CN2916587Y

CN2916587Y - Electrode resistance measuring and measured value recording and management apparatus for electromagnetic flow meter converter

Info

Publication number: CN2916587Y
Application number: CN 200620042961
Authority: CN
Inventors: 马博; 李兴化
Original assignee: PRIS INSTRUMENT (SHANGHAI) CO Ltd
Current assignee: Prais Instruments (Shanghai) Co., Ltd.
Priority date: 2006-06-20
Filing date: 2006-06-20
Publication date: 2007-06-27
Anticipated expiration: 2016-06-20

Abstract

The utility model discloses an electrode resistance measuring and value record management device of electromagnetic flow meter converter and relates to the technical field of electromagnetic measurement; the device comprises: a sensor electrode resistance measuring circuit, comprising a two symmetrical electrodes of the sensor in the tube and a front-embedded amplifier connected with the two symmetrical electrodes and tube separately. Measuring signals of the two symmetrical electrodes compare with a constant flow source and is delivered to the CPU through the front-embedded amplifier and A virgule D converter; a clock chip and a large capacity FRAM memorizer, connected with the CPU of the converter separately and used for recording and storing flow measuring values of the sensor by the time set by the CPU. The utility model is able to check the using status of the sensor electrode at real times so as to discover abnormal problems in time. The product can also manage measuring values.

Description

The electrode resistance of electromagnetic flowmeter converter is measured and measured value record management device

Technical field

The utility model relates to Techniques in Electromagnetic Measurement, and the electrode resistance that particularly relates to a kind of electromagnetic flowmeter converter is measured and measured value record management device technique.

Background technology

Electromagnetic flowmeter is the principle of work according to Faraday's electromagnetic induction law, is used for measuring the instrument of conducting liquid volumetric flow rate.Electromagnetic flowmeter is made up of electromagnetic flow transducer and electromagnetic flux converter, and connects demonstration, record, integrating, and regulation meter or computer network constitute Flow Measuring System.

Sensor is installed on the process pipe, and it is used for the flow velocity of conducting liquid (flow) is transformed into the induced potential signal linearly.Converter provides the exciting current in work magnetic field to sensor, and accepts its induced potential signal.Current signal unified, standard, voltage signal, frequency signal and digital communication signal are handled, amplify and be converted into to flow velocity (flow) signal.For indicating instrument, recorder, regulation meter and computer network are realized remote indication, record, integrating, control and the adjusting to flow.

Converter is by low frequency square wave (double frequency, high frequency) constant current source field circuit; Differential preamplifier; Main amplifier with low-pass filter; Synchronized sampling, holding circuit; The translation circuit of analog current output and frequency output and flow accumulation; One-chip computer CPU and peripheral memory, keyboard display driver, digital communication circuit; Subsidiary function is as status alert, blank pipe warning circuit; Power circuit etc.Element circuit is formed the formation measuring system.During the eighties to the nineties, the advanced technology (being exactly to have adopted top said time division multiplier to do calculation process) that some product of the future has adopted operation of analog quantity to combine with the digital quantity computing, since the nineties, converter generally enters the digital intellectualization epoch based on one-chip computer.

Fig. 1 is the intelligent converter system principle of work of Typical Digital type.Can see the basic hardware structure of converter.Although still bound analog device in the metering circuit among the figure, these only are the linear amplification for signal, are not the main bodys of measuring.Compare with early stage intelligent converter, circuit shown in the accompanying drawing 1 does not have the sample circuit and the integrating circuit of hardware, and converter is the digital operation based on software fully.

The utility model content

At the defective that exists in the above-mentioned prior art, technical problem to be solved in the utility model provides a kind of electrode of detecting sensor in real time behaviour in service, find that in time electrode is unusual, the measured value record is implemented the electrode resistance of the electromagnetic flowmeter converter of management and measured and measured value record management device.

In order to solve the problems of the technologies described above, the electrode resistance of a kind of electromagnetic flowmeter converter provided by the utility model is measured and measured value record management device, comprising:

One sensor electrode resistance measuring circuit, comprise sensor two symmetry electrodes in the conduit, the prime amplifier that connects two symmetry electrodes and pipe earth end respectively, the A/D converter that connects the prime amplifier output terminal, and the constant current source that connects two symmetry electrodes and pipe earth end respectively, the output terminal of A/D converter connects CPU; After the measuring-signal of two symmetry electrodes and the constant current source comparison, through prime amplifier and A/D converter input CPU;

Clock chip and high capacity FRAM storer connect the CPU of converter respectively, the time real time record that is used for setting by CPU, preserve the flow measurements of sensor on time.

Further, time of setting of described CPU is respectively to preserve once, enter after one day by preserving every day, enter after one month by preserving, enter in every month by each hour and preserves per year after 1 year.

Utilize the electrode resistance of the electromagnetic flowmeter converter that the utility model provides to measure and measured value record management device, owing to be provided with the metering circuit of direct survey sensor electrode resistance in the converter, not only can in measurement, often differentiate conductive fluid and whether be full of pipeline, whether contaminated, the covering of the electrode of detecting sensor in real time simultaneously, be corroded, whether test fluid electric conductivity changes, and sends the unusual information of electrode at any time; Owing to be provided with clock chip and high capacity FRAM in the converter, the time real time record of setting by CPU, preserve the flow measurements of sensor on time, just can in the FRAM storer, remain with the flow measurements of of that month each hour, per 4 hours electrode resistance value also has the front historical record value of a month every day, every month; The historical record that flow has been arranged can provide the reference numerical value relatively of the use traffic same period to the user; The historical record value that electrode resistance has been arranged can provide the information of reference data and maintenance for the reliability of user's use traffic meter.

Description of drawings

Fig. 1 is the block diagram of the intelligent converter of Typical Digital type in the prior art;

Fig. 2 is the block diagram of the intelligent converter of the utility model embodiment Typical Digital type;

Fig. 3 is the sensor electrode resistance measuring circuit block diagram of the utility model embodiment;

Fig. 4 is the timing diagram of flow signal and electrode resistance measured waveform among the utility model embodiment.

Embodiment

Below in conjunction with description of drawings embodiment of the present utility model is described in further detail, but present embodiment is not limited to the utility model, every employing analog structure of the present utility model and similar variation thereof all should be listed protection domain of the present utility model in.

As shown in Figure 2, the electrode resistance of a kind of electromagnetic flowmeter converter that the utility model embodiment is provided is measured and measured value record management device, adds the sensor electrode resistance measuring circuit in the intelligent converter of Typical Digital type; As shown in Figure 3, the sensor electrode resistance measuring circuit of described converter, comprise sensor two symmetry electrode A, B in the conduit, the prime amplifier that connects two symmetry electrode A, B and pipe earth end respectively, the A/D converter that connects the prime amplifier output terminal, and the constant current source that connects two symmetry electrode A, B and pipe earth end respectively, the output terminal of A/D converter connects CPU; The measuring-signal of two symmetry electrode A, B and constant current source relatively after, through prime amplifier and A/D converter input CPU.

The sequential relationship of flow signal and electrode resistance measured waveform as shown in Figure 4, wherein, T1 is the positive half cycle of flow signal, T2 is the negative half period of flow, t1 is the sampling time of positive half cycle flow signal, t2 is the sampling time of negative half period flow signal; T3 is the voltage that constant current source flows through electrode A convection cell resistance, and T4 is the voltage that constant current source flows through electrode B convection cell resistance, and t3 is the sampling time that positive half cycle electrode resistance is measured, and t4 is the sampling time that the negative half period electrode resistance is measured.CPU timesharing chronologically records the voltage signal of flow signal and electrode pair fluid.Because it is certain to flow through the electric current of resistance between the electrode pair fluid, so can measure flow and electrode resistance respectively.

As shown in Figure 2, the electrode resistance of the utility model embodiment electromagnetic flowmeter converter is measured and measured value record management device adds clock chip and high capacity FRAM storer in the intelligent converter of Typical Digital type, to measure flow value by the CPU setting preserved once by 1 hour, enter after one day and preserve by every day, enter after one month and preserved, enter after 1 year and preserve per year by every month.Simultaneously the electrode resistance value that detects was preserved once in per 4 hours, carry arrives the sky then, Month And Year is preserved.That is to say that remain with the flow measurements of of that month each hour in the FRAM storer, per 4 hours electrode resistance value also has the front historical record value of a month every day, every month.

The prime amplifier that uses among the utility model embodiment, A/D converter, clock chip, high capacity FRAM storer and cpu chip all are the prior art that those skilled in the art were familiar with, and this instructions is not just done to understand specifically further.

In the utility model embodiment, use the electrode resistance testing circuit of constant current source method, the detecting electrode resistance value is not subjected to the influence of signal wire cable length with interior measurement at 200m linearly.The electrode abnormal alarm can pass through menu setting, is applicable to the fluid media (medium) of different conductivity.The blank pipe of software design is reported to the police and is fixed on more than the electrode resistance greater than minimum conductivity, does not need to be provided with high alarm setting.

Menu can be provided with the start time of historical record.Software can be selected the interval time of measurement data record.

Claims

1, a kind of electrode resistance of electromagnetic flowmeter converter is measured and measured value record management device, it is characterized in that, comprising:

One sensor electrode resistance measuring circuit, comprise sensor two symmetry electrodes in the conduit, the prime amplifier that connects two symmetry electrodes and pipe earth end respectively, the A/D converter that connects the prime amplifier output terminal, and the constant current source that connects two symmetry electrodes and pipe earth end respectively, the output terminal of A/D converter connects CPU; The measuring-signal of two symmetry electrodes and constant current source comparison are through prime amplifier and A/D converter input CPU;