CN103292951B - Pressure transformer with trend extracting function - Google Patents

Abstract

The invention discloses a pressure transformer with a trend extracting function. The pressure transformer comprises a signal conditioning unit, a casing and a display module, wherein the signal conditioning unit is connected and packed in the casing, and the display module is arranged on the outer side of the casing, further connected with the signal conditioning unit and used for displaying parameters. The signal conditioning unit comprises an information storing module and a trend extracting module, wherein the information storing module is used for storing signals and system parameters, the trend extracting module is respectively connected with the information storing module and the display module, the trend extracting module can extract pressure information stored in the information storing module, the trend extracting module can acquire trend pressure signals in a set time quantum through operation, and the display module can display the extracted trend signals. The pressure transformer uses the trend extracting module to extract and operate pressure signals in a period in the information storing module, so that data change trend in the period can be extracted, and analysis on pressure signals is facilitated.

Description

There is the pressure unit of trend abstraction function

Technical field

The present invention relates to a kind of pressure unit, particularly a kind of pressure unit with trend abstraction function.

Background technology

Pressure unit in field application such as oil, coking, steel mill and power plant widely.Along with the raising of the digitized progress in oil field and the automaticity such as coke-oven plant, steel mill, the reliability of pressure unit, accuracy and intelligent characteristic are had higher requirement.In the occasion that some is special, the data of testing under needing non-volatile recording at the scene, and the variation tendency that will extract data within a period of time, be more conducive to the analysis to pressure signal.

The method of empirical mode decomposition is a kind of new low frequency signal extracting method, and the essence of the method utilizes the characteristic time scale of signal to obtain intrinsic fluctuation mode, thus reach the object of decomposition data.Compare with traditional low frequency signal extracting method, such as low-pass filtering method etc., the advantage that the method has is that the low frequency signal extracted is more true and reliable, the particularly marginal portion of signal, the reason due to algorithm can not be caused to occur the phenomenon of low-frequency distortion, and in currently used empirical mode decomposition method, its algorithm is complicated, calculated amount is large, operation efficiency is low, and the margin signal extracted is true not, is not suitable for the requirement of embedded system.

Summary of the invention

In order to realize the trend abstraction function of pressure unit pressure signal, the requirement under making it meet some test case, embodiments provides a kind of pressure unit with trend abstraction function.

Described technical scheme is as follows: a kind of pressure unit with trend abstraction function, comprise signal condition unit, housing and display module, described signal condition unit connection encapsulation is in described housing, described display module is arranged at the outside of described housing and is connected with described signal condition unit, for the display of parameter, described signal condition unit comprises:

Information storage module, for the storage of signal and systems parameter; Described information storage module is provided with at least three data storage areas for preventing system data to lose efficacy, the systematic parameter of described pressure unit is stored in each data storage area respectively, when system needs to use the systematic parameter stored, systematic parameter corresponding in each data storage area is extracted, and the ineffectiveness of systematic parameter is judged;

Trend abstraction module, be connected respectively with described information storage module, display module, it extracts the pressure information that described information storage module stores, and obtains the trend pressure signal in the set time period by computing, and extracted pressure trend signal is shown by described display module.

Ineffectiveness judgement is carried out to the systematic parameter stored in data storage area described in each, specifically comprises,

When extract each data storage area in systematic parameter whole identical time, the system parameter data that each data storage area stores is effective; The systematic parameter that data storage area stores if wherein exist is different from the systematic parameter that other each data storage area stores, then judge the system parameter data inefficacy stored.

Further, described trend abstraction module is embedded with empirical mode decomposition algorithm, pressure information in described information storage module carries out obtaining the pressure trend signal in the set time period after computing through empirical mode decomposition algorithm, and the calculation procedure of the mode screening stopping criterion of wherein said empirical mode decomposition algorithm is as follows:

Step one: setting stops parameter P ₁, P ₂, P ₃numerical value;

Step 2: calculate Amplitude Ration

$A_r=\frac{\left|m_k\right|}{|U_k-L_k|}$

Wherein, U _kfor the coenvelope value of kth time sieve selected signal, L _kfor corresponding lower envelope value, m _kfor the local mean value of coenvelope and lower envelope;

Step 3: calculate A _rallly in sequence be greater than P ₁the data amount check of value, if the summation of this number and A _rthe ratio of total number of sequence is less than P ₂, and A _rin sequence, any one value is all less than P ₃, then the decomposition of this intrinsic mode function terminates.

Preferably, the slope continuation methods such as the edge effect employing in described empirical mode decomposition algorithm, concrete grammar is:

Utilize the pressure signal of coenvelope line and lower envelope line edge to try to achieve slope K, and obtained slope K is moved to the extreme point of end; There is according to two neighboring pole value point on same envelope the time point of the principle deterministic trend extreme point in the identical time interval; Namely the trend extreme point on trend time point is obtained by extension slope K line.

Further, the housing of described transmitter is also provided with the RS485 digital interface realizing communication with host computer, for realizing uploading in real time of force value and trend pressure signal.

The beneficial effect of the technical scheme that the embodiment of the present invention provides is:

(1) there is trend abstraction function.Be integrated with trend abstraction and computing module function in transmitter provided by the present invention, the general trend of pressure change in a period of time can be extracted and shown by display unit, handled easily personnel on site check;

(2) have employed low frequency Processing Algorithm.The method that the process of low frequency signal be have employed to empirical mode decomposition realizes, and improves the stopping criterion of this algorithm, improves operation efficiency, decreases calculated amount, makes it the requirement that more can adapt to embedded system;

(3) edge effect of empirical mode decomposition algorithm is improved.Employing waits slope continuation method to take full advantage of the tendency information of original signal, makes the trend of trend extreme point and the original signal obtained by continuation basically identical, makes the signal of the trend signal, particularly edge extracted more authentic and valid.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is pressure unit general structure cross-sectional schematic provided by the present invention;

Fig. 2 is the distribution schematic diagram of 4 resistance on induction chip in Fig. 1;

Fig. 3 is signal pre-processing module schematic diagram provided by the present invention;

Fig. 4 is the power principle figure of signal processing module provided by the present invention;

Fig. 5 is signal amplification module schematic diagram provided by the present invention;

Fig. 6 is signal acquisition module schematic diagram provided by the present invention;

Fig. 7 is information storage module schematic diagram provided by the present invention;

Fig. 8 is display module schematic diagram provided by the present invention;

Fig. 9 is for waiting slope continuation technical schematic diagram;

In figure: 1-housing; 2-signal condition unit; 3-pressure-sensitive chip; 4-impulse connecting pipe.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

A kind of pressure unit that there is trend function and extract that the present invention proposes, its structural representation is shown in Fig. 1, be made up of the impulse connecting pipe 1 of threaded and sealing ring, pressure-sensitive core body 2, signal condition unit 3 and housing 4, what wherein pressure-sensitive core body adopted is that sputtered film technique is made.Described Signal-regulated kinase comprises signal condition hardware circuit and signal condition algorithm, this module and pressure-sensitive core body finally in the housing packed, impulse connecting pipe 1 is connected with pipeline thread.

Pressure-sensitive core body have employed sputtering method, selects 17-4PH stainless steel as the basic material of pressure containing disk, and grind and after polishing, sputter insulation course and alloy-layer thereon, recycling photoetching and etching are made.The core surface prepared is integrated with 4 resistance, as shown in Figure 2, is in the maximum distortion district of pressure containing disk, by photoetching process, they is formed resistance bridge, pressure signal is converted into bridge road output voltage signal.

Because pressure-sensitive core body have employed Sputtering Thinfilm Technology, therefore synthesis precision of the present invention, zero temperature, temperature control are all very superior, and long-time stability are good, and design parameter is as follows:

Synthesis precision: 0.05 ~ 0.2 grade;

Zero temperature drift: be less than 0.002%FS/ DEG C;

Zero crossing time drifts about: be less than 0.1%FS/;

Measure pressure: 0.5MPa ~ 220MPa;

Operating temperature range :-40 DEG C ~ 80 DEG C;

Arm resistance: 1 ~ 3K Ω;

Between the viewing area of pressure trend: 1-365 days;

Output form: digital output (RS485) or 4 ~ 20mA.

Signal condition unit comprises signal pre-processing module, signal amplification module, signal acquisition module, information storage module, trend abstraction module and display module.Wherein signal pre-processing module have employed low-pass filtering and eliminates the mode of high frequency interference and realize, and adopt RC passive filtering method when concrete operations, the chip that signal amplification module adopts is LM324, as shown in Figure 5; The chip that signal acquisition module adopts is Max125, as shown in Figure 6; That information storage module adopts is FLASH chip SST39VF400B8; As shown in Figure 7, signal pre-processing module adopts digital signal processing chip TMS 320VC33, as shown in Figure 3; LCD MODULE adopts NH12864, can Chinese display and figure, as shown in Figure 8.

For the storage of the important parameter of pressure unit own, for meeting the standard of zero tolerance, systematic parameter (as calibration coefficient, pressure zero value, display cycle data, communications parameter etc.) is copied at least identical three parts, is stored in the different data storage area of FLASH chip.When system needs to use the parameter stored, corresponding parameter in each data storage area will all be taken out by system, voting method is adopted to produce effective application parameter, do the data failure that can prevent FLASH memory from storing under some fortuitous events like this, improve the reliability that parameter stores, here voting method specifically refers to: when extract each data storage area in systematic parameter whole identical time, the system parameter data that each data storage area stores is effective; The systematic parameter that data storage area stores if wherein exist is different from the systematic parameter that other each data storage area stores, then judge the system parameter data inefficacy stored.

Pressure unit of the present invention has pressure trend abstraction function, and operator can set preserving cycle of data, the shortlyest can be set as one day, the longlyest can be set to 1 year, and the mode exceeding the data acquisition first-in first-out of a year is replaced automatically.Carry out computing to the data acquisition empirical mode decomposition algorithm preserved, system extracts low frequency signal automatically, the pressure trend namely in this cycle.

The ultimate principle of empirical mode decomposition is wherein as follows:

First find maximum value and the minimal value of signal, by 3 spline-fittings, thus obtain coenvelope curve and the lower enveloping curve of signal, lower enveloping curve mean value to a point in calculating, thus obtain a mean value curve m1, if analytic signal is x (t), then

x(t)-m ₁＝C ₁

Theoretically, C1 is the first rank intrinsic mode function, then, from original signal, deducts C1, can obtain the approximation component R1 of signal.

x(t)-C ₁＝R ₁

To the process that R1 repeats above, just can obtain second-order intrinsic mode function, by each the screening of empirical mode decomposition algorithm to signal, just can obtain multiple intrinsic mode function and an approximation component Rn of signal, thus signal can be expressed from the next:

$x\left(t\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i+R_n$

The present invention rule of thumb mode decomposition algorithm carries out the data operation of pressure signal, by changing traditional mode screening stopping criterion, the standard of employing and phase adjust signal, substantially reduces calculated amount, and the precision calculated can be ensured, ensure the accuracy of data processing.

The mode screening stopping criterion that tradition adopts is as follows:

$s_d=\underset{t=0}{\overset{T}{\mathrm{\Σ}}}\left[\frac{{\left|(h_{1(k-1)}\left(t\right)-h_{1k}\left(t\right))\right|}^2}{h_{1(k-1)}^2\left(t\right)}\right]$

In formula, T represents the time span of signal, h _{1 (k-1)}(t) and h _1kt () is kth and kth-1 the selection result in screening Intrinsic mode functions process, s _drepresentative value be generally taken between 0.2 ~ 0.3.

Present invention employs the another kind of standard close with traditional standard, this standard is selecting in process the global property and local characteristics that consider signal to " sieve " of signal, relative to original mode screening stopping criterion, mode screening stopping criterion provided by the present invention is more reasonable in realization.

Its mode screening stopping criterion calculation procedure is exemplified below:

(1) setting stops parameter P ₁, P ₂, P ₃, P ₁get 0.025, P ₂get 0.5, P ₃get 0.05.

(2) Amplitude Ration is calculated

$A_r=\frac{\left|m_k\right|}{|U_k-L_k|}$

Wherein, U _kfor the coenvelope value of kth time sieve selected signal, L _kfor corresponding lower envelope value, the local mean value of coenvelope and lower envelope is denoted as m _k;

(3) A is calculated _rallly in sequence be greater than P ₁the data amount check of value, if the value that the summation of this number obtains divided by total number of sequence is less than P ₂, and A _rin sequence, any one value is all less than P ₃, then the decomposition of this intrinsic mode function terminates.

When processing the edge effect of empirical mode decomposition algorithm, employing waits slope continuation method, its ultimate principle utilizes the signal of edge to obtain slope, then utilization waits the method for slope continuation to try to achieve corresponding extreme point, this continuation method takes full advantage of the tendency information of original signal, make the trend of extreme point and the original signal obtained by continuation basically identical, make the signal of the trend signal, particularly edge extracted more authentic and valid.Max0, max1 etc. in Fig. 9 are corresponding maximum point, and min0, min1 etc. are corresponding minimum point, and max0, min0 such as to pass through at the trend extreme point that slope continuation obtains.As can be seen from Figure 9, the slope k 1 calculated by max1 and min2 is moved to end points place, and will ensure the time interval Δ t of first extreme point max0 and max1 calculated _maxequal with the time interval of max1 and max2.On the basis calculating max0, go out corresponding minimal value according to same computing method continuation above.

Pressure unit of the present invention has crystal display, namely on housing, display module is provided with, can the pressure trend Signal aspects extracted in a period of time in LCD screen, handled easily personnel check, and pressure unit has the digital interface (RS485) realizing with host computer communicating, and real-time force value and trend pressure signal can be uploaded with the form of digital signal.

It should be noted that: the device of the pressure unit that above-described embodiment provides is when extracting trend pressure signal, only be illustrated with the division of above-mentioned each functional module, in practical application, can distribute as required and by above-mentioned functions and be completed by different functional modules, inner structure by equipment is divided into different functional modules, to complete all or part of function described above, repeat no more here.

The invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

All or part of step in the embodiment of the present invention, can utilize software simulating, and corresponding software program can be stored in the storage medium that can read, as CD or hard disk etc.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. one kind has the pressure unit of trend abstraction function, comprise signal condition unit, housing and display module, described signal condition unit connection encapsulation is in described housing, described display module is arranged at the outside of described housing and is connected with described signal condition unit, for the display of parameter, it is characterized in that, described signal condition unit comprises:

Information storage module, for the storage of signal and systems parameter, it is at least provided with three data storage areas for preventing system data to lose efficacy, the systematic parameter of described pressure unit is stored in each data storage area respectively, when system needs to use the systematic parameter stored, systematic parameter corresponding in each data storage area is extracted, and the ineffectiveness of systematic parameter is judged;

Trend abstraction module, be connected respectively with described information storage module, display module, it extracts the pressure information that described information storage module stores, and obtain the trend pressure signal in the set time period by computing, described display module receives the pressure trend signal that described trend abstraction module is extracted, and is shown;

Described trend abstraction module is embedded with empirical mode decomposition algorithm, pressure information in described information storage module carries out obtaining the pressure trend signal in the set time period after computing through empirical mode decomposition algorithm, and the calculation procedure of the mode screening stopping criterion of wherein said empirical mode decomposition algorithm is as follows:

Step one: setting stops parameter P ₁, P ₂, P ₃numerical value;

Step 2: calculate Amplitude Ration

$A_r=\frac{\left|m_k\right|}{|U_k-L_k|}$

Wherein, U _kfor the coenvelope value of kth time sieve selected signal, L _kfor corresponding lower envelope value, m _kfor the local mean value of coenvelope and lower envelope;

Step 3: calculate A _rallly in sequence be greater than P ₁the data amount check of value, if the summation of this number and A _rthe ratio of total number of sequence is less than P ₂, and A _rin sequence, any one value is all less than P ₃, then the decomposition of this intrinsic mode function terminates.

2. pressure unit according to claim 1, is characterized in that, it is characterized in that,

Ineffectiveness judgement is carried out to the systematic parameter stored in data storage area described in each, specifically comprises:

When extract each data storage area in systematic parameter whole identical time, the system parameter data that each data storage area stores is effective; The systematic parameter that data storage area stores if wherein exist is different from the systematic parameter that other each data storage area stores, then judge the system parameter data inefficacy stored.

3. pressure unit according to claim 1, is characterized in that,

The slope continuation methods such as the edge effect employing in described empirical mode decomposition algorithm, concrete grammar is:

Utilize the pressure signal of coenvelope line and lower envelope line edge to try to achieve slope K, and obtained slope K is moved to the extreme point of end; There is according to two neighboring pole value point on same envelope the time point of the principle deterministic trend extreme point in the identical time interval; Namely the trend extreme point on trend time point is obtained by extension slope K line.

4., according to the arbitrary described pressure unit of claim 1-3, it is characterized in that,

The housing of described transmitter is also provided with the RS485 digital interface realizing communication with host computer, for realizing uploading in real time of force value and trend pressure signal.