CN2309574Y

CN2309574Y - Portable intelligent stray current measuring apparatus

Info

Publication number: CN2309574Y
Application number: CN 97250413
Authority: CN
Inventors: 郑立群; 李洪锡; 高洪雷; 林海潮; 杜鹃; 左晋; 荀伟
Original assignee: METAL CORROSION AND PROTECTION
Current assignee: Zhongke Engineering Research Center for Corrosion Control, Shenyang
Priority date: 1997-08-12
Filing date: 1997-08-12
Publication date: 1999-03-03
Anticipated expiration: 2007-08-12

Abstract

The utility model belongs to a current measuring device. The utility model has the circuit structure that the device is composed of an artificial circuit and a digital circuit, wherein, the artificial circuit is composed of an input circuit, an amplifying circuit, a logic switching circuit, a sample retaining circuit and an artificial conversion circuit; the digital circuit takes an 8031 single-chip as a core and is simultaneously connected with a flip-latch, a program memory, a digital memory and a code identifying device. Signals measured by the artificial circuit are amplified. An analog to digital converter changes the analogue signals into digital quantity, and outputs the digital quantity by a terminal after the treatment of 8031. The utility model has the advantages of simple structure, high measuring speed and high precision, and can accomplish multi-path long-distance measurement.

Description

Portable intelligent stray current measuring instrument

The utility model belongs to a kind of current measuring device.

Generally under normal circumstances, electric current all flows in the conductor of appointment according to designing requirement, and owing to variation or certain reason of external condition, one part of current has been left the conductor of appointment and flowed in original unnecessary conductor, this part electric current is called stray current, as subway, tramcar.Because loose contact between the various tracks, when locomotive driving is arranged, some electric current is flowed to the earth or other medium from track, form stray current, because the existence of these stray currents, the nearby underground pipeline of city and manufacturing district and open-air remote transportation pipe line, this stray current leaves metallic conductor and enters soil media from a certain surf zone of underground pipeline, this surf zone is impelled anodic solution to quicken, thereby produces the corrosion failure that stray current causes.

Be the corrosion failure effect that prevents that above stray current from causing, the purpose of this utility model provides a kind of portable intelligent stray current measuring instrument, utilize this measuring instrument, can effectively solve since the stray current of engineering to the monitoring of the corrosion failure effect of miscellaneous equipment.

Structural design of the present utility model is this realization: the control circuit of this portable intelligent stray current measuring instrument is that digital circuit two parts of core are formed by mimic channel with 8031 single-chip microcomputers, wherein artificial circuit part is formed (as shown in Figure 1) by input circuit, amplifying circuit, logic switching circuit, sampling hold circuit and analog conversion circuit, its connection is that the front is two tunnel input IN ₁, IN ₂, on the equipment from measurement point, each path secondary amplifies C ₁C ₃And C ₂C ₄Connect logic switch U respectively ₁Input end X ₀X ₁, the output of logic switch is connected to the input end of sampling holder LF398, and its output is connected to the input end (as shown in Figure 2) of high-precision a/d converter AD574A; Digital circuit part is a core with 8031 single-chip microcomputers, and is made up of latch, memory under program, data memory and decoder, and its connection is the data terminal of 8031 single-chip microcomputers, by data bus respectively with latch U ₉, memory under program U ₈, data memory U ₇, U ₈Parallel connection of data terminal, 8031 single-chip microcomputer address ends connect decoder U with above-mentioned component address end is parallel respectively by address bus ₁₀Three input end A, B, C connect decoder U with 8031 three-address end respectively ₁₀Output connect with the control end CS of A/D converter, the reading and writing end of 8031 single-chip microcomputers by NAND gate circuit oppositely output connect (as shown in Figure 3) with the LE control end of A/D converter; In control circuit, also be provided with the display module circuit U ₅With clock signal circuit U ₄Data terminal connects with A/D converter, 8031 single-chip data ends by data bus respectively; in instrument control circuit, also be provided with negative pressure holding circuit (as shown in Figure 5), each road power supply+5V ,+12V ,-12V exports pilot lamp display voltage taking alarm imbalance state by balanced amplifier LM393 respectively.

Advantage of the present utility model: circuit structure is simple, and test speed is fast, and function is complete, and the precision height connects with communication interface and to input to host computer, can finish the multichannel Distance Test.

Structure of the present utility model is provided by following examples and accompanying drawing.

Fig. 1 is a portable intelligent stray current tester overall block-diagram;

Fig. 2 is portable intelligent stray current tester simulation part electrical schematic diagram;

Fig. 3 is a portable intelligent stray current tester numerical portion electrical schematic diagram;

Fig. 4 is a portable intelligent stray current tester numerical portion electrical schematic diagram;

Fig. 5 is portable intelligent stray current tester negative pressure display principles figure.

Its circuit structure as shown in drawings, the used device of circuit: input amplifier C ₁, C ₂Be CA3140, C ₃, C ₄Be OP-07, logic switch is 4051, and sampling holder is LF398, CPU 8031, latch is 74LS373, and memory under program is 27128, and data memory is 62256, decoder is 74HC138, A/D converter is AD574A, and display apparatus module is EDM1602, and clock module is MC146818, the negative supply display amplifier is LM393, and Fig. 3 and Fig. 4 a, 2 of b join.

Its principle of work: entire circuit is linked by mimic channel and digital circuit, gets on two points of tens meters～hundreds of of underground pipeline rice and draws slotted line, joins with the input end of analog signal of stray current measuring instrument, is IN ₁, IN ₂End links to each other over the ground, when flowing through pipeline, stray current will on the pipeline of this tens meters～hundreds of rice, produce pressure drop, the current signal of instrument collection is sent into channel selector switch after amplifying, be input to sampling holder LF398 again, usually sampling holder is in the sampling following state, before starting A/D, LF398 is set to export hold mode, to guarantee the stable of input signal, voltage signal is finally delivered to A/D converter, and analog signal conversion is become digital signal, is handled by 8031 single-chip microcomputers again, its result exports on display, and stray current is measured.

Claims

1. portable intelligent stray current measuring instrument, the control circuit that it is characterized in that this measuring instrument is that digital circuit two parts of core are formed by mimic channel with 8031 single-chip microcomputers, wherein artificial circuit part is made up of input circuit, amplifying circuit, logic switching circuit, sampling hold circuit and analog conversion circuit, its connection is that the front is two tunnel input IN ₁, IN ₂, on the equipment from measurement point, each path secondary amplifies C ₁C ₃And C ₂C ₄Connect logic switch U respectively ₁Input end X ₀X ₁, the output of logic switch is connected to the input end of sampling holder LF398, and its output is connected to the input end from precision A/D converter AD574A; Digital circuit part is a core with 8031 single-chip microcomputers, and is made up of latch, memory under program, data memory and decoder, and its connection is the data terminal of 8031 single-chip microcomputers, by data bus respectively with latch U ₉, memory under program U ₈, data memory U ₇, U ₈Parallel connection of data terminal, 8031 single-chip microcomputer address ends connect decoder U with above-mentioned component address end is parallel respectively by address bus ₁₀Three input end A, B, C connect decoder U with 8031 three-address end respectively ₁₀Output connect with the control end CS of A/D converter, the reading and writing end of 8031 single-chip microcomputers by NAND gate circuit oppositely output connect with the LE control end of A/D converter.

2. by the described measuring instrument of claim 1, it is characterized in that in control circuit, also being provided with the display module circuit U ₅With clock signal circuit U ₄Data terminal connects with A/D converter, 8031 single-chip data ends by data bus respectively.

3. by the described measuring instrument of claim 1, it is characterized in that in control circuit, being provided with the negative pressure holding circuit, each road power supply+5V ,+12V ,-12V exports pilot lamp display voltage imbalance state taking alarm by balanced amplifier LM393 respectively.