Capacitance type level gauge

Products overview:

ZW - DB701 seriesCore parts adopt advanced radio frequency capacitance detection circuit through 16 bit single chip microcomputer through a precise temperature compensation and the linear correction, into a standard electrical signals (usually 4 ~ 20 mA).Optional HART, CANBUS, 485 communication protocols for system configuration.All series transmitter has self-calibration function, the user can through the two buttons "zero", "range" automatic calibration, to adapt to the different requirements of various kinds of complicated place.

Second, the working principle:

ZW - DB701 series capacitor input type level gauge adopts diffusion silicon or ceramic piezoresistive effect of sensitive element, the static pressure into electrical signals.After temperature compensation and the linear correction.Converted into a standard 4-20 madc current signal output.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: liquid surface atmospheric pressure;

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 series capacitor input type level gauge is widely used in petroleum, chemical industry, light industry, medicine, metallurgy, food and other industrial systems, as well as hydrological measurement and monitoring, dam water level measurement, ships and navigation system, city and water system, circulating water and sewage treatment system, etc.

Four, the main features:

1, good stability, high precision, the inputting type directly into the liquid level transmitter of the measured medium, install and use is very convenient.

2, solid structure, no moving parts, high reliability, long service life from water and oil to larger viscosity paste 3, shape measurement can be performed, not by foaming measured medium, deposition, the influence of the electrical characteristics of wide range of temperature compensation.Cable type liquid level transmitter has a power reverse polarity protection and overload current limit protection.

Five, the technical parameters:

1, the measuring range: 0.3 ~ 100 m precision (optional) by the user: 0.2, 0.5, 1.0;

2, working temperature: - 20 ~ 80 ℃;

3, the output signal: two wire 4 ~ 20 madc;

4, power supply voltage: 24 VDC standards (12 ~ 36 VDC);

5, insensitive area: plus or minus 1.0% or less FS.

6, load capacity: 0-600 Ω;

7, relative humidity: 85% or less.

8, protection grade: IP68;

9, explosion-proof marks: Exia Ⅱ CT4-6.

Six, installation and debugging methods:

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 liquid level position in zui 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 at zui highs, 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, the output current automatically adjusts to 20 ma.

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.

Seven, note:

1, the supply of products with product certificate and instruction manual with the product serial number, technical parameters, wiring diagram, production date, etc. Please check carefully to avoid using wrong.

2, when installation should be according to the product connection and screw type, check the site interface is consistent with the product interface.For screw thread interface, should slow tightened, pay attention to the sealing, can't add the torque directly to the transmitter shell, can only add on the six-party transducer interface.

3, connection should be in strict accordance with the company I use for connection.

4, this product is a precision in instrument, banned free disassembly, collision, drop, play hard.

5, the transmitter power can work, but warm up 30 minutes output stability.

6, if discovery is unusual, in use should turn off the power and stop using, check, or directly to our technical department.

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

8, installation and use process should pay attention to not put the induction of the skin of the wire broken.

9, when installation induction leads to at least more than 10 cm away from the pool wall, otherwise not accurate measurement.

10, all four fluorine structure and lever type level ground wire must be measured medium conduction, and measurements are not accurate.

11, installation site should take effective lightning protection measures.

12, the series of any liquid level transmitter enclosure must be reliable grounding, grounding resistance should be less than 4 Ω.

13, according to the security gate flame-proof certification, its installation should be according to the requirements of the specification.

Eight, selection of code:

Nine, design selection and ordering information:

1, model specifications: ZW - DB700 input type level gauge series;

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

3, measurement 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.