RF capacitive bar type level meter

Productoverview:

ZW-LT702 series The core components of the RF capacitance detection circuit is advanced after 16 bit microcontroller after temperature compensation and precise linear correction, converted into standard electric signal (4~20 mA). The optional HART, CANBUS, 485 communication protocol system configuration. The whole series transmitter has self calibration function, the user can through the two buttons to "zero" and "range" automatic calibration, with different requirements to adapt to a variety of complex sites.

Two, work principle:

ZW-LT702 Series RF capacitive bar type level meter based on capacitive sensor, when the liquid level transmitter into the measured liquid in a certain depth, the pressure sensor at level formula: P = P.G.H + Po

Type:

P: welcome to the pressure liquid level transmitter

P: the measured liquid density

G: the local acceleration of gravity

Po: the surface atmospheric pressure

H: transmitter input liquid depth

At the same time, the pressure of the liquid into the positive pressure chamber through the gas sensor of stainless steel, then vacuum cavity pressure sensor and Po on the surface of the sensor is connected to offset on the back of the Po, the sensors for pressure: P.G.H, obviously, by measuring the pressure of P, can get the level of depth.

Three, application:

ZW-LT702 Series RF capacitive bar type level meter suitable for high temperature and high pressure, strong corrosion, easy to crystallize, easy to plug the harsh conditions of continuous detection of various liquids. The water level measurement for sewage, pH value, and the boiler, the machine without any movable or elastic components, impact resistance, convenient installation, high reliability, high precision. Float, can replace the traditional input type, differential pressure type liquid level transmitter used in various occasions.

Four, main features:

1, has the advantages of simple structure, without any movable or elastic components, so high reliability, little maintenance. Under normal circumstances, do not have regular large, medium and small repair.

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

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

4 measurements, especially suitable for acid, alkali and other strong corrosive liquids.

5, perfect overcurrent and overvoltage protection and power supply polarity protection.

Five, technical parameters:

Measuring range: 0.2-20 meters;

Accuracy: + 0.5% + 1%;

Probe temperature: -40~+250 degrees;

The transmitter to adapt to the environment temperature: -40~+60 degrees;

Allow the pressure: -0.1MPa~2.5MPa;

Medium: conductivity is not the end of the 10-3S/m of acid and alkali, water and other non conducting liquid crystal;

Power supply voltage: DC12-35V (isolated DC21-27V);

The non isolated line, three line: 20mA;

Three wire ends of isolation: <32mA;

Three terminal four line: <35mA;

Output signal: 4-20mA (0-10mA, 0-20mA);

Output protection: 27mA;

Voltage isolation between the measurement and the output power: 1000V;

Range adjustment range and zero migration: = + 30%FS;

The transmitter body size: Phi 76 * 85.

Six, level transmitter installation and debugging:

1, the liquid level transmitter with a plurality of installation, in order to adapt to different site conditions. When the site does not provide M20 * 1.5 internal thread or flange processing facilities, can choose the wall mounted, horizontal tube type and vertical tube type three installation options, make your handy in the on-site installation.

In 2, medium measuring greater liquidity, in order to prevent the sensor sharp swings the user can choose to play a stable weight attachment, the role of the sensor with weight must be to the weight of objects into the bottom of the container, so as not to pull the bad conductor.

3, in the field of environment is bad, the user should choose the sensor protection cover to protect the sensor, the measurement accuracy of the foreign body to avoid being damaged or infected.

4, the use of bar type liquid level transmitter, if not the metal containers, you need to put a wire connecting the bottom of the container with the transducer shell, otherwise the measurement is not accurate.

This product has been calibrated at the factory, if you need to adjust the site can take the following methods:

1, the debugging method of intelligent circuit:

The zero - position when the liquid level is low, at the same time, press the "Z" button and the "S" button for 8 seconds and then release the "Z" button, the output current is automatically adjusted to 4mA.

Full - field adjusting when the liquid level is high, at the same time, press the "Z" button and the "S" button for 8 seconds and then release the "S" button, the output current is automatically adjusted to 20mA.

2, the debugging method of analog circuit:

When the liquid level in the lower limit, the screwdriver is rotated slowly "Z" potentiometer, observe the meter readings close to 4mA.

When the liquid level in the cap with a screwdriver, slowly rotating "S" potentiometer, observe the meter readings close to 20mA.

Repeat 2-3 times, until the zero and span are respectively 4mA and 20mA accurately.

After adjustment, we should tighten the lid.

Seventh, measurement system:

The measurement system is intrinsically safe.

This type of pressure, differential pressure transmitter with intrinsically safe circuit, suitable for explosive hazardous area explosion-proof grade ExiallCT4-CT6.

In system loop shielded signal cable must be used, and reliable grounding. The measurement system wiring diagram only to the output signal of 4-20mA and 0-10mA as an example,

The liquid level transmitter has the advantages of reliable operation, stable performance, small size, light weight, low cost, design a variety of forms, convenient installation, no need to support. Electronic circuit board with microprocessor based, can automatically eliminate the influence of temperature change on the sensor accuracy.

This series of products can be equipped with liquid crystal display LCD for local operation.

Intelligent output at the same time with HART communication function.

Eight, matters needing attention:

1, all products are used with delivery instructions and certificate, including product number, technical parameters, the factory date, please carefully check, so wrong.

2, the power supply should be strictly in accordance with the instructions of my company wiring connection.

3, the use of abnormal findings, should turn off the power, stop using, check, or directly to the technical department of our company.

4, transportation and storage should restore the original packaging and store in a cool, dry and ventilated warehouse.

Nine, the selection of encoding:

Ten, design selection and ordering information:

1, specifications: ZW-LT700 series capacitance level meter;

2, the measured medium Name: medium density;

3, measurement range: also known as nominal length;

4, working pressure: pressure;

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

6, material requirements: wetted materials;

7, supporting the supply of flanges, bolts and nuts, valve, sealing washers and other accessories;

8 standard: flange and flange nominal diameter, DN20, DN25, DN50, DN80, DN100 etc.;

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

9, customer service service commitment:

1, I sold by the company level transmitter series product quality problems within 12 months, responsible for free maintenance.

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

3, the warranty period if the user use undeserved, cause damage to the product, our company is responsible for the maintenance, collect the damaged parts cost.

4, after the warranty period of product quality problems, our company is responsible for the maintenance, collect the damaged parts cost.

5, if the user needs to our service, our company in the province of the user service personnel arrived at the scene within 12 hours, arrived at the scene 48 hours outside users.