CN202836867U - Pressure transmitter capable of trend extraction - Google Patents

Abstract

The utility model discloses a pressure transmitter capable of trend extraction. The pressure transmitter comprises a signal conditioning unit, a housing and a display module, wherein the signal conditioning unit is connected with the housing and packaged inside the housing; the display module is arranged outside the housing, connected with the signal conditioning unit and used for displaying parameters; and the signal conditioning unit comprises an information storage module and a trend extraction module. The information storage module is used for storing signals and system parameters; the trend extraction module is respectively connected with the information storage module and the display module, extracts pressure information stored by the information storage module, and obtains a pressure trend signal within a set time quantum via operation; and the display module displays the pressure trend signal extracted by the display module. According to the utility model, the trend extraction module extracts and operates pressure signals within a time quantum in the information storage module, thereby extracting data change trend within the time quantum, and being more helpful for pressure signal analysis.

Description

Pressure unit with trend abstraction function

Technical field

The utility model relates to a kind of pressure unit, particularly a kind of pressure unit with trend abstraction function.

Background technology

Pressure unit is used very extensive in fields such as oil, coking, steel mill and power plant.Along with the raising of the automaticities such as the digitized progress in oil field and coke-oven plant, steel mill, reliability, accuracy and the intelligent characteristic of pressure unit are had higher requirement.In some special occasion, need the data of testing under the at the scene non-volatile recording, and will extract the variation tendency of 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 party's nature of law is to utilize the characteristic time scale of signal to obtain intrinsic fluctuation mode, thereby reaches the purpose 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 that extracts is more true and reliable, the marginal portion of signal particularly, can not cause the phenomenon that occurs low-frequency distortion owing to the reason of algorithm, in the currently used empirical mode decomposition method, its algorithm is complicated, calculated amount is large, operation efficiency is low, and the margin signal that extracts is true not, is not suitable for the requirement of embedded system.

The utility model content

In order to realize the trend abstraction function of pressure unit pressure signal, make it satisfy requirement under some test case, the utility model embodiment 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, be used for the demonstration of parameter, described signal condition unit comprises:

Information storage module is used for the storage of signal and systems parameter;

The trend extraction module, be connected respectively with described information storage module, display module, it extracts the pressure information that described information storage module is stored, and obtains the trend pressure signal that sets in the time period by computing, and described display module is shown the pressure trend signal that extracts.

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

The beneficial effect of the technical scheme that the utility model embodiment provides is:

Has the trend abstraction function.Integrated trend is extracted and the computing module function in the transmitter provided by the utility model, can extract the general trend of a period of time internal pressure variation and shown by display unit, and the handled easily personnel check at the scene;

Description of drawings

In order to be illustrated more clearly in the technical scheme among the utility model embodiment, the accompanying drawing of required use was done to introduce simply during the below will describe embodiment, apparently, accompanying drawing in the following describes only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.

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

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

Fig. 3 is signal pre-processing module schematic diagram provided by the utility model;

Fig. 4 is the power principle figure of signal processing module provided by the utility model;

Fig. 5 is signal amplification module schematic diagram provided by the utility model;

Fig. 6 is signal acquisition module schematic diagram provided by the utility model;

Fig. 7 is information storage module schematic diagram provided by the utility model;

Fig. 8 is display module schematic diagram provided by the utility model;

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

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

Embodiment

For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing the utility model embodiment is described in further detail.

A kind of pressure unit with the extraction of trend function that the utility model proposes, its structural representation is seen Fig. 1, be comprised of threaded and impulse connecting pipe 1, pressure-sensitive core body 2, signal condition unit 3 and housing 4 sealing ring, what wherein the pressure-sensitive core body adopted is that sputtered film technique is made.Described signal condition module comprises signal condition hardware circuit and signal condition algorithm, and this module and pressure-sensitive core body finally are encapsulated in the housing, and impulse connecting pipe 1 is connected with pipeline thread.

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

Because the pressure-sensitive core body adopted Sputtering Thinfilm Technology, therefore synthesis precision of the present utility model, 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: less than 0.002%FS/ ℃;

Zero point time drift: less than 0.1%FS/;

Gaging pressure: 0.5MPa～220MPa;

Operating temperature range :-40 ℃～80 ℃;

Arm resistance: 1～3K Ω;

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

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

The signal condition unit comprises signal pre-processing module, signal amplification module, signal acquisition module, information storage module, trend extraction module and display module.Wherein signal pre-processing module has adopted the mode of low-pass filtering elimination high frequency interference to realize that adopt RC passive filtering method when concrete operations, the chip that the 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 TMS320VC33, as shown in Figure 3; LCD MODULE adopts NH12864, can Chinese display and figure, as shown in Figure 8.

Storage for the important parameter of pressure unit own, for meeting the standard of zero tolerance, systematic parameter (such as calibration coefficient, pressure zero value, display cycle data, communications parameter etc.) is copied into identical at least three parts, is stored in the different data storage area of FLASH chip.When system need to use the parameter of storage, system will all take out the corresponding parameter in each data storage area, adopt the voting method to produce effective application parameter, do like this data failure that can prevent that the FLASH storer from storing under some fortuitous events, improved the reliability of Parameter storage, the voting method here specifically refers to: whole when identical when the systematic parameter in each data storage area that extracts, the system parameter data that each data storage area is stored is effective; If the systematic parameter that each data storage area of systematic parameter and other that wherein exists a data memory block to store is stored is different, judge that then the system parameter data of storing lost efficacy.

Pressure unit of the present utility model has the pressure trend abstraction function, the operator can set the cycle of save data, the shortlyest can be set as one day, the longlyest can be set to 1 year, exceed the mode automatic replacement of the data first-in first-out in 1 year.The data empirical mode decomposition algorithm of preserving is carried out computing, and system's automatic lifting takes out low frequency signal, namely should interior pressure trend of cycle.

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

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

x(t)-m ₁=C ₁

Theoretically, C1 is the first rank intrinsic mode function, then, deducts C1 from original signal, gets final product the approximation component R1 of picked up signal.

x(t)-C ₁=R ₁

Process above R1 repeated just can obtain the second-order intrinsic mode function, by each the screening of empirical mode decomposition algorithm to signal, and a plurality of intrinsic mode functions and an approximation component Rn that just can picked up 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 utility model 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 has reduced calculated amount greatly, and can guarantee the precision calculated, guarantee the accuracy that data are processed.

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

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

T represents the time span of signal, h in the formula _{1 (k-1)}(t) and h _1k(t) be k and k-1 the selection result in screening basic model component process, s _dRepresentative value generally be taken between 0.2～0.3.

The utility model has adopted the another kind of standard close with traditional standard, this standard is selected global property and the local characteristics that considers signal in the process at " sieve " to signal, with respect to original mode screening stopping criterion, mode screening stopping criterion provided by the utility model 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) calculate the amplitude ratio

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

Wherein, U _kBe the coenvelope value of signal in the k time screening, L _kBe corresponding lower envelope value, the local mean value of coenvelope and lower envelope is denoted as m _k

(3) calculate A _rAll are greater than P in the sequence ₁The data amount check of value is if the value that the summation of this number obtains divided by total number of sequence is less than P ₂, and A _rAny one value is all less than P in the sequence ₃, then the decomposition of this intrinsic mode function finishes.

When processing the edge effect of empirical mode decomposition algorithm, employing waits the slope continuation method, its ultimate principle is to utilize 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 the extreme point that obtains by continuation and original signal basically identical, so that the signal of the trend signal, particularly edge that extract is more authentic and valid.Max0 among Fig. 9, max1 etc. are corresponding maximum point, and min0, min1 etc. is corresponding minimum point, the trend extreme point that max0, min0 obtain for the slope continuation such as passing through.As can be seen from Figure 9, the slope k 1 that calculates by max1 and min2 is moved to the end points place, and will guarantee first extreme point max0 of calculating and the time interval Δ t of max1 _MaxEquate with the time interval of max2 with max1.On the basis that calculates max0, go out corresponding minimal value according to top same computing method continuation.

Pressure unit of the present utility model has crystal display, namely be provided with display module at housing, can be presented at the pressure trend signal that extracts in a period of time on the LCD screen, handled easily personnel check, and pressure unit has the digital interface (RS485) of communicating by letter with the host computer realization, can upload real-time force value and trend pressure signal with the form of digital signal.

Need to prove: the device of the pressure unit that above-described embodiment provides is when the trend of extraction pressure signal, only the division with above-mentioned each functional module is illustrated, in the practical application, can as required the above-mentioned functions distribution be finished by different functional modules, the inner structure of the equipment of being about to is divided into different functional modules, to finish all or part of function described above, repeat no more here.

Above-mentioned the utility model embodiment sequence number does not represent the quality of embodiment just to description.

All or part of step among the utility model embodiment can utilize software to realize, corresponding software program can be stored in the storage medium that can read, such as CD or hard disk etc.

The above only is preferred embodiment of the present utility model, and is in order to limit the utility model, not all within spirit of the present utility model and principle, any modification of doing, is equal to replacement, improvement etc., all should be included within the protection domain of the present utility model.

Claims (2)

1. 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, be used for the demonstration of parameter, it is characterized in that described signal condition unit comprises:

Information storage module is used for the storage of signal and systems parameter, and it is provided with three data storage areas that are used for preventing the system data inefficacy at least, and the systematic parameter of described pressure unit is stored in respectively in each data storage area;

The trend extraction module, be connected respectively with described information storage module, display module, it extracts the pressure information that described information storage module is stored, and obtain the trend pressure signal that sets in the time period, described display module receives the pressure trend signal that described trend extraction module extracts, and it is shown.

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

Also be provided with the RS485 digital interface that realizes communication with host computer on the housing of described transmitter, be used for realizing uploading in real time of force value and trend pressure signal.

Images