kind of passive power distribution isolator and 0～20mA signal passive isolator, it is characterized in that: the circuit of forming by output of complementary symmetrical expression emitter-base bandgap grading and high-frequency transformer: Vi+end and-hold input end to be connected to source device for isolator, Vo+end with-hold output terminal into isolator; One end of resistance R 1 with an end of the collector of triode T1 and capacitor C 3 be connected to Vi+end; One end of the negative terminal of the other end of resistance R 1 and diode D1, capacitor C 1 and the base stage of triode T1 connect; One end of the other end of the negative terminal of the anode of diode D1 and diode D2, capacitor C 1, capacitor C 2 and the end of coil resistance r1 connect; The other end of resistance r1 is connected with an end of inductance L 1; One end of the emitter of the emitter of the other end of inductance L 1 and triode T1, triode T2 and inductance L 2 connects; The other end of inductance L 2 is connected with an end of inductance L 3; One end of the other end of the other end of inductance L 3 and capacitor C 3 and capacitor C 4 connects; The base stage of one end of the anode of diode D2 and resistance R 2, the other end of capacitor C 2 and triode T2 connects; The other end of resistance R 2 with the other end of the collector of triode T2 and capacitor C 4 be connected to Vi-end; The negative terminal of one end of inductance L 4 and the anode of diode D3 and diode D4 connects; One end of the other end of inductance L 4 and capacitor C 5 and an end of capacitor C 6 connect; The negative terminal of diode D3 with an end of the other end of capacitor C 5 and capacitor C 7 be connected to Vo+end; The anode of diode D4 with the other end of the other end of capacitor C 6 and capacitor C 7 be connected to Vo-end.

2, a kind of passive power distribution isolator according to claim 1 and 0～20mA signal passive isolator, it is characterized in that: R1, R2 are the identical resistance of resistance in the described circuit, D1, D2 are the diode of same model, and T1 is a NPN type triode, and T2 is the positive-negative-positive triode.

3, a kind of passive power distribution isolator according to claim 1 and 0～20mA signal passive isolator, it is characterized in that: C1, C2 are the alternating voltage shunt capacitance in the described circuit, r1, L1, L2 are step-up transformer, r1 is a transformer secondary coil resistance, L1 is a transformer secondary coil inductance, and the connection between them is connected to input end through C1, C2.

4, a kind of passive power distribution isolator according to claim 1 and 0～20mA signal passive isolator, it is characterized in that: L2 is a transformer polar curve circle inductance just in the described circuit, capacitor C 3, C4 appearance value equate, L3 is a mutual inductor polar curve circle inductance just, L4 is a mutual inductor secondary coil inductance, and they are connected with triode T1, T2.

5, a kind of passive power distribution isolator according to claim 1 and 0～20mA signal passive isolator is characterized in that: D3, D4 are the diode of same model in the described circuit.