CN112763804B - Loop resistance detection device based on excitation pulse signals - Google Patents
Loop resistance detection device based on excitation pulse signals Download PDFInfo
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- CN112763804B CN112763804B CN202011566490.3A CN202011566490A CN112763804B CN 112763804 B CN112763804 B CN 112763804B CN 202011566490 A CN202011566490 A CN 202011566490A CN 112763804 B CN112763804 B CN 112763804B
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- 238000001514 detection method Methods 0.000 title claims abstract description 33
- 230000005284 excitation Effects 0.000 title claims abstract description 18
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 29
- 238000001914 filtration Methods 0.000 claims abstract description 14
- 239000003990 capacitor Substances 0.000 claims description 90
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 17
- 229910052710 silicon Inorganic materials 0.000 claims description 17
- 239000010703 silicon Substances 0.000 claims description 17
- 239000003381 stabilizer Substances 0.000 claims description 14
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- 230000008901 benefit Effects 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 10
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000000872 buffer Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
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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
- G01R1/36—Overload-protection arrangements or circuits for electric measuring instruments
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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 buck rectifying and filtering module, a switching 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, wherein the mains supply is connected with the buck rectifying and filtering module, the buck rectifying and filtering module is connected with the switching voltage stabilizing module, the switching 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 resistance detection module, and compared with the prior art, the invention has the beneficial effects that: the invention has the advantages of overcurrent protection circuit, overvoltage protection circuit, undervoltage protection circuit and 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 of the detection loop is directly measured by a universal meter, and the potentiometer is taken as an example, the two ends of the '1' and the '2' are measured by the ohm stops of the universal meter, the readings of the resistor are the nominal resistance of the potentiometer, and if the pointer of the universal meter is not moving or the resistance is quite different, the potentiometer is damaged. And B, detecting whether the movable arm of the potentiometer is in good contact with the resistor disc. The two ends of the '1', '2' (or '2', '3') are measured by the ohm shelves of the universal meter, the rotating shaft of the potentiometer is rotated to the position close to the 'off' in the anticlockwise direction, and the smaller the resistance value is, the better the resistance value is. And then the rotary shaft is slowly rotated clockwise, the resistance value is gradually increased, and the pointer in the gauge head is smoothly moved. When the mandrel is rotated to the extreme position "3", the resistance should be close to the nominal value of the potentiometer. If the pointer of the universal meter has a jumping phenomenon in the rotation process of the shaft handle of the potentiometer, the fault that the movable contact has poor contact is indicated.
Although the loop resistance detection device in the current market can be used for detecting the resistance value of the resistor, the protection strength of a protection circuit is insufficient, and protection measures are often lacking, so that the circuit is low in safety and easy to damage, and needs improvement.
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 set forth in the background art.
In order to achieve the above purpose, the present invention provides the following technical solutions:
The utility model provides a return circuit resistance detection device based on excitation pulse signal, includes mains supply, step-down rectification filter module, switching regulator module, overvoltage protection module, undervoltage 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 switching regulator module, and overvoltage protection module connects overvoltage protection module, and undervoltage protection module connects overcurrent protection module, and overcurrent protection module connects overheat protection module, and overheat protection module connects pulse signal module, and pulse signal module connects resistance detection module.
As still further aspects of the invention: the step-down rectifying and filtering module consists 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 stabilizing module consists 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 consists of a potentiometer RP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a triode V1, a controllable precise voltage stabilizing source D5 and an integrated circuit U2, the undervoltage protection module consists of a potentiometer RP3, a resistor R8, a resistor R9, a resistor R10, a capacitor C6, a diode D7, a relay J2 and a switch S2, the overcurrent protection module is composed of a resistor R11, a resistor R12, a potentiometer RP4, a voltage VCC and an amplifier U3, the overheat protection module is composed of a resistor R13, a resistor R14, a capacitor C6, a potentiometer RP5, a switch S3, a triode V2, a silicon controlled rectifier D9, a relay J3 and a diode D10, the pulse signal module is composed of 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 the resistor detection module is composed of a resistor R18, a diode D13, a 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 positive electrode of the diode D1 and the negative electrode of the diode D3, the other end of the output end of the transformer W is connected with the positive electrode of the diode D2 and the negative electrode of the diode D4, the negative electrode of the diode D1, the capacitor C1 and the inductor L1, the positive electrode of the diode D3 is connected with the positive electrode of the diode D4, the other end of the capacitor C1, the capacitor C2 and the resistor R1, the other end of the switch S1 is connected with the resistor R2, the other end of the resistor R2 is connected with the capacitor C3 and the input end of the voltage regulator U1, the grounding end of the voltage regulator 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 output end of the voltage regulator 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, the 8-pin of the integrated circuit U2, a resistor R5, a resistor R6, the positive electrode 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 the 2-pin of the integrated circuit U2, the 3-pin of the integrated circuit U2 and a resistor R4, the other end of the resistor R4 is connected with the 5-pin of the integrated circuit U2, a capacitor C5, a resistor R7 and the negative electrode of the controllable precise voltage stabilizing source D5, the other end of the capacitor C5 is connected with the 4-pin of the integrated circuit U2, the base electrode of a triode V1 and the other end of the resistor R5, the other end of the resistor R7 is connected with the emitter of a triode V1, the reference electrode of the controllable precise voltage stabilizing source D5, the collector of the triode V1 is connected with the other end of the resistor R6, the other end of the potentiometer RP3 is connected with a resistor R8, a capacitor C9, the other end of the resistor R8 is grounded, the other end of the resistor C6 is connected with the positive electrode of the diode D6, the other end of the diode D6 is connected with the positive electrode of the diode D7, the other end of the diode D7 is connected with the other end of the diode D10 is connected with the positive electrode of the relay 2, and the other end of the diode D10 is connected with the other end of the diode is grounded.
The other end of the switch S2 is connected with the resistor R11 and the power end of the amplifier U3, the other end of the resistor R11 is connected with the same-phase end of the amplifier U3, the grounding end of the amplifier U3 is grounded, the same-phase end of the amplifier U3 is connected with the potentiometer RP4, the other end of the potentiometer RP4 is connected with the resistor R12, the other end of the resistor R12 is connected with the voltage VCC, the output end of the amplifier U3 is connected with the switch S3, the resistor R13, the resistor R14 and the collector of the triode V2, the other end of the resistor R13 is connected with the potentiometer RP5, the capacitor C6 and the base of the triode V2, the other end of the potentiometer RP5 is grounded, the other end of the capacitor C6 is grounded, the emitter of the triode V2 is connected with the control electrode of the controllable silicon D9, the other end of the resistor R14 is connected with the anode of the controllable silicon D9, the cathode of the controllable silicon D9 is connected with the cathode of the relay J3 and the diode D10, the other end of the relay J3 is grounded, and the anode 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, the pin 4 of the integrated circuit U4 and the pin 8 of the 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 the pin 7 of the 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 D11, the anode of the diode D11 is connected with a resistor R16, the other end of the resistor R16 is connected with the cathode of the diode D12, the pin 2 of the integrated circuit U4, the pin 6 of the integrated circuit U4 and a capacitor C7, the other end of the capacitor C7 is grounded, the pin 1 of the integrated circuit U4 is grounded, the pin 5 of the integrated circuit U4 is connected with a capacitor C8, the other end of the capacitor C8 is grounded, the pin 3 of the integrated circuit U4 is connected with a resistor R17, the other end of the resistor R17 is connected with the anode of a diode D13 and the ammeter A, the cathode of the diode D13 is connected with the resistor R18, the other end of the resistor R18 is grounded, the other end of the ammeter A is connected with a resistor RC to be tested, the other end of the voltmeter V is grounded, and the other end of the resistor is connected with the resistor to be tested.
As still further aspects of the invention: the diodes D1, D2, D3, D4, D11, D12 are current limiting diodes, D8, D10 are voltage stabilizing diodes.
As still further aspects 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 if the voltage applied to the negative resistance light emitting diodes does not reach the rated voltage, the negative resistance light emitting diodes are not conducted.
As still further aspects of the invention: the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are polar capacitors.
As still further aspects 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 still further aspects of the invention: the audion V1 and the audion V2 are NPN audions.
As still further aspects of the invention: the model of the voltage stabilizer U1 is 7805, the model of the integrated circuit U2 is ICL8211, the model of the amplifier U3 is LM324, and the model of the integrated circuit U4 is 555 timer.
As still further aspects of the invention: the diode D1, the diode D2, the diode D3 and the diode D4 form a bridge rectifier circuit.
As still further aspects of the invention: the control electrode of the silicon controlled rectifier D9 is connected with the emitter electrode of the triode V2.
As still further aspects of the invention: the reference electrode of the controllable precise voltage stabilizing source D5 is connected with the resistor R7 and the emitter electrode of the triode V1.
Compared with the prior art, the invention has the beneficial effects that: the invention has the advantages of overcurrent protection circuit, overvoltage protection circuit, undervoltage protection circuit and 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 LM 324.
Fig. 5 is a structural diagram of a thyristor.
Fig. 6 is a pin diagram of a 555 timer.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments of the present invention are included in the protection scope of the present invention.
Example 1: referring to fig. 1, a loop resistance detection device based on excitation pulse signals is used for a mains supply passing through a power supply, a step-down rectifying and filtering module used for an AC-AC and an AC-DC, a switching voltage stabilizing module used for conducting a circuit and stably outputting fixed voltage, an overvoltage protection module used for inputting an oversized protection circuit, an undervoltage protection module used for inputting an undershoot protection load, an overcurrent protection module used for inputting an oversized protection circuit, an overheat protection module used for outputting pulse signals, a resistance detection module used for detecting resistance values, wherein the mains supply is connected with the step-down rectifying and filtering module, the step-down rectifying and filtering module is connected with a switching voltage stabilizing module, the switching voltage stabilizing module is connected with an 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 overheat protection module is connected with the pulse signal module, and the pulse signal module is connected with the resistance detection module.
The specific circuit is shown in fig. 2, the step-down rectifying and filtering 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 and voltage stabilizing 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 R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a triode V1, a controllable precise voltage stabilizing source D5 and an integrated circuit U2, the undervoltage protection module is composed of a potentiometer RP3, a resistor R8, a resistor R9, a resistor R10, a capacitor C6, a diode D7, a relay J2 and a switch S2, the overcurrent protection module is composed of a resistor R11, a resistor R12, a potentiometer RP4, a voltage VCC and an amplifier U3, the overheat protection module is composed of a resistor R13, a resistor R14, a capacitor C6, a potentiometer RP5, a switch S3, a triode V2, a silicon controlled rectifier D9, a relay J3 and a diode D10, the pulse signal module is composed of 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 the resistor detection module is composed of a resistor R18, a diode D13, a 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 transformer W is a step-down transformer, high-voltage alternating current is changed into low-voltage alternating current, 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, the capacitor C2 and the resistor R1, the diode D2, the diode D3 and the diode D4 form a bridge rectifier circuit, and the alternating current is changed into direct current, 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 inductor L1, the capacitor C1 and the capacitor C2 play a role in filtering, unstable direct current is changed into stable direct current, the other end of the switch S1 is connected with the resistor R2, the other end of the resistor R2 is connected with the capacitor C3 and the input end of 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 voltage stabilizer RP1 is grounded, the resistance value of the potentiometer RP1 is regulated, 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, 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, the No. 8 pin of the integrated circuit U2, a resistor R5, a resistor R6, the positive electrode of the controllable precise voltage stabilizing source D5, a potentiometer RP3 and a switch S2, the other end of the resistor RP2 is connected with the No. 2 pin of the integrated circuit U2, the No. 3 pin of the integrated circuit U2 and a resistor R4, the other end of the resistor R4 is connected with the No. 5 pin of the integrated circuit U2, a capacitor C5, a resistor R7 and the negative electrode of the controllable precise voltage stabilizing source D5, the voltage received by the overvoltage protection module is larger, the output voltage of the No. 4 pin of the integrated circuit U2 is larger, the conduction degree of the triode V1 is increased, the other end of the capacitor C5 is connected with the No. 4 pin of the integrated circuit U2, the base electrode of the triode V1 and the other end of the resistor R5, the other end of the resistor R7 is connected with the emitter of the triode V1 and the reference electrode of the controllable precise voltage stabilizing source D5, the collector of triode V1 connects the other end of resistance R6, the other end of potentiometre RP3 connects resistance R8, electric capacity C6, resistance R9, the other end ground connection of resistance R8, the other end ground connection of electric capacity C6, the positive pole of diode D6 is connected to the other end of resistance R9, the positive pole of diode D7 is connected to the negative pole of diode D6, the negative pole of diode D7 is connected to resistance R10, relay J2, the negative pole of diode D8, diode D6, diode D7 is the load steady voltage diode, the voltage that adds on this diode does not reach rated voltage, then this diode does not switch on, the other end ground connection of resistance R10, the other end ground connection of relay J2, the other end of relay J2 is connected to the positive pole of diode D8, when relay J2 is in operation, switch S2 is closed, when relay J2 is out of operation, switch S2 is opened.
The other end of the switch S2 is connected with the resistor R11 and the power end of the amplifier U3, the other end of the resistor R11 is connected with the same phase end of the amplifier U3, the grounding end of the amplifier U3 is grounded, the same phase end of the amplifier U3 is connected with the potentiometer RP4, the other end of the potentiometer RP4 is connected with the resistor R12, the other end of the resistor R12 is connected with the voltage VCC, the output end of the amplifier U3 is connected with the switch S3, the resistor R13, the resistor R14 and the collector of the triode V2, the other end of the resistor R13 is connected with the potentiometer RP5, the capacitor C6 and the base of the triode V2, the other end of the potentiometer RP5 is grounded, the other end of the capacitor C6 is grounded, the emitter of the triode V2 is connected with the control electrode of the controllable silicon D9, the other end of the resistor R14 is connected with the positive electrode of the controllable silicon D9, the negative electrode of the controllable silicon D9 is connected with the negative electrode of the diode D10, the other end of the relay J3 is grounded, the positive electrode of the diode D10 is connected with the other end of the relay J3, the resistor R13 is a negative temperature-sensitive resistor, when the temperature reaches 60 ℃, the negative temperature R13 is reached, the negative temperature value, the switch S3 is reduced, and the relay J3 is opened when the switch is opened, and the switch is not closed.
The other end of the switch S3 is connected with a resistor R15, a pin 4 of the integrated circuit U4 and a pin 8 of the 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 7 of the integrated circuit U4 and the positive electrode of a diode D12, the other end of the potentiometer RP6 is connected with the negative electrode of a diode D11, the positive electrode of the diode D11 is connected with a resistor R16, the other end of the resistor R16 is connected with the negative electrode of the diode D12, a pin 2 of the integrated circuit U4, a pin 6 of the integrated circuit U4 and a capacitor C7, the other end of the capacitor C7 is grounded, the capacitor C7 is charged by the lower end of the sliding end of the resistor R15-potentiometer RP 6-the diode D12, the upper end of the sliding end of the resistor R16-diode D11-potentiometer RP6 is discharged through the pin 7 of the integrated circuit U4, the pin 1 of the integrated circuit U4 is grounded, the pin 5 of the integrated circuit U4 is connected with the capacitor C8, the other end of the capacitor C8 is grounded, the pin 3 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 emits light to display that the circuit voltage, the current and the working temperature are 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 detected and the voltmeter V, the other end of the voltmeter V is connected with the other end of the resistor RC to be detected, and the other end of the resistor RC to be detected is grounded.
The working principle of the invention is as follows: closing a switch S1, outputting stable current to the input end of a voltage stabilizer U1 (7805) by a mains supply through voltage reduction rectification filtering, wherein the voltage on a capacitor C4 is the sum of the voltage on a resistor R3 and a potentiometer RP1, the voltage of the voltage stabilizer U1 is the voltage on the resistor R3, the resistor R3 and the potentiometer RP1 are connected in series, the resistance of the potentiometer RP1 is regulated, the voltage of the potentiometer RP1 is changed, the output voltage is changed, when the input voltage of an integrated circuit U2 is overlarge, the output voltage of a pin 4 of the integrated circuit U2 is increased, the conduction of a triode V1 is increased, the voltage on a resistor R7 is increased, the voltage of a control electrode of a controllable precise voltage stabilizing source D5 is increased, the output voltage of the negative electrode of the controllable precise voltage stabilizing source is reduced, the overlarge voltage originally is reduced, and the safety of the circuit during overvoltage is ensured; when the voltage input to the resistor R8 is reduced, namely the voltage on the load light-emitting diode D6 and the negative resistance light-emitting diode D7 is reduced, and when the voltage is too small to reach the rated voltage of the negative resistance light-emitting diode D6 and the rated voltage of 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 up to achieve the purpose of under-voltage protection; when the current on the resistor R11 is overlarge, namely the voltage of the inverting terminal of the amplifier U3 (LM 324) is overlarge, 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 in 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, the silicon controlled rectifier is conducted, the relay J3 works, and the switch S3 pops open, so that the purpose of overheat protection of the circuit is achieved; the capacitor C7 is charged and discharged to enable the voltage of the No. 2 pin and the No. 6 pin of the integrated circuit U4 (555 timer) to change, so that 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 ammeter 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.
Example 2, based on example 1, fig. 3 is a pin diagram of ICL8211, and ICL8211 is a micropower bipolar monolithic integrated circuit, which is mainly used for precision voltage detection and precision voltage generation. The integrated circuit is composed of a precision reference voltage, a comparator and a pair of output buffers/drivers, respectively. Its main advantage is that it can make power supply work under very low voltage and current, and ordinary standard power supply can not be adapted to these working occasions. Meanwhile, due to their unique characteristics, ICL8211 is very useful in many auxiliary circuits, such as current sources, overvoltage protection, programmable reference voltage sources, and power failure protection applications.
Fig. 4 is a pin diagram of LM324, a four op amp with true differential inputs for LM324 series devices. They have some significant advantages over standard op amps for single power applications. The four-amplifier may operate at a power supply as low as 3.0 volts or as high as 32 volts with a quiescent current that is one fifth of the quiescent current of MC 1741. The common mode input range includes a negative power supply, thus eliminating the necessity of employing an external biasing element in many applications.
Fig. 5 is a schematic diagram of a silicon controlled rectifier (Silicon Controlled Rectifier), which is called SCR for short, and is a high-power electrical device, which is called thyristor. 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 control 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 commonly used for timers, pulse generators and oscillating circuits. 555 may be used as a delay device, flip-flop, or firing element in a 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 characteristics 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 disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (10)
1. The loop resistance detection device based on the excitation pulse signal comprises a mains supply, a buck rectifying and filtering module, a switching 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 buck rectifying and filtering module, the buck rectifying and filtering module is connected with the switching voltage stabilizing module, the switching 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 resistance detection module;
The step-down rectifying and filtering module consists 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 stabilizing module consists 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 consists of a potentiometer RP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C5, a triode V1, a controllable precise voltage stabilizing source D5 and an integrated circuit U2, the undervoltage protection module consists of a potentiometer RP3, a resistor R8, a resistor R9, a resistor R10, a capacitor C6, a diode D7, a relay J2 and a switch S2, the overcurrent protection module is composed of a resistor R11, a resistor R12, a potentiometer RP4, a voltage VCC and an amplifier U3, the overheat protection module is composed of a resistor R13, a resistor R14, a capacitor C6, a potentiometer RP5, a switch S3, a triode V2, a silicon controlled rectifier D9, a relay J3 and a diode D10, the pulse signal module is composed of 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 the resistor detection module is composed of a resistor R18, a diode D13, a 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 positive electrode of the diode D1 and the negative electrode of the diode D3, the other end of the output end of the transformer W is connected with the positive electrode of the diode D2 and the negative electrode of the diode D4, the negative electrode of the diode D1, the capacitor C1 and the inductor L1, the positive electrode of the diode D3 is connected with the positive electrode of the diode D4, the other end of the capacitor C1, the capacitor C2 and the resistor R1, the other end of the switch S1 is connected with the resistor R2, the other end of the resistor R2 is connected with the capacitor C3 and the input end of the voltage regulator U1, the ground end of the voltage regulator 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 voltage regulator U1 is grounded, and the output end of the voltage regulator 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, an 8 pin of an integrated circuit U2, a resistor R5, a resistor R6, the positive electrode 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 a2 pin of the integrated circuit U2, a 3 pin of the integrated circuit U2 and a resistor R4, the other end of the resistor R4 is connected with a 5 pin of the integrated circuit U2, a capacitor C5, a resistor R7 and the negative electrode of the controllable precise voltage stabilizing source D5, the other end of the capacitor C5 is connected with a 4 pin of the integrated circuit U2, the base electrode of a triode V1 and the other end of the resistor R5, the other end of the resistor R7 is connected with an emitter of a triode V1, the reference electrode of the controllable precise voltage stabilizing source D5, the collector of the triode V1 is connected with the other end of the resistor R6, the other end of the potentiometer RP3 is connected with a resistor R8, a capacitor C6 and a resistor R9, the other end of the resistor R8 is grounded, the other end of the resistor C6 is connected with the positive electrode of the diode D6, the other end of the diode D6 is connected with the positive electrode of the diode D7, the other end of the diode D7 is connected with the other end of the diode D10, and the other end of the relay is connected with the diode D10 is grounded, and the other end of the diode is connected with the diode 2J 2;
The other end of the switch S2 is connected with a resistor R11 and a power end of the amplifier U3, the other end of the resistor R11 is connected with the same-phase end of the amplifier U3, the grounding end of the amplifier U3 is grounded, the same-phase 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, the output end of the amplifier U3 is connected with a switch S3, a resistor R13, a resistor R14 and a collector electrode of a triode V2, the other end of the resistor R13 is connected with a potentiometer RP5, a capacitor C6 and a base electrode of the 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 V2 is connected with a control electrode of a controllable silicon D9, the other end of the resistor R14 is connected with a positive electrode of the controllable silicon D9, a negative electrode of the controllable silicon D9 is connected with a negative electrode of 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, the pin 4 of the integrated circuit U4 and the pin 8 of the 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 the pin 7 of the 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 D11, the anode of the diode D11 is connected with a resistor R16, the other end of the resistor R16 is connected with the cathode of the diode D12, the pin 2 of the integrated circuit U4, the pin 6 of the integrated circuit U4 and a capacitor C7, the other end of the capacitor C7 is grounded, the pin 1 of the integrated circuit U4 is grounded, the pin 5 of the integrated circuit U4 is connected with a capacitor C8, the other end of the capacitor C8 is grounded, the pin 3 of the integrated circuit U4 is connected with a resistor R17, the other end of the resistor R17 is connected with the anode of a diode D13 and the ammeter A, the cathode of the diode D13 is connected with the resistor R18, the other end of the resistor R18 is grounded, the other end of the ammeter A is connected with a resistor RC to be tested, the other end of the voltmeter V is grounded, and the other end of the resistor is connected with the resistor to be tested.
2. The loop resistance detection device based on the excitation pulse signal according to claim 1, wherein the diode D1, the diode D2, the diode D3, the diode D4, the diode D11, the diode D12, the current limiting diode, the diode D8, and the diode D10 are zener diodes.
3. The loop resistance detection device based on the excitation pulse signal according to claim 2, wherein 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 diode is not turned on when the voltage applied to the negative resistance light emitting diode does not reach the rated voltage.
4. The loop resistance detection device based on the excitation pulse signal according to claim 1, wherein the capacitor C1, the capacitor C2, the capacitor C3, and the capacitor C4 are polar capacitors.
5. The loop resistance detection device based on the excitation pulse signal according to claim 1, wherein the resistor R13 is a negative temperature-sensitive resistor, and the resistance value of the temperature-sensitive resistor R13 decreases sharply when the temperature reaches 60 ℃.
6. The loop resistance detection device based on excitation pulse signals according to claim 1, wherein the transistors V1 and V2 are NPN transistors.
7. The excitation pulse signal based loop resistance detection apparatus according to claim 1, wherein the voltage regulator U1 is 7805, the integrated circuit U2 is ICL8211, the amplifier U3 is LM324, and the integrated circuit U4 is 555 timer.
8. The excitation pulse signal-based loop resistance detection apparatus 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 control electrode of the thyristor D9 is connected to the emitter of the transistor V2.
10. The loop resistance detection device based on excitation pulse signals according to claim 6, wherein the reference electrode of the controllable precision voltage stabilizing source D5 is connected with the resistor R7 and the emitter electrode of the triode V1.
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