CN112763804A - Loop resistance detection device based on excitation pulse signal - Google Patents
Loop resistance detection device based on excitation pulse signal Download PDFInfo
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- CN112763804A CN112763804A CN202011566490.3A CN202011566490A CN112763804A CN 112763804 A CN112763804 A CN 112763804A CN 202011566490 A CN202011566490 A CN 202011566490A CN 112763804 A CN112763804 A CN 112763804A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
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Abstract
The invention discloses a loop resistance detection device based on an excitation pulse signal, which comprises a mains supply, a voltage reduction rectification filter module, a switch voltage stabilization module, an overvoltage protection module, an undervoltage protection module, an overcurrent protection module, an overheat protection module, a pulse signal module and a resistance detection module, wherein the mains supply is connected with the voltage reduction rectification filter module, the voltage reduction rectification filter module is connected with the switch voltage stabilization module, the switch voltage stabilization module is connected with the overvoltage protection module, the overvoltage protection module is connected with the undervoltage protection module, the undervoltage protection module is connected with the overcurrent protection module, the overcurrent protection module is connected with the overheat protection module, the overheat protection module is connected with the pulse signal module, and the pulse signal module is connected with the resistance detection module. The invention has an overcurrent protection circuit, an overvoltage protection circuit, an undervoltage protection circuit and an overheat protection circuit, and has strong circuit protection capability when the circuit fails, so that the safety coefficient of a user is higher.
Description
Technical Field
The invention relates to the field of resistance detection, in particular to a loop resistance detection device based on an excitation pulse signal.
Background
The resistance value of the detection loop resistor is directly measured by a universal meter, taking a potentiometer as an example, the two ends of 1 and 2 are generally measured by using an ohmic baffle of the universal meter, the reading value is the nominal resistance value of the potentiometer, and if the pointer of the universal meter is not moved or the resistance values are greatly different, the potentiometer is damaged. B, detecting whether the contact between the movable arm of the potentiometer and the resistor disc is good or not. The two ends of 1 and 2 (or 2 and 3) are measured by using an ohm gear of a multimeter, and the rotating shaft of the potentiometer is rotated to a position close to off in a counterclockwise direction, wherein the smaller the resistance value, the better. And then the shaft handle is slowly rotated clockwise, the resistance value is gradually increased, and the pointer in the meter head is stably moved. When the mandrel is rotated to the extreme position "3", the resistance should be close to the nominal value of the potentiometer. For example, the pointer of the multimeter has a jumping phenomenon in the rotation process of the shaft handle of the potentiometer, which indicates that the movable contact has a fault of poor contact.
Although the loop resistor detection device on the market at present can be used for detecting the resistance value of the resistor, the protection strength of the protection circuit is not enough, and often the protection measures are not enough, so that the safety of the circuit is low, the circuit is easy to damage, and improvement is needed.
Disclosure of Invention
The present invention is directed to a loop resistance detection device based on an excitation pulse signal, so as to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
the utility model provides a return circuit resistance detection device based on excitation pulse signal, includes mains supply, step-down rectification filter module, switch voltage stabilizing module, overvoltage protection module, under-voltage protection module, overcurrent protection module, overheat protection module, pulse signal module and resistance detection module, mains supply connects step-down rectification filter module, and step-down rectification filter module connects switch voltage stabilizing module, and overvoltage protection module is connected to switch voltage stabilizing module, and overvoltage protection module connects under-voltage protection module, and overcurrent protection module is connected to under-voltage protection module, and overheat protection module connects overheat protection module, and pulse signal module connection resistance detection module is connected to overheat protection module.
As a still further scheme of the invention: the voltage reduction rectification filter module is composed of a transformer W, a diode D1, a diode D2, a diode D3, a diode D4, a capacitor C1, a capacitor C2, an inductor L1 and a resistor R1, the switching voltage stabilization module is composed of a switch S1, a resistor R2, a resistor R3, a potentiometer RP1, a capacitor C3, a capacitor C4 and a voltage stabilizer U1, the overvoltage protection module is composed of a potentiometer RP2, a resistor R2, a capacitor C2, a triode V2, a controllable precise voltage stabilization source D2 and an integrated circuit U2, the undervoltage protection module is composed of a potentiometer RP2, a resistor R2, a capacitor C2, a diode D2, a relay J2 and a switch S2, the overcurrent protection module is composed of a resistor R2, the pulse signal detection circuit comprises a triode V2, a silicon controlled rectifier D9, a relay J3 and a diode D10, a pulse signal module comprises a resistor R15, a resistor R16, a potentiometer RP6, a diode D11, a diode D12, a capacitor C7, a capacitor C8 and a resistor R17, and a resistor detection module comprises a resistor R18, a diode D13, an ammeter A, a voltmeter V and a resistor RC to be detected.
The input end of the transformer W is connected with a mains supply, one end of the output end of the transformer W is connected with the anode of the diode D1 and the cathode of the diode D3, the other end of the output end of the transformer W is connected with the anode of the diode D2 and the cathode of the diode D4, the cathode of the diode D1 is connected with the cathode of the diode D2, the capacitor C1 and the inductor L1, the anode of the diode D3 is connected with the anode of the diode D4, the other end of the capacitor C1 and the capacitor C2, the other end of an inductor L1 is connected with the other end of a capacitor C2, the other end of a resistor R1 and a switch S1, the other end of a switch S1 is connected with a resistor R2, the other end of a resistor R2 is connected with the input ends of a capacitor C3 and a voltage stabilizer U1, the grounding end of a voltage stabilizer U1 is connected with a resistor RP1 and a resistor R3, the other end of a capacitor C3 is grounded, the other end of a potentiometer RP1 is grounded, the output end of a voltage stabilizer U1 is connected with the other end of a resistor R3 and a capacitor C4, and the other end of a capacitor C4 is.
The output end of the voltage stabilizer U1 is connected with a potentiometer RP2, a pin 8 of an integrated circuit U2, a resistor R5, the anode of a controllable precise voltage stabilization source D5, a potentiometer RP5 and a switch S5, the other end of the resistor RP5 is connected with a pin 2 of the integrated circuit U5, a pin 3 of the integrated circuit U5 and the resistor R5, the other end of the resistor R5 is connected with a pin 5 of the integrated circuit U5, a capacitor C5, a resistor R5 and the cathode of the controllable precise voltage stabilization source D5, the other end of the capacitor C5 is connected with a pin 4 of the integrated circuit U5, the base of a triode V5 and the other end of the resistor R5, the other end of the resistor R5 is connected with the emitter of a triode V5, the reference pole of the controllable precise voltage stabilization source D5, the collector of the triode V5 is connected with the other end of the resistor R5, the resistor R5 is connected with the other end of the potentiometer RP5, the resistor R5 is grounded, and the voltage stabilization source C5, the other end of the resistor R9 is connected with the anode of the diode D6, the cathode of the diode D6 is connected with the anode of the diode D7, the cathode of the diode D7 is connected with the cathodes of the resistor R10, the relay J2 and the diode D8, the other end of the resistor R10 is grounded, the other end of the relay J2 is grounded, and the anode of the diode D8 is connected with the other end of the relay J2.
The other end of the switch S2 is connected with a resistor R11 and power supply ends of an amplifier U3, the other end of the resistor R11 is connected with a non-inverting end of the amplifier U3, a grounding end of the amplifier U3 is grounded, the non-inverting end of the amplifier U3 is connected with a potentiometer RP4, the other end of the potentiometer RP4 is connected with a resistor R12, the other end of the resistor R12 is connected with a voltage VCC, an output end of the amplifier U3 is connected with a switch S3, a resistor R13, a resistor R14 and a collector of a triode V2, the other end of the resistor R13 is connected with a potentiometer RP5, a capacitor C6 and a base of a triode V2, the other end of the potentiometer RP5 is grounded, the other end of the capacitor C6 is grounded, an emitter of the triode V6 is connected with a control electrode of a thyristor D36, the negative electrode of the thyristor D9 is connected with the negative electrodes of the relay J3 and the diode D10, the other end of the relay J3 is grounded, and the positive electrode of the diode D10 is connected with the other end of the relay J3.
The other end of the switch S3 is connected with a resistor R15, a pin No. 4 of an integrated circuit U4, a pin No. 8 of an integrated circuit U4, the other end of a resistor R15 is connected with a potentiometer RP6, the sliding end of the potentiometer RP6 is connected with a pin No. 7 of an integrated circuit U4 and the anode of a diode D12, the other end of the potentiometer RP6 is connected with the cathode of the diode D6, the anode of the diode D6 is connected with a resistor R6, the other end of the resistor R6 is connected with the cathode of the diode D6, the pin No. 2 of the integrated circuit U6, the pin No. 6 of the integrated circuit U6, a capacitor C6, the other end of the capacitor C6 is grounded, the pin No. 5 of the integrated circuit U6 is connected with the capacitor C6, the other end of the capacitor C6 is grounded, the pin No. 3 of the integrated circuit U6 is connected with a resistor R6, the other end of the diode D6 is connected with the anode of the diode D6, the other end of the ammeter A is connected with a resistor RC to be tested and a voltmeter V, the other end of the voltmeter V is connected with the other end of the resistor RC to be tested, and the other end of the resistor RC to be tested is grounded.
As a still further scheme of the invention: the diode D1, the diode D2, the diode D3, the diode D4, the diode D11 and the diode D12 are current-limiting diodes, and the diode D8 and the diode D10 are voltage-stabilizing diodes.
As a still further scheme of the invention: the diode D13 is a light emitting diode, the diode D6 and the diode D7 are negative resistance light emitting diodes, and the negative resistance light emitting diodes are not conducted when the voltage applied to the negative resistance light emitting diodes does not reach the rated voltage.
As a still further scheme of the invention: the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are polar capacitors.
As a still further scheme of the invention: the resistor R13 is a negative temperature sensitive resistor, and when the temperature reaches 60 ℃, the resistance value of the temperature sensitive resistor R13 is sharply reduced.
As a still further scheme of the invention: the triode V1 and the triode V2 are NPN triodes.
As a still further scheme of the invention: the voltage stabilizer U1 model is 7805, the integrated circuit U2 model is ICL8211, the amplifier U3 model is LM324, and the integrated circuit U4 model is 555 timer.
As a still further scheme of the invention: the diode D1, the diode D2, the diode D3 and the diode D4 form a bridge rectifier circuit.
As a still further scheme of the invention: and the control electrode of the controllable silicon D9 is connected with the emitter of the triode V2.
As a still further scheme of the invention: and the reference electrode of the controllable precise voltage-stabilizing source D5 is connected with the resistor R7 and the emitter of the triode V1.
Compared with the prior art, the invention has the beneficial effects that: the invention has an overcurrent protection circuit, an overvoltage protection circuit, an undervoltage protection circuit and an overheat protection circuit, and has strong circuit protection capability when the circuit fails, so that the safety coefficient of a user is higher.
Drawings
Fig. 1 is a schematic diagram of a loop resistance detection device based on an excitation pulse signal.
Fig. 2 is a circuit diagram of a loop resistance detection device based on an excitation pulse signal.
Fig. 3 is a pin diagram of ICL 8211.
Fig. 4 is a pin diagram of the LM 324.
Fig. 5 is a structural diagram of the thyristor.
FIG. 6 is a pin diagram of the 555 timer.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.
Example 1: referring to fig. 1, a loop resistance detection device based on an excitation pulse signal, a mains supply passing through a power supply, a voltage-reducing rectifying filter module for AC-AC and AC-DC, a switching regulator module for circuit conduction and stable output of a fixed voltage, an overvoltage protection module for an input voltage over-large protection circuit, an undervoltage protection module for an input voltage under-small protection load, an overcurrent protection module for an input current over-large protection circuit, an overheat protection module for a temperature over-high disconnection circuit, a pulse signal module for outputting a pulse signal, a resistance detection module for detecting a resistance value of a resistor, wherein the mains supply is connected with the voltage-reducing rectifying filter module, the voltage-reducing rectifying filter module is connected with the switching regulator module, the switching regulator module is connected with the overvoltage protection module, and the overvoltage protection module is connected with the undervoltage protection module, the undervoltage protection module is connected with the overcurrent protection module, the overcurrent protection module is connected with the overheat protection module, the overheat protection module is connected with the pulse signal module, and the pulse signal module is connected with the resistance detection module.
As shown in fig. 2, the buck rectifier filter module is composed of a transformer W, a diode D1, a diode D2, a diode D3, a diode D4, a capacitor C1, a capacitor C2, an inductor L1, and a resistor R1, the switching regulator module is composed of a switch S1, a resistor R2, a resistor R3, a potentiometer RP1, a capacitor C3, a capacitor C4, and a regulator U1, the overvoltage protection module is composed of a potentiometer RP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a triode V1, a controllable precision voltage regulator D1, and an integrated circuit U1, the undervoltage protection module is composed of a potentiometer RP1, a resistor R1, a capacitor C1, a diode D1, a relay J1, and a switch S1, the overcurrent protection module is composed of a resistor R1, a resistor R1, an overheat protection module R1, and an overheat protection module is composed of a resistor R1, and an overheat protection module R1, the pulse signal detection circuit comprises a capacitor C6, a potentiometer RP5, a switch S3, a triode V2, a controlled silicon D9, a relay J3 and a diode D10, a pulse signal module comprises a resistor R15, a resistor R16, a potentiometer RP6, a diode D11, a diode D12, a capacitor C7, a capacitor C8 and a resistor R17, and a resistor detection module comprises a resistor R18, a diode D13, an ammeter A, a voltmeter V and a resistor RC to be detected.
The input end of a transformer W is connected with a mains supply, one end of the output end of the transformer W is connected with the anode of a diode D1 and the cathode of a diode D3, the other end of the output end of the transformer W is connected with the anode of a diode D2 and the cathode of a diode D4, the transformer W is a step-down transformer and converts high-voltage alternating current into low-voltage alternating current, the cathode of a diode D1 is connected with the cathode of a diode D2, a capacitor C1 and an inductor L1, the anode of a diode D3 is connected with the anode of a diode D4 and the other end of a capacitor C1, a capacitor C2 and a resistor R1, a diode D1, a diode D2, a diode D3 and a diode D4 form a bridge rectifier circuit and convert the alternating current into direct current, the other end of the inductor L1 is connected with the other end of a capacitor C2, the other end of a resistor R1, a switch S1, an inductor L1, a capacitor C1 and a capacitor C1 play, the other end of the resistor R2 is connected with the input ends of a capacitor C3 and a voltage stabilizer U1, the grounding end of the voltage stabilizer U1 is connected with the resistor RP1 and the resistor R3, the other end of the capacitor C3 is grounded, the other end of the potentiometer RP1 is grounded, the resistance value of the potentiometer RP1 is adjusted, the output voltage of the voltage stabilizer U1 can be changed, the output end of the voltage stabilizer U1 is connected with the other end of the resistor R3 and the capacitor C4, and the other end of the capacitor C4 is grounded.
The output end of the voltage stabilizer U1 is connected with a potentiometer RP2, a pin 8 of an integrated circuit U2, a resistor R5, a resistor R6, the anode of a controllable precise voltage stabilizing source D5, a potentiometer RP3 and a switch S2, the other end of the resistor RP2 is connected with a pin 2 of the integrated circuit U2, a pin 3 of the integrated circuit U2 and a resistor R4, the other end of the resistor R4 is connected with a pin 5 of the integrated circuit U2, a capacitor C5, a resistor R7 and the cathode of the controllable precise voltage stabilizing source D7, the output voltage of the pin 4 of the integrated circuit U7 is larger when the voltage received by the overvoltage protection module is larger, so that the conduction degree of the triode V7 is increased, the other end of the capacitor C7 is connected with the pin 4 of the integrated circuit U7, the base of the triode V7 and the other end of the resistor R7, the other end of the resistor R7 is connected with the emitter of the triode V7 and the reference electrode of the controllable precise voltage stabilizing source D7, and the collector of the triode, the other end of the potentiometer RP3 is connected to a resistor R8, a capacitor C6 and a resistor R9, the other end of the resistor R8 is grounded, the other end of the capacitor C6 is grounded, the other end of the resistor R9 is connected to the anode of a diode D6, the cathode of a diode D6 is connected to the anode of a diode D7, the cathode of a diode D7 is connected to the resistor R10, the relay J2 and the cathode of a diode D8, the diodes D6 and D7 are load stabilizing diodes, the voltage applied to the diodes does not reach the rated voltage, the diodes are not conducted, the other end of the resistor R10 is grounded, the other end of the relay J2 is grounded, the anode of the diode D8 is connected to the other end of the relay J2, when the relay J2 is operated, the switch S2 is closed, and the switch S2 is opened when.
The other end of the switch S2 is connected to the power supply terminal of the resistor R11 and the amplifier U3, the other end of the resistor R11 is connected to the non-inverting terminal of the amplifier U11, the ground terminal of the amplifier U11 is grounded, the non-inverting terminal of the amplifier U11 is connected to the potentiometer RP 11, the other end of the potentiometer RP 11 is connected to the resistor R11, the other end of the resistor R11 is connected to the voltage VCC, the output terminal of the amplifier U11 is connected to the switch S11, the resistor R11, the collector of the transistor V11, the other end of the resistor R11 is connected to the potentiometer RP 11, the capacitor C11 and the base of the transistor V11, the other end of the potentiometer RP 11 is grounded, the other end of the capacitor C11 is grounded, the emitter of the transistor V11 is connected to the control electrode of the thyristor D11, the other end of the resistor R11 is connected to the anode of the thyristor D11, the cathode of the thyristor D11 is connected to the cathode of the relay J11, the cathode of the, the resistor R13 is a negative temperature sensitive resistor, when the temperature reaches 60 ℃, the resistance of the negative temperature sensitive resistor R13 is sharply reduced, when the relay J3 works, the switch S3 springs open, when the relay J3 does not work, the switch S3 is closed.
The other end of the switch S3 is connected with a resistor R15, a pin No. 4 of an integrated circuit U4 and a pin No. 8 of an integrated circuit U4, the other end of the resistor R15 is connected with a potentiometer RP6, the sliding end of the potentiometer RP6 is connected with a pin No. 7 of an integrated circuit U4 and the anode of a diode D12, the other end of the potentiometer RP6 is connected with the cathode of a diode D6, the anode of the diode D6 is connected with a resistor R6, the other end of the resistor R6 is connected with the cathode of a diode D6, the pin No. 2 of the integrated circuit U6, the pin No. 6 of the integrated circuit U6 and a capacitor C6, the other end of the capacitor C6 is grounded, the capacitor C6 is charged through the resistor R6-the lower end of the sliding end of the potentiometer RP 6-the diode D6, the upper end of the integrated circuit U6 is discharged through the pin No. 7 of the integrated circuit U6, the sliding end of the integrated circuit U6 is grounded through the resistor R6-diode D6, the other end of the capacitor C8 is grounded, a No. 3 pin of the integrated circuit U4 is connected with the resistor R17, the other end of the resistor R17 is connected with the anode of the diode D13 and the ammeter A, the cathode of the diode D13 is connected with the resistor R18, the diode D13 is used for displaying the voltage, the current and the working temperature of the circuit in a light-emitting mode and is normal, the other end of the resistor R18 is grounded, the other end of the ammeter A is connected with the resistor RC to be tested and the voltmeter V, the other end of the voltmeter V is connected with the other end of the resistor RC to be tested, and.
The working principle of the invention is as follows: the switch S1 is closed, a mains supply outputs stable current to an input end of a voltage stabilizer U1 (7805) through voltage reduction, rectification and filtering, the voltage on a capacitor C4 is the sum of the voltage on a resistor R3 and the voltage on a potentiometer RP1, the voltage stabilizer U1 outputs fixed voltage, the voltage is the voltage on a resistor R3, the resistor R3 and the potentiometer RP1 are connected in series, the resistance value of the potentiometer RP1 is adjusted, the voltage of the potentiometer RP1 is changed, the output voltage is changed, when the input voltage of the integrated circuit U2 is overlarge, the output voltage of a No. 4 pin of the integrated circuit U2 is increased, the conduction of a triode V1 is increased, the voltage on the resistor R7 is increased, the voltage of a controller of a controllable precision voltage-stabilizing source D5 is increased, the negative output voltage of the controllable precision voltage-stabilizing source is reduced, the overlarge voltage is reduced originally, and the; when the voltage input to the resistor R8 is reduced, namely the voltages of the load light-emitting diode D6 and the negative resistance light-emitting diode D7 are reduced, and when the voltage is too low to reach the rated voltages of the negative resistance light-emitting diode D6 and the negative resistance light-emitting diode D7, no current passes through the circuit, so that the relay J2 does not work, and the switch S2 pops open to achieve the purpose of undervoltage protection; when the current of the resistor R11 is too large, namely the voltage of the resistor R11 is too large, namely the voltage of the inverting terminal of the amplifier U3 (LM 324) is too large, so that the voltage of the inverting terminal of the amplifier U3 is higher than the voltage of the non-inverting terminal, and the output terminal of the amplifier U3 is not at the output voltage, thereby achieving the purpose of overcurrent protection; when the circuit temperature reaches 60 ℃, the resistance value of the resistor R13 is sharply reduced, so that the voltage on the potentiometer RP5 is increased, the triode V2 is conducted, the control electrode of the silicon controlled rectifier D9 is conducted by the voltage and the silicon controlled rectifier, the relay J3 works, and the switch S3 pops open, so that the purpose of circuit overheating protection is achieved; the capacitor C7 enables the voltage of the No. 2 pin and the No. 6 pin of the integrated circuit U4 (555 timer) to change through charging and discharging, the No. 3 pin of the integrated circuit U4 regularly outputs square wave signals, the ammeter A measures the resistance value of the resistor RC to be measured, the voltmeter measures the voltage of the resistor RC to be measured, and the resistance value of the resistor RC to be measured is obtained according to R = V/A.
Fig. 4 is a pin diagram of LM324, a four operational amplifier with true differential inputs for the LM324 family of devices, with true differential inputs. They have some significant advantages over standard operational amplifiers for single power applications. The four-amplifier can operate on a supply as low as 3.0 volts or as high as 32 volts with a quiescent current of one-fifth that of the MC 1741. The common mode input range includes a negative supply, thus eliminating the necessity of using an external biasing element in many applications.
Fig. 5 is a structural diagram of a thyristor, which is a high-power electrical component, also called a thyristor, and Silicon Controlled Rectifier (SCR) is for short. It has the advantages of small volume, high efficiency, long service life, etc. In an automatic control system, the device can be used as a high-power driving device to realize the control of high-power equipment by using a low-power control.
Fig. 6 is a pin diagram of a 555 timer, which is an integrated circuit chip and is commonly used for timers, pulse generators and oscillator circuits. 555 may be implemented as a delay device, flip-flop, or oscillation element in the circuit.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. A loop resistance detection device based on an excitation pulse signal comprises a mains supply, a voltage-reducing rectification filter module, a switch voltage-stabilizing module, an overvoltage protection module, an undervoltage protection module, an overcurrent protection module, an overheat protection module, a pulse signal module and a resistance detection module, and is characterized in that the mains supply is connected with the voltage-reducing rectification filter module, the voltage-reducing rectification filter module is connected with the switch voltage-stabilizing module, the switch voltage-stabilizing module is connected with the overvoltage protection module, the overvoltage protection module is connected with the undervoltage protection module, the undervoltage protection module is connected with the overcurrent protection module, the overcurrent protection module is connected with the overheat protection module, the overheat protection module is connected with the pulse signal module, and the pulse signal module is connected with;
the voltage reduction rectification filter module is composed of a transformer W, a diode D1, a diode D2, a diode D3, a diode D4, a capacitor C1, a capacitor C2, an inductor L1 and a resistor R1, the switching voltage stabilization module is composed of a switch S1, a resistor R2, a resistor R3, a potentiometer RP1, a capacitor C3, a capacitor C4 and a voltage stabilizer U1, the overvoltage protection module is composed of a potentiometer RP2, a resistor R2, a capacitor C2, a triode V2, a controllable precise voltage stabilization source D2 and an integrated circuit U2, the undervoltage protection module is composed of a potentiometer RP2, a resistor R2, a capacitor C2, a diode D2, a relay J2 and a switch S2, the overcurrent protection module is composed of a resistor R2, the pulse signal detection circuit comprises a triode V2, a silicon controlled rectifier D9, a relay J3 and a diode D10, a pulse signal module comprises a resistor R15, a resistor R16, a potentiometer RP6, a diode D11, a diode D12, a capacitor C7, a capacitor C8 and a resistor R17, and a resistor detection module comprises a resistor R18, a diode D13, an ammeter A, a voltmeter V and a resistor RC to be detected;
the input end of the transformer W is connected with a mains supply, one end of the output end of the transformer W is connected with the anode of the diode D1 and the cathode of the diode D3, the other end of the output end of the transformer W is connected with the anode of the diode D2 and the cathode of the diode D4, the cathode of the diode D1 is connected with the cathode of the diode D2, the capacitor C1 and the inductor L1, the anode of the diode D3 is connected with the anode of the diode D4, the other end of the capacitor C1 and the capacitor C2, the other end of the inductor L1 is connected with the other end of the capacitor C2, the other end of the resistor R1 and the switch S1, the other end of the switch S1 is connected with the resistor R2, the other end of the resistor R2 is connected with the input ends of the capacitor C3 and the voltage stabilizer U1, the grounding end of the voltage stabilizer U1 is connected with the resistor RP1 and the resistor R3, the other end of the capacitor C3 is grounded, the other end of the potentiometer RP1 is grounded, the output end of the voltage stabilizer U1 is connected with the other end of the resistor R3 and the capacitor C4, and the other end of the capacitor C4 is;
the output end of the voltage stabilizer U1 is connected with a potentiometer RP2, a pin 8 of an integrated circuit U2, a resistor R5, the anode of a controllable precise voltage stabilization source D5, a potentiometer RP5 and a switch S5, the other end of the resistor RP5 is connected with a pin 2 of the integrated circuit U5, a pin 3 of the integrated circuit U5 and the resistor R5, the other end of the resistor R5 is connected with a pin 5 of the integrated circuit U5, a capacitor C5, a resistor R5 and the cathode of the controllable precise voltage stabilization source D5, the other end of the capacitor C5 is connected with a pin 4 of the integrated circuit U5, the base of a triode V5 and the other end of the resistor R5, the other end of the resistor R5 is connected with the emitter of a triode V5, the reference pole of the controllable precise voltage stabilization source D5, the collector of the triode V5 is connected with the other end of the resistor R5, the resistor R5 is connected with the other end of the potentiometer RP5, the resistor R5 is grounded, and the voltage stabilization source C5, the other end of the resistor R9 is connected with the anode of the diode D6, the cathode of the diode D6 is connected with the anode of the diode D7, the cathode of the diode D7 is connected with the resistor R10, the relay J2 and the cathode of the diode D8, the other end of the resistor R10 is grounded, the other end of the relay J2 is grounded, and the anode of the diode D8 is connected with the other end of the relay J2;
the other end of the switch S2 is connected with a resistor R11 and power supply ends of an amplifier U3, the other end of the resistor R11 is connected with a non-inverting end of the amplifier U3, a grounding end of the amplifier U3 is grounded, the non-inverting end of the amplifier U3 is connected with a potentiometer RP4, the other end of the potentiometer RP4 is connected with a resistor R12, the other end of the resistor R12 is connected with a voltage VCC, an output end of the amplifier U3 is connected with a switch S3, a resistor R13, a resistor R14 and a collector of a triode V2, the other end of the resistor R13 is connected with a potentiometer RP5, a capacitor C6 and a base of a triode V2, the other end of the potentiometer RP5 is grounded, the other end of the capacitor C6 is grounded, an emitter of the triode V6 is connected with a control electrode of a thyristor D36, the negative electrode of the controlled silicon D9 is connected with the negative electrodes of the relay J3 and the diode D10, the other end of the relay J3 is grounded, and the positive electrode of the diode D10 is connected with the other end of the relay J3;
the other end of the switch S3 is connected with a resistor R15, a pin No. 4 of an integrated circuit U4, a pin No. 8 of an integrated circuit U4, the other end of a resistor R15 is connected with a potentiometer RP6, the sliding end of the potentiometer RP6 is connected with a pin No. 7 of an integrated circuit U4 and the anode of a diode D12, the other end of the potentiometer RP6 is connected with the cathode of the diode D6, the anode of the diode D6 is connected with a resistor R6, the other end of the resistor R6 is connected with the cathode of the diode D6, the pin No. 2 of the integrated circuit U6, the pin No. 6 of the integrated circuit U6, a capacitor C6, the other end of the capacitor C6 is grounded, the pin No. 5 of the integrated circuit U6 is connected with the capacitor C6, the other end of the capacitor C6 is grounded, the pin No. 3 of the integrated circuit U6 is connected with a resistor R6, the other end of the diode D6 is connected with the anode of the diode D6, the other end of the ammeter A is connected with a resistor RC to be tested and a voltmeter V, the other end of the voltmeter V is connected with the other end of the resistor RC to be tested, and the other end of the resistor RC to be tested is grounded.
2. The loop resistance detection device according to claim 1, wherein the diode D1, the diode D2, the diode D3, the diode D4, the diode D11, the diode D12 are current limiting diodes, the diode D8, and the diode D10 are voltage stabilizing diodes.
3. The device according to claim 2, wherein the diode D13 is a light emitting diode, the diodes D6 and D7 are negative resistance light emitting diodes, and the negative resistance light emitting diode is not turned on when the voltage applied to the negative resistance light emitting diode does not reach the rated voltage.
4. The excitation pulse signal-based loop resistance detection device of claim 1, wherein the capacitors C1, C2, C3 and C4 are polar capacitors.
5. The loop resistance detection device based on the excitation pulse signal as claimed in claim 1, wherein the resistor R13 is a negative temperature sensitive resistor, and the resistance of the temperature sensitive resistor R13 decreases sharply when the temperature reaches 60 ℃.
6. The device according to claim 1, wherein the transistors V1 and V2 are NPN transistors.
7. The excitation pulse signal-based loop resistance detection device of claim 1, wherein the voltage regulator is U1 model 7805, the integrated circuit is U2 model ICL8211, the amplifier is U3 model LM324, and the integrated circuit is U4 model 555 timer.
8. The loop resistance detection device according to claim 2, wherein the diode D1, the diode D2, the diode D3 and the diode D4 constitute a bridge rectifier circuit.
9. The device according to claim 6, wherein the gate of the thyristor D9 is connected to the emitter of the transistor V2.
10. The loop resistance detection device according to claim 6, wherein the reference electrode of the controllable precise voltage regulator D5 is connected to the resistor R7 and the emitter of the transistor V1.
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Cited By (1)
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| CN114182566A (en) * | 2021-12-08 | 2022-03-15 | 浙江华章科技有限公司 | Pulp flow box valve opening control system |
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| CN112763804B (en) | 2024-05-28 |
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