CN1055248A - A kind of servo amplifier - Google Patents

Abstract

The invention belongs to a kind of automatic controller system that is used for, with the important supplementary instrument of electronic execution machine interface, can with DDZ, constitute varitrol as DDZ-type instrument etc.Adopted electric current input channel high-barrier from, high precision series type differential amplifier; operate as normal signal, supervisory protective signal voltage comparator, AC contact-less switch and trigger circuit thereof, unit such as the malfunctioning monitoring and protection circuit of varitrol fault constitute machine system.

Description

A kind of servo amplifier

The invention belongs to a kind of automatic controller system that is used for, with the important supplementary instrument of electronic execution machine interface, can with DDZ, constitute varitrol as DDZ-II type or DDZ-III type instrument etc.

General known servoamplifier has two types of magnetrol and no magnetrols.During the supporting use of the servoamplifier of magnetrol type and commonly used DKJ, DKZ type electric operator, following shortcoming is arranged:

Manufacture craft process complexity, poor stability, cost is higher;

Output control circuit adopts large-scale metal shell diode, and the AC contact-less switch that one-way SCR is formed occupies very big assembling space;

The soft magnetic material variation greatly, zero point drift, sensitivity instability;

The complete machine gain disperses, and switching characteristic is bad and adjustment is difficult.

The servoamplifier of known no magnetrol type remains in following shortcoming;

Circuit design and structural manufacturing process level are lower;

The action return difference is big, and balance quality is relatively poor, and stability is not good enough, adjustment inconvenience;

The input channel isolation resistance is not high and input resistance is nonstandard.

When the known servoamplifier of the above-mentioned type was used for varitrol, regular meeting caused varitrol action in various degree malfunctioning, and often influence safety in production causes the accident.

The objective of the invention is to design a kind of servo amplifier, it is terse to make it circuit, rational in infrastructure, with low cost, and adjustment is convenient; Item technical performance indexs such as stability, sensitivity, zero point drift, return difference, operation precision and input channel isolation resistance all are better than known all kinds servoamplifier; and possess the malfunctioning monitoring and protection function of varitrol fault, so that remedy the deficiency on the general known servoamplifier function.

The objective of the invention is to adopt following method to realize;

The present invention has adopted electric current input channel high-barrier from, high precision series type differential amplifier; operate as normal signal, supervisory protective signal voltage comparator; output channel bidirectional triode thyristor AC contact-less switch and trigger circuit thereof, unit such as the malfunctioning monitoring and protection circuit of varitrol fault constitute machine system.

Characteristics of the present invention are:

Circuit offset voltage, the temperature drift of series type differential amplifier all are able to good compensation, amplifier precision height, and good stability, and have very high equivalent input resistance; Adopt one-level to isolate differential amplifier circuit, simplified the circuitry system.

In voltage comparator circuit, can suitably adjust the feedback quantity of small signal comparer positive feedback link according to the regulating system concrete property, make switch machine output keep suitable return difference, so that when preventing the varitrol operate as normal, the electric operator action is too frequent.

Be provided with the malfunctioning monitoring and protection circuit of varitrol fault; when varitrol breaks down when malfunctioning; can in time send alerting signal, and can make controlled device maintain malfunctioning preceding position, avoid effectively because of the malfunctioning loss that may cause of varitrol.

Below with reference to accompanying drawing the present invention is described in further detail.

Fig. 1 is an electronic circuit schematic diagram of the present invention.

With reference to Fig. 1, the present invention partly is made up of isolation differential amplifier A, voltage comparator B, AC contact-less switch C, monitoring and protection circuit unit D etc.Isolate differential amplifier A by integrated dual operational amplifier A1, A2, elements such as resistance R 1-R13 constitute.R1 and R2 are respectively two electric current input channel sample resistances, and R3 and R4 are input current common-mode isolation resistance, and R11 and R12 are zero-regulator resistor, and R13 is that resistance is regulated in amplifier gain.Voltage comparator B is by integrated four-operational amplifier A3-A6, diode D1-D2, and elements such as resistance R 14-R35, R51-R54 constitute.Wherein, A3, D1-D3, R14-R19, R51, R2 have formed work small-signal forward voltage comparer, "+" input end of A3 meets prime output V01 through R14, "-" input end is obtained dividing potential drop+Vl of reference power supply+V8 through R15 on R17, when V01 〉=+the output V02 of A3 reaches on the occasion of saturation voltage during Vl.A4, D4-D6, R20-R25, R53, R54 have formed work small-signal reverse voltage comparer, obtain dividing potential drop-Vl of negative reference power supply-V8 on R23, are connected to "+" input end of A4 through R21; When prime output voltage V 01 is a negative value, "-" input end through R20 acts on A4 reaches |-V01| 〉=| during-Vl|, A4 output V03 is on the occasion of saturation voltage.

In the circuit of voltage comparator B, R17 and R23 be used for adjusting the forward and reverse threshold value reference voltage+Vl of work small-signal and-Vl, R29 and R34 be used to adjust the protection large-signal forward and reverse threshold value reference voltage+VH and-VH.

AC contact-less switch C is by triode T1-T4, unijunction transistor Q1, Q2, and diode D13-D18, capacitor C1-C4, resistance R 36-R47, R55, R56 trigger transformer B1, B2, inductance L 1, L2, elements such as bidirectional triode thyristor SCR1 and SCR2 are formed.V02 is a positive voltage when prime output, makes the T1 conducting through R36, and T2 ends; By the flip-flop operation that elements such as Q1, C1, R39, B1 are formed, controllable silicon SCR 1 is open-minded.When V03 output positive voltage, T3 conducting T4 ends; Flip-flop operation by elements such as Q2, C2, R45, B2 are formed makes controllable silicon SCR 2 open-minded.

Monitoring and protection circuit unit D is by triode T5-T7, diode D19, and resistance R 48-R50, elements such as relay J K are formed.When the automatic regulator system breaks down when malfunctioning, protection large-signal voltage comparator output V04 is a positive voltage, the one tunnel through R48, R49, make T5, T6 conducting, short circuit C1, C2, trigger circuit are blocked, SCR1, SCR2 all can not open.Another road makes the T7 conducting through R50, and relay J K adhesive drives this machine outer sound, light alarm system.For just in case the bidirectional triode thyristor fault also can be protected under the situation, two groups of normally closed contacts of JK can be serially connected with respectively in SCR1, the SCR2 output loop.Also can draw control line, keep " spacing " function midway at C1, C2 two ends.

As inserting by terminals P 1, P2 as a marking current IF of varitrol, on the R1 that isolates differential amplifier A, produce voltage signal, anodally cause "+" input end of A1 through P5, negative pole meets its reference point G through R3.Another marking current IT is inserted by terminals P 3, P4, and the voltage signal that produces on R2 is added in "+" input end of A2 through R6.The output voltage V 01 of amplifier and the difference of two current signals are strict proportionate relationship.When IT＞IF, V01 is that V01 is a negative value when, IT＜IF.

Complete machine principle of work of the present invention is as follows:

With the external connection terminal P3 of the present invention, P4 serial connection regulator output current IT, terminals P 1, P2 are connected in series electronic execution seat in the plane and put feedback current IF, and terminals P 5, P6 are connected on respectively in the forward and reverse running control loop of execution machine, and terminals P 7, P8 connect acoustooptic alarm system.With the servoamplifier as DDZ-II type varitrol is example, is in the varitrol among the operate as normal, and when IT＞IF, isolating differential amplifier A output V01 is positive voltage; When reaching IT-IF＞0.15mA, making work small signal comparer output V02 is positive voltage, the T1 conducting, and T2 ends, and SCR1 is triggered open-minded, and electronic execution machine turns round to deciding direction.Position feedback electric current I F increases thereupon, makes IT-IF＜0.15mA, and V02 becomes negative value, and T1 ends, the T2 conducting, and SCR1 turn-offs, and the execution machine shuts down.As input current IF＞IT, and when reaching IF-IT＞0.15mA, it is positive voltage that the negative voltage output of V01 makes work small signal comparer output V03, opposite trigger circuit work, and SCR2 is open-minded, and the execution machine is turned round towards other direction.The position feedback current following reduces, and after IF-IT＜0.15mA, the execution machine stops.

Varitrol breaks down when malfunctioning; sudden big difference must appear between IT and the IF; small-signal output when the output voltage V 01 of isolation differential amplifier A is far longer than operate as normal; making protection large-signal voltage comparator output V04 is positive voltage; Drive Protecting Circuit has been blocked passage; the JK adhesive enters the monitoring and protection duty.

The present invention is because the malfunctioning monitoring and protection circuit of varitrol fault that is provided with high reliability, can sets up arbitrarily; become good, the practical difunctional servo amplifier of a kind of performance, remedied the deficiency of general known servoamplifier on function.

Claims (1)

1; a kind of automatic controller system that is used for; servo amplifier with electronic execution machine interface; it is characterized in that: this servoamplifier is by isolating differential amplifier A; voltage comparator B; AC contact-less switch C; monitoring and protection circuit unit D forms; isolate differential amplifier A by integrated dual operational amplifier A1; A2; elements such as resistance R 1-R13 constitute; voltage comparator B is by integrated four-operational amplifier A3-A6; diode D1-D2; resistance R 14-R35; the R51-54 element constitutes; AC contact-less switch C is by triode T1-T4; unijunction transistor Q1; Q2, diode D13-D18, capacitor C1-C4; resistance R 36-R47; R55; R56; trigger transformer B1; B2, inductance L 1; L2, bidirectional triode thyristor SCR1 and SCR2 element are formed; monitoring and protection circuit unit D is by triode T5-T7; diode D19, resistance R 48-R50, relay J K element is formed.

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