Product introduction
Pressure (gauge) / absolute pressure transmitter is a pressure signal measured at atmospheric pressure (or vacuum), only one port is connected to the process pipe.
The working principle is that when a silicon single crystal material is subjected to an extremely small strain by an external force, the state of the electron energy level of the internal atomic structure changes, thereby causing a drastic change in its resistivity. This physical effect is called a piezoresistive effect. Using the principle of piezoresistive effect, the integrated process technology is used to dope and diffuse, and along the characteristic crystal orientation on the single crystal silicon wafer, the strain resistance is formed to form the Wheatstone bridge, and a force-sensitive and force-electric conversion is made. Detected in one diffused silicon sensor.
When the pressure acts directly or indirectly on the surface of the silicon wafer to cause a slight deformation of the diaphragm, the high-precision circuit for measuring the deformation of the silicon wafer transforms this tiny deformation into a voltage signal proportional to the pressure, and is compensated by temperature and pressure. This voltage signal is then converted to an industry standard 4-20 mA current signal or a 1-5 V voltage signal using a dedicated chip.
Since the measuring diaphragm detecting circuit uses an integrated circuit and contains a linear and temperature compensating circuit internally, high precision and high stability can be achieved, and it is convenient for use in various complicated industrial environments.
Technical performance
Use object: liquid, gas or steam
Measuring range: See selection specification sheet
Output signal: 4~20mA dc. Output, superimposed HART protocol digital signal (two-wire system)
Power supply: External power supply 24V dc., power supply range 12V ~ 45V
Load characteristics:
Hazardous location installation:
Explosion-proof ExdIIBT5Gb; (Explosion-proof certificate number: CE16.1163)
Intrinsically safe type ExiaIICT4/T5/T6Ga; (Explosion proof number: CE15.2354X)
Migration features:
At the minimum range (40:1 range compression ratio), the maximum positive transition zero is 39/40 times the upper range limit, the maximum negative transition zero can be the lower range limit, and the absolute pressure transmitter has no negative transition. (No matter the output form, after the positive and negative migration, the upper and lower limits of the range must not exceed the limit of the range)
temperature range:
The electronic circuit board works at -40 to 85 ° C;
Sensitive components work at -40 ~ 85 ° C;
Storage temperature -40 ~ 85 ° C;
With digital display -25 ~ 75 ° C (running);
-40 to 85 ° C (no damage);
Relative humidity: 0 to 95%
Overpressure limit: The pressure transmitter that applies 2 to 5 times the maximum range is not damaged.
Volume change: less than 0.16cm3
Resistance: The time constant is adjustable from 0.1 to 32.0s.
Start-up time: 3s, no need to warm up.
Technical indicators
(Unmigration, 316 stainless steel isolation diaphragm and other standard test conditions.)
Accuracy: ±0.1%, ±0.075%
Stability: ±0.2%/12 months of the maximum range
Temperature effect: Temperature error including zero and span is ±0.2%/20°C of maximum range
Power supply effect: less than 0.005%/V of the output range.
Vibration effect: In any axial direction, the frequency is 200 Hz and the error is ±0.05%/g of the maximum range.
Load impact: As long as the input transmitter voltage is higher than 12V, there is no load influence in the load working area.
Installation position influence: The maximum zero error can be generated no more than 0.10kPa, which can be eliminated by calibration, and has no effect on the range; the measurement body has no influence on the flange rotation.
Application and selection:
Ordinary pressure transmitter is the most commonly used measuring instrument in industrial process control. It is widely used in various automatic control systems, such as aerospace, military, petrochemical, chemical, oil well, electric power, shipbuilding, building materials, pipelines, etc. . Generally used in the measurement of the pressure or absolute pressure of liquid, gas or steam, the medium temperature is not too high, the corrosion is not strong, the viscosity is not high, and it is not easy to crystallize.
Selection note:
Before selecting the type, the user should specify the temperature, corrosiveness, measurement range, explosion-proof of the tested medium, whether it is necessary to prohibit the oil treatment, and the flange connection of the membrane box is required for the medium to be easily crystallized or viscous.
