CN104344811B - A kind of gas chamber piston gradient on-line detecting system and method - Google Patents

Abstract

The present invention provides a kind of gas chamber piston gradient on-line detecting system, including the double-shaft tilt angle sensor connected by RS485 bus and transducer；Transducer accesses existing control system by the way of DP cable is with Profibus DP slave station；Transducer includes that the UART being sequentially connected with turns RS485 electrical level transferring chip, microprocessor, DP slave station protocol process chip and DP bus physical interface chip, and microprocessor calculates gas chamber piston incline direction angle for the data gathered according to double-shaft tilt angle sensor.Present system uses the transducer of independent research, in the converter the data collected are processed, existing control system is accessed again in the way of Profibus DP slave station, unified interface on hardware, the convenient control system accessing various brands, present system forward data almost without doing any programing work in the controls, is mainly shown by user, improves compatibility.

Description

A kind of gas chamber piston gradient on-line detecting system and method

Technical field

The invention belongs to gas chamber piston condition monitoring field in metallurgy industry, be specially a kind of gas chamber piston and incline Gradient on-line detecting system and method.

Background technology

Along with the fast development of steel industry, smelter is more and more heavier to the comprehensive utilization producing coal gas in smelting process Depending on, the most large-scale gas chamber obtains increasing extensively application in smelter.Piston is as particularly important in gas chamber Parts, its operation is the most normally particularly important for gas chamber.

Time properly functioning, piston moves up and down along with the inflation/deflation of gas chamber.Owing to not having between piston and whole cabinet Any being rigidly connected, be only to rely on top wire rope to make it balance, and piston weighs a few kiloton, it is mainly by coal gas in cabinet Pressure supported, therefore piston may produce a certain degree of inclination in running, when reaching to a certain degree, It is possible to coal gas overvoltage or leakage in piston clamp rail, cabinet can occur, for rubber diaphragm sealed gas chamber it is also possible to tear Rubber membrane, causes heavy losses.Therefore, in gas chamber running, the strict running status detecting piston is needed.

For piston running status, traditional detection mode is by differential pressure transmitter measure setup oil around piston Tank or the oil level change carried in oil duct calculate the gradient of piston.Along with the inclination of piston, the liquid level in oil tank around Also can change therewith, after measuring, the liquid level of these three or four points can calculate the gradient of piston.Although this survey Amount mode precision can meet requirement, but cost of investment is high, construction bothers and later maintenance workload is big.

Summary of the invention

The technical problem to be solved in the present invention is: provide a kind of gas chamber piston gradient on-line detecting system and method, The precision of gradient in on-line checking piston running can be improved, and access use in the way of Profibus-DP slave station The existing control system in family, low cost, compatibility are strong.

The present invention solves that the technical scheme that above-mentioned technical problem is taked is: a kind of gas chamber piston gradient is examined online Examining system, it is characterised in that: it includes double-shaft tilt angle sensor and the transducer connected by RS485 bus；Double-shaft tilt angle passes Sensor for detecting the inclination angle in gas chamber piston plane two vertical direction, transducer by DP cable with Profibus-DP from The mode stood accesses existing control system；

Described transducer includes that the UART being sequentially connected with turns RS485 electrical level transferring chip, microprocessor, DP slave station protocol Processing chip and DP bus physical interface chip, microprocessor calculates coal gas for the data gathered according to double-shaft tilt angle sensor Cabinet tilting of the piston angle and direction.

By said system, described double-shaft tilt angle sensor is arranged in Flameproof box, and Flameproof box is arranged on piston edge On piston dam, keep relative level with the piston flat surface after leveling.

A kind of gas chamber piston gradient utilizing above-mentioned gas chamber piston gradient on-line detecting system to realize is examined online Survey method, it is characterised in that: it comprises the following steps:

S1, definition X, Y-axis are orthogonal coordinate axes in piston flat surface, the measurement direction of double-shaft tilt angle sensor and X, The direction of Y is parallel to each other, and the former horizontal plane of piston is primary plane β, and the piston center of circle is X, the intersection point O of Y-axis, and piston radius is R, piston Along straight line MN run-off the straight, the plane after inclination is γ, in plane γ, if B point is piston flat surface the highest after tilting Point, the vertical dimension between it and plane β is H, and ∠ BOB₁=θ, then θ is X-axis forward and tilt peak direction along inverse The incline direction of conterclockwise angle, i.e. piston；OB₁、OB₂Radius in X, Y-axis, then its angle ∠ after being respectively B₁OB₂=90 °, it is a ' that obliquity sensor records X-direction top rade, and Y direction top rade is b '；

S2, the initial data that collects uses following algorithm be filtered processing:

Y_k=(1-j) * X_k+j*Y_k-1(1),

In formula (1), j is filter factor, its span between 0～1, X_kFor current sample values, Y_k-1For the last time Filter result, Y_kFor present filter result；

The X-direction top rade a ' recorded and Y direction top rade b ' is filtered respectively through formula (1), obtains Filtered X-direction top rade a and filtered Y direction top rade b；

S3, it is calculated following parameter:

$H=R\sqrt{{\sin }^{2}a+{\sin }^{2}b}$

$\mathrm{\θ}=\arctan \left(\frac{\sin b}{\sin a}\right)$

In formula,For the angle between plane γ after primary plane β and inclination；

S4, according to X, Y-axis piston flat surface is divided into four quadrants,

1) if a>0, b>0, then it represents that piston peak at I quadrant, 0 °<θ<90 °；

2) if a<0, b>0, then it represents that piston peak at ii quadrant, 90 °<θ<180 °；

3) if a < 0, b < 0, then it represents that piston peak at ii I quadrant, 180 ° < θ < 270 °；

4) if a>0, b<0, then it represents that piston peak at iv quadrant, 270 °<θ<360 °；

5) if a=0, b > 0, then it represents that piston along Y-axis positive direction tilt, θ=90 °；

6) if a=0, b < 0, then it represents that piston along Y-axis negative direction tilt, θ=270 °；

7) if b=0, a > 0, then it represents that piston along X-axis positive direction tilt, θ=0 °；

8) if b=0, a < 0, then it represents that piston along X-axis negative direction tilt, θ=180 °；

9) if a=0, b=0, then it represents that piston is horizontal, without tilt.

The invention have the benefit that

1, present system uses the transducer of independent research, processes the data collected in the converter, then In the way of Profibus-DP slave station, access existing control system, on hardware, first unified interface, facilitate present system Accessing PLC or the DCS control system of various brand, secondly user is almost without doing any extra programming work in PLC or DCS Make, only need in PLC or DCS by present system configuration to former control system, and native system uploaded data show in HMI , improve compatible and convenient and reliable.

2, initial data is first filtered processing by the inventive method, then uses specific algorithm to calculate, it is possible to disappear Except interference signal, improve computational accuracy.

Accompanying drawing explanation

Fig. 1 is hardware frame figure.

Fig. 2 is the hardware circuit diagram of transducer in Fig. 1.

Fig. 3 is inclination angle algorithm principle figure.

Fig. 4 is X, Y-direction original angle signal graph.

Fig. 5 is the X after signal processing, Y-signal figure.

Fig. 6 is to the angle of inclination figure calculated before and after original data processing.

Fig. 7 is sensor in-site installation schematic diagram.

In figure: 1-piston, 2-double-shaft tilt angle sensor, 3-Flameproof box, 4-1 column.

Detailed description of the invention

Below in conjunction with instantiation, the present invention will be further described.

The present invention provides a kind of gas chamber piston gradient on-line detecting system, as it is shown in figure 1, it includes passing through RS485 The double-shaft tilt angle sensor of bus connection and transducer；Double-shaft tilt angle sensor is used for detecting gas chamber piston plane two Vertical Square Inclination angle upwards, transducer accesses existing control system by the way of DP cable is with Profibus-DP slave station；

Described transducer includes that the UART being sequentially connected with turns RS485 electrical level transferring chip, microprocessor, DP slave station protocol Processing chip and DP bus physical interface chip, microprocessor calculates coal gas for the data gathered according to double-shaft tilt angle sensor Cabinet tilting of the piston angle and direction.Double-shaft tilt angle sensor is the market universal product, and its precision is up to 0.004 °, and Width funtion is powered (DC9～36V).

Utilizing the inclination angle in high-precision dual-axis obliquity sensor on-line checking gas chamber piston plane two vertical direction, it is defeated Going out signal is RS485 signal, and signal accesses the transducer of independent research, and transducer has two effects: one is original according to two Dip angle signal calculates angle of inclination and the peak incline direction of whole piston area, and two are to provide Profibus-DP interface, Be equivalent to as a Profibus-DP slave station, whole detecting system is accessed user's control system, directly will finally calculate knot Fruit gives user.Do so several benefit: 1, by the nonstandard protocol conversion of sensor be the mark commonly used in industrial control field Quasi-Profibus-DP agreement, facilitates detecting system to access PLC or the DCS control system of various brands；2, user almost without PLC or DCS does any programing work, mainly will detecting system forward data be shown in HMI by PLC or DCS.

Transducer uses STM32 series A RM processor to use VPC3 special logical as MCU, Profibus-DP communication part News chip auxiliary, as in figure 2 it is shown, the present embodiment uses 32 Cortex-M3 core A RM chips of ST company STM32F103ZET6, as the MCU of whole system, uses the ADM2587 of ADI company to turn RS485 level conversion core as UART Sheet, uses the VPC3+C/S chip of profichip company to process chip as DP slave station protocol, uses the ADM2486 of ADI company As DP bus physical interface chip.RS485 interface chip ADM2587 and DP interface chip ADM2486 has isolation features, Thus ensure that the whole system capacity of resisting disturbance in industrial applications, improve the reliability of whole system.

Profibus-DP agreement is applied widely at present, and many equipment are all with DP interface, but its underlying protocol is non- The most complicated, if quite big by its difficulty of producer's self-developing of leaving, then Siemens takes the lead in being proposed a asic chip SPC3, Profichip company is proposed again function and the VPC3 of the completely compatible SPC3 of software afterwards, supplies relative to the 5V of SPC3 Electricity, VPC3 compatibility 5V/3.3V powers, and its power consumption is lower, is more suitable for current low-voltage power supply trend, and therefore we have selected The VPC3 chip of Profichip company is as the communication chip of transducer.

VPC3 follows PROFIBUS standard agreement, and user has only to understand PROFIBUS standard agreement related content and chip Technology contents can oneself coding, by control chip to realize the exploitation of slave station.

VPC3 Internal latches/register-bit in front 21 address locations (00H～15H), organizational parameter be positioned in RAM from The unit that 16H starts, user buffer region is positioned at the unit started from 40H.Mode register 0,1,2 and status register, Interrupt control register, house dog are all located at front 21 address locations.Buffer structure is write based on organizational parameter.This Outward, General Parameters arranges data (such as station address, device id etc.) and state shows that (such as general controls order etc.) also stores At these unit.Mode register 0 and depositor 2 must carry out assignment under off-line state, once power on, cannot revise. Some of mode register 1 controls parameter and must modify in application process.

Preferably, described double-shaft tilt angle sensor is arranged in Flameproof box, and Flameproof box is arranged on the piston of piston edge On dam, keep relative level with the piston flat surface after leveling.

According to national regulations, gas chamber piston upper area is 1st district, and double-shaft tilt angle sensor is not intrinsic safety type instrument Table, it is therefore desirable to double-shaft tilt angle sensor is loaded and has in the Flameproof box of flame proof function, site operation personnel only need to consider every The installation of quick-fried case.Flameproof box must be installed after piston flat surface leveling is checked and accepted again, and mounting means (is above opened for being horizontally mounted Lid), it is proposed that it is arranged on by the piston dam of the piston edge of cement casting, does with the signal preventing piston shake from causing Disturb, must assure that the piston flat surface after Flameproof box and leveling keeps relative level simultaneously.It should be noted that and pass through owing to being difficult to The mode of machinery adjusts Flameproof box and reaches abswolute level, and native system provides relative zero function to carry out software correction.

As it is shown in fig. 7, wherein slash region representation piston dam on piston 1 limit, Flameproof box 3 is arranged on piston dam, Double-shaft tilt angle sensor 2 is arranged in Flameproof box 3, and Flameproof box 3 width need to (this figure be with No. 1 with certain root post of gas chamber Column 4 is illustrated) alignment.Defining the center of circle and pointing to column direction is X-axis forward, and tangential direction is Y-axis, and incline direction angle represents With X-axis forward angle in the counterclockwise direction, scope is 0～360 °.

Owing to double-shaft tilt angle sensor has feed cable and two cables of 485 communication cables, and the upper and lower stroke of piston is up to Tens meters, therefore two set cable collection devices need to be set at top land, prevent piston from twining mutually between each cable when moving up and down Around knotting.Cable collection device does not has power part, is only that the deadweight relying on cable is wound around, so from piston to gas chamber top This section of cable must use flexible cable just can be relatively easy to be wound in cable collection device.

A kind of gas chamber piston gradient utilizing above-mentioned gas chamber piston gradient on-line detecting system to realize is examined online Survey method, it comprises the following steps:

S1, definition X, Y-axis are orthogonal coordinate axes in piston flat surface, the measurement direction of double-shaft tilt angle sensor and X, The direction of Y is parallel to each other, and the former horizontal plane of piston is primary plane β, and the piston center of circle is X, the intersection point O of Y-axis, and piston radius is R, piston Along straight line MN run-off the straight, the plane after inclination is γ, in plane γ, if B point is piston flat surface the highest after tilting Point, the vertical dimension between it and plane β is H, and ∠ BOB₁=θ, then θ is X-axis forward and tilt peak direction along inverse The incline direction of conterclockwise angle, i.e. piston；OB₁、OB₂Radius in X, Y-axis, then its angle ∠ after being respectively B₁OB₂=90 °, it is a ' that obliquity sensor records X-direction top rade, and Y direction top rade is b '.

S2, the initial data that collects uses following algorithm be filtered processing:

Y_k=(1-j) * X_k+j*Y_k-1(1),

In formula (1), j is filter factor, its span between 0～1, X_kFor current sample values, Y_k-1For the last time Filter result, Y_kFor present filter result.

The X-direction top rade a ' recorded and Y direction top rade b ' is filtered respectively through formula (1), obtains Filtered X-direction top rade a and filtered Y direction top rade b；

S3, it is calculated following parameter:

$H=R\sqrt{{\sin }^{2}a+{\sin }^{2}b}$

$\mathrm{\&theta;}=\arctan \left(\frac{\sin b}{\sin a}\right)$

In formula,For the angle between plane γ after primary plane β and inclination；

S4, according to X, Y-axis piston flat surface is divided into four quadrants,

1) if a>0, b>0, then it represents that piston peak at I quadrant, 0 °<θ<90 °；

2) if a<0, b>0, then it represents that piston peak at ii quadrant, 90 °<θ<180 °；

3) if a < 0, b < 0, then it represents that piston peak at ii I quadrant, 180 ° < θ < 270 °；

4) if a>0, b<0, then it represents that piston peak at iv quadrant, 270 °<θ<360 °；

5) if a=0, b > 0, then it represents that piston along Y-axis positive direction tilt, θ=90 °；

6) if a=0, b < 0, then it represents that piston along Y-axis negative direction tilt, θ=270 °；

7) if b=0, a > 0, then it represents that piston along X-axis positive direction tilt, θ=0 °；

8) if b=0, a < 0, then it represents that piston along X-axis negative direction tilt, θ=180 °；

9) if a=0, b=0, then it represents that piston is horizontal, without tilt.

The following is the original angle signal at two days two nights of certain steel mill's continuous acquisition, frequency acquisition is 1Hz, as shown in Figure 4, 200 points altogether.It can be seen that the fluctuation of upper signal of whole time period is more obvious from figure, it is primarily due to double-shaft tilt angle and passes Sensor precision the highest (after arithmetic point 3), when gas chamber runs, piston has rocked and may result in output angle and become Changing, and whole piston diameter is up to nearly 70 meters (150,000 cabinet), top land is to be spliced by one piece of block plate, and twin shaft inclines The change of angle transducer output angle is it could even be possible to be because local steel plate vibration rather than made because of rocking of whole piston Become.In figure, the amplitude of the upper and lower saltus step of original angle signal is at about ± 0.02 °, although amplitude is little, but due to itself its absolute Angle is the least, and result of calculation is had a great impact by the most this saltus step.And from actual process object analysis, whole work Plug weight weighs thousands of ton, it is impossible to rocking the most back and forth, its tilting procedure must be a process the most slowly.Therefore Primary signal must be processed, eliminate interference signal.

Native system uses following algorithm to process primary signal:

Y_k=(1-a) * X_k+a*Y_k-1(1),

In formula (1), a is filter factor, and its span is between 0～1, and general value is relatively big, X_kFor present sample Value, Y_k-1For last filter result, Y_kFor present filter result.According to its computing formula it can be seen that this filtering result Depend primarily on output valve rather than the contribution to filtering output of the sampled value of last time, equally this sampled value of filtering last time It is smaller for the output valve of filtering last time, but output result can be had correcting action, simulate bigger inertia Functions of low-pass filter.This algorithm has good inhibiting effect to PERIODIC INTERFERENCE, and it is higher to be applicable to vibration frequency Occasion, but it can cause delayed phase, and its delay degree depends on a value size, and a is the biggest, and filter result is the most delayed.Fig. 4 Middle signal is filtered by formula (1), and its result is as shown in Figure 5.

Comparison diagram 4 and Fig. 5, after finding filtering, signal is smoothened, eliminates the saltus step up and down of primary signal.

Although filtering eliminates shake, solve the saltus step of the primary signal impact on detecting system subsequent calculations, but with The problem that sample also brings along signal lag.Filter factor a is the biggest, and filter result is the most smooth, but sensitivity decrease, signal lag Seriously；Filter factor a is the least, and filter result sensitivity is the highest, but shake severity, it is therefore necessary to select a suitable filtering system Number, takes into account both sides impact.

If directly using initial data to calculate, its result saltus step is bigger, it will severe jamming operator are real to piston The judgement of border ruuning situation, as shown in Figure 6, it can be clearly seen that signal quality obtains bigger improvement after the filtering.

Algorithm principle is as follows:

Whole measuring principle is as shown in Figure 3, it is assumed that X, Y orthogonal coordinate axes, inclination angle in being former piston flat surface in figure The measurement direction of sensor is parallel to each other with the direction of X, Y.The former horizontal plane of piston is primary plane β, and the piston center of circle is the friendship of X, Y-axis Point O, piston radius is R, and piston is along straight line MN run-off the straight, and the plane after inclination is γ, in plane γ, if B point is for inclining The peak of piston flat surface after tiltedly, the vertical dimension between it and plane β is H, and ∠ BOB₁=θ, then θ is X-axis forward With inclination peak direction angle in the counterclockwise direction, the i.e. incline direction of piston；OB₁、OB₂X, Y-axis after being respectively On radius, then its angle ∠ B₁OB₂=90 °, it is a ' that obliquity sensor records X-direction top rade, and Y direction top rade is b′；The X-direction top rade a ' recorded and Y direction top rade b ' is filtered, after being filtered respectively through formula (1) X-direction top rade a and filtered Y direction top rade b.

Respectively from B₁、B₂Making vertical line to primary plane β, intersection point is C₁、C₂, make h₁=B₁C₁、h₂=B₂C₂, then:

h₁=Rsina (2),

h₂=Rsinb (3),

If angle is between plane γ after primary plane β and inclinationI.e. make a vertical line, intersection point from B point to plane β For C, thenIn Δ OBC:

In plane γ, from B₁Point is a vertical line B to radius OB₁B′₁, at Δ OB₁B′₁In:

OB′₁=Rcos θ (5),

Due to MN ⊥ OB, B₁B′₁⊥ OB andTherefore MN//B₁B′₁；Simultaneously becauseAndTherefore B₁B′₁//β.Therefore from B '₁It is vertical line B ' to plane β₁C′₁, intersection point is C '₁, then:

h₁=B '₁C′₁(6),

At Δ OB '₁C′₁In,OB ' is known again according to formula (5)₁=Rcos θ, then:

According to formula (2) (6) (7), can obtainThat is:

In like manner from B₂Point is a vertical line B to radius OB₂B′₂, then OB '₂=Rsin θ, in like manner can obtain:

Can obtain according to (9)/(8):

Formula (3), (4) square summation respectively can obtain:

Therefore finally can obtain conclusion: 1. $H=R\sqrt{{\sin }^{2}a+{\sin }^{2}b}$

②

③ $\mathrm{\&theta;}=\arctan \left(\frac{\sin b}{\sin a}\right)$

The peak height away from former piston flat surface after wherein H is tilting of the piston,For tilting of the piston plane and primary plane Between angle, θ is X-axis forward and tilt peak direction angle in the counterclockwise direction, the i.e. incline direction of piston.

Owing to piston may circumferentially tilt in any one angle, therefore the angle in obliquity sensor output X, Y-axis Can just can bear.As it is shown on figure 3, whole piston flat surface to be divided into four quadrants.According to X, Y direction folder measured by obliquity sensor Angle determines tilting of the piston orientation angle θ.

1) if a>0, b>0, then it represents that piston peak at I quadrant, 0 °<θ<90 °；

2) if a<0, b>0, then it represents that piston peak at ii quadrant, 90 °<θ<180 °；

3) if a < 0, b < 0, then it represents that piston peak at ii I quadrant, 180 ° < θ < 270 °；

4) if a>0, b<0, then it represents that piston peak at iv quadrant, 270 °<θ<360 °；

Also several special circumstances:

5) if a=0, b > 0, then it represents that piston along Y-axis positive direction tilt, θ=90 °；

6) if a=0, b < 0, then it represents that piston along Y-axis negative direction tilt, θ=270 °；

7) if b=0, a > 0, then it represents that piston along X-axis positive direction tilt, θ=0 °；

8) if b=0, a < 0, then it represents that piston along X-axis negative direction tilt, θ=180 °；

9) if a=0, b=0, then it represents that piston is horizontal, without tilt.

Above example is merely to illustrate Computation schema and the feature of the present invention, its object is to make the technology in this area Personnel will appreciate that present disclosure and implement according to this, and protection scope of the present invention is not limited to above-described embodiment.So, all depend on The equivalent variations made according to disclosed principle, mentality of designing or modification, all within protection scope of the present invention.

Claims (2)

1. utilize the gas chamber piston gradient online test method that gas chamber piston gradient on-line detecting system realizes, It is characterized in that:

Gas chamber piston gradient on-line detecting system includes double-shaft tilt angle sensor and the conversion connected by RS485 bus Device；Double-shaft tilt angle sensor for detecting the inclination angle in gas chamber piston plane two vertical direction, transducer by DP cable with The mode of Profibus-DP slave station accesses existing control system；

Described transducer includes that the UART being sequentially connected with turns RS485 electrical level transferring chip, microprocessor, the process of DP slave station protocol Chip and DP bus physical interface chip, microprocessor calculates gas chamber for the data gathered according to double-shaft tilt angle sensor and lives Plug angle of inclination and direction；

This method comprises the following steps:

S1, definition X, Y-axis are orthogonal coordinate axes in piston flat surface, measurement direction and X, Y of double-shaft tilt angle sensor Direction is parallel to each other, and the former horizontal plane of piston is primary plane β, and the piston center of circle is X, the intersection point O of Y-axis, and piston radius is R, piston edge Straight line MN run-off the straight, the plane after inclination is γ, in plane γ, if B point be tilt after the peak of piston flat surface, Vertical dimension between it and plane β is H, and ∠ BOB₁=θ, then θ is that X-axis forward is counterclockwise with edge, inclination peak direction The incline direction of the angle in direction, i.e. piston；OB₁、OB₂Radius in X, Y-axis, then its angle ∠ B after being respectively₁OB₂ =90 °, it is a ' that obliquity sensor records X-direction top rade, and Y direction top rade is b '；

S2, the initial data that collects uses following algorithm be filtered processing:

Y_k=(1-j) * X_k+j*Y_k-1(1),

In formula (1), j is filter factor, its span between 0～1, X_kFor current sample values, Y_k-1For last time filtering knot Really, Y_kFor present filter result；

The X-direction top rade a ' recorded and Y direction top rade b ' is filtered respectively through formula (1), is filtered After X-direction top rade a and filtered Y direction top rade b；

S3, it is calculated following parameter:

$H=R\sqrt{{\sin }^{2}a+{\sin }^{2}b}$

$\mathrm{\&theta;}=\arctan \left(\frac{\sin b}{\sin a}\right)$

In formula,For the angle between plane γ after primary plane β and inclination；

S4, according to X, Y-axis piston flat surface is divided into four quadrants,

1) if a>0, b>0, then it represents that piston peak at I quadrant, 0 °<θ<90 °；

2) if a<0, b>0, then it represents that piston peak at ii quadrant, 90 °<θ<180 °；

3) if a < 0, b < 0, then it represents that piston peak at ii I quadrant, 180 ° < θ < 270 °；

4) if a>0, b<0, then it represents that piston peak at iv quadrant, 270 °<θ<360 °；

5) if a=0, b > 0, then it represents that piston along Y-axis positive direction tilt, θ=90 °；

6) if a=0, b < 0, then it represents that piston along Y-axis negative direction tilt, θ=270 °；

7) if b=0, a > 0, then it represents that piston along X-axis positive direction tilt, θ=0 °；

8) if b=0, a < 0, then it represents that piston along X-axis negative direction tilt, θ=180 °；

9) if a=0, b=0, then it represents that piston is horizontal, without tilt.

Gas chamber piston gradient online test method the most according to claim 1, it is characterised in that: described twin shaft inclines Angle transducer is arranged in Flameproof box, and Flameproof box is arranged on the piston dam of piston edge, protects with the piston flat surface after leveling Hold relative level.