Differential Pressure/High Static Differential Pressure

Work principle: when pressure acting directly or indirectly on the surface of measuring membrane, small deformation will occur on the diaphragm, high-precision circuit will transform the small deformation into voltage signal which is in direct proportion to the pressure, after compensation of temperature and pressure, then dedicated chip will transform the voltage signal into industrial standard 4-20mA current signal or 1-5V voltage signal. Measuring membrane has adopted integrated circuit, inner containing linear compensation circuit and temperature compensation circuit, which ensures its high accuracy and high stability, and makes it suitable for using in all kinds of complicated industrial environment.

Feature:  

● Adoption of microprocessor enhances its flexibility and function;

 ● Have strong self-diagnostic capability;

● Without mutual effect between zero adjustment and range adjustment;

● Complete function of remote & local setting and calibration;

● Two-wire system, conforming to HART protocol and capable of uninterrupted output with HART protocol terminal communication;

● To compensate for temperature and static pressure by adopting digitized compensation technology;

● Good stability, high accuracy, adjustable damping and good single track overload ability;

● Without mechanical drive parts, little maintenance work, strong resistance to vibration;

● All general parts satisfy to the convenience of maintenance;

● Membrane that contacts medium is optional for all-weather use.

  Technical performance

 Using object: liquid, gas or steam

Measuring scope: refer to model & specification table

Output signal: 4~20mA DC Output, overlay HART protocol digital signal (two-wire system)

Power supply: external power supply 24V DC. Power supply range 12V~45V

Load characteristic:

Hazardous area installation: Explosion-proof type dIICT5;

                        Intrinsic safety type iaIICT5;

Shift characteristic: when it is at minimum range (range compression ratio is 40:1), maximum positive zero shift is 39/40 times of upper limit value of range, maximum negative zero shift is lower limit value of range, and absolute pressure transmitter has no negative shift. (Regardless of what kind of output method, after positive and negative shift, the upper & lower limit could not exceed the range limitation)

Temperature range:

                Electric circuit board work at -40~85℃；

                Sensing element work at -40~104℃

                Storage temperature: -40~85℃

                With digital display: -25~65℃ (normal operation)

-40~85℃ (with no damage)

Relative humidity: 0~95%

Overpressure limit: DP type, add 0(absolute pressure) ~13MPa pressure transmitter has no damage. High static type can bear 31MPa static pressure or unidirectional pressure at most.

Volume variation: be less than 0.16cm³

Damping: time constant is adjustable within 0.2~32.0s.

Starting time: 3s, preheating is unnecessary.

  Technical index

(On the occasion that there is no shift, 316 stainless steel isolation membrane and other standard test)

Accuracy: ±0.1%, ±0.2%

Stability: maximum measuring range×±0.25%/6months

Temperature influence: zero temperature deviation is ±0.5%/55℃ of maximum range

Including total temperature deviation of zero and range is ±1.0%/55℃ of maximum range

                      Note: range 3 temperature influence deviation shall be doubled.

   Static pressure influence: (when DP type is outputting at linear) zero deviation: after adding static pressure 140kgf/cm², zero point deviation of range 4. 5 is ±0.25% of maximum range, zero point deviation of range of 3. 6. 7. 8 is ±0.5% of maximum range. This is system deviation, before installation, calibrate transmitter zero point as per actual static pressure to eliminate this deviation;

                      (When HP type is outputting at linear) zero point deviation: after adding static pressure 31.2MPa, zero point deviation will be less than ±2.0% of maximum range. This is system deviation, and can be eliminated, by calibrating transmitter zero point as per actual static pressure before installation.

   Power source influence: be less than output range×0.005%/V

   Vibration influence: at any axis, frequency is 200Hz, deviation is ±0.05%/g of maximum range

   Load influence: as long as transmitter input voltage is higher than 12V, no loading influence will occur in loading working zone

   Influence of installation position: zero point deviation is no more than 0.25kPa, which could be eliminated by calibration and will bring no influence on the range; measuring proper will bring no influence to corresponding flange.