Capacitive liquid level transmitter

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Capacitive liquid level transmitter core parts adopt advanced radio frequency capacitance detection …

Products overview:

ZW - DB701/702 seriesCapacitive liquid level transmitterWith simple structure, strong and durable and stable form of variable capacitor, variable capacitance by pressure on the diaphragm and fixed in the cavity of the insulation of the electrode, when pressure changes, to produce slightly buckling deformation of diaphragm, and thus changed the spacing between the poles, adopt unique subtle change of capacitance detection circuit test, and linear processing and temperature compensation.Sensor output is proportional to the measured pressure of dc voltage or current signal.Ingenious structure, high performance materials, and the perfect combination of advanced detection circuit, gives the capacitance pressure transmitter with high performance.

Second, the working principle:

ZW - DB701/702 series capacitive liquid level transmitter based on capacitance induction principle, when the liquid level transmitter into the liquid to be tested in a certain depth, the sensor to meet the pressure on liquid surface formula is: Ρ = rho. We + Po

Type:

P: the pressure on the transmitter into liquid level

Rho: the measured liquid density

G: the local acceleration of gravity

Po: atmospheric pressure on the surface of liquid

H: transmitter into the depth of the liquid

At the same time, through the gas leading stainless steel will be introduced to the liquid pressure sensor of positive pressure cavity, and atmospheric pressure on the surface of the liquid Po and sensors connected to the negative pressure cavity, to offset the Po on the reverse of the sensor, the sensor measured pressure is: rho. We, obviously, through the acquisition of pressure P, can get the depth of the liquid level.

Applications:

ZW - DB701/702 series capacitive liquid level transmitter can be applied to high pressure, strong corrosion, easy to crystallization, easy to jam, prevent the liquid level under special conditions such as cold junction of continuous testing, can be widely used in electric power, metallurgy, chemical industry, food, pharmaceutical and other industries and sewage treatment, boiler steam drum, pulverized coal level measurement of packages and other places.

Four, the main features:

There were 1, simple structure, moving or elastic components, so the reliability is extremely high, little maintenance.In general, don't have to do regular large, medium and small maintenance.

2, a variety of signal output, convenient for different system configurations.

3, suitable for high temperature and high pressure container level measurement, and the measured value is not affected by the temperature of the liquid to be tested, proportion, and the shape of the container, pressure influence.

4, especially suitable for the measurement of strong corrosive liquid such as acid, alkali.

5, perfect over-current, over-voltage, power supply polarity protection.

Five, the technical parameters:

Measuring range: 0.2 to 20 meters;

Pure c: plus or minus 0.5% plus or minus 1%;

Agent very heat-resistant: - 40 ~ + 250 ℃;

Transmitter to adapt to the environment temperature: - 40 ~ + 60 ℃;

Allow the container pressure: 0.1 MPa to 2.5 MPa;

Measuring medium: conductivity in 10-3 s/m not at the end of the acid, alkali, such as water non-crystalline conductive liquid.

The power supply voltage: DC12-35 v (isolation type to DC21-27 v);

The isolation, three-wire system: 20 ma;

On both ends of the isolated three-wire system: < 32 ma;

Three-terminal isolated four wire: < 35 ma;

4-20 ma output signals: (0 to 10 ma, 0 to 20 ma);

The output protection: 27 ma;

Measurement, output, power supply isolation between compression: 1000 v;

Range adjustment range and zero migration: p plus or minus 30% FS.

Transmitter body size: Φ 76 x 85.

Six, measurement system:

Measurement system for this type.

This safety type pressure, differential pressure transmitter adopts the intrinsically safe circuit, suitable for explosion-proof grade ExiallCT4 - CT6 explosion danger area.

Shielding signal cable must be used in the system circuit, and reliable grounding.Below are just 4-20 ma output signal and the measurement system of 0 to 10 ma, for example the wiring diagram,

Liquid level transmitter has reliable operation, stable performance, small volume, light weight, low cost, refined design, a variety of structural form, easy installation, without stents.Circuit board USES the microprocessor based electronic technology, can automatically eliminate the influence of temperature change on the sensor precision.

This series of products can be equipped with LCD liquid crystal display (LCD), to facilitate the local operation.

Intelligent output with HART communication function at the same time.

Seven, installation and commissioning:

1, cable type and lever type liquid level transmitter has many installation fixed way, so as to adapt to different site conditions.When the site will not be able to provide M20 x 1.5 in the process facilities such as thread or the flange, can choose wall installation type, horizontal pipe frame and vertical posture, such as three optional installation way, make you comfortable when installation.

2, when measuring liquidity larger medium, to prevent violent oscillation sensor, the user can choose counterweight attachment, to have the effect of stable sensors, add weight must to put weight objects in the bottom of the container, in order to avoid pull bad sensing wires.

In the field environment is bad, the user should choose sensor shield to protect sensor, to avoid the foreign body damage or affect the accuracy of measurement.

3, when using the lever type liquid level transmitter, if not metal containers, you need to put the transmitter of the shell with a wire access the bottom of the container, otherwise not accurate measurement.

This product in the factory has a calibration, if need on-site adjustment can adopt the following methods:

1, using intelligent circuit debugging methods:

The zero -- -- -- -- -- - when the liquid level position is low, at the same time hold down the "Z" key and "S" key 8 seconds after release at the same time, then "Z" key press, the output current automatically adjusts to 4 ma.

Field adjustable full -- -- -- -- -- - when the liquid level high, at the same time hold down the "Z" key and "S" key 8 seconds after release at the same time, then the "S" key press, automatic adjustment to 20 ma output current.

2, USES the method of analog circuit debugging:

When the liquid level in the next period, use the screwdriver slowly rotating "Z" potentiometer, observe the ammeter reading close to 4 ma.

When the liquid level in the limited time, use a screwdriver slow rotation "S" potentiometer, observe 20 ma current meter reading is close.

So above 2 to 3 times repeatedly, until zero and range are accurate 20 ma ma and 4, respectively.

After adjust, should tighten the lid of the transmitter.

Eight, appearance and installation method:

Appearance:

Cable type liquid level transmitter consists of shell, amplifier, terminal blocks, helmets, hollow wire, etc, according to the needs of the user can choose a pointer table, LCD display meter.

Installation method:

1, choose easy to place for installation operation and maintenance;

2, shall be installed as far as possible away from the vibration source;

3, should be far away from heat source as far as possible;

4 when inputting type liquid level transmitter installation, cable, metal probe to sink to the bottom of the container.

Nine, note:

1, who supply products with instruction manual and the certificate of approval, including product number, technical parameters, production date, etc., please check carefully, lest use wrong.

2, connect the power supply shall be in strict accordance with my company connection wiring instructions.

Found in 3, the use of exception, should turn off the power and stop using, check, or directly to our technical department.

4 should be restored the original packaging, transportation, storage, stored in a cool, dry and ventilated warehouse.

Ten, selection of details:

1, indicate the measuring range (level of), for some special medium, indicate the density of the medium.

2, type selection, attention should be paid to contact with the product of the measured medium material compatibility, for special medium, can be customized.

More than 3, the product installation in the thunderstorm area, the order should be marked "lightning", recommend that users install against lightning protection device at the scene, and make sure products and power grounding.

4, about the selection of gas leading cable length: general than the actual level of 1 ~ 2 meters long.

Eleven, selection of coding:

Twelve, design selection and ordering information:

1, model specifications: ZW - DB700 series;

2, the name of the measured medium, medium density;

3, instrument measuring range: can also be referred to as the nominal length;

4, work pressure, work under pressure;

5, working temperature: measuring the temperature of the liquid;

6, material requirements: liquid material;

7, whether matching supply flange, bolts, nuts, valves, fittings, such as sealing washer;

8, flange standard: nominal size of the flange, 3/4 ", DN25, (, DN80, DN100, etc;

9, special requirements: before ordering, please indicate in detail.

After-sales service commitment:

1, our company sold by liquid level transmitter series products within twelve months appear quality problem, is responsible 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.