CN212845790U

CN212845790U - Small capacity relay characteristic detector

Info

Publication number: CN212845790U
Application number: CN202021080414.7U
Authority: CN
Inventors: 卫宏; 陆鹏
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2020-06-12
Filing date: 2020-06-12
Publication date: 2021-03-30
Anticipated expiration: 2030-06-12

Abstract

The utility model discloses a small capacity relay characteristic detector, including single chip microcomputer control circuit, voltage detection circuit, current detection circuit, contact detection circuit, communication circuit, display circuit, alarm circuit, relay control circuit and keying circuit all are connected with single chip microcomputer control circuit; the utility model discloses a low capacity relay characteristic detector regards as main control unit with the singlechip, and the measurement object is low capacity relay, and key test relay's action voltage, return voltage, action current, action time to accomplish the demonstration. The measurement accuracy is high, and data transmission is stable, has satisfied the design requirement to have high operating value. The purpose of ensuring the stability of the system by detecting the characteristics of the relay can be met.

Description

Small capacity relay characteristic detector

Technical Field

The utility model relates to a relay test technical field, concretely relates to low capacity relay characteristic detector.

Background

With the continuous development of power systems, the size of the power systems is getting larger and larger, and each component of each line in the system must be equipped with relay protection in order to ensure the safe and stable operation of the power systems. The relay is an important component of relay protection and plays an important role in the system. The performance of the relay directly determines the reliability, selectivity, speed and sensitivity of the protection. As a common electrical component, the reliability of the relay directly affects the reliability of the entire system. The relay is a common control electric appliance and is widely applied to an electric power system, so that the relay testing device has important significance.

Although the detection technology of relay parameters starts late in China, relevant relay detectors appear in the nineties of the last century. In these years, due to the continuous promotion of research on the aspect by the foreign countries, researchers in China also burst the enthusiasm for research, and the research on the aspect in China also rises to a new height.

Zhao Gui Ping and Shao Wu of the university of fertilizer industry have had intensive research on the test of the time parameter of the relay, have studied the comprehensive test about mixed time delay relay in the action time and release time. But no measurements are extended for other parameters.

A novel relay parameter detector is developed by Sun Lihua of Hebei science and technology university, and parameters such as action voltage, return voltage, action delay and the like of a relay can be well detected by using an 89C51 single chip microcomputer. However, the use of a servo motor for voltage regulation has a certain physical error.

Disclosure of Invention

The utility model aims to solve the technical problem that not enough to above-mentioned prior art provides a low capacity relay characteristic detector, and this low capacity relay characteristic detector uses the singlechip as main control unit, and the measurement object is low capacity relay, and key test relay's action voltage, return voltage, action current, action time to accomplish the demonstration. The measurement accuracy is high, and data transmission is stable, has satisfied the design requirement to have high operating value. The purpose of ensuring the stability of the system by detecting the characteristics of the relay can be met.

In order to realize the technical purpose, the utility model discloses the technical scheme who takes does:

a small-capacity relay characteristic detector comprises a single chip microcomputer control circuit, a voltage detection circuit, a current detection circuit, a contact detection circuit, a communication circuit, a display circuit, an alarm circuit, a relay control circuit and a key circuit, wherein the voltage detection circuit, the current detection circuit, the contact detection circuit, the communication circuit, the display circuit, the alarm circuit, the relay control circuit and the key circuit are all connected with the single chip microcomputer control circuit;

the voltage detection circuit comprises a power tube TIP122, a chip LM358 and a DAC0832 chip, wherein a pin 1 and a pin 2 of the power tube TIP122 are both connected with a 12V power supply, a pin 3 of the power tube TIP122 is connected with a resistor R2, a resistor R2 is simultaneously connected with a resistor R3 and a pin 2 of the chip LM358, a pin 1 of the chip LM358 is simultaneously connected with the contact detection circuit and the 12V power supply, a pin 3 of the chip LM358 is connected with a pin 8 of the DAC0832 chip, a resistor R3 and a pin 4 of the chip LM358 are both connected with a ground wire, a pin 8 of the chip LM358 is connected with the 12V power supply, a pin 1, a pin 17, a pin 3, a pin 10, a pin 18, a pin 2 and a pin 12 of the DAC0832 chip are all connected with the ground wire, a pin 11 of the DAC0832 chip is connected with the ground wire through a diode D1, a pin 19, a pin 9 and a pin 20 of the DAC0832 chip are all connected with the power supply, and the pin 5, the pin 6, the pin 7, the pin 13, the pin 14, the pin 15 and the pin 16 are all connected with a singlechip control circuit.

As a further improved technical scheme of the utility model, the single chip microcomputer control circuit comprises a single chip microcomputer STC12C5A60S2, a resistor R1, a resistor R2, a capacitor C3, a key S1, a capacitor C1, a capacitor C2 and a crystal oscillator Y1, the pin 9 of the single chip microcomputer STC12C5A60S2 is simultaneously connected with one end of a resistor R1, a resistor R2 and a capacitor C3, the other end of the resistor R1 is connected with one end of a key S1, the other end of the key S1 and the other end of the capacitor C3 are both connected with a power supply VCC, the other end of the resistor R2 is connected with a ground wire, a pin 18 of the singlechip STC12C5A60S2 is simultaneously connected with one end of a crystal oscillator Y1 and one end of a capacitor C1, the pin 19 of the single chip microcomputer STC12C5A60S2 is simultaneously connected with the other end of the crystal oscillator Y1 and one end of the capacitor C2, the other ends of the capacitor C1 and the capacitor C2 are both connected with a ground wire, a pin 20 of the singlechip STC12C5A60S2 is connected with the ground wire, and a pin 40 of the single chip microcomputer STC12C5A60S2 is connected with a power supply VCC.

As a further improved technical proposal of the utility model, the current detection circuit comprises an ACS712 chip and a PCF8591 chip, the

pins

1 and 2 of the ACS712 chip are connected to each other and then to the relay control circuit, pin 3 and pin 4 of the ACS712 chip are connected to each other and then to the contact detect circuit, pin 5 of the ACS712 chip is connected to ground, pin 6 of the ACS712 chip is connected to ground through capacitor C4, pin 7 of the ACS712 chip is connected to pin 1 of the PCF8591 chip, pin 8 of the ACS712 chip is connected to VCC and pin 8 is connected to ground through capacitor C5, the pin 14 and the pin 16 of the ACS712 chip are connected to a power supply VCC, the pin 12, the pin 13, the pin 5, the pin 6, the pin 7 and the pin 8 of the ACS712 chip are connected to a ground wire, pin 9 of the ACS712 chip is connected to pin 17 of the single-chip STC12C5a60S2, and a pin 10 of the ACS712 chip is connected with a pin 16 of a singlechip STC12C5A60S 2.

As the utility model discloses further modified technical scheme, contact detection circuit includes the relay and the resistance R8 that await measuring, the one end connecting ground wire of the coil of the relay that awaits measuring, the other end of coil and voltage detection circuit in chip LM358 'S pin 1 be connected, the relay that awaits measuring is opened end in usual through resistance R8 and is connected with the power VCC, and the end in usual is connected with singlechip STC12C5A60S 2' S pin 13, the common port connecting ground wire of the relay that awaits measuring.

As the utility model discloses further modified technical scheme, alarm circuit includes resistance R13, triode Q2, diode D2 and bee calling organ, resistance R13 'S one end is connected with singlechip STC12C5A60S 2' S pin 25, and resistance R13 'S the other end is connected with triode Q2' S base, triode Q2 'S collecting electrode is connected with bee calling organ' S one end, bee calling organ 'S other end connecting power VCC, bee calling organ' S both ends are connected with diode D2.

As the utility model discloses further modified technical scheme, relay control circuit includes solid state relay, resistance R5, triode Q1, resistance R6 and resistance R7, pin 1 and pin 2 of ACS712 chip are connected in solid state relay and the current detection circuit, solid state relay is connected with the 12V power, and solid state relay passes through resistance R5 and is connected with triode Q1 'S collecting electrode, triode Q1' S projecting pole connection ground wire, triode Q1 'S base passes through resistance R6 simultaneously and is connected with resistance R7' S one end and singlechip STC12C5A60S2 'S pin 12, and resistance R7' S the other end VCC that connects.

As a further improved technical solution of the present invention, the key circuit includes a key S2, a key S3, a key S4, a key S5, a resistor R9, a resistor R10, a resistor R11, and a resistor R12, one end of the key S2, a key S3, a key S4, and a key S5 is connected to the ground, the other end of the key S2 is connected to the power VCC through a resistor R9 and is connected to the pin 24 of the single chip STC12C5a60S2, the other end of the key S3 is connected to the power VCC through a resistor R10 and is connected to the pin 23 of the single chip STC12C5a60S2, the other end of the key S4 is connected to the power VCC through a resistor R11 and is connected to the pin 22 of the single chip STC12C5a60S2, and the other end of the key S5 is connected to the power VCC through a resistor R12 and is connected to the pin 21 of the single chip STC12C5a60S 2.

As a further improved technical scheme of the utility model, the display circuit includes LCD1602 display screen, slide rheostat RP1 and exclusion P1, pin 1 and pin 16 of LCD1602 display screen all connect the ground, pin 2 and pin 15 of LCD1602 display screen all connect the +5V power, pin 3 of LCD1602 display screen connects the ground through slide rheostat RP1, pin 4 of LCD1602 display screen is connected with pin 26 of singlechip STC12C5A60S2, pin 6 of LCD1602 display screen is connected with pin 27 of singlechip STC12C5A60S2, pin 5 of LCD1602 display screen is connected with pin 28 of singlechip STC12C5A60S2, pin 7 of LCD1602 display screen is connected with pin 39 of singlechip STC12C5A60S2 and pin 7 is connected with exclusion P1, pin 8 of LCD1602 display screen is connected with pin 38 of singlechip STC 5A60S2 and pin 8 is connected with pin 1, pin 8 of LCD 1602C 5A60S2 is connected with pin 4839 and pin 589 of singlechip STC 5S 16 and pin 4839, pin 10 of the LCD1602 display screen is connected with pin 36 of the single-chip microcomputer STC12C5a60S2 and pin 10 is connected with exclusion P1, pin 11 of the LCD1602 display screen is connected with pin 35 of the single-chip microcomputer STC12C5a60S2 and pin 11 is connected with exclusion P1, pin 12 of the LCD1602 display screen is connected with pin 34 of the single-chip microcomputer STC12C5a60S2 and pin 12 is connected with exclusion P1, pin 13 of the LCD1602 display screen is connected with pin 33 of the single-chip microcomputer STC12C5a60S2 and pin 13 is connected with exclusion P1, pin 14 of the LCD1602 display screen is connected with pin 32 of the single-chip microcomputer STC12C5a60S2 and pin 14 is connected with exclusion P1.

As a further improved technical proposal of the utility model, the communication circuit comprises a MAX3232 chip and a serial port DB9, pin 1 of the MAX3232 chip is connected with pin 3 through a capacitor C7, pin 4 of the MAX3232 chip is connected with pin 5 through a capacitor C8, pin 11 of the MAX3232 chip is connected with pin 11 of the single chip microcomputer STC12C5a60S2, pin 12 of the MAX3232 chip is connected with pin 10 of the single chip microcomputer STC12C5a60S2, pin 15 of the MAX3232 chip is connected with a ground wire, a capacitor C9 is connected between pin 15 and pin 6, pin 13 and pin 14 of the MAX3232 chip are both connected with a serial port DB 68, pin 2 of the MAX3232 chip is connected with a power VCC through a capacitor C6, pin 16 of the MAX3232 chip is connected with the power VCC, one end of a resistor R14 is connected with the power VCC, the other end of the resistor R357323 is connected with pin 11 of the MAX3232 chip through a light emitting diode DS1, one end of the resistor R15 is connected with the power VCC, and the other end of the resistor R7312.

The utility model has the advantages that:

the utility model discloses regard as main control unit with the singlechip, designed a relay characteristic tester, the measurement object is the low capacity relay, and key test relay's operating voltage, return voltage, action current, action time to accomplish the demonstration. The comprehensive judgment of the relay characteristics is realized through the controllable power supply, the Hall element and the timer in the singlechip.

The hardware circuit of the testing device mainly comprises a singlechip control circuit, a voltage detection circuit, a current detection circuit, a contact detection circuit, a communication circuit, a display circuit, an alarm circuit, a relay control circuit and a key circuit. The relay characteristic tester with the single-chip microcomputer STC12C5A60S2 as a main chip realizes time, voltage and current signal testing, data processing, keyboard scanning and liquid crystal display. The software part mainly comprises a single chip control program and an upper computer for communication, the operation is convenient, and the man-machine interaction is realized.

Tests show that the system detects relay parameters, the system runs reliably, the measurement precision is high, data transmission is stable, the design requirements are met, and the system has high operation values. The purpose of ensuring the stability of the system by detecting the characteristics of the relay can be met.

Drawings

Fig. 1 is an overall hardware block diagram of the present embodiment.

Fig. 2 is a schematic diagram of the contact detection circuit of the present embodiment.

Fig. 3 is a schematic diagram of a voltage detection circuit according to the present embodiment.

Fig. 4 is a schematic diagram of a current detection circuit according to the present embodiment.

Fig. 5 is a schematic diagram of the single chip microcomputer control circuit of the present embodiment.

Fig. 6 is a schematic diagram of the alarm circuit of the present embodiment.

Fig. 7 is a schematic diagram of a relay control circuit according to the present embodiment.

Fig. 8 is a schematic diagram of a key circuit according to the present embodiment.

Fig. 9 is a schematic diagram of a display circuit according to the present embodiment.

Fig. 10 is a schematic diagram of a communication circuit according to the present embodiment.

Fig. 11 is a general flow chart of the test of the present embodiment.

FIG. 12 is a flowchart illustrating the operation voltage testing process of the present embodiment.

Fig. 13 is a return voltage test flowchart of the present embodiment.

FIG. 14 is a flow chart of the operation current test according to the present embodiment.

FIG. 15 is a flowchart illustrating the operation time testing process according to the present embodiment.

Detailed Description

The following further description of embodiments of the invention is made with reference to the accompanying drawings:

the present embodiment provides a small-capacity relay characteristic detector, which is used for detecting an operating voltage, a return voltage, an operating current, and an operating time of a relay, and completing display.

Wherein the operating voltage ("current"): when a certain amount of voltage ("current") is supplied to the relay, which happens to cause the relay to act, the voltage ("current") at this time is the operating voltage ("current").

Wherein the return voltage is: after a voltage overload is provided to power the relay, the voltage or current value is gradually reduced until the voltage value at which the relay contacts just cut off.

Wherein the action delay time: at the rated input voltage, the time from the instant the energizing value is switched on to the shock action of the relay after a given delay time.

As shown in fig. 1, the small-capacity relay characteristic detector comprises a single chip microcomputer control circuit, a voltage detection circuit, a current detection circuit, a contact detection circuit, a communication circuit, a display circuit, an alarm circuit, a relay control circuit and a key circuit, wherein the voltage detection circuit, the current detection circuit, the contact detection circuit, the communication circuit, the display circuit, the alarm circuit, the relay control circuit and the key circuit are all connected with the single chip microcomputer control circuit.

Testing principle of each parameter:

voltage: the idea of a controllable power supply is mainly adopted, controllable analog voltage is output through D/A conversion, and then the voltage is amplified through a power tube and an operational amplifier. During the detection process, the single chip control analog voltage is increased from zero, and after the contact detection module detects the action of the relay, the value at the moment is recorded, and the current value and the output are recorded after the arithmetic data are processed.

Current: the action current is measured by a hall element. The hall element is easily interfered by a magnetic field, so the interference of the magnetic field needs to be avoided as much as possible in the measuring process. The Hall element used in the method converts a current value into a voltage value, so that the current can be measured only after the voltage value is converted by the A/D module and data processing is carried out during measurement.

Time: the pull-in time measurement is realized by using a single chip microcomputer to control a solid state relay switch network system, the system can simultaneously turn on a 12V solid state relay coil and control a timer to start timing, and an electric shock detection is used for determining whether the relay is turned off or on. The pull-in time measured after the relay has been actuated is the absorption time of the relay.

In the embodiment, the single chip microcomputer STC12C5A60S2 is used as a main processor of a single chip microcomputer control circuit, the function test is selected through a key circuit, the obtained data is displayed on a display screen of a display circuit and is transmitted to an upper computer through a communication circuit, and if the test data exceeds a specified range, a buzzer of an alarm circuit gives an alarm. The functional test mainly comprises voltage, current and time data, and the related chips used are mainly DAC0832, LM358, TIP122, PCF8591 and ACS 712. The voltage and the current are detected by the numerical control power supply, the time is detected by the timer in the single chip microcomputer, and the acquired data are displayed after being subjected to function operation.

As shown in fig. 2, the contact detection circuit of this embodiment includes a relay to be detected and a resistor R8, one end of a coil of the relay to be detected is connected to a ground, the other end of the coil is connected to pin 1 of a chip LM358 in the voltage detection circuit, a normally open end of the relay to be detected is connected to a power VCC through a resistor R8, the normally open end of the relay to be detected is connected to a pin 13 of a monolithic STC12C5a60S2 in the monolithic control circuit, and a common end of the relay to be detected is connected to the ground.

The contact detection circuit is an important part of the detection system. The main principle of the relay is that whether the relay acts is judged according to the high-low level condition of a pin 13 of a connected singlechip STC12C5A60S 2. A high level represents no action and a low level represents action. The principle is that a Schmitt trigger in the singlechip detects the high and low levels of a pin and sends a signal to a data register, and an internal bus distinguishes the level state of a serial port. When the normally open switch is closed, the serial port is grounded through a pull-up resistor R8, and the internal bus of the singlechip recognizes that the serial port is at a low level. Otherwise, the same principle is applied.

When the pin of the singlechip is at high level, the normally open switch is in a disconnected state, the serial port is not grounded through the pull-up resistor R8, and therefore the relay to be tested is in an inactive state. When the pin of the singlechip is at low level, the normally open switch is in a closed state at the moment, and the serial port is grounded through a pull-up resistor R8, so that the relay to be tested is in an action state.

When the parameter of the detection system detects the condition, the motion state of the relay to be detected is used as the condition in most of the time, so that the contact detection circuit is an important mark for measuring accuracy.

As shown in fig. 3, the voltage detection circuit of this embodiment includes a power tube TIP122, a chip LM358 and a DAC0832 chip, where pin 1 and pin 2 of the power tube TIP122 are both connected to a 12V power supply, pin 3 of the power tube TIP122 is connected to a resistor R2, a resistor R2 is simultaneously connected to a resistor R3 and pin 2 of the chip LM358, pin 1 of the chip LM358 is simultaneously connected to a contact detection circuit and a 12V power supply, pin 3 of the chip LM358 is connected to pin 8 of the DAC0832 chip, the resistor R3 and pin 4 of the chip LM358 are both connected to a ground, pin 8 of the chip LM358 is connected to a 12V power supply, pin 1, pin 17, pin 3, pin 10, pin 18, pin 2 and pin 12 of the DAC0832 chip are all connected to a ground, pin 11 of the DAC0832 chip is connected to a ground through a diode D083 1, pin 19, pin 9 and pin 20 of the DAC0832 chip are all connected to a power supply, and pin VCC 4 of the DAC0832 chip is connected to a VCC 083, And the pin 5, the pin 6, the pin 7, the pin 13, the pin 14, the pin 15 and the pin 16 are all connected with a singlechip control circuit.

The voltage detection circuit uses a DAC0832 chip to generate a controlled analog voltage. DAC0832 is comprised of an 8-bit D/a converter including two input registers and other registers such that DAC083 has three input modes appropriate for the various circuit needs, i.e., double buffer, single buffer, and direct communication ("D/a asynchronous input request") synchronous conversion, etc. The result of the D/a conversion is produced in the form of a current. This power function can be performed by a high input impedance linear operational amplifier if a corresponding analog signal is required. The transmitted feedback resistor may be externally connected through an inherent resistance within the RFB reference plate.

An LM358 operational amplifier chip in a voltage detection circuit includes two separate high gain amplifiers and internal frequency compensation, which includes a single, wide voltage range power supply and a dual power mode of operation. The range of use includes sensor amplifiers, dc gain blocks and all other operational amplifiers that can be powered by a single power source. The power supply voltage range is wide, and comprises a single power supply and a double power supply, and has the following characteristics: low power current, battery current, low input current, input voltage, and low distortion current. Wide common mode input voltage and wide common mode output voltage 0- (V)_CC-1.5) V. LM358 includes two high gain discharges separated and compensated by an internal frequency.

However, since the current after the arithmetic amplification is insufficient to drive the relay to operate, the power tube circuit is required to amplify the current. The power tube used here is TIP122, darlington, which is a compound tube. It is connected to form two or three new equivalent transistor internal transistors. The amplifying transistor is the product of two transistors. In the design of this electronic circuit, the Darlington process is often used for power amplifiers and regulated voltage supplies. The Darlington tube has large amplification factor, which is larger than that of common power three-stage tube, so that the Darlington tube is designed and selected to amplify current. In the embodiment, the Darlington tube is mainly used for improving the driving capability, and the amplification effect is excellent. In addition, the darlington tube is also used as a receiving tube in the optoelectronic coupler.

As shown in fig. 4, the current detection circuit in the present embodiment includes an ACS712 chip and a PCF8591 chip, the

pins

ACS712 is a hall effect based linear 2.1 volt isolation with conductors and low resistance current sensor fully integrated circuit. It has the following properties: (1) output range 5.0V, high output sensitivity, (2) hysteretic output voltage with alternating current or direct current proportionality, (3) extremely stable output voltage, (4) near zero, (5) no hysteretic voltage. ACS712 may provide a cost-effective solution for accurate ac or dc current sensing of industrial, commercial, and communication systems. Typical applications include engine control, load detection and management, switching power supply surges and preventing malfunctions. The device has a low polarization detection circuit and a linear hall copper current circuit near the wafer surface. The copper set application creates a magnetic field from the current path that can be induced and converted to a proportional voltage with an integrated heat. It should be used to avoid electromagnetic interference. The Holic BICMOS of stable shift type low polarization provides accurate proportional voltage, and can provide accurate programming when in operation.

The detected current is converted into a voltage signal through a chip, so that an AD module (namely a modular PCF8591 chip) needs to be converted, and data is transmitted to a single chip for processing.

PCF8591 is a CMOS 8-bit data acquisition device that includes four analog inputs (where a is an analog voltage input, one output and a serial I2C bus interface). The 3 a0, a1, and a2 are used to program hardware address tags, enabling up to eight devices PCF 8591I2C on the bus without the need for additional hardware. The address, control and data pass through the device on two bi-directional I2C bus lines. The device includes: a worksheet for analog inputs, a multiplexer function on eight-bit analog conversion, and tracking and maintenance functions.

The ADC of PCF8591 is close, the conversion rate is moderate, but its speed is blocked in I2C communications. Due to the slow communication speed of I2C, the PCF8591 hardware interface principle circuit board interconnection method is directly rate dependent. Due to the speed limitations of I2C, AD and DA are low speeds of PCF8591 integration, primarily for low conversion and desirably low cost, battery powered devices, e.g., measured voltages. Cell, measurement when the battery supply voltage is lower than a certain value, and battery change alarm. Each component of the I2C bus system is sent to the device with an active address activation. The address includes a fixed portion and a programmable portion. The programmable portion must be configured based on the addresses a0, a1, and a2 quotation marks. In the I2C bus protocol, the address must be sent to satisfy the actual condition, e.g., in the first byte. The last bit of the address byte is a read/write bit to define the direction of the subsequent data transfer. And then the data is transmitted to a single chip microcomputer and then processed by using modular conversion and an I2C protocol to obtain the numerical value of the current.

In this embodiment, as shown in fig. 5, the single chip microcomputer control circuit includes a single chip microcomputer STC12C5a60S2, a resistor R1, a resistor R2, a capacitor C3, a key S1, a capacitor C1, a capacitor C2, and a crystal oscillator Y1, a pin 9 of the single chip microcomputer STC12C5a60S2 is simultaneously connected to one ends of a resistor R1, a resistor R2, and a capacitor C3, the other end of the resistor R1 is connected to one end of a key S1, the other end of the key S1 and the other end of the capacitor C3 are both connected to a power source VCC, the other end of the resistor R2 is connected to a ground, a pin 18 of the single chip microcomputer STC12C5a60S2 is simultaneously connected to one ends of a crystal oscillator Y1 and a capacitor C1, a pin 19 of the single chip microcomputer STC12C5a60S 1 is simultaneously connected to the other end of the crystal oscillator Y1 and one end of the capacitor C1, the other end of the single chip microcomputer STC12C 1 and the ground pin 20 a 5C 1 are connected to the ground wire STC 5a ground.

The main processor of this embodiment is STC12C5a60S2, modified 8051CPU, 1T, single clock/machine cycle, conventional 8051 operating voltage of 5.5 volts instruction code is identical, operating at 3.3 volts, with average 8051 operating in the frequency range (0-35 MHz), with EEPOM functionality of 0-420 MHz. There are 4 16-bit timers, 8051, which are consistent with the conventional dual timer/timer, one I/O interface, 7 external interrupts, one along interrupt or low level interrupt.

A reset circuit: the reset circuit comprises a resistor R1, a resistor R2, a capacitor C3 and a key S1. Reset circuitry ("reset RAM" and one register value) for performing an initialization operation on-chip reset. The RC oscillator in STC12C5a60S2 monolithic integration can be used directly as a clock source, and usually it does not need an external crystal oscillator. However, the internal RC oscillator is less accurate, the 5V monolithic is typically between 11 mhz and 15 mhz, the temperature variation is large, and external crystal resonance is required. The inner program size of STC12C5a60S2 is 60KB, not extended.

In this embodiment, as shown in fig. 6, the alarm circuit includes a resistor R13, a transistor Q2, a diode D2, and a buzzer, one end of the resistor R13 is connected to a pin 25 of the single-chip STC12C5a60S2, the other end of the resistor R13 is connected to a base of the transistor Q2, a collector of the transistor Q2 is connected to one end of the buzzer, the other end of the buzzer is connected to a power source VCC, and two ends of the buzzer are connected to the diode D2.

The principle of the design of the alarm circuit is that when a pin connected with a buzzer is at a low level, the buzzer works to make a sound. When the measured parameters are not in the specified range and the user needs to be reminded of safety, the buzzer can give out sound alarm. Although the hardware circuit and principle are simple, the circuit is still an indispensable circuit.

In this embodiment, as shown in fig. 7, the relay control circuit includes a solid-state relay, a resistor R5, a transistor Q1, a resistor R6 and a resistor R7, the solid-state relay is connected with pin 1 and pin 2 of the ACS712 chip in the current detection circuit, the solid-state relay is connected with a 12V power supply, the solid-state relay is connected with a collector of a transistor Q1 through a resistor R5, an emitter of a transistor Q1 is connected with a ground wire, a base of the transistor Q1 is connected with one end of a resistor R7 and a pin 12 of a single chip microcomputer STC12C5a60S2 through a resistor R6, and the other end of the resistor R7 is connected with a power supply VCC.

The principle of the relay control circuit is that when a pin of a single chip microcomputer connected with the relay control circuit is at a high level, a solid-state relay is conducted, a normally open switch of the solid-state relay is closed, and a normally closed switch of the solid-state relay is opened. When the connected singlechip pin is low level, the solid state relay is closed, and the normally open switch of the solid state relay is opened and the normally closed switch is closed. The hardware circuit is mainly used for switching the measuring module, for example, when time parameters need to be detected, a key is pressed down, a pin of the single chip microcomputer becomes a high level, the solid-state relay is conducted, a relay loop needing to be tested is conducted, the timer starts to work, and the main function of the module is a switching function. The solid-state relay in the relay control circuit adopts a 5V relay with the model number of JQC-3 FF-S-Z.

In this embodiment, as shown in fig. 8, the key circuit includes a key S2, a key S3, a key S4, a key S5, a resistor R9, a resistor R10, a resistor R11, and a resistor R12, one end of each of the key S2, the key S3, the key S4, and the key S5 is connected to a ground, the other end of the key S2 is connected to a power source VCC through a resistor R9 and is connected to a pin 24 of a monolithic computer STC12C5a60S2, the other end of the key S3 is connected to the power source VCC through a resistor R10 and is connected to the pin 23 of the monolithic computer STC12C5a60S2, the other end of the key S4 is connected to the power source VCC through a resistor R9 and is connected to a pin 22 of the monolithic computer STC12C5a60S2, and the other end of the key S5 is connected to the power source VCC through a resistor R12 and is connected to a pin 21 of the monolithic computer STC 12C.

The key circuit can well coordinate and switch the function of the relay characteristic detector, the keys are respectively connected with the I/O ports of the single chip microcomputer through 10K pull-up resistors, and the single chip microcomputer sets the function of the keys through a program. The system includes four keys, which function as follows: measuring the action voltage of the relay; measuring a return voltage of the relay; measuring the action current of the relay; and measuring the action time of the relay.

In this embodiment, as shown in fig. 9, the display circuit includes an LCD1602 display, a sliding rheostat RP1 and a resistor P1, pin 1 and pin 16 of the LCD1602 display are both connected to ground, pin 2 and pin 15 of the LCD1602 display are both connected to a +5V power supply, pin 3 of the LCD1602 display is connected to ground through a sliding rheostat RP1, pin 4 of the LCD1602 display is connected to pin 26 of a single-chip STC12C5a60S2, pin 6 of the LCD1602 display is connected to pin 27 of a single-chip STC12C5a60S2, pin 5 of the LCD1602 display is connected to pin 28 of a single-chip STC12C5a60S2, pin 7 of the LCD1602 display is connected to pin 39 of a single-chip STC12C5a60S2 and pin 7 is connected to pin 1, pin 8 of the LCD display is connected to pin 38 of a C5a60S2 and pin 8 is connected to a1, pin 9 of the LCD1602 is connected to pin 1602 of a resistor P9 of the resistor P9 and pin 53912 a 10 of the resistor P465 a 1602, pin 9 of the LCD1602 is connected to pin 9 and pin 9 of the single-chip STC12C5a 10, pin 11 of the LCD1602 display screen is connected with pin 35 of singlechip STC12C5A60S2 and pin 11 is connected with exclusion P1, pin 12 of the LCD1602 display screen is connected with pin 34 of singlechip STC12C5A60S2 and pin 12 is connected with exclusion P1, pin 13 of the LCD1602 display screen is connected with pin 33 of singlechip STC12C5A60S2 and pin 13 is connected with exclusion P1, pin 14 of the LCD1602 display screen is connected with pin 32 of singlechip STC12C5A60S2 and pin 14 is connected with exclusion P1.

The parameters measured in this example are displayed on the LCD1602 screen. Since there are not many parameter characters displayed, the display screen is not used, but rather, display screen 1602 is used. It includes a plurality of network character bits, each of which can display a character. The content is displayed as 16 × 2, may be displayed in two lines of the liquid crystal cell 16, and is displayed in english, numerals and symbols. Tracking the translation is used for the main power consumption in the liquid crystal display circuit.

In this embodiment, as shown in fig. 10, the communication circuit includes a MAX3232 chip and a serial DB9, pin 1 of the MAX3232 chip is connected with pin 3 through a capacitor C7, pin 4 of the MAX3232 chip is connected with pin 5 through a capacitor C8, pin 11 of the MAX3232 chip is connected with pin 11 of the single chip microcomputer STC12C5a60S2, pin 12 of the MAX3232 chip is connected with pin 10 of the single chip microcomputer STC12C5a60S2, pin 15 of the MAX3232 chip is connected with a ground wire, a capacitor C9 is connected between pin 15 and pin 6, pin 13 and pin 14 of the MAX3232 chip are both connected with a serial port DB 68, pin 2 of the MAX3232 chip is connected with a power VCC through a capacitor C6, pin 16 of the MAX3232 chip is connected with the power VCC, one end of a resistor R14 is connected with the power VCC, the other end of the resistor R357323 is connected with pin 11 of the MAX3232 chip through a light emitting diode DS1, one end of the resistor R15 is connected with the power VCC, and the other end of the resistor R7312. The communication circuit of the present embodiment is used for connection with an external PC.

As shown in fig. 11, after the system is powered on, the test flow chart of this embodiment first initializes each module circuit, and after the initialization is completed, selects an item to be tested by a key, and tests corresponding parameters of parameters such as pull-in voltage (i.e., action voltage), return voltage, pull-in current (i.e., action current), and delay closing time. Once the items needing to be tested are determined, a corresponding interrupt is entered, and the corresponding control instructions are executed. If the test items need to be switched, the test items can be switched by pressing the keys. At the same time, the collected data is displayed in real time on the LCD1602 liquid crystal display.

Voltage sensing is used in DAC0832 element which generates an analog voltage by the DA function of the element and then generates sufficient voltage by the amplifier circuit to enable the relay to operate. Action voltage test principle: firstly, a low initial value voltage (the relay is not closed) is set, and the voltage is slowly increased through a numerical control power supply, and the voltage is increased by a small fixed value every time. Through contact detection, when the relay contact is detected to work (relay pull-in), the voltage is stopped to be increased, and the voltage is the action voltage at the moment. And finally outputting the voltage value at the moment. The operation voltage test flow is shown in fig. 12.

Return voltage measurement principle: a high voltage value is set (the relay pull-in/contact detection circuit can detect that the relay is pulled in), and the voltage is slowly reduced by the numerical control power supply, so that a small fixed value is reduced each time. When the contact detection circuit detects that the relay is not engaged, the voltage reduction is stopped, and the voltage at this time is the return voltage. And finally outputting the voltage value at the moment. The return voltage test flow is shown in fig. 13.

The current detection software is complex, firstly, the ACS712 element which converts the detected current into voltage and outputs the voltage is used for measuring the current, and the single chip microcomputer cannot directly read the voltage, so that the AD conversion is needed for converting parameters. Therefore, the current is converted by the AD function of PCF8591, and the value of the current is obtained by calculation after the conversion, and is displayed and communicated with an upper computer. The operation current test flow is shown in fig. 14.

The on-off of the solid-state relay is controlled through an I/O port of the single chip microcomputer, the solid-state relay is triggered by low level, and when the serial port is at low level, the solid-state relay acts. When the solid-state relay is conducted, the timer starts to count time, and meanwhile, the coil of the relay starts to be electrified, wherein the design precision of the timer is designed to be one millisecond by software. And then the contact detection circuit detects whether the relay acts, and if the switch of the relay acts, the singlechip controls the timer to stop timing. After a delay of 5 milliseconds, the solid-state relay is closed and the power supply to the relay coil is stopped. And finally, processing the parameters of the timer, and displaying the parameters measured by the relay on a display screen. The action time test flowchart is shown in fig. 15.

Firstly, looking up the manual to obtain the standard value of the measured parameter, and then comparing with the measured value. The parameters of the relay IE255 can be obtained according to a manual of the relay IE255, and the action current is 75 mA; the pull-in voltage is less than 80% of the rated voltage, namely less than 9.6V, and the relay has a label value of 8.2V through tests. The return voltage is more than 10% of the rated voltage, namely more than 1.2V, and the relay has a label value of 2.0V through the test. The action time is less than 20ms, and the value of the relay is marked to be 3.8ms by looking up data.

Tables 1 to 4 below show specific experimental data and error comparisons.

Table 1: pull-in voltage test results:

test point	Test value (V)	Standard value (V)	Absolute error	Relative error
						1	8.02	8.2	-0.18	2.2％
2	8.15	8.2	-0.05	0.6％
					3	7.90	8.2	-0.30	3.6％
4	8.25	8.2	-0.05	0.6％
					5	8.05	8.2	-0.15	1.1％
6	8.12	8.2	-0.08	1.0％
					7	8.25	8.2	0.05	0.6％
8	7.96	8.2	-0.24	2.9％
					9	8.15	8.2	-0.05	0.6％
10	8.22	8.2	0.02	0.2％

By summarizing the data of the pull-in voltage through the table, the relative error of the parameter is between 0.6 and 2.9 percent, and the measured parameter can be accurately obtained.

Table 2: returning a voltage test result:

by summarizing the data of the return voltage through the table, it can be known that the relative error of the parameter is between 2% and 20.5%, and sometimes the error is large, but the parameter condition of the relay is met.

Table 3: action current test result:

test point	Test value (mA)	Standard value (mA)	Absolute error	Relative error
						1	76	75	1	1.3％
2	68	75	-7	9.3％
					3	76	75	1	1.3％
4	72	75	-3	4.0％
					5	78	75	3	4.0％
6	74	75	-1	1.3％
					7	126	75	51	68.0％
8	69	75	-6	8.0％
					9	68	75	-7	9.3％
10	67	75	-8	10.7％

The data of the action current are summarized through the table, and a large error is removed, so that the relative error of the parameter is between 1.3% and 10.7%, and the measured parameter can be accurately obtained.

Table 4: action time test results:

by summarizing the data of the action time through the table, the relative error of the parameter is between 0 and 7.9 percent, and the measured parameter can be accurately obtained.

Through the comparison and analysis, the relay characteristic detector can accurately detect parameters.

The protection scope of the present invention includes but is not limited to the above embodiments, the protection scope of the present invention is subject to the claims, and any replacement, deformation, and improvement that can be easily conceived by those skilled in the art made by the present technology all fall into the protection scope of the present invention.

Claims

1. The utility model provides a low capacity relay characteristic detector which characterized in that: the device comprises a singlechip control circuit, a voltage detection circuit, a current detection circuit, a contact detection circuit, a communication circuit, a display circuit, an alarm circuit, a relay control circuit and a key circuit, wherein the voltage detection circuit, the current detection circuit, the contact detection circuit, the communication circuit, the display circuit, the alarm circuit, the relay control circuit and the key circuit are all connected with the singlechip control circuit;

2. The small capacity relay characteristic detector according to claim 1, characterized in that: the single-chip microcomputer control circuit comprises a single-chip microcomputer STC12C5A60S2, a resistor R1, a resistor R2, a capacitor C3, a key S1, a capacitor C1, a capacitor C2 and a crystal oscillator Y1, a pin 9 of the single-chip microcomputer STC12C5A60S2 is simultaneously connected with one ends of a resistor R1, a resistor R2 and a capacitor C3, the other end of the resistor R1 is connected with one end of a key S1, the other end of the key S1 and the other end of the capacitor C3 are both connected with a power supply VCC, the other end of the resistor R2 is connected with a ground wire, a pin 18 of the single-chip microcomputer STC12C5A60S2 is simultaneously connected with one ends of the crystal oscillator Y1 and the capacitor C1, a pin 19 of the single-chip microcomputer STC 12A 60S 1 is simultaneously connected with the other end of the capacitor C1 and one end of the capacitor C1, the pin STC 12A 60S 1 is connected with the ground wire 20 of the single-chip microcomputer STC1, and the single-chip microcomputer STC 3640.

3. The small capacity relay characteristic detector according to claim 2, characterized in that: the current detection circuit comprises an ACS712 chip and an PCF8591 chip, wherein a pin 1 and a pin 2 of the ACS712 chip are connected with a relay control circuit, a pin 3 and a pin 4 of the ACS712 chip are connected with a contact detection circuit, a pin 5 of the ACS712 chip is connected with a ground wire, a pin 6 of the ACS712 chip is connected with a ground wire through a capacitor C4, a pin 7 of the ACS712 chip is connected with a pin 1 of the PCF8591 chip, a pin 8 of the ACS712 chip is connected with a power VCC and a pin 8 is connected with the ground wire through a capacitor C5, a pin 14 and a pin 16 of the ACS712 chip are both connected with a power VCC, a pin 12, a pin 13, a pin 5, a pin 6, a pin 7 and a pin 8 of the ACS712 chip are all connected with the ground wire, a pin 9 of the ACS712 chip is connected with a pin 17 of an STC12C5A60S2 of a single chip, and a pin 10 of the ACS 712.

4. The small capacity relay characteristic detector according to claim 3, characterized in that: contact detection circuit includes the relay and the resistance R8 that await measuring, the one end of the coil of the relay that awaits measuring is connected the ground wire, and the other end and the voltage detection circuit of coil LM358 ' S pin 1 are connected, the relay that awaits measuring ' S normal start end passes through resistance R8 and is connected with power VCC, and the normal start end is connected with singlechip STC12C5A60S2 ' S pin 13, the common port of the relay that awaits measuring is connected the ground wire.

5. The small capacity relay characteristic detector according to claim 4, characterized in that: alarm circuit includes resistance R13, triode Q2, diode D2 and bee calling organ, the one end of resistance R13 is connected with singlechip STC12C5A60S2 'S pin 25, and the other end of resistance R13 is connected with triode Q2' S base, triode Q2 'S collecting electrode is connected with bee calling organ' S one end, the other end connecting power VCC of bee calling organ, the both ends of bee calling organ are connected with diode D2.

6. The small capacity relay characteristic detector according to claim 5, characterized in that: the relay control circuit includes solid state relay, resistance R5, triode Q1, resistance R6 and resistance R7, pin 1 and pin 2 of ACS712 chip are connected among solid state relay and the current detection circuit, solid state relay is connected with the 12V power, and solid state relay passes through resistance R5 and is connected with triode Q1 'S collecting electrode, triode Q1' S projecting pole connects the ground wire, triode Q1 'S base passes through resistance R6 and is connected with resistance R7' S one end and singlechip STC12C5A60S2 'S pin 12 simultaneously, and the power VCC is connected to resistance R7' S the other end.

7. The small capacity relay characteristic detector according to claim 6, characterized in that: the key circuit comprises a key S2, a key S3, a key S4, a key S5, a resistor R9, a resistor R10, a resistor R11 and a resistor R12, one end of the key S2, a key S3, a key S4 and a key S5 is connected with a ground wire, the other end of the key S2 is connected with a power supply VCC through a resistor R9 and is connected with a pin 24 of a singlechip STC12C5A60S2, the other end of the key S3 is connected with the power supply VCC through a resistor R10 and is connected with a pin 23 of the singlechip STC12C5A60S2, the other end of the key S4 is connected with the power supply VCC through a resistor R11 and is connected with a pin 22 of the singlechip STC12C5A60S2, the other end of the key S5 is connected with the power supply VCC through a resistor R12 and is connected with a pin 21 of the singlechip STC12C5A60S 2.

8. The small capacity relay characteristic detector according to claim 7, characterized in that: the display circuit comprises an LCD1602 display screen, a sliding rheostat RP1 and a resistor exclusion P1, wherein a pin 1 and a pin 16 of the LCD1602 display screen are both connected with a ground wire, a pin 2 and a pin 15 of the LCD1602 display screen are both connected with a +5V power supply, a pin 3 of the LCD1602 display screen is connected with the ground wire through the sliding rheostat RP1, a pin 4 of the LCD1602 display screen is connected with a pin 26 of a singlechip STC12C5A60S2, a pin 6 of the LCD1602 display screen is connected with a pin 27 of the singlechip STC12C5A60S2, a pin 5 of the LCD1602 display screen is connected with a pin 28 of the singlechip STC12C5A60S2, a pin 7 of the LCD1602 display screen is connected with a pin 39 of the singlechip STC 12A 60S2 and a pin 7 is connected with the resistor exclusion P1, a pin 8 of the LCD1602 display screen is connected with a pin 38 of the singlechip STC12C5A60S2 and a pin 8 is connected with the resistor exclusion P1, a pin 9 of the singlechip STC 12A 60S2 and a pin 5399 of the singlechip STC 10 is connected with a pin 1A 9 and a pin 68510 of the singlechip STC 10, pin 11 of the LCD1602 display screen is connected with pin 35 of singlechip STC12C5A60S2 and pin 11 is connected with exclusion P1, pin 12 of the LCD1602 display screen is connected with pin 34 of singlechip STC12C5A60S2 and pin 12 is connected with exclusion P1, pin 13 of the LCD1602 display screen is connected with pin 33 of singlechip STC12C5A60S2 and pin 13 is connected with exclusion P1, pin 14 of the LCD1602 display screen is connected with pin 32 of singlechip STC12C5A60S2 and pin 14 is connected with exclusion P1.

9. The small capacity relay characteristic detector according to claim 8, characterized in that: the communication circuit comprises a MAX3232 chip and a serial port DB9, wherein a pin 1 of the MAX3232 chip is connected with a pin 3 through a capacitor C7, a pin 4 of the MAX3232 chip is connected with a pin 5 through a capacitor C8, a pin 11 of the MAX3232 chip is connected with a pin 11 of a singlechip STC12C5A60S2, a pin 12 of the MAX3232 chip is connected with a pin 10 of the singlechip STC12C5A60S2, a pin 15 of the MAX3232 chip is connected with a ground wire, a capacitor C9 is connected between the pin 15 and the pin 6, the pin 13 and the pin 14 of the MAX3232 chip are both connected with a serial port DB9, the pin 2 of the MAX3232 chip is connected with a power supply through a capacitor C6, a pin 16 of the MAX3232 chip is connected with a power supply VCC, one end of a resistor R14 is connected with the power supply VCC, the other end of the resistor R15 is connected with the pin 11 of the MAX32 chip through a light emitting diode DS 1.