Smart differential pressure transmitter

ZW3851DP series intelligent differential pressure transmitter is the introduction of foreign advanced technology and equipment in the production of new type of transducer, the key raw materials, components and parts are imported, the whole machine after assembled and tested strictly, this product has the advanced design principle, the variety specification is complete, installation convenient use, etc.Due to the aircraft appearance on the total integration of the current domestic zui is popular, strong commonality and replace ability.For the continuous improvement of the domestic automation level and the development, this series of products in addition to the design cabinet and delicate, more has introduced HART field bus protocol of intelligent function

Second, the working principle:

ZW3851DP series intelligent differential pressure transmitter is two kinds of medium pressure ventilation with high and low pressure chamber, two functions in the delta components (i.e., sensitive element) on either side of the segregation on the diaphragm, through spacer and components on both sides of the filling liquid to measure the diaphragm.Measuring diaphragm and on both sides of the insulation on the electrodes of a capacitor.When we have different pressure on both sides, to cause measuring diaphragm displacement, the displacement and stress is directly proportional to the difference, so both sides capacitance range, through the link of oscillation and demodulation, is converted into is proportional to the pressure signal.

Applications:

ZW3851DP series intelligent differential pressure transmitter is used to work in high pressure environment measure liquid, gas or liquid level, flow and pressure of steam, then into 4 ~ 20 ma DC signal output intelligent transmitter can communication with HART hａnd operator, through its setting, monitor or with upper unit into the scene monitoring system.

Four, the main features:

1, the super performance measurement for pressure, differential pressure, liquid level, flow measurement;

2, digital precision: + (-) 0.05%;

3, the simulation precision: + + (-) (-) 0.75% 0.1% F.S;

4, the whole performance: + 0.25 F.S (-);

5, stability: 0.25% 6 months;

6, span ratio: 100:1;

7, measuring rate: 0.2 S;

8, miniaturization (2.4 kg) stainless steel flange, easy to install;

9, process connection compatible with other products, the realization of measurement;

10, with H alloy sheath of sensors (technology), and achieved excellent cold and hot stability;

11, 16 computer;

13, standard 4-20 ma, with digital signal based on HART protocol, remote control;

13, support to the field bus and upgrade based on the technology of field control.

Five, the technical parameters:

1, use object: liquid, gas and steam;

2, measuring range: 0-1600 to 10000 kpa;

3, the output signal: 4 ~ 20 ma DC (special for four wire system);220 v AC power supply, 0 ~ 10 ma DC output;

4, power supply: 12 ~ 45 v DC, general is 24 v DC;

5, load characteristic: related to the power supply, when a power supply voltage on load capacity as shown in figure 3, RL load impedance and voltage Vs relation is: RL 50 or less (v - 12);

6, indicator: pointer linear indication 0 ~ 99% scale and the LCD liquid crystal display;

7, explosion-proof grade: a: flameproof (Exd Ⅱ BT5 or Exd Ⅱ CT6);B: this Ann model (Exia Ⅱ CT6 or Ex ib Ⅱ CT6);

8, range and zero: external continuous adjustable;

9, plus or minus migration: zero after positive transfer and negative transfer, range, measurement range, of the absolute value of the upper limit and lower limit are less than 99% of the measurement range limit.Zui dazheng zui small adjustment range migration quantity of 500%;Zui big

10, zui small amount of negative transfer of calibration range 600%;

11, temperature range: operating temperature range: - 20 ~ + 88 ℃.

Six, troubleshooting methods:

If the differential pressure transmitter problems encountered in the use process, we can use the following three methods to solve.

1, test:

1.1, replace detection: will doubt defective parts replacement, judge fault position.Such as: suspected transmitter circuit board failure, can be temporary replacement, to determine the reason.

1.2, division test: will measure circuit split into several parts, such as: power supply, signal output, signal transmitting, signal detection, according to the points of inspection, by Jane to numerous, situated, narrow range, find out the fault location

1.3, open circuit detection: separately from the rest parts of the suspected fault and to see whether the fault disappear, if lost, then determine the malfunction, or step into the next search, such as: smart differential pressure transmitter can't normal Hart, telecommunication, power supply can be disconnected from the table body, the method of field plus a power transmitter power to communicate, to see if the cable stack 2 KHZ electromagnetic signals interfere with communication.

1.4, short circuit detection: in the case of security, the related part of the loop short directly, such as: small difference transmitter output value, guide pressure pipe can be disconnected, from a valve directly to the outside differential pressure signal directly led to the differential pressure transmitter, on both sides to observe the transmitter output, to determine the pipeline wall, leakage of connectivity.

2, questionnaire:

Review before failure of flint, smoke, odor, power supply change, lightning, damp, wrong operation, and maintenance.

3, intuitive method:

Observation circuit of external injury, guide of pressure pipe leaking, overheating in the circuit and power supply switch state, etc.

Differential pressure transmitter is the introduction of foreign advanced technology and equipment in the production of new type of transducer, differential pressure transmitter is usually divided into intelligent differential pressure transmitter, high static pressure differential pressure transmitter and three types of differential pressure transmitter.

Seven, notable matters of installation:

Differential pressure transmitter and throttling device supporting the use of time, met the pressure is low, in the calculation of time often to such a situation, it is calculated the maximum differential pressure is the micro differential pressure, it puts forward high demands on the differential pressure transmitter.

Guide the installation of pressure pipe problem:

1, the differential pressure transmitter because of its small scale, the installation position and different stress caused by uneven pressure changes.(30 degrees slope, will produce 0.2 KPa pressure from left) left.Such a situation, especially in and supporting the use of pig and flowmeter, it is important to note that the installation of the differential pressure transmitter.

2, prevent the transmitter medium in contact with the corrosive or overheating;

3, prevent the dross in the guide tube deposition;

4, guide pressure pipe should be as short as possible;

5, on both sides of fluid column pressure head tube should keep balance;

6, pressure pipe should be installed in the temperature gradient and temperature fluctuation is small, no shock and vibration;

Field measurement, the method of reduce error:

1, guide pressure pipe should be as short as possible;

2, when measuring liquid vapor pressure pipe should be connected up to the flow process piping, its Angle should not be less than 1/12;

3, for gas measurement, pressure pipe should be connected to the flow process piping, down the slope shall be not less than 1/12;

4, liquid guide to avoid high pressure pipe laying, gas guide pipe layout to avoid low;

5, two guide pressure pipe should maintain the same temperature;

6, to avoid friction influence, guide pipe diameter should be large enough;

7, fluid-filled guide should be no gas in the pressure tube;

8, when using a spacer, on both sides of liquid level to the same pipe.

Eight, use the matters needing attention:

1, the differential pressure transmitter before use must be the measuring range, zero drift, accuracy and error of static pressure after school.

2, after installation in the transmitter, I still need to check before driving a variety of job stress, temperature transmitter, the measuring range, drift, etc.To see if and actual situation, if there are discrepancies, you must find out the reason and correct to drive.

3, open and stop when, should avoid instrument under unidirectional static pressure.

Nine,Selection of code:

Ten, design selection and ordering information:

1, ZW3851DP series Numbers, symbols of differential pressure transmitter type specification table must fill in the clear, accurate.

2, if you have positive and negative migration, must indicate the migration amount value.

3, differential pressure transmitter to match three valve group, the throttle device, need to be indicated separately.

4, according to the user specified range checking.If the user has no rules, set at maximum range in the transmitter, the check will be carried out under room temperature and atmospheric pressure.

5, need labeling station number, should be indicated when ordering.

6, if the remote transmitter should be used in vacuum and high temperature occasion, special label when you order.

After-sales service commitment:

1, our company sold by differential pressure transmitter series products appear quality problem, within twelve months for free maintenance.

2, the warranty period, any quality problems such as the products of our company, my company is responsible for free repair or replacement.

3, the warranty period, such as user improper use, damaged products, my company is responsible for the maintenance, charge damage parts cost.

4, after the warranty period appear quality problem, my company is responsible for the maintenance, charge damage parts cost.

5, such as user need to my company site services, to users in the province I company service personnel to reach the site within 12 hours, fujian association of foreign languages and user reach the site within 48 hours.