Explosion-proof differential pressure transmitter

I. Product Overview:

ZW3351DR series explosion-proof micro-differential pressure transmitter adopts imported high-quality pressure sensor chip. It accesses the environmental temperature, pressure and input/output characteristic correction parameters of the sensor through built-in memory E2PROM, and then calculates with CPU microprocessor to automatically compensate temperature, non-linear correction, V/I conversion and A/D conversion. It outputs 4-20mA standard signal and superimposes a symbol on the analog signal. Digital signals communicate with HART protocol. In communication, the frequency signal has no disturbance effect on the signal of 4-20mA.

II. Working Principle:

ZW3351DR series explosion-proof micro-differential pressure transmitter measures two kinds of pressure of medium into high and low pressure chamber, which acts on the isolation diaphragm of the two sides of the delta element (i.e. the sensitive element), and transmits them to both sides of the measuring diaphragm through the isolator and the filling liquid in the element. A capacitor is formed by measuring the diaphragm and the electrodes on both sides of the insulating sheet. When the pressure on both sides is inconsistent, the displacement of the diaphragm is proportional to the pressure difference, so the capacitance on both sides is different, and the signal is converted into a signal proportional to the pressure through oscillation and demodulation.

3. Application occasions:

ZW3351DR series explosion-proof differential pressure transmitter is used to measure liquid level, flow rate and pressure of liquid, gas or steam under high working pressure environment, and then convert it into 4-20mA DC signal output. Intelligent type can communicate with HART hand-operated device, through which setting, monitoring or composing on-site monitoring system with upper computer.

Fourth, main characteristics:

1. Super measurement performance for pressure, differential pressure, liquid level and flow measurement;

2. Digital accuracy: +(-) 0.05%;

3. Stability: 0.25% for 60 months;

4. Range ratio: 100:1;

5. Measurement rate: 0.2S;

6. Miniaturized (2.4kg) stainless steel flange, easy to install;

7. Process connection is compatible with other products to realize measurement.

8. The sensor (technology) with H-alloy sheath has achieved excellent cold and thermal stability.

9. Microdifferential pressure transmitter with 16-bit computer;

10. Standard 4-20mA, with HART-based digital signal, remote control supports upgrading to fieldbus and field control technology.

Technical parameters:

1. Targets: liquids, gases and vapors;

2. Measurement range: 0.25-1.5KPa;

3. Output signal: 4-20mA DC (special for four-wire system); 220V AC power supply, 0-10mA DC output;

4. Power supply: 12-45V DC, generally 24V DC;

5. Load characteristics: related to power supply, with load capacity at a certain power supply voltage; the relationship between load impedance RL and power supply voltage Vs is: RL < 50 (Vs-12);

6. Indicator table: pointer linear indicator 0-99% calibration and LCD liquid crystal display;

7. Explosion-proof grade: a: Exd II BT5 or Exd II CT6; b: intrinsically safe type (Exia II CT6 or Ex IB II CT6);

8. Range and Zero: External continuous adjustable.

6. When using differential pressure transmitter, the following three points should be paid attention to:

1. Before using the differential pressure transmitter, it is necessary to recalibrate its measuring range, zero drift, accuracy and static pressure error.

2. After the transmitter is installed, it is necessary to check the working pressure, working temperature, measuring range and drift of various transmitters before driving. See if it is consistent with the actual situation, if there are any discrepancies, we must find out the reasons and correct them before we can drive.

3. When opening or stopping, one-way static pressure should be avoided.

Seventh, type selection coding: