CN203745543U

CN203745543U - Active network internal resistance measuring device

Info

Publication number: CN203745543U
Application number: CN201420014560.8U
Authority: CN
Inventors: 秦辉
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-10
Filing date: 2014-01-10
Publication date: 2014-07-30
Anticipated expiration: 2024-01-10

Abstract

The utility model discloses an active network internal resistance measuring device which is composed of a single chip microcomputer, a digital instrument special integrated circuit MAX133, a LCD display module DMC16230, a serial-in parallel-out 8-bit shift register 74LS164, a decoder 74LS138, an analog switch, a resistor divider network, a red pen and a black pen. The active network internal resistance measuring device of the utility model can be used to fast and accurately measure active network internal resistance, and greatly reduce the labor intensity of manual active network internal resistance measurement.

Description

Active network internal resistance measurement device

Technical field

The utility model relates to a kind of active network internal resistance measurement device.

Background technology

The measurement of active network internal resistance at present generally adopts the method for experiment to obtain relevant data, then carries out data processing, finally obtains the internal resistance value of active network, and the process of measuring active network internal resistance is not only complicated, and the error of measurement result is larger.

Summary of the invention

Numerous and diverse in order to overcome the process of current measurement active network internal resistance, the drawback that error is large, the utility model provides a kind of active network internal resistance measurement device.

The utility model solves the technical scheme that its technical matters adopts: a kind of active network internal resistance measurement device, and it is by integrated circuit (IC) 1, IC2, IC3, IC4, IC5, analog switch, resistance pressure-dividing network, red test pencil, black meter pen composition, it is characterized in that: integrated circuit (IC) 1 is single-chip microcomputer, integrated circuit (IC) 2 is digital instrument special IC MAX133, integrated circuit (IC) 3 is LCD display module DMC16230, integrated circuit (IC) 4 is for sealing in and going out 8 bit shift register 74LS164, integrated circuit (IC) 5 is code translator 74LS138, and in analog switch, K1 is single-pole double-throw (SPDT) analog switch, K2, K3 is double-pole single-throw (D.P.S.T.) analog switch, K2, the public control end of K3, K4, K5, K6, K7, K8, K9 is respectively single-pole single-throw (SPST) analog switch, and the pin Y0 of integrated circuit (IC) 5 is connected with the control end of analog switch K1, the pin Y1 of integrated circuit (IC) 5 and analog switch K2, the control end of K3 is connected, the pin Y2 of integrated circuit (IC) 5, Y3, Y4, Y5, Y6, Y7 respectively with analog switch K4, K5, K6, K7, K8, the control end of K9 is connected, and resistance pressure-dividing network is by R1, R2, R3, R4, R5, R6, R7 composition, the resistance value of R1 is 0.5k, the resistance value of R2 is 2k, the resistance value of R3 is 2.995k, the resistance value of R4 is 17.995k, the resistance value of R5 is 47.995k, the resistance value of R6 is 197.995k, the resistance value of R7 is 497.995k, analog switch K4, K5, K6, K7, K8, one end of K9 is connected with red test pencil respectively, analog switch K4, K5, K6, K7, K8, the other end of K9 respectively with resistance R 2, R3, R4, R5, R6, R7 is connected.

Pin P1.0, P1.1, the P1.2 of integrated circuit (IC) 1 are connected with pin A0, A1, the A2 of integrated circuit (IC) 5 respectively, and the pin P1.7 of integrated circuit (IC) 1 is connected with the pin STC of integrated circuit (IC) 5.

The pin RXD of integrated circuit (IC) 1 is connected with pin DSA, the DSB of integrated circuit (IC) 4, and the pin TXD of integrated circuit (IC) 1 is connected with the pin CP of integrated circuit (IC) 4.

Pin P3.2, P3.3, the P1.7 of integrated circuit (IC) 1 are connected with pin RS, R/W, the E of integrated circuit (IC) 3 respectively.

Pin P1.3, P1.4, P1.5, the P1.6 of integrated circuit (IC) 1 are connected with pin D0, D1, D2, the D3 of integrated circuit (IC) 2 respectively, and pin P3.4, P3.5, the P3.7 of integrated circuit (IC) 1 are connected with pin RD, WR, the ALE of integrated circuit (IC) 2 respectively.

Pin Q0, the Q1 of integrated circuit (IC) 4, Q2, Q3, Q4, Q5, Q6, Q7 are connected with pin DB0, DB1, DB2, DB3, DB4, DB5, DB6, the DB7 of integrated circuit (IC) 3 respectively.

Black meter pen is connected with the pin COM of integrated circuit (IC) 2.

The beneficial effects of the utility model are: can measure rapidly and accurately active network internal resistance, greatly alleviate the labour intensity of manual measurement active network internal resistance.

Brief description of the drawings

Fig. 1 is the structural drawing of active network internal resistance measurement device.

Embodiment

According to equivalent source theorem, active network can be equivalent to a voltage source E and the resistance (circuit that active network internal resistance r) is in series.Known according to Circuit theory, the computing formula of active network internal resistance is: r=(U/E-1) R-Δ R, the internal resistance that wherein r is active network, U is the voltage at pull-up resistor two ends, E is by the terminal voltage of the voltage source of active network equivalence, R is pull-up resistor, in the time that K2 disconnects, the value of R is the resistance value of R2, in the time that K2 is closed, the value of R is the resistance value of R2 after in parallel with R1, the value of Δ R should change with the difference of the analog switch of conducting, the value of actual Δ R is for removing R1, the equivalent resistance of all pull-up resistors beyond R2, the various values of Δ R are stored in the storer of single-chip microcomputer, when the work of active network internal resistance measurement instrument, single-chip microcomputer utilizes table-look-up instruction automatically to identify the analog switch of conducting according to the size of E value, to choose the value of different Δ R.

The principle of work of E value metering circuit.After single-chip microcomputer initialization, P1.0, P1.1, P1.2 output low level, input end A0, A1, the A2 of code translator 74LS138 are " 0 ", then single-chip microcomputer makes P1.7 end be reset to low level, it is " 0 " that P1.7 end low level makes the Enable Pin STC of code translator 74LS138, code translator starts the data of A0, A1, the input of A2 end to carry out decoding, make Y0 end for significant level " 0 ", other output pin is inactive level " 1 ", the low level of Y0 end makes 2,3 two contact conductings of analog switch K1, thereby straight the connecing with the voltage input end of MAX133 of meter is connected.Now, because the control end of other analog switch except K1 is 1, so analog switch all disconnects, obviously the resistor voltage divider circuit that now R1, R2, R3, R4, R5, R6, R7 form all with circuit disconnection, the voltage that now MAX133 measures is that two test pencils touch the voltage E between 2 of tested effective source networks.Single-chip microcomputer is read into the value of E in single-chip microcomputer storer and is preserved by D0, D1, D2, D3 data bus.

The principle of work of U value metering circuit.Single-chip microcomputer is controlled data according to the size of E value from P1.0, P1.1, the output of P1.2 end, through code translator 74LS138 decoding, in its output terminal Y1, Y2, Y3, Y4, Y5, Y6, Y7, has one at least for low level, the corresponding analog switch conducting of this low level control, resistance pressure-dividing network is started working.Meanwhile the output terminal Y0 of code translator becomes inactive level " 1 ", and the high level of Y0 end disconnects 2,3 two contacts of analog switch K1,2,1 two contact conductings of analog switch K1, and visible MAX133 will become measuring voltage U from measuring voltage E.

The principle of work of r value display circuit.Single-chip microcomputer and character type LCD display module DMC16230 adopt extended serial mode interface, expand 8 delivery outlets with sealing in and going out 8 bit shift register 74LS164.Can save like this 6 I/O lines of single-chip microcomputer, save the limited interface resource of single-chip microcomputer.Single-chip microcomputer by value substitution formula r=(U/E-1) the R-Δ R of the U measuring, E, R, Δ R, obtains active network internal resistance r by operation relevant procedures, finally the value of r is shown by display module DMC16230.

Software for Design.According to the functional requirement of active network internal resistance measurement device, mainly design initialize routine, process of measurement, zero correction program, shown data processing and display driving software.

Claims

1. an active network internal resistance measurement device, it is by integrated circuit (IC) 1, IC2, IC3, IC4, IC5, analog switch, resistance pressure-dividing network, red test pencil, black meter pen composition, it is characterized in that: integrated circuit (IC) 1 is single-chip microcomputer, integrated circuit (IC) 2 is digital instrument special IC MAX133, integrated circuit (IC) 3 is LCD display module DMC16230, integrated circuit (IC) 4 is for sealing in and going out 8 bit shift register 74LS164, integrated circuit (IC) 5 is code translator 74LS138, and in analog switch, K1 is single-pole double-throw (SPDT) analog switch, K2, K3 is double-pole single-throw (D.P.S.T.) analog switch, K2, the public control end of K3, K4, K5, K6, K7, K8, K9 is respectively single-pole single-throw (SPST) analog switch, and the pin Y0 of integrated circuit (IC) 5 is connected with the control end of analog switch K1, the pin Y1 of integrated circuit (IC) 5 and analog switch K2, the control end of K3 is connected, the pin Y2 of integrated circuit (IC) 5, Y3, Y4, Y5, Y6, Y7 respectively with analog switch K4, K5, K6, K7, K8, the control end of K9 is connected, and resistance pressure-dividing network is by R1, R2, R3, R4, R5, R6, R7 composition, the resistance value of R1 is 0.5k, the resistance value of R2 is 2k, the resistance value of R3 is 2.995k, the resistance value of R4 is 17.995k, the resistance value of R5 is 47.995k, the resistance value of R6 is 197.995k, the resistance value of R7 is 497.995k, analog switch K4, K5, K6, K7, K8, one end of K9 is connected with red test pencil respectively, analog switch K4, K5, K6, K7, K8, the other end of K9 respectively with resistance R 2, R3, R4, R5, R6, R7 is connected.

2. active network internal resistance measurement device according to claim 1, it is characterized in that: pin P1.0, P1.1, the P1.2 of integrated circuit (IC) 1 are connected with pin A0, A1, the A2 of integrated circuit (IC) 5 respectively, and the pin P1.7 of integrated circuit (IC) 1 is connected with the pin STC of integrated circuit (IC) 5.

3. active network internal resistance measurement device according to claim 1, is characterized in that: the pin RXD of integrated circuit (IC) 1 is connected with pin DSA, the DSB of integrated circuit (IC) 4, and the pin TXD of integrated circuit (IC) 1 is connected with the pin CP of integrated circuit (IC) 4.

4. active network internal resistance measurement device according to claim 1, is characterized in that: pin P3.2, P3.3, the P1.7 of integrated circuit (IC) 1 are connected with pin RS, R/W, the E of integrated circuit (IC) 3 respectively.

5. active network internal resistance measurement device according to claim 1, it is characterized in that: pin P1.3, P1.4, P1.5, the P1.6 of integrated circuit (IC) 1 are connected with pin D0, D1, D2, the D3 of integrated circuit (IC) 2 respectively, pin P3.4, P3.5, the P3.7 of integrated circuit (IC) 1 are connected with pin RD, WR, the ALE of integrated circuit (IC) 2 respectively.

6. active network internal resistance measurement device according to claim 1, is characterized in that: pin Q0, the Q1 of integrated circuit (IC) 4, Q2, Q3, Q4, Q5, Q6, Q7 are connected with pin DB0, DB1, DB2, DB3, DB4, DB5, DB6, the DB7 of integrated circuit (IC) 3 respectively.

7. active network internal resistance measurement device according to claim 1, is characterized in that: black meter pen is connected with the pin COM of integrated circuit (IC) 2.