Diffused silicon pressure transmitter

1 Product Features

The main characteristics of the pressure transmitter is anti-overload and anti-impact. The over-voltage can reach multiple times of the measuring range. Even if the measuring element is directly hit with a hard object, it will not damage it, and it has no effect on the measurement accuracy;

High stability, better than 0.1% full scale per year, this technical indicator has reached the level of intelligent pressure gauge; temperature drift is small, because the mediation fluid in the pressure measuring element is cancelled, so the sensor not only obtains a high measurement accuracy, and Minimally affected by temperature gradients;

The pressure transmitter has wide applicability, convenient installation and maintenance, and can be installed in any position.

2 Technical parameters

Pressure transmitter main technical indicators

Measuring range: -100KPa to 60MPa

Accuracy grade: 0.1, 0.2, 0.5

Ambient temperature: -40 to 70°C

Medium temperature: -40 ~ 125 °C (temperature compensation -20 ~ 80 °C)

Long-term stability: better than 0.1% F. S/year

Working voltage: 12.5~36VDC -AC220v

Output signal: 4-20mA (two-wire system) 0/1-5VDC (three-wire system)

Volume migration: can do a standard scale 10:1 migration

Vibration effect: Any axis, 200Hz/g is 0.01% F. S

Transmitter protection class: IP65

Explosion-proof: iaIICT4, intrinsically safe

Associated device: LB802

Material: Die cast aluminum

Diaphragm is 96% alumina ceramic

Process connection is 316L stainless steel

Sealing ring: NBR, silicone rubber, fluorine rubber

Accuracy grade: 0.25 grade basic error ± 0.25%

Nonlinear error: 0.3 level ≤ ± 0.3% FS

Hysteresis error: ≤±0.3%FS

Output characteristics:

10-10mA output, load resistance 0-15KΩ

24-20mA output, load resistance 0-600Ω

3 Constant current output internal resistance greater than 10MΩ

4 two-wire 4-20mA output: standard power supply DC24V

Explosion-proof mark: (RPT-III): Exia II CT4-6

â—†Features of diffusion silicon pressure transmitter

High precision, the highest precision up to 0.1% FS, external zero and full-scale adjustment optional, suitable for measuring low pressure range, overload pressure.

Main Specifications

Accuracy

0.1%F·S 0.25%F·S 0.5%F·S

Measuring range

-95KPa~35MPa optional

Measuring medium

Liquid, gas, steam

Storage temperature

-40°C~125°C

Operating temperature

-10°C~80°C

Anti-corrosion materials

316L stainless steel ceramic PTFE

Temperature effect

<0.02%/°C

Load Resistance

≤750Ω

Overload capacity

One to two times the measuring range

Mechanical protection

IP65

humidity

≤95%RH

Output

Two-wire 4~20mA DC

Associated equipment

EXZ231B type safety barrier

weight

<1Kg

Zero temperature coefficient

Less than 0.02%/°C

Full temperature coefficient

Less than 0.02%/°C

voltage

24V DC

Explosion-proof grade

iaIICT5

Installation position

no effect

3 working principle

The pressure signal is transmitted to the electronic device and the pressure is displayed on the computer

The principle is roughly:

The hydraulic signal of pressure is converted into an electrical signal (4-20mA)

The linear relationship between pressure and voltage or current size is generally proportional.

Therefore, the voltage or current output from the transmitter increases with pressure.

This gives a relationship between pressure and voltage or current:

The two pressures of the measured medium of the pressure transmitter are passed into the high and low pressure chambers. The low pressure chamber pressure is atmospheric pressure or vacuum and acts on the isolation diaphragms of the delta element (ie, the sensitive element) through the spacers and The filling liquid in the element is sent to both sides of the measuring diaphragm. The pressure transmitter consists of a capacitor formed by the measuring diaphragm and the electrodes on both sides of the insulating sheet. When the pressures on both sides are inconsistent, the measuring diaphragm is displaced, and the displacement is proportional to the pressure difference. Therefore, the capacitance on both sides is not equal, and the signal is proportional to the pressure through the oscillation and demodulation steps.

The diffusion silicon pressure transmitter can be used with various types of moving coil indicator, digital pressure gauge, and electronic potentiometer. The pressure transmitter can also be used with various automatic adjustment systems or computer systems.

working principle

The diffusion silicon pressure transmitter turns the temperature signal into an electrical signal through a temperature sensor. The preamplifier amplifies and filters the electrical signal and sends it to the CPU's A/D converter module for analog to digital conversion. Finally, the CPU Data processing and display and PWM output. The block diagram is as follows:

By the side of the media ---> sensor ---> electronic circuit ---> output signal

The pressure of the measured medium directly acts on the ceramic/diffusive silicon diaphragm of the sensor, so that the diaphragm generates a small displacement proportional to the medium pressure. Under normal operation, the maximum displacement of the diaphragm is not more than 0.025 mm. The electronic circuit detects this. After a displacement, this displacement is converted into a standard industrial measurement signal corresponding to this pressure. During overpressure, the diaphragm is directly attached to the solid ceramic substrate/diffusion silicon. Since the gap between the diaphragm and the substrate is only 0.1 mm, the maximum displacement of the diaphragm during overpressure is only 0.1 mm, so the structure is guaranteed The tablet does not produce excessive deformation. The sensor has good stability and high reliability.

4 product selection

Pressure Transmitters

Code

sensor type

A

Dry thick film piezoresistive ceramic sensor

B

Dry type thick film capacitive ceramic sensor

Code

Installation method

K

M20×1.5 Inner hole Ф11.4mm

A

NPT1/2 inner hole Ф 11.4mm

M

G 1/2 DIN16288

R

G 1/2 inner bore Ф 11.4mm

T

User special requirements

Code

Accuracy level

E

Level 0.5

K

Level 0.2

M

Level 0.1

Code

Display method

N

No live display

A

0-100% linear pointer meter display

Code

Pressure type

G

Gauge

A

Absolute pressure

Code

Options

B

Intrinsically safe, non-normal type

0-60MPa

Instrument selection

Selection table:

No S code measurement range

ABGAP-2400 0-6～40kPa

ABGAP-2500 0-40～250kPa

ABGAP-2600 0-0.16～1kPa

ABGAP-2700 0-0.4~2.50KPa

ABGAP-2800 0-1.6~10Mpa

Code structure material

Flange fitting exhaust/discharge valve isolation diaphragm filling liquid

F22 316 stainless steel 316 stainless steel 316 stainless steel silicone oil

F23 316 Stainless Steel 316 Stainless Steel Hastelloy C

F24 316 stainless steel 316 stainless steel Monel

F25 316 Stainless Steel 316 Stainless Steel

F33 Hastelloy C Hastelloy C Hastelloy C

F35 Hastelloy C Hastelloy C é’½

F44 Monel Monel Monair

Code Option

M1 O～10% linear indicator

M2 digital display header

M3 LCD display header

B1 tube bending bracket

B2 Mounted Curved Bracket

B3 tube mounting bracket

D1 flange side exhaust/discharge valve on top

D2 flange side exhaust/discharge valve in lower part

E1 ordinary cable connector

E2 explosion-proof cable connector

G1 Waist flange

G2 welded pipe fittings

d Explosion-proof

i

5 transmitter

The diffusion silicon pressure transmitter has the advantages of reliable operation, stable performance, easy installation and use, small size, light weight, high performance-cost ratio, and can be widely used in various positive and negative pressure measurements. The diffusion silicon pressure transmitter uses imported diffused silicon or ceramic cores as pressure sensing elements. The sensor signals are converted into 0-10mA or 4-20mA unified output signals by high performance electronic amplifiers. Pressure transmitters can replace traditional remote pressure gauges, Hall elements, differential transmitters, and have DDZ-II and DDZ-III transmitter performance.

6 product advantages

Analog Features

● High precision

● Range, zero external continuous adjustable

● Good stability

● Up to 500% positive migration and up to 600% negative migration

● Two-wire system

● Adjustable damping, over pressure resistance

● Solid sensor design

● No mechanical moving parts, less maintenance

● Light weight (2.4kg)

● All series of unified structure, strong interchangeability

● Miniaturization (166mm total height)

● Optional diaphragm material for contact with media

● Unilateral overpressure

● Low pressure cast aluminum alloy housing

Smart features:

●Super measurement performance for pressure, differential pressure, level, flow measurement

●Digital accuracy: +(-)0.05%

● Analog Accuracy: +(-)0.75%+(-)0.1%FS

● Full performance: +(-)0.25FS

● Stability: 0.25% 60 months

● Turndown ratio: 100:1

● Measurement rate: 0.2S

● Miniaturized (2.4kg) stainless steel flange for easy installation

● The process connection is compatible with other products to achieve the best measurement

● The only sensor (patented technology) using H alloy sheath in the world achieves excellent cold and thermal stability

● Intelligent transmitter with 16-bit computer

Standard 4-20mA with digital signal based on HART protocol, remote control

● Support upgrades to fieldbus and field-based control technology.

7 related questions

1, the transmitter to measure what kind of pressure: first determine the system to confirm the maximum measured pressure, in general, you need to select a transmitter with a pressure range of about 1.5 times greater than the maximum. This is mainly because in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular up and down fluctuations. This momentary peak can damage the pressure sensor, the continuous high pressure value or a little beyond the transmitter. Calibrating the maximum value will shorten the life of the sensor, however, as this will reduce the accuracy. Thus, a buffer can be used to reduce the pressure burr, but this will reduce the sensor's response speed. Therefore, when selecting the transmitter, it is necessary to fully consider the pressure range, accuracy and stability.

2, what kind of pressure media: we have to consider is the pressure transmitter measured by the medium, viscous liquids, mud will plug the pressure interface, solvent or corrosive substances will not destroy the transmission and these Material directly in contact with the medium. These factors will determine whether to select the direct isolation membrane and the material directly in contact with the medium. The material of the contact pressure medium part of the general pressure transmitter is made of 316 stainless steel. If your medium is not corrosive to 316 stainless steel, then basically all pressure transmitters are suitable for your measurement of medium pressure. If your The medium is corrosive to 316 stainless steel. Then we must use a chemical seal. This not only can measure the pressure of the medium, but also can effectively prevent the medium from contacting the wetted part of the pressure transmitter, thus protecting the pressure from changing. The transmitter extends the life of the pressure transmitter.

3, the transmitter needs much accuracy: determine the accuracy of the non-linear, hysteresis, non-repetitive mechanical and electrical business network, temperature, zero offset calibration, the impact of temperature. But mainly by non-linear, hysteresis, non-repeating, the higher the precision, the higher the price. Each type of electronic meter will have an accuracy error, but because of the different levels of accuracy in each country, for example, the accuracy of national standards such as China and the United States is the best part of the sensor's linearity, which is what we usually do. The accuracy of the measurement range is between 10% and 90%; while the accuracy of the European standard is the worst part of the linearity, which is what we commonly refer to as 0 to 10% and 90% to 100% of the inverse of the measurement. Between the accuracy. If the European standard accuracy is 1%, the accuracy of the Chinese standard is 0.5%.

4, the transmitter temperature range: Usually a transmitter will calibrate two temperature ranges, the normal operating temperature range and temperature compensation range. The normal operation temperature range refers to the temperature range when the transmitter is not destroyed in the working state. When the temperature compensation range is exceeded, the application performance index may not be achieved. The temperature compensation range is a typical range that is smaller than the operating temperature range. Working within this range, the transmitter will definitely reach its proper performance. Temperature changes affect its output in two ways. One is zero drift; the other is affecting full-scale output. Eg +/-X%/°C of full scale, +/-X%/°C of reading, +/-X% of full scale when out of temperature range, +/-X% of reading when within temperature compensation range , without these parameters leads to uncertainty in use. Whether the degree of change in transmitter output is caused by pressure changes or temperature changes is the most complicated part of understanding how to use the transmitter.

5, what kind of output signal needs to be obtained: mV, V, mA and frequency output digital output, what kind of output depends on many factors, including the distance between the transmitter and the system controller or display, whether there is "noise" or Other electronic interference signals. Do you need amplifiers, amplifier locations, etc. For many OEMs with short distances between transmitters and controllers, the most economical and effective solution is to use a mA output transmitter. If you need to amplify the output signal, it is best to use a transmitter with built-in amplification. For long-distance transmission or presence of strong electronic interference signals, it is best to use a mA-level output or a frequency output. In environments with high RFI or EMI specifications, special protections or filters must be considered in addition to the selection of mA or frequency output. (As a result of various acquisition needs, there are many kinds of output signals from pressure transmitters on the market, mainly 4...20mA, 0...20mA, 0...10V, 0...5V, etc., but The more common ones are 4...20mA and 0...10V. Among the output signals I mentioned above, only 4...20mA is a two-wire system. We say that the output is a few-wire system. Grounding or shielding, all other three-wire system)

6, choose what kind of excitation voltage: the type of output signal determines how to choose the excitation voltage. Many amplification transmitters have built-in voltage regulators, so their supply voltage range is large. Some transmitters are quantitatively configured and require a stable operating voltage. Therefore, a working voltage that can be obtained determines whether a sensor with a regulator is used. When selecting a transmitter, the operating voltage and the system cost must be comprehensively considered.

7. Do you need an interchangeable transmitter: Determine if the required transmitter can accommodate multiple systems. In general, this is important. Especially for OEM products. Once the product is delivered to the customer, the cost of the customer's calibration is considerable. If the product has good interchangeability, then even changing the transmitter used will not affect the overall system performance.

8, the transmitter needs to maintain stability after overtime work: Most of the transmitter will have a "drift" after overtime work, so it is necessary to understand the stability of the transmitter before purchase, this kind of pre-work energy Reduce the troubles that will arise in future use.

9, the transmitter's package: The transmitter's package, especially it is often easy to ignore it is the rack, but this point in the future will gradually expose its shortcomings. The transmission of the optional transmitter must take into consideration the working environment, humidity, and how to install the transmitter in the future. Will there be strong impact or vibration.

10. What kind of connection is used between the transmitter and other electronic devices: Is it necessary to use a short-distance connection? If you use long-distance connections, do you need to use a connector?

11. Others: After confirming some of the above parameters, we must also confirm the process connection interface of your pressure transmitter and the supply voltage of the pressure transmitter; if you are using it under special circumstances, consider explosion protection and protection class.

8 common faults

1. When installing, the pressure sensitive part of the transmitter should be perpendicular to the direction of gravity. If the installation conditions are limited, the transmitter should be adjusted to zero to the standard value.

2, the residual pressure does not come out, so the sensor's zero position can not come down. The best way to eliminate this reason is to remove the sensor and see if the zero position is normal. If the zero position is normal, replace the seal and try again.

3, pressure transmitter output does not change, and then pressurize the transmitter output suddenly changes, pressure transmitter zero can not go back. The cause of this phenomenon is most likely caused by the pressure sensor seal.

4. Whether it meets the power supply requirements; there is no wiring error between the power supply and the transmitter and the load device. No voltage or reversed polarity on the transmitter terminals can cause the transmitter to output no voltage signal.

5, pressure sensor and transmitter housing generally need to be grounded, signal cable must not be mixed with the power cable laying, sensors and transmitters should avoid strong electromagnetic interference around. Sensors and transmitters should be cycled according to industry regulations during use.

6. When selecting pressure sensors and transmitters, the user should fully understand the working conditions of the pressure measurement system and make reasonable choices according to their needs so that the system can work in the best condition and reduce the project cost.

7. Transfer to the two sides of the measuring diaphragm through the spacer and the filling liquid in the element. Measure the diaphragm and the electrodes on both sides of the insulating sheet to form a capacitor.

8, pressure transmitter requires inspection once a week, once a month inspection, mainly to remove the dust inside the instrument, a serious inspection of electrical components, the current value of the output should be always proofread, the pressure transmitter is weak inside, certain To be separated from the outside world by strong electricity.