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The metal tube float flow meter is a variable area flow measuring instrument commonly used in industrial automation process control. It has the characteristics of small size, large detection range and convenient use. It can be used to measure the flow of liquids, gases and vapors, and is especially suitable for medium flow measurement with low flow rates and small flows. What are the advantages of metal tube float flow meter products?

1. High temperature resistance, high pressure resistance and corrosion resistance

The ability to measure high temperature, high pressure fluids is a major advantage of metal float flow meters, which measure liquid and gas flows up to 400℃and pressures up to 70 MPa. In this case,  the floating position can not be observed with the human eye, but the flow rate can be indicated by the magnetic coupling induction display system. The flow meter itself is often made of high quality stainless steel, some lined with engineering plastics to measure corrosive fluids.

2. Wide range of applications

Flexible design according to flow process parameters. For example, at low temperatures, if the medium tends to crystallize and solidify. Or to prevent the low temperature fluid from absorbing heat from the outside. Or when the fluid in the pipeline passes through the instrument at a temperature higher than room temperature, due to the temperature drop, the float does not work properly, the fluid viscosity has a significant change affecting the measurement of special needs,Or the fluid viscosity has a significant change affecting the special needs of the measurement, the flow meter with jacket insulation design can be used; the flow pulsation is large, and the flow meter with damping measures can be selected; the jacketed heat preservation flow meter can vacuum the interlayer to achieve the purpose of heating and heat preservation; when measuring high temperature fluid. A heat sink is designed in front of the indicator.

3. Flexible interface

The metal tube float flow meter can conveniently meet the installation conditions of the field pipeline.The inlet and outlet of the metal tube float flow meter can be designed with the structure of vertical inflow and horizontal outflow, vertical inflow and vertical outflow, horizontal inflow and outflow, and horizontal inflow and horizontal flow with different heights.

4. Remote measurement and control, intelligent operation

The metal float flow meter has no auxiliary power supply in the measurement field in many cases, and the pointer display flow does not need to be driven by an external power supply. Usually, the display has a modular remote analog signal output interface (4 mA to 20 mA). More advanced is also equipped with a digital interface compatible with the HART communication protocol, which can be used to calibrate and test the linearity of the transmitter by manual operation or PC programming, or to perform on-site parameter tuning and computer integration to implement remote measurement and control.

Disadvantages of metal tube float flow meters:

1. When the fluid is used and the factory calibration fluid is different, the flow indication value correction is required. The rota meter for liquids is usually calibrated with water, and the gas is calibrated with air. If the actual density and viscosity of the fluid are different, the flow rate deviates from the original index value and is corrected for conversion.

2. The glass rotator flow meter has the risk of fragile glass tubes, especially for non-guided structure floats for gas.

3. Most structural float flow meters can only be used for pipeline installations from bottom to top vertical flow.

4. Rotor flow meter application is limited to small and medium diameter pipe. Ordinary full flow type rotary flow meter cannot be used for large diameter. Glass tube rotor flow meter has maximum diameter of 150mm, metal rotor flow meter is 200mm, and larger diameter can only be used with diverting flow instrument.

Modern sensors vary widely in principle and structure. How to select   sensors  reasonably according to specific measurement purposes, measurement objects and measurement environment is the first problem to be solved when measuring a certain quantity. When the sensor is determined, the matching measurement method and measuring device can be determined. The success or failure of the measurement results largely depends on whether the sensor's selection is reasonable.

1. Determine the type of sensor according to the measured object and measurement environment

To carry out a specific measurement work, we must first consider the principle of the sensor,which needs to be determined after analyzing various factors.Because, even if measuring the same physical quantity, there are also many kinds of sensors to choose, which principle of sensor is more suitable, then we need to consider the following specific problems according to the characteristics of the measured quantity and the use conditions of the sensor: the size of the measurement range; the requirements of the measured position on the volume of the sensor; the measurement method is Contact or non-contact; signal extraction method, wired or non-contact measurement; the source of the sensor, domestic or imported,  the price can withstand or not,or self-developed.

After considering the above issues, you can determine which type of sensor to use and then consider the specific performance of the sensor.

2. Sensitivity selection

Generally, in the linear range of the sensor, the higher the sensitivity of the sensor is, the better. Because only the sensitivity is high, the value of the output signal corresponding to the measured change is relatively large, which is beneficial to signal processing.However, it should be noted that the sensitivity of the sensor is high, and the external noise that is not related to the measurement is easily mixed in, and is amplified by the amplification system, which affects the measurement accuracy. Therefore, the sensor itself should be required to have a high signal-to-noise ratio, and the interference signal introduced from the outside is reduced.

The sensitivity of the sensor is directional. When the measurement is a single vector and its directivity requirements are high, other sensors with small sensitivity should be selected; if the measurement is a multi-dimensional vector, the cross sensitivity of the sensor is required to be as small as possible.

3. Frequency response characteristics

The frequency response characteristics of the sensor determine the frequency range to be measured.The measurement conditions must be kept undistorted within the allowable frequency range. In fact, the response of the sensor always has a certain delay, and the shorter the delay time, the better. The frequency response of the sensor is high, the measurable signal frequency range is wide. Due to the structural characteristics, the inertia of the mechanical system is large, and the frequency of the measurable signal is low because of the sensor with low frequency.

In dynamic measurement, the response characteristics should be based on the characteristics of the signal (steady state, transient, random, etc.) to avoid excessive error.

4. Linear range

The linear range of the sensor is the range in which the output is proportional to the input. In theory, within this range, the sensitivity remains constant. The wider the linear range of the sensor, the larger the range and the guaranteed measurement accuracy. When selecting a sensor, when the type of sensor is determined, it is first necessary to see if its range meets the requirements. But in reality, any sensor can't guarantee absolute linearity, and its linearity is relative. When the required measurement accuracy is relatively low, within a certain range, the sensor with less nonlinear error can be approximated as linear, which will bring great convenience to the measurement.

5. Stability

The ability of a sensor to remain unchanged after a period of use is called stability. In addition to the structure of the sensor itself, the factors affecting the long-term stability of the sensor are mainly the use environment of the sensor. Therefore, in order to make the sensor have good stability, the sensor must have strong environmental adaptability.

Before selecting a sensor, investigate the environment in which it is used, select the appropriate sensor according to the specific use environment, or take appropriate measures to reduce the environmental impact. The stability of the sensor has a quantitative index, and it should be calibrated again before use to determine whether the performance of the sensor has changed.In some cases where the sensor is required to be used for a long period of time and cannot be easily replaced or calibrated, the selected sensor has stricter stability requirements and can withstand the test for a long time.

6.Accuracy

Accuracy is an important performance index of sensor, it is an important link related to the measurement accuracy of the whole measurement system.The higher the accuracy of the sensor, the more expensive it is. Therefore, the accuracy of the sensor can be as long as   meets the accuracy requirements of the entire measurement system, and it is not necessary to select too high. This makes it possible to select a cheaper and simpler sensor among the many sensors that meet the same measurement purpose.

If the purpose of the measurement is qualitative analysis, with high repetition accuracy can be selected.but the sensor with high absolute value accuracy is not suitable. If it is for quantitative analysis, it is necessary to obtain precise measurement values, it is necessary to select a sensor with an accuracy class that meets the requirements.For some special applications, if you can't choose the right sensor, you need to design and manufacture the sensor yourself.The performance of the home-made sensor should meet the requirements for use.

Principle of magnetic flapper level indicator

The magnetic flapper level indicator is mounted on the outside or above the tank to indicate and control the seal type in the tank.The drain valve  and the connecting flange can be installed as needed.The indicator is composed of magnetic color plates. When the magnetic float ball in the main pipe flips with the liquid level rising, the liquid level can be displayed. A magnetic switch or a remote transmitter can also be installed on the main pipe to output switch signals or analog signals. It is suitable for high temperature, high pressure, corrosion resistant and other occasions.Local display and remote control.The main pipe adopts seamless steel pipe, and the connecting pipe is welded by a pull hole, and the inside is free from scratches.The mounting method can be side-mounted and top-mounted, and the lower end of the body is sealed.

Purchase on selection of magnetic flapper level indicator

Magnetic flapper level indicator is also called magnetic level gauge, magnetic column level gauge,magnetic float level gauge. It works on the principle of magnetic coupling. The product makes up for the multiple shortcomings of glass tube level gauge which can not work under high temperature and high pressure and is fragile.

Magnetic flapper level indicator has two mounting methods: side mount and top mount. No matter which way, the remote transmission device can be bundled, so that the liquid level gauge can display the liquid level on site and remotely monitor the liquid level. The magnetic flapper level indicator can be called a remote transmission type magnetic flapper level indicator.

Although the process of making a magnetic flapper level indicator is very simple, but the magnetic flapper level indicator as measuring instrument, especially remote transmission type magnetic flapper level indicator.It is difficult to guarantee the quality of the products without a production license if they are not examined by the Quality Supervision Bureau.Therefore, it is necessary to choose a manufacturer with a production license and good reputation for purchasing the magnetic flapper level indicator.The price may be slightly higher, but the quality of the product is guaranteed and the after-sales service is guaranteed.

In fact, the vacuum gauge is a kind of pressure gauge.

There are several kinds of work principles.

Classification by vacuum gauge measurement principle

Directly measured vacuum gauge, which directly measures the force per unit area, has:

(1) Static liquid level vacuum gauge: The pressure is measured by the liquid level difference at both ends of the U-shaped tube.

(2) Elastic element vacuum gauge:The surface of the container connected to the vacuum is subjected to pressure to generate elastic deformation to measure the magnitude of the pressure value.

Indirectly measured vacuum gauge, when the pressure is 10-1 Pa, the force acting on the surface of 1 cm 2 is only 10-5 N, and it is obviously difficult to measure such a small force. However, the change in pressure can be measured indirectly based on changes in physical quantities associated with gas pressure at low pressure. Vacuum gauges belonging to this category are:

(1) Compressed vacuum gauge: The principle is to apply Boyle's law on the basis of the U-tube, that is,a certain amount of gas to be tested  is subjected to isothermal compression to increase the pressure,  so as to be measured by a U-tube vacuum gauge. Then calculate the measured pressure using the relationship between volume and pressure.

(2) Heat conduction vacuum gauge: It is made by the principle that the heat conduction of gas under low pressure is related to pressure. Commonly used are resistance vacuum gauges and thermocouple vacuum gauges.

(3) Thermal radiation vacuum gauge: The principle of thermal radiation of gas under low pressure is related to pressure.

(4) Ionization vacuum gauge: The principle that the gas molecules are impacted and ionized by the charged particles under low pressure,and the generated ion current changes with the electric power.Such as: hot cathode ionization vacuum gauge, cold cathode ionization vacuum gauge and radioactive ionization vacuum gauge.

(5) Discharge tube indicators:The degree of vacuum is determined by the nature of the gas discharge condition and the discharge color are related to pressure, generally only as a qualitative measurement.

(6) Viscous vacuum gauge: The principle of external friction is used to exchange the momentum of the gas and the vessel wall under low pressure. Such as diaphragm vacuum gauge and magnetic suspension rotor vacuum gauge.

(7) Field-induced microscopy:The pressure is calculated by the relationship between adsorption and desorption time and pressure.

(8) Partial pressure vacuum gauge: The mass spectrometry technique is used to measure the partial pressure of the mixed gas. Commonly used are quadrupole mass spectrometers, cyclotron mass spectrometers, and radio frequency mass spectrometers.

Vacuum gauges are generally used for negative pressure. Compared with ordinary pressure gauges, it is only the difference between the range of pneumatic pressure and the accuracy.

The measurement range of the vacuum pressure gauge is 0-1 atmosphere, and the ordinary pressure gauge is usually an amount of atmospheric pressure of 0-tens, several hundred or even more. The measured readings will be much more accurate when the range is selected.

1. Measuring principle of radar level meter

The radar liquid level meter adopts the operating mode of transmitting -reflection-receiving.The antenna of the radar level meter emits electromagnetic waves,which are reflected by the surface of the measured object and then received by the antenna.The time from transmitting to receiving of electromagnetic waves is proportional to the distance to the liquid surface.The formula is as follows: D=CT/2

In the formula, D——the distance from the radar level meter to the liquid level; C——the speed of light; T—— the running time of electromagnetic waves.

Radar level meter records the duration time of pulse wave,and the transmission speed of electromagnetic wave is constant, then the distance from the liquid surface to the radar antenna can be calculated to know the liquid level of the liquid surface.  

In practice, there are two ways for radar level meters,namely, frequency-modulated continuous wave and pulse wave.The liquid level meter adopting the frequency-modulated continuous wave technology has large power consumption and must adopt a four-wire system, and the electronic circuit is complicated.The liquid level meter using radar pulse wave technology has low power consumption and can be powered by two-wire system 24V DC, which is easy to achieve intrinsic safety, high accuracy and wider application range.The VEGAPULS radar level meter uses pulsed microwave technology.Its antenna system emits a pulse beam with a frequency of 6.3 GHz and a duration time of 0.8 ns,and then pauses for 278 ns.During the pause period of the pulse transmission,the antenna system will act as a receiver,receive the reflected wave, and simultaneously perform echo image data processing to give the indication and the electric signal.

2. Characteristics of radar level meter

(1) Radar level meter adopts integrated design ,without movable parts,no mechanical wear, long service life.

(2) The electromagnetic wave emitted by the radar level meter can pass through the vacuum without any transmission medium, and has the characteristics of being free from the influence of the atmosphere, steam and volatile fog in the tank, and can be used for the liquid level measurement of the volatile medium,such as crude benzene.

(3) The radar level meter can be used for liquid level measurement of almost all liquids.When the electromagnetic wave is reflected on the surface of the liquid level, the signal will attenuate.When the signal attenuates too much,the radar level meter can not detect enough electromagnetic wave signal. Conducting medium can reflect electromagnetic wave well.For the VEGAPULS radar level meter, even micro-conducting substances can reflect enough electromagnetic waves.Non-conductive media with dielectric constant greater than 1.5 (the dielectric constant of air is 1.0) can also ensure sufficient reflected waves,and the larger the dielectric constant, the stronger the reflected signal. In practical,almost all media can reflect enough reflected waves.   

(4) Non-contact measurement is adopted, which is not affected by physical properties such as density and concentration of liquid in the tank.

(5) The measuring range is large, and the largest measuring range is 0~35m,which can be used for liquid level measurement of high temperature and high pressure.

(6) The antenna and other key components are made of high-quality materials, which have strong corrosion resistance and can adapt to a strong corrosive environment.

(7) Rich in functions,with a false wave learning function. Enter the actual liquid level of the liquid level,the software can automatically identify the false echo from the liquid level to the antenna,and eliminate the interference of these waves.

(8) The parameter setting is convenient,and can be set by the simple operation key on the liquid level meter.It can also be set remotely or directly to the communication end of the level meter by using the HART protocol operator or a PC equipped with VEGA Visual Operating software.

When installing and using the thermocouple temperature sensor, you should pay attention to the following matters to ensure the measurement results:

1. Error caused by improper installation

For example, the installation position and insertion depth of the thermocouple cannot reflect the real temperature of the furnace.In other words, the thermocouple should not be installed too close to the door and heating place, the insertion depth should be at least 8-10 times of the diameter of  the protective pipe;The gap between the protective sleeve and the wall of the thermocouple is not filled with adiabatic substances,so that the heat in the furnace overflows or the cold air invades.Therefore, the gap between the thermocouple protective pipe and the hole of the furnace wall should be blocked by adiabatic substances such as refractory mud or asbestos rope to avoid the convection of hot and cold air, which affects the accuracy of temperature measurement;The cold end of the thermocouple is too close to the furnace to make the temperature exceed 100 ℃; Thermocouples should be installed as far as possible to avoid strong magnetic fields and strong electric fields. Therefore, thermocouples and power cables should not be installed in the same conduit to avoid errors caused by interference; The thermocouple cannot be installed in the area where the measured medium rarely flows.When the temperature of the gas in the pipe is measured by a thermocouple, the thermocouple must be installed against the flow velocity direction and fully in contact with the gas.

2. Error caused by insulation deterioration

For example,the thermocouple is insulated, too much dirt or salt residue of the protective pipe and the drawing board may lead to poor insulation between the thermocouple and the furnace wall,and it is more serious at high temperature,which not only causes the loss of the thermoelectric potential but also introduces interference.  

3. Error caused by thermal inertia

Because of the thermal inertia of the thermocouple,the indication value of instrument is behind the change of the measured temperature, which is especially prominent in the rapid measurement.Therefore, thermocouples with thinner thermal electrodes and smaller diameters of protective pipes should be used as much as possible.When the temperature measurement environment permits, the protective pipe can even be removed.Because of the measurement lag, the amplitude of temperature fluctuation detected by thermocouple is smaller than that of furnace temperature fluctuation.The larger the measurement lag, the smaller the amplitude of the thermocouple fluctuation, and the greater the difference from the actual furnace temperature.When the temperature is measured or controlled by a thermocouple with a large time constant, although the temperature displayed by the meter fluctuates little, the fluctuation of the actual furnace temperature may be large.In order to accurately measure the temperature, a thermocouple with a small time constant should be selected. The time constant is inversely proportional to the heat transfer coefficient, and is proportional to the diameter of the hot end of the thermocouple, the density of the material, and the specific heat, if the time constant is to be reduced, the most effective way is to reduce the size of the hot end as much as possible, in addition to increasing the heat transfer coefficient.In use, it is usually a material with good thermal conductivity, a protective pipe with a thin tube wall and a small inner diameter. In the more precise temperature measurement,a bare wire thermocouple without a protective sleeve is used, but the thermocouple is easily damaged and should be corrected and replaced in time.

4. Thermal resistance error

At high temperatures, if there is a layer of coal ash on the protective pipe, dust attached to it, the thermal resistance increases, hindering the conduction of heat, at this time the temperature indication is lower than the true value of the measured temperature.Therefore, the external cleaning of the protective pipe of thermocouple should be kept to reduce the error.

V-cone flow meter is a new type of differential pressure flow meter.In addition to all the advantages of differential pressure flow meter,the V-cone flow meter has the lowest requirement for straight pipe section in all differential pressure flow meters.Here are the main features and technical parameters of the V-cone flow meter:

1. High accuracy and high repeatability

The measurement accuracy of V-cone flow meter can reach + 0.5% and repeatability is between ±0.1%.

2. Wide range

The range of the V-cone flow meter is beyond the traditional differential pressure flow meter, and the range ratio can reach 10:1.

3. No harsh requirements for straight pipe section

The V-cone can effectively improve the profile of the flow velocity distribution, making it more able to reduce the requirements for upstream straight pipe sections than other differential pressure instruments. The V-cone upstream straight pipe section 1-2D, downstream 3-5D.This greatly reduces the cost consumption and trouble of the user on the straight pipe section.

4. self-cleaning function

Acceleration of the flow velocity at the pipe wall makes the viscous impurities,condensate,and dust in the fluid can not be deposited or adhered to the pipe wall near the V cone and the cone,and the pressure guiding hole is not easily blocked.

5. Wear resistance, good long-term stability

The cone throttling element is designed to be obtuse. When the fluid passes through the cone, the boundary layer is formed,leaving the fluid out of the throttling element.The boundary layer effect prevents the dirty fluid from wearing the throttling element,while its self-cleaning function keeps the inner diameter of the pipe constant.Therefore, its β value remains unchanged for a long time,so there is no need to repeatedly calibrate,and has long-term stability.

6.Stable differential pressure signal

Traditional differential pressure flow meters have a "signal jump" phenomenon, which means that even if the fluid flow is stable,the signal pulsations still exist.The constant eddy current caused by the common orifice plate produces low-frequency, large-amplitude interference signals, which seriously affects the stability of differential pressure and the V-cone flow meter is the opposite. It produces a small vortex with high frequency and low amplitude, which has little effect on the stability of the differential pressure.Typical applications:coke oven gas, flue gas,  propylene gas,natural gas, hydrogen, nitrogen, organic gases, air, circulating water, multiphase liquid, slurry, liquefied petroleum gas, feedstock oil, ammonia steam, etc.

7.Small relative pressure loss

Because there is no sharp edge, the pressure loss caused by V-cone flow meter is constant and much smaller than that caused by orifice plate.

8. Wide range

It can measure liquid, gas, steam and gas-liquid two-phase medium. The flow conditions can be from low temperature to supercritical state, the working temperature is up to 800℃,the maximum pressure is 40 MPa,and the differential pressure signal generated is from the lowest  less than 0.1 KPa to the highest 10 KPa.

1. Meter size. That is, the size of the meter, this is a very basic problem. The digital display meter should be installed on the cabinet, so it is necessary to consider the overall coordination. If it is too large, it may not be installed. If it is too small, the display number will not be seen clearly . In addition, the large-sized instrument generally has strong  functional extensibility, and the same function price may be expensive,and the small-sized instrument may have poor functional extensibility.At present, the international standard sizes of digital display meter plates are mainly as follows: 48*24mm; 48*48mm; 48*96mm; 72*72mm; 96*96mm; 96*48mm; 160*80mm.  

2. Display digits.This is directly related to the measurement accuracy of the digital display meter.Generally speaking, the higher the display digits, the more accurate the measurement,and the more expensive the price, mainly the following:two digits (99, special); three digits (999, very few); three and a half digits (1999, the general digital display meter is the mainstream); four digits (9999, intelligent digital display is the mainstream); four and a half digits (19999); four and three-quarters digits(39999);five digits and more than five digits (common in counters, accumulative meters and high-end instruments),users can select several digits digital display meters according to measurement accuracy requirements.

3. Input signal. Refers to the measurement signal directly input into the instrument.Some industrial signals are directly connected to the instrument to measure. Some signals are connected to the instrument after being converted,and the nature of the measurement signal must be clarified.Otherwise,the instrument can not be used, or even damage the instrument and the original equipment. To find out the type of signal: current or voltage, AC or DC, pulse signal or linear signal, etc., but also to understand the size of the signal. The name of the meter is not the same concept as the input signal. For example, the input signal is a 0-75mVdc ammeter (the name is an ammeter, but the input signal is a voltage signal because the current is passed through the shunt to obtain the voltage signal); the input signal is 0- 10Vdc tachometer (name is tachometer, input signal is voltmeter, because the inverter converts the speed signal into voltage signal).

4. Working power. All digital display meters require working power. The working power of the digital display meter mainly includes: 220Vac; 110/220Vac; 85-265VAC/DC switching power supply, 24Vdc (generally customized), 5Vdc (small panel meter).

5. Instrument function.Instrument functions are generally modular,optional, the price of the instrument will vary with the function, The digital display meter mainly has the following optional functions:alarm function and the number of groups of alarm output(i.e. relay action output), feed power output and output voltage size and power, transmitting output and transmitting output type(4-20mA) Or 0-10V, etc.), communication output and communication methods and protocols (RS485 or RS232, Modbus or other protocols), for the regulating control Instruments, optional functions are more,specifically, refer to the manufacturer's selection spectrum to select a standard model, and communicate with the manufacturer and confirm that it is correct before ordering.

6. Several important parameters should be paid attention to:  measurement accuracy (the smaller the value is more accurate),response speed (the smaller the value，the faster the response),the working environment, temperature coefficient (the smaller the value is less affected by temperature),overload capacity.

7. Special requirements. If the user has special requirements, it should be proposed to let the manufacturer confirm whether it can meet the requirements. Do not take it for granted. For example, IP protection level, high temperature working place, strong interference occasion, special signal occasion, special working mode, etc.

In fact, the selection of digital display meter is not complicated.For simple digital display meter,you can buy it to use.For those users who use it for the first time or choose a digital display meter with complex function, as long as you grasp the above points, you can also purchase the right product.

The magnetic flapper level indicator, also called the magnetic float level gauge,is a kind of field level gauge that the magnetic float picks up reed switch of the corresponding position in the sensor while the rise and fall of liquid level,so that the total resistance (or voltage) in the sensor changes correspondingly, and then converts the change of resistance (or voltage) into the standard current output of 4-20mA DC through the transmitter.

When purchasing a magnetic flapper level indicator, you should pay attention to:

1. The parameters of the product must be known in advance. For example, the corrosive medium needs anti-corrosion material, and the anti-corrosion grade varies according to the corrosive grade of the medium.

2. The special condition of the equipment also determines the installation method of the magnetic flapper level indicator, because some occasions are not suitable or not applicable at all.

Therefore, when purchasing, the user should first make clear the operating situation of their equipment and what the medium is, and then consider how to choose the magnetic flapper level indicator from the following aspects:

(1) The magnetic flapper level indicator should be tightly attached to the main leading pipe of the liquid level gauge and fixed with a stainless steel hoop;

(2)The induction surface should be oriented and tightly attached to the main leading pipe.

(3) The zero position of the magnetic flapper level indicator shall be on the same horizontal line as the zero position indication of the liquid level gauge;

(4) The connection between the magnetic flapper level indicator and the display instrument or the industrial computer is preferably laid by a protective tube alone or with a shielded two-core cable;

After the inlet hole of the junction box is laid, the sealing is required to be good, so as to prevent the intrusion of rainwater and moisture, so that the remote transmission instrument can not work normally. The junction box should be covered in time after the repair or debugging is completed.

Finally, users also need to remove impurities from the main leading pipe from time to time depending on the medium.

With the continuous development of digital technology and microcomputer technology, digital display meters and new display and recording instruments with single-chip microcomputer as the core are more and more widely used in the field of industrial automation and industrial control. The digital display meter, like the pointer meter, matches with various sensors and transmitters to measure electric power, pressure, level, liquid level, flow rate and temperature, and directly displays the measured results in digital form.

Classification of digital display meters:

According to the signal form: ammeter, voltmeter, frequency meter...

According to the number of measurements:single point meter, multi-point meter

According to function: simple display, display alarm meter, display transmission meter, display communication meter, display record meter, multi-function meter, etc.

Characteristics of single loop digital display controller

Simple measurement and display controller adopts modular structure scheme, simple structure, easy operation, cost-effective,and high cost performance. It is suitable for plastics, food, packaging machinery and other industries.

★Single channel input, dual screen LED digital display.

★ With 33 kinds of signal input functions, the input signal type can be arbitrarily selected,and the measurement accuracy is 0.3%.

★The resolution of thermal resistance\thermocouple signal can be switched: 1°C or 0.1°C.

★ With upper and lower limit alarm function, with LED alarm lamp indication.

★ The voltage and current transmission output signals are optional.

★ Support RS485 serial interface, using standard MODBUS RTU communication protocol.

★ With DC24V feed output,power distribution for field transmitter.

★ Photoelectric isolation technology is used each other among input, output, power supply, and communication.

★It has many outline dimensions and styles for users to choose.

★ After the parameter is set, the password is locked, and the parameter setting is permanently saved after power off.