Monocrystalline Silicon Sensors Smart Pressure Differential Pressure Transmitter

Smart pressure Differential pressure transmitter circuit design using microprocessor core and auxiliary modular design of advanced digital isolation technology,
the instrument has a very high noise immunity and stability, while the use of digital compensation technology temperature,
static pressure compensation to improve the measurement accuracy, reduces the temperature drift, with good long-term stability, high reliability, strong self-diagnostic ability.
By the built-in absolute pressure and temperature sensors, measurement error correction, to enhance the performance differential pressure transmitter.
The latest external three-button design, the latest external three-button design, with self-diagnosis and remote capabilities,
with infrared wireless setup functions to meet the requirements for safe operation in hazardous areas, is to facilitate quick menu operation,
and complete all the parameter settings, or use Hart protocol for communication, computer Hart can install the software remotely operated handheld Hart goods,
completion of the measurement configuration information.

II、The principle
Principle sensors: monocrystalline silicon sensors using micro-machining technology (MEMS) precision manufacturing,
high and low pressure is transmitted to the single-crystal silicon sensor diaphragm and fill fluid through, when the force imbalance of the Wheatstone bridge resistance value changes,
the use of current excitation, and the differential pressure is converted into a linear change in output voltage.

Gauge and absolute pressure measurement principle: Pressure sensor transmitter for pressure measurement occasions, according to the reference end of the pressure difference,
the corresponding output signal can be divided into the gauge and absolute pressure, compound gauge indicates gauge range from less than to greater than the current atmospheric pressure.
Gauge reference terminal for the current atmospheric pressure, differential pressure transmitter pressure measurement commonly used micro-pressure range,
measuring range -100KPa-2MPa, the minimum range 500Pa, 4-20mA output signal corresponding to the measured pressure value;
absolute pressure reference terminal for the absolute vacuum pressure , commonly used measuring range 0-2MPa, minimum range 5KPa,
4-20mA output signal corresponding to the measured pressure values.
Principle of differential pressure measurement: differential pressure transmitter for measuring differential pressure, differential pressure transmitter differential pressure
range often have high static pressure overload and high precision characteristics, low-side and high-pressure side can be used as a reference and measurement end end use, c
ommonly used measuring range -2MPa-2MPa, minimum range 200Pa, static pressure and overload highest 40MPa, according to the formula △ P = PH-PL or △ P = PL-PH, 4-20mA output signal
corresponding to the differential pressure.
Hydrostatic level measurement principle: level measurement, the output signal according to the formula P = ρgh, static pressure vessel communicating with the atmosphere and
the liquid level is proportional to the pressure, differential pressure transmitter for the process industry 4-20mA process container corresponding to the level change from zero to full.
DP Level measurement principle: there is a change in the static pressure inside a closed container often, high and low ends of the differential pressure transmitter, while access to internal static pressure,
can eliminate internal static pressure effects, according to the formula △ P = ρgh, liquid level changes into a linear relationship between the differential pressure,
differential pressure transmitter for clean airtight container filled with insulating liquid medium or small magazine for level measurement medium, 4-20mA output signal corresponding to the level from zero to full change.

The principle of gas / vapor / liquid flow measurement: process industry site commonly used in differential pressure transmitter for supporting orifice plate gas / vapor / liquid flow
measurement of high static pressure of the pipeline, according to the formula Qv = k (dP / pr) ½ and Qm = k (dP × pr) ½, volume flow and mass flow are linearly related to
the differential pressure △ P, differential pressure transmitter for gas / vapor / liquid flow measurement, output signal 4-20mA corresponding to the gas / vapor / liquid flow from zero to full-scale change.

III、The main features of
Compact appearance, light weight.
The new external clear button.
Range migration, range migration ratio 100: 1.
Damping: 0 to 32 seconds adjustable, step 0.1 seconds.
Zero and full compensation correction.
Output current multi-point calibration.
Display multiple monitoring variables, selectable pressure units.
Ultra-low temperature OLED display (-40～70 ℃).
Output current prescribing capabilities.
With self-diagnosis and fault alarm output.
With EEPROM non-volatile memory, power-down is not afraid of having the original calibration data loss and data recovery.
Communication via HART handheld and in-situ button remote, local configuration parameter settings and functions. Full insulation package, excellent anti-jamming capability.
Insulating monocrystalline silicon sensing element is mounted inside the sensor diaphragm, measuring pressure by diaphragm and filling liquid is passed, in order to achieve a full insulation package,
avoid temperature measurement and the environment, electrical interference and mechanical vibration.
Frequency response capability. Single crystal silicon material having excellent properties, which exceeds the natural resonant frequency of 500Hz, the pressure is transmitted to the sensitive element,
immediately sensed signal is converted to an output, the overall response time of less than 5mS, suitable for high frequency dynamic occasions.
Powerful anti-overload. Double overload protection technology, the center of the diaphragm and the diaphragm form a dual overload, normal measurement, the diaphragm contact pressure deformation,
filling liquid is passed to the center of the diaphragm and the sensing element, diaphragm and robust diaphragm body has figured corrugated structure, a high and low ends of the pressure is too large,
the center of the diaphragm is deformed under pressure to avoid excessive filling liquid is passed to the sensitive components, complete diaphragm close diaphragm body,
even if the pressure continues to increase, but also filled with liquid no longer passed to the sensitive components to achieve overload protection, excellent elastic properties of silicon materials,
the latter does not affect the normal measure.
Modular sensor in production sensor cycle tested in accordance with the scope of work pressure and temperature for six temperature ranges and 15-point linear compensation,
all calculations are retained in the sensor film and the internal built-in memory, in a subsequent production or maintenance, the transmission module can read data memory, high precision output.
IV、The performance parameters
Process material: liquid, gas, steam.
Output signal: two-wire 4-20mA, in line with NAMUR NE43 specification superimposed digital signal (HART protocol).
Power: minimum supply voltage 9VDC, maximum supply voltage 45VDC.
Display: 0LED display three lines, five characters, plus units, bar graph display.
Explosion properties: Explosion, waterproof sealed enclosure; Intrinsically Safe.
Zero and span mediation: through digital communication or local adjustment button, independently of each other.
Ambient temperature: -40～85 ℃.
Digital temperature: -40～70 ℃.
Fault Warning: If the sensor or circuit fails, automatic diagnosis function will automatically output 3.6 or 21.0mA (user preset).
Measuring range: Pressure 0-0.125KPa to 0-7MPa / gauge 0-0.125KPa to 0-42MPa / absolute pressure 0-200KPa to 0-2.1MPa.
Accuracy: ± 0.075% of range.
Stability: 0.1% / year, of 0.25% / 3 years.

Applications