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In the field of industrial automation, the unification of signal standards is crucial. It is directly related to whether the entire industrial production system can operate efficiently and stably. In the early development of industrial automation, the issue of instrument signal standards was like a thorny problem, which seriously restricted the further development of the industry.   In the early days, there was no unified signal standard for instruments in the field of industrial automation. This is like being in a city without traffic rules, where vehicles drive randomly and in chaos. The signal standards of instruments and meters produced by different manufacturers vary widely.   This directly causes the design of many downstream equipment to become extremely complex. Take the design of displays as an example. Since they have to adapt to various signal standards, engineers need to spend a lot of time and energy adjusting circuits and optimizing programs. Not only that, the installation and maintenance costs of the equipment have also increased significantly. Imagine that maintenance personnel need to master the signal standards and debugging methods of many different devices. This is undoubtedly a huge challenge. Moreover, compatibility issues between different signal standards often lead to inability to communicate properly between devices, thus affecting the smooth progress of the entire production process.   Faced with this problem, many manufacturers have proposed their own solutions. Among the many suggestions, the main focus is on electrical signals. Various electrical signal standards have been proposed, and competition is fierce. Some manufacturers believe that a specific electrical signal range is more suitable for the needs of industrial automation, while other manufacturers insist that their own solutions have more advantages. Although this situation of a hundred flowers blooming has promoted technological innovation to a certain extent, it has also brought more chaos to the industry. Everyone is waiting for a widely recognized standard to emerge.   After a long period of precipitation and market testing, two widely accepted signal standards finally emerged. One is the pneumatic signal standard, selected as 20 - 100kPa.   Pneumatic signal standards: In some situations with extremely high explosion-proof requirements and harsh environments, pneumatic signals are still used. The common pneumatic signal standard range is 20100kPa. For example, in certain hazardous areas in petrochemical and other industries, pneumatic instruments use compressed air as the signal transmission medium to transmit measured values ​​or control instructions in the form of changes in air pressure. The advantage of this signal standard is that it is intrinsically safe and does not produce dangerous factors such as electric sparks. However, the disadvantage is that the response speed is relatively slow and the signal transmission distance is limited, generally within tens of meters.   Pneumatic signals have unique advantages in some specific industrial scenarios. For example, in flammable and explosive environments, pneumatic signals are safer and more reliable. The other is the electric signal standard, 4-20mA has become the well-deserved gold standard.   4-20mA current signal: This is one of the most widely used analog signal standards in industrial fields. 4mA represents the lower limit of the signal, which usually corresponds to the zero point of the measured variable; 20mA represents the upper limit of the signal, which corresponds to the full range of the measured variable. For example, in temperature measurement, if the measurement range is 0°C100°C, 4mA may correspond to 0°C, and 20mA may correspond to 100°C. This signal standard has the advantages of strong anti-interference ability and long transmission distance. The general transmission distance can reach hundreds of meters or even thousands of meters, and can meet the signal transmission needs between different devices in most industrial sites.   The 4-20mA standard stands out mainly because it has many advantages. First, it has good anti-interference ability. In industrial production sites, there are various electromagnetic interferences. If the signal is easily interfered, it will lead to increased measurement and control errors and affect production quality. The 4-20mA signal can remain relatively stable in a complex electromagnetic environment, ensuring accurate data transmission.   Secondly, its transmission distance is relatively long. In large industrial enterprises, the distance between devices may be relatively long, and signals are easily attenuated during transmission. The strength and characteristics of the 4 - 20mA signal enable it to maintain good performance over long distances. In addition, this standard also enables fault diagnosis of signals. When the signal current is 0mA, it most likely indicates that there is a fault in the line, making it easier for maintenance personnel to find and solve the problem in time.   Although with the continuous development of science and technology, industrial automation is gradually transitioning to digitalization, and digital signals have shown great advantages in many aspects, analog signal transmitters are still widely used. This also fully reflects the strong vitality of the 4-20mA standard. Analog signal transmitters have the advantages of low cost, high reliability, and mature technology. In some industrial scenarios that are cost-sensitive and do not require particularly high signal accuracy, analog signal transmitters are still the first choice. Moreover, many existing industrial equipment are designed based on the 4-20mA standard. If all are to be replaced with digital equipment, not only will the cost be huge, but there will also be many problems such as technical transformation and personnel training.   The unification of instrument signal systems in industrial automation is an inevitable requirement for industry development. As an electric signal standard, 4-20mA stands out in the fierce competition and still plays an important role in current industrial production. As technology continues to advance, it may complement digital signals and jointly promote the development of industrial automation to a higher level.

When the pressure transmitter is installed on site, there are many phenomena related to incorrect process parameters reflected by the pressure and differential pressure transmitters: there are problems with the pressure guide pipe being blocked, problems with the installation of throttling devices, condensation tanks, and pressure guide pipes that are not standardized, problems with electromagnetic interference, and maintenance problems, etc. This article analyzes some of the main problems and causes encountered in the use of pressure transmitters!   1. The transmitter has no output Inspection and testing 1. Check whether the transmitter power supply is connected reversely; 2. Measure the power supply of the transmitter to see if there is 24V DC voltage; 3. If it is equipped with a meter, check whether the meter is damaged (you can short-circuit the two wires of the meter first. If the short circuit is normal, it means the meter is damaged); 4. Connect the ammeter into the 24V power supply circuit to check whether the current is normal; 5. Is the power supply connected to the power input end of the transmitter?   Solution 1. Connect the power supply with correct polarity. 2. It must be ensured that the power supply voltage supplied to the transmitter is ≥12V (that is, the voltage at the power input terminal of the transmitter is ≥12V). 3. If there is no power supply, check whether the circuit is disconnected and whether the detection instrument is selected incorrectly (input impedance should be ≤250Ω); 4. If the meter head is damaged, you need to replace the meter head. If it is normal, it means that the transmitter is normal. At this time, you should check whether other instruments in the loop are normal. 5. Connect the power cord to the power terminal block.   2. Transmitter output ≥20mA Inspection and testing 1. Is the transmitter power supply normal? 2. Whether the actual pressure exceeds the selected range of the pressure transmitter; 3. Is the pressure sensor damaged? Severe overload sometimes damages the isolation diaphragm. 4. Whether the wiring is loose; 5. Is the power cord wiring correct?   Solution 1. If the transmitter power supply is less than 12VDC, you should check whether there is a large load in the loop. The input impedance of the transmitter load should comply with RL≤(transmitter supply voltage-12V)/(0.02A) Ω 2. Re-select a pressure transmitter with an appropriate range. 3. If the pressure sensor is damaged, it must be sent back to the manufacturer for repair. 4. Connect the wires and tighten them. 5. The power cord should be connected to the corresponding terminal.   3. Transmitter output ≤ 4mA Inspection and testing 1. Is the transmitter power supply normal? 2. Whether the actual pressure exceeds the selected range of the pressure transmitter; 3. Is the pressure sensor damaged? Severe overload sometimes damages the isolation diaphragm.   Solution 1. If the transmitter power supply is less than 12VDC, you should check whether there is a large load in the loop. The input impedance of the transmitter load should comply with RL≤(transmitter supply voltage-12V)/(0.02A) Ω 2. Re-select a pressure transmitter with an appropriate range. 3. If the pressure sensor is damaged, it must be sent back to the manufacturer for repair. 4. The pressure indication is incorrect Inspection and testing 1. Is the transmitter power supply normal? 2. Is the reference pressure value correct? 3. Is the measuring range of the pressure indicating instrument consistent with the measuring range of the pressure transmitter? 4. Are the input and corresponding wiring of the pressure indicating instrument correct? 5. The input impedance of the transmitter load should comply with RL≤(transmitter supply voltage-12V)/(0.02A) Ω 6. Is the input terminal open when the multi-point paper recorder is not recording? 7. Whether the corresponding equipment shell is grounded 8. Whether the wiring is separated from the AC power supply and other power supplies 9. Is the pressure sensor damaged? Severe overload sometimes damages the isolation diaphragm. 10. Whether there is sand, impurities, etc. in the pipeline that blocks the pipeline. If there are impurities, the measurement accuracy will be affected; 11. Is the temperature of the pipeline too high? The operating temperature of the pressure sensor is -25~85℃, but in actual use it is best to be within -20~70℃.   Solution 1. If the transmitter power supply is less than 12VDC, you should check whether there is a large load in the loop. The input impedance of the transmitter load should comply with RL≤(transmitter supply voltage -12V)/(0.02A) Ω. 2. If the accuracy of the reference pressure gauge is low, you need to replace it with a higher-precision pressure gauge. 3. The measuring range of the pressure indicating instrument must be consistent with the measuring range of the pressure transmitter. 4. If the input of the pressure indicating instrument is 4~20mA, the output signal of the transmitter can be directly connected; if the input of the pressure indicating instrument is 1~5V, a resistor with an accuracy of one thousandth or more and a resistance of 250Ω must be connected to the input end of the pressure indicating instrument, and then connected to the input of the transmitter. 5. The input impedance of the transmitter load should comply with RL≤. If it does not comply, corresponding measures can be taken according to the difference: such as increasing the supply voltage (but must be lower than 36VDC), reducing the load, etc. 6. If the input end of the multi-point paper recorder is open when there is no recording, then: 1. No other load can be carried; 2. Use another recorder with an input impedance of ≤250Ω when there is no recording. 7. The corresponding equipment shell should be grounded. 8. Separate wiring from AC power and other power sources. 9. If the pressure sensor is damaged, it must be sent back to the manufacturer for repair. 10. When there is sand, impurities, etc. in the pipeline that blocks the pipeline, the impurities need to be cleaned and a filter screen should be installed in front of the pressure interface. 11. If the temperature of the pipeline is too high, add a buffer tube to dissipate heat. It is best to add some cold water to the buffer tube before use to prevent overheating.

Steel No. Characteristics Use   30418Cr--8Ni is a widely used steel with good corrosion resistance, heat resistance, low temperature strength and mechanical properties. Good thermal workability for stamping, bending, etc., no heat treatment hardening phenomenon (non-magnetic, operating temperature minus 196°C to minus 800°C) Household products (categories 1 and 2 tableware, kitchen cabinets, indoor pipelines, water heaters, boilers, bathtubs), auto parts (windshield wipers, mufflers, molded products), medical equipment, building materials, chemicals, food industry, agriculture, ship parts   304L18Cr--8Ni--Low Carbon As a low-C 304 steel, its corrosion resistance is similar to that of 304 steel under normal conditions, but after welding or stress relief, its corrosion resistance is excellent. It can maintain good corrosion resistance without heat treatment and is generally used below 400 degrees Celsius (non-magnetic, operating temperature is minus 196 degrees Celsius to minus 800 degrees Celsius). It is used in large outdoor machines in the chemical, coal, and petroleum industries that require high resistance to grain boundary corrosion, building materials, heat-resistant parts, and parts that are difficult to heat treat.   Cu should be added to 304J113Cr-7.7Ni-2Cu, which has good formability, especially wire drawing properties and aging crack resistance, and can help mold products with complex shapes. Its corrosion resistance. Its corrosion resistance is the same as 304 steel. Thermos flasks, kitchen sinks, pots, kettles, thermos lunch boxes, door handles, textile processing machines.   31618Cr-12Ni-2.5Mo should be added with Mo, so its corrosion resistance, atmospheric corrosion resistance and high temperature strength are particularly good, and it can be used under harsh conditions. Excellent work hardening properties (non-magnetic) Equipment used in seawater, chemical, dye, papermaking, oxalic acid, fertilizer and other production equipment; photography, food industry, coastal area facilities, ropes, CD rods, bolts, nuts   316L18Cr-12Ni-2.5Mo Low Carbon As a low C series of 316 steel, in addition to having the same characteristics as 316 steel, it has excellent resistance to grain boundary corrosion. Among the uses of 316 steel, there are products with special requirements for resistance to grain boundary corrosion.   32118Cr-9Ni-Ti adds Ti element to 304 steel to prevent grain boundary corrosion. Suitable for use at temperatures from 430 degrees Celsius to 900 degrees Celsius. Aircraft, exhaust pipe, boiler drum Ferritic steel 409L11.3C-0.17Ni-low C, U. Due to the addition of Ti element, its high temperature corrosion resistance and high temperature strength are better. Products such as automobile exhaust pipes, heat exchangers, camouflage boxes, etc. that are not heat treated after welding Ferritic steel 43016Cr, as a representative steel type of ferritic steel, has low thermal expansion rate, excellent formability and oxidation resistance. Heat-resistant appliances, burners, home appliances, Class 2 tableware, kitchen sinks, exterior decorative materials, bolts, nuts, CD rods, screens. Martensitic steel 41013Cr---Low carbon As a representative steel of martensitic steel, although it has high strength, it is not suitable for use in harsh corrosive environments. It has good processability and is hardened by heat treatment (magnetic). Blades, mechanical parts, petroleum refining equipment

1. Industry macro situation 1. Market size and growth engines Global market: It is expected to reach US$120 billion in 2026, with an annual growth rate of approximately 4.5%, with the Asia-Pacific region (especially China and India) contributing more than 50% of the increase. Growth drivers: Industry 4.0 promotes the digital transformation of production lines, and the demand for sensors and smart instruments surges; The expansion of new energy (photovoltaic/hydrogen/energy storage) and semiconductor production capacity has driven the purchase of high-precision measurement equipment; Environmental protection regulations are becoming stricter, and online water quality/gas monitoring instruments have become a necessity. 2. Changes in the competitive landscape Head company news: Siemens acquires edge computing instrument companies to strengthen its IIoT layout; Emerson spins off its process automation business and goes public independently; domestic manufacturers Sichuan Instruments and Concentrator Technology accelerate overseas mergers and acquisitions. The Rise of the “Hidden Champion”: Technically specialized small and medium-sized enterprises have emerged in subdivided fields (such as laser gas analysis and nanoscale displacement sensors), accounting for more than 60% of the niche market. 2. Core technology breakthroughs 1. Iteration of sensing technology Technical Direction Typical Progress Optical sensing Quantum dot spectrometer miniaturization (mobile phone size enables full spectrum analysis of ultraviolet and near-infrared) MEMS/NEMS aluminum nitride piezoelectric MEMS flow chip has an accuracy of 0.5%FS and reduces power consumption by 80% Biosensing CRISPR-Cas12a coupled electrochemical sensor enables real-time detection of water pathogens Wireless passive sensing surface acoustic wave (SAW) temperature/pressure sensor, no need for batteries and can work in high temperature (800℃) environment for a long time 2. Intelligent evolution path From "measurement" to "perception": The instrument has a built-in AI chip (such as Horizon Rising Sun X3) to realize abnormal pattern recognition (such as pump cavitation feature extraction) and adaptive range adjustment. Digital twin integration: The real-time data of the instrument is synchronized to the three-dimensional model of the factory, supporting virtual calibration and fault preview (such as predicting the pH electrode life decay curve). The sprouting of open source ecology: Some companies release instrument communication protocol SDK (such as Modbus-TCP expansion package), allowing users to customize data cleaning algorithms. 3. In-depth analysis of key application areas 1. Key scenarios of energy transition Photovoltaic manufacturing: The film thickness measurement accuracy of the ellipsometer exceeds 0.1nm, helping to increase PERC cell efficiency to 25.6%; the IV tester integrates EL (electroluminescence) detection and completes crack identification within 3 seconds. Hydrogen energy industry chain: Proton exchange membrane electrolyzers need to simultaneously monitor hydrogen purity (≥99.97%), dew point (≤-40°C), and pressure (3MPa) to promote the standardization of multi-parameter analyzers. Energy storage safety monitoring: The fiber Bragg grating temperature sensor is implanted into the lithium battery module to provide a 20-minute advance warning of thermal runaway with an accuracy of ±0.5°C. 2. High-end manufacturing precision revolution Semiconductors: The wafer stage laser interferometer has a positioning resolution of 5pm (picometer level) and supports the 3nm process; the atomic force microscope (AFM) is combined with machine learning to realize automatic classification of surface defects. Aerospace: The blade profiler uses blue light three-dimensional scanning, with the measurement speed increased to 2 million points per second and an accuracy of 2 μm; the engine test bench needs to simultaneously collect 2,000+ channels of vibration/pressure/temperature data. 3. Precision in life sciences Cell therapy: The flow cytometer integrated mass spectrometry detection (CyTOF) can simultaneously analyze 40+ protein markers, with a single cell throughput of 1,000 cells/second. Gene sequencing: The cost of the nanopore sequencer MiniON Mk1C has dropped to US$1,000, and it can detect pathogen gene mutations in real time in the field. 4. New Trends in Standards and Compliance 1. Update of international standards IEC 63278-1:2026: Industrial Internet of Things instrument data security specifications require encrypted transmission and local storage to support physical isolation. ISO 13374:2025 revision: The data format of mechanical equipment condition monitoring instruments is standardized and compatible with the ISO 15926 oil and gas data model. 2. Industry mandatory certification Pharmaceutical field: Starting from 2026, only analytical instruments that comply with USP <1058> standards can be used for FDA declaration data collection (focusing on chromatographic and spectroscopic instruments). Carbon emission monitoring: The EU CBAM requires imported steel, cement and other products to be accompanied by an annual report of CO₂ concentration monitoring instruments calibrated by a third party.

Environmental Instruments specializes in the production of various types of pressure transmitters, temperature transmitters, temperature sensors, liquid level transmitters and related accessories. The product has received support from the National Science and Technology Commission from design, development to success. The National Science and Technology Commission invested more than 6 million yuan and invited internal experts and academicians of the Russian Academy of Sciences to jointly develop the product. After that, the company itself continued to update and improve, and developed a series of pressure transmitters, temperature transmitters and liquid level transmitters that are stable, reliable, cheap and high-quality, suitable for various industrial automation measurement and control, and became a professional transmitter manufacturer.   Recently, many friends have asked about the difference between temperature transmitters and temperature sensors. Today we will talk about the differences between thermocouples and thermal resistors in temperature transmitters!   Advantages of thermocouples in temperature transmitters:   Thermocouples are one of the most commonly used temperature detection components in industry. The working principle of thermocouples is based on the Seeback effect, which is a physical phenomenon in which two conductors of different compositions are connected at both ends to form a loop. If the temperatures of the two connecting ends are different, a thermal current will be generated in the loop. The advantages are:   ①High measurement accuracy. Because the thermocouple is in direct contact with the measured object, it is not affected by the intermediate medium.   ②Wide measuring range. Commonly used thermocouples can continuously measure from -50 to +1600°C. Some special thermocouples can measure as low as -269°C (such as gold, iron, nickel and chromium) and as high as +2800°C (such as tungsten-rhenium).   ③Simple structure and easy to use. Thermocouples are usually composed of two different metal wires, and are not limited by size or opening. They have protective sleeves on the outside, making them very convenient to use. Temperature compensation of thermocouple cold junction:   Since the materials of thermocouples are generally relatively expensive (especially when precious metals are used), and the distance between the temperature measurement point and the instrument is very long, in order to save thermocouple materials and reduce costs, compensation wires are usually used to extend the cold end (free end) of the thermocouple to the control room where the temperature is relatively stable, and connect it to the instrument terminals. It must be pointed out that the thermocouple compensation wire only functions to extend the hot electrode and move the cold end of the thermocouple to the instrument terminal in the control room. It itself cannot eliminate the influence of the cold end temperature change on the temperature measurement and has no compensation effect. Therefore, other correction methods need to be used to compensate for the impact on temperature measurement when the cold end temperature t0≠0℃.   When using the thermocouple compensation wire, you must pay attention to the matching model, the polarity cannot be wrong, and the temperature of the compensation wire and the thermocouple connection end cannot exceed 100°C.   Thermal resistance   Thermal resistance is the most commonly used temperature detector in medium and low temperature areas. Its main features are high measurement accuracy and stable performance. Among them, platinum thermal resistance has the highest measurement accuracy. It is not only widely used in industrial temperature measurement, but also made into a standard benchmark instrument.   Thermal resistance temperature measurement principle and materials:   Thermal resistance temperature measurement is based on the characteristic that the resistance value of a metal conductor increases as the temperature increases. Thermal resistors are mostly made of pure metal materials. Currently, platinum and copper are the most widely used. In addition, thermal resistors have begun to be made of materials such as nickel, manganese and rhodium.   Regarding the temperature transmitter, you can take a look at the following introduction:   1. Purpose of temperature transmitter   Temperature transmitter is used for temperature measurement. This article defines a temperature transmitter as a temperature measurement device that uses a temperature sensor for temperature detection and converts the signal of the temperature sensor into a standard current signal and a standard voltage signal through a conversion circuit.   2. Classification of temperature transmitters   From the signal output interface, it is divided into 4~20ma, 0~10ma, 0~20ma, 0~5v, 0~10v, etc., or digital/frequency interface and other interfaces;   From the structure and installation form, it is divided into wall-mounted type, air duct type, and probe type;   From the distance between the temperature sensor and the conversion circuit, it is divided into integrated or split type;   There are also explosion-proof and other types of products.   The above is about the difference between temperature transmitter and temperature sensor. For more information about instruments, please pay attention to Environmental Instruments. If you have any selection questions, you can also call us directly.

Recently, many new and old customers of environmental engineering instruments have asked us about some problems encountered during the installation process of pressure sensors and the installation location of pressure sensors. Today, the editor will tell us what to pay attention to during the installation process of pressure sensors and introduce the installation location:   What is a pressure sensor: The sensor is a piezoresistive pressure sensor, which is made by utilizing the piezoresistive effect of single crystal silicon material and integrated circuit technology. Piezoresistive sensors are commonly used for the measurement and control of pressure, tension, pressure difference and other physical quantities that can be converted into changes in force (such as liquid level, acceleration, weight, strain, flow, vacuum).   Correct installation method of pressure sensor:   (1) Use appropriate instruments to verify the frequency response value of the pressure sensor under normal atmospheric pressure and standard temperature conditions.   (2) Verify the correctness of the pressure sensor coding and corresponding frequency response signal.   Pressure sensor determines specific installation location   In order to determine the number and specific installation location of the pressure sensor, each inflatable section of the inflatable net needs to be considered.   (1) The pressure sensor must be installed along the cable, at the cable joint. If possible, it is best to install it at the joint, and install a sensor at both ends of the cable. .   (2) Each cable should be equipped with no less than 4 pressure sensors, and there are certain requirements for the distance between pressure sensors at special locations. Two pressure sensors close to the telephone exchange should not be more than 200m apart.   (3) Install one at the beginning and end of each cable.   (4) One should be installed at the branch point of each cable. If the two branch points are close to each other (less than 100 m), only one can be installed.   (5) Where the cable laying method (overhead, underground) changes, a   (6) For unbranched cables, because the cable programs of the barrier lines are consistent, the installation distance of the pressure sensors should not be more than 500m, and the total number should be no less than 4.   (7) In order to facilitate the determination of the pressure sensor failure point, in addition to installing the pressure sensor at the starting point, another one must be installed 150~200m away from the starting point. Of course, economic and technical factors must be considered in the design. Where there is no need to install a pressure sensor, there should be no need to install it.   The PB8100 series diffused silicon high-precision pressure sensor/transmitter produced by Environmental Instruments uses high-precision, high-stability and high-reliability diffused silicon pressure sensing elements and imported high-quality integrated circuits. It is an industrial pressure transmitter with high precision, good reliability and stability, and long service life. It is used to measure the pressure of liquids or gases. It is an on-site remote pressure and liquid level measuring instrument that converts the pressure or liquid level into a standard electrical signal. Due to its excellent performance, the PB8100 series pressure transmitter can replace imported high-grade pressure transmitters and be used in occasions with high requirements for measurement or measurement and control accuracy. It can have explosion-proof characteristics and good impact resistance.     Check size   If the size of the mounting hole is inappropriate, the threaded part of the high-temperature melt pressure sensor will be easily worn during the installation process. This will not only affect the sealing performance of the equipment, but also prevent the sensor from fully functioning, and may even cause safety hazards. Only suitable mounting holes can avoid thread wear (thread industry standard 1/2-20UNF2B). Usually, a mounting hole measuring instrument can be used to detect the mounting hole to make appropriate adjustments.   Pressure sensors are used in all walks of life, especially in industry. There are many pressure sensors used, but industry generally requires pressure sensors to be anti-corrosion. The pressure sensor joints and chambers are integrally processed with imported stainless steel. The stainless steel material used as the pressure transmitter body has high corrosion resistance and good attenuation performance, and can monitor any medium that is compatible with 316L. Below we will also introduce the anti-corrosion techniques of pressure sensors.   The above is the installation problem of the pressure sensor and the things that need to be paid attention to when installing the pressure sensor. I hope it can help you. If you have any questions, please leave a message or contact us by phone!  

There are several types of liquid level sensors   1. Float type liquid level sensor The float-type liquid level transmitter changes the magnetic float ball into a float, and the liquid level sensor is designed based on Archimedes' buoyancy principle. The float type liquid level transmitter uses tiny metal film strain sensing technology to measure the liquid level, boundary level or density of the liquid. It can perform regular setting operations through on-site buttons during operation.   2. Float type liquid level sensor The float level transmitter consists of a magnetic float, a measuring conduit, a signal unit, an electronic unit, a junction box and installation parts. Generally, the specific gravity of the magnetic float is less than 0.5. It can float above the liquid surface and move up and down along the measuring conduit. The conduit is equipped with a measuring element, which can convert the measured liquid level signal into a resistance signal proportional to the liquid level change under the action of external magnetism, and convert the electronic unit into a 4-20mA or other standard signal output.   The liquid level sensor is a modular circuit, which has the advantages of acid resistance, moisture resistance, shock resistance, corrosion resistance, etc. The circuit contains a constant current feedback circuit and an internal protection circuit, which can prevent the maximum output current from exceeding 28mA, thus reliably protecting the power supply and preventing the secondary instrument from being damaged.   3. Hydrostatic liquid level sensor The transmitter works based on the measurement principle of hydrostatic pressure. It generally uses a silicon pressure pressure sensor to convert the measured pressure into an electrical signal, which is then amplified by an amplification circuit and compensated by a compensation circuit, and finally output in the form of 4-20mA or 0-10mA current.  

1. Overview:   PB8100 series diffused silicon high-precision pressure transmitter uses high-precision, high-stability and high-reliability diffused silicon pressure sensing elements and imported high-quality integrated circuits. It is an industrial pressure transmitter with high precision, good reliability and stability, and long service life. It is used to measure the pressure of liquids or gases and various liquids. The PB8100 series pressure transmitter is an on-site remote pressure and liquid level measuring instrument that converts the pressure or liquid level into a standard electrical signal. Due to its excellent performance, it can replace imported high-grade pressure transmitters and be used in occasions with high requirements for measurement or measurement and control accuracy. It can have explosion-proof characteristics and good impact resistance.     2. Application scope of pressure transmitter   Industrial site process pressure control Light industrial machinery, medical equipment Pressurized pneumatic control and detection system Water conservancy and hydropower power plants, constant pressure water supply Navigation and shipbuilding industry Aerospace field Petrochemical industry 3. Characteristics of pressure transmitter   Wide measuring range: optional within -0.1~60MPa; minimum range 0~10kPa Power supply and output two-wire system (only for 420mA output) High precision, high stability, high reliability IP65 enclosure protection grade, suitable for outdoor installation With reverse polarity protection and current limiting protection Anti-lightning strike, strong resistance to radio frequency interference Unique design ensures good waterproof hammer impact performance (optional)

Industrial automation instruments: focus on the development of main control system devices and intelligent instruments, special and dedicated automation instruments based on fieldbus technology; comprehensively expand service areas, promote the digitization, intelligence, and networking of instrumentation systems, complete the transformation of automated instruments from analog technology to digital technology, and achieve more than 60% of digital instruments within 5 years; accelerate the commercialization of automation software with independent intellectual property rights. Electrical instrumentation: focus on the development of long-life electric energy meters, electronic electric energy meters, special electrical measuring instruments and automatic power grid measurement management systems. By 2005, the domestic market share of mid- to low-end electrical instruments and meters should reach 95%; by 2010, the domestic market share of mid- and high-end electrical instruments and meters should reach 80%. 　　  Scientific testing instruments: focus on the development of process analysis instruments, environmental monitoring instruments, industrial furnace energy-saving analysis instruments, and new products such as dynamic balancing of auto parts, power testing and vehicle performance detectors, geodesic meters, electronic speed testers, measuring global positioning systems and other experimental machines and laboratory instruments required by basic industries. The products are mainly mid-range products with high technical content, accounting for 50% to 60% of the total output value by 2005. 　　  Environmental protection instrumentation: Focus on the development of environmental protection monitoring automation control system products for atmospheric environment and water environment. In view of the need to strengthen environmental law enforcement, accelerate the pace of environmental protection construction, increase investment in environmental protection construction, and cultivate the environmental protection industry, a new growth point of the national economy, facing the huge market of more than 5,000 environmental testing stations and a large number of urban sewage treatment and corporate wastewater treatment in my country, the environmental protection instrumentation industrial product market will see substantial growth in the future. According to incomplete statistics from relevant parties, in 1998, the output value of my country's environmental protection instrumentation and monitoring systems was approximately 1.17 billion yuan. By 2005, it will expand to 4.2 billion yuan, reaching the international advanced level in the late 1990s. The domestic market share will reach 50% to 60%, and by 2010, it will expand to 11 billion yuan. By 2010, the domestic market share will reach more than 70%. It can be seen that its market prospects are very broad. Analytical chemistry instruments: Key research directions include: First, high-throughput analysis, that is, a large number of samples can be analyzed and tested per unit time. The second is extreme condition analysis, in which single-molecule and single-cell analysis and manipulation are currently hot topics. The third is online, real-time, on-site or in-situ analysis, that is, from sample collection to data output, achieving rapid or one-stop analysis. The fourth is joint technology, that is, connecting two (or more than two) analysis technologies to complement each other to complete more complex analysis tasks. The combination of hyphenated technology and hyphenated instruments, especially the emergence of triple or even quadruple systems, has become an important direction in the development of modern analytical instruments. The fifth is array technology. If joint analysis technology is regarded as a serial method in computers, then array technology is equivalent to a parallel computing method in computers. As with computers, array methods are the best option for dramatically increasing analysis speed or sample batch throughput. Once the parallel array idea is perfectly combined with integration and chip fabrication technology, analytical chemistry will move into new areas. 　　  Instrument components: During the “Tenth Five-Year Plan” and before 2010, develop a batch of marketable and effective products as soon as possible, with the variety share reaching 70% to 80%, and the market share of high-end products reaching more than 60%. Through scientific and technological public relations and new product development, the product quality level has reached the international level in the late 1990s, and some products are close to the advanced level of similar foreign products.  Medical instruments, with a focus on medical optical instruments; medical ultrasound instruments, with digital imaging, high-end black-and-white ultrasound, color ultrasound, and color ultrasound transducers as key R&D technologies; large-scale medical instruments and clinical information systems, such as X-ray image processing systems and open-type superconducting magnetic resonance imaging (MRI) systems; and large-scale, high-energy, intelligent tumor treatment systems. 　　 　　 Based on the needs identified by China’s national economic and social development, and with a full understanding of international trends in the instrumentation sector, the state has formulated the following strategic objectives for the development of instruments and meters: Over the next 10 to 15 years, by fully leveraging China’s rapid economic growth and vast market advantages, vigorously promote applied research on new technologies and processes in the instrumentation sector, master key technologies such as the design and manufacturing processes of various instruments and meters, narrow the overall gap between China’s instrumentation industry and international standards to 3 to 5 years, ensure that approximately 30% of products reach the internationally advanced level for their respective periods, the capability of domestically produced instruments and meters to support major engineering projects will reach over 85%, and they will capture a market share of over 75% in the domestic market. 　　 　　 Modern instruments and meters play a vital role and hold an important position in today’s society. Faced with the urgent demands of China’s national economy, science and technology, national defense construction, and all aspects of social life, the development of instruments and meters must be accelerated.  

Inspection method of absolute pressure transmitter:   1. Record the atmospheric pressure value, assuming it is A (kPa), the measurement range is 0~B (kPa), 24VDC, output 4~20mA 2. Calculation method of output current: Changes in output current caused by changes in atmospheric pressure: [(A-100kPa)/B] × (20-4) The output current at each pressure value should be the corresponding theoretical value plus [(A-100kPa)/B]×(20-4), which is the theoretical value under the current atmospheric pressure. For example, the current atmospheric pressure is 101.5kPa, the measurement range is 0~400kPa, and the output signal is 4~20mA: Changes in output current: [(A-100kPa)/B]×(20-4)= [(101.5-100kPa)/400]×(20-4)=0.06mA Therefore, 0.06mA is added to the theoretical value of each test point:       Pressure value (kPa) 10 100 200 300 400 Output current value 4.460 8.060 12.060 16.060 20.060 Note: The output current at 10kPa is calculated as follows, 4 mA+〔(10/400)×(20-4)〕+0.060 mA=4+ 0.4+ 0.060= 4.460 mA   3. Assume that the current atmospheric pressure is 101.0 (kPa), the measurement range is 0~200 (kPa), 24VDC, and the output is 0~5V, then: Change in output voltage: [(A-100kPa)/B]×(5V-0V)= [(101-100kPa)/200]×(5-0)=0.025V Therefore, 0.025V is added to the theoretical value of each test point:       Pressure value (kPa) 10 50 100 150 200 Output voltage value (V) 0.275 2.025 3.025 4.025 5.025 Note: The output current at 10 kPa is calculated as follows, [(10/200)×(5-0)]+0.025 V= 0.25+ 0.025= 0.275 V

In the traditional industrial equipment maintenance model, regardless of the status of the equipment, a fixed time period is followed for shutdown and maintenance. This method is costly and may miss the real budding period of faults. Today, with the maturity of smart transmitter technology, a more advanced and economical maintenance strategy - predictive maintenance (PdM) - is becoming a new standard in the process industry. Technical experts from Yuyao Environmental Engineering Automation Instrument Factory pointed out that modern smart transmitters are no longer simple data collectors, but also "health monitors" installed on equipment, providing the most critical data source for predictive maintenance.          The core of predictive maintenance is to continuously monitor the operating status parameters of equipment (such as vibration, temperature, pressure, etc.) and use data analysis to identify early fault characteristics, so as to arrange maintenance in a planned manner before a fault occurs. Smart transmitters play an irreplaceable role in this. Take the smart pressure transmitter produced by Environmental Instruments as an example. In addition to outputting the main process variable (pressure value) of 4-20mA, its built-in microprocessor can also continuously monitor and diagnose multiple health indicators of itself and the process.          For example, it can monitor the extreme temperature recording of the sensor module, the stability of the output current, and the slight drift trend of zero point and span. More advanced smart transmitters can also analyze the frequency and pattern of process pressure fluctuations. Abnormal fluctuation patterns are often early signs of pump cavitation, valve oscillation or pipe blockage. All this diagnostic data can be seamlessly integrated into the plant's asset management system (AMS) or predictive maintenance software platform through digital communication protocols such as HART, Profibus PA or FF.          By collecting and analyzing these multi-dimensional "health data" over a long period of time, the system can build a digital model of the normal operation of the equipment. Once the real-time data continues to deviate from the model, the system will automatically issue an early warning, prompting maintenance personnel to pay attention to specific potential problems with specific equipment. For example, "The outlet pressure transmitter of the No. 3 feed pump shows low-frequency oscillation characteristics, and the impeller is suspected to be slightly worn. It is recommended to check the next planned shutdown." This revolutionizes the reactive nature of maintenance, transforming maintenance activities from "time-based" to "condition-based".          Environmental Instruments is continuously strengthening its capabilities in this area in its new generation of products. The company believes that providing smart transmitters with powerful built-in diagnostics and stable data output is a fundamental step to help customers achieve digital transformation and move towards smart factories. In the future, the value of the transmitter will not only lie in the measurement itself, but also in the in-depth information it carries to optimize the operation and maintenance of the entire production system.

A liquid level transmitter is a transmitter, an instrument that measures its height through pressure. The price of a liquid level switch is about one or two hundred yuan each. The cheaper ones are more than ten or twenty yuan, and the expensive ones are several hundred yuan. The price of a liquid level transmitter is affected by many aspects, such as brand, category, specification, market, etc. If you have any selection questions, you can contact us.     The liquid level transmitter is a measuring instrument for measuring liquid level. It has many advantages such as good stability, flexible use, strong durability, and easy maintenance. It has certain applications in industry, metallurgy, electric power, pharmaceuticals, water supply and drainage and other fields.    Liquid level transmitter debugging method:     1. Unscrew the protective cover and connect an external standard 24VDC power supply and ammeter (requires an accuracy of 0.2% or above) to adjust.     2. When there is no liquid in the input liquid level transmitter, adjust the zero point resistor so that the output current is 4mA.     3. Add liquid to the input-type liquid level transmitter to the full range, and adjust the full-range resistor so that the output current is 20mA.     4. Repeat the above steps two or three times until the signal is normal     5. Please enter 25%, 50%, and 75% signals respectively to check the error of the input liquid level transmitter.     6. For non-aqueous media, when calibrating the submersible level transmitter with water, the pressure generated by the density of the medium actually used should be converted. For example: when the medium density is 1.3, the 1.3m water level calibration should be used when calibrating the 1m range.     7. After adjustment, tighten the protective cover.     8. The calibration cycle of the input liquid level transmitter is once a year. Precautions for liquid level transmitter     1. Confirm whether the output voltage of the power supply is correct; the positive and negative connections of the power supply correspond to the positive and negative wiring of the product; the maximum height of the liquid level is within the range of the product;     2. The pressure sensor of the probe is a precision device. Users should not disassemble it by themselves when using it, let alone touch the diaphragm to avoid damage to the product;     3. Please avoid the liquid level transmitter cable connector (where the warning sign is posted) from being immersed in water, causing water to enter the ventilation line and causing water damage to the liquid level transmitter;     4. Please avoid the cable of the liquid level transmitter from being scratched by a knife or other sharp metal objects, which may cause water damage to the transmitter.   Before choosing to buy, it is necessary to understand and compare in many aspects. Huangong Instrument Factory will answer your selection questions. We have been working hard for more than 20 years.

1. Install as shown below; the inclination angle of the transmitter should not be less than 45 degrees.   2. If the measurement medium is water vapor, you should first add an appropriate amount of cold water into the buffer tube when installing the pressure transmitter (as shown in the figure) 3. The length of the buffer tube can be determined by the heat dissipation situation. Generally, it is advisable to ensure that the temperature t ≤ 70°C transmitted to the pressure transmitter.   4. When the temperature is too high, the length of the ordinary connecting pipe can be appropriately lengthened to ensure that the temperature on the pressure transmitter is not higher than 70 degrees, which can increase the service life of the pressure transmitter. 5. There should be no leakage in the entire test pipeline. (Once there is leakage, heat will be brought up, and the temperature on the pressure transmitter will be too high, thus damaging the pressure transmitter) 6. If the measurement medium is water vapor, when the gas supply is interrupted, the needle valve should be closed; when used again, wait for the steam pressure in the pipeline to stabilize before opening the needle valve to prevent the changing high pressure in the pipeline from damaging the sensor. Generally, the needle valve should not be opened too large, as long as the pressure transmitter can clearly feel the pressure change.   7. If it is a remote gas supply (such as power plant gas supply), a pressure reducing valve must be installed at the regional air inlet to ensure that the pressure in the gas consumption area does not fluctuate greatly to reduce the excessive instantaneous pressure caused by the resonance of the on-site gas supply. (Controversial) Precautions for using pressure transmitters for high-temperature steam:   Add a pipe, connect one end to the pipeline, and the other end to the pressure transmitter. Because the pressure in the pipe can be transmitted, but the gas cannot flow, the lengthened pipe can play a role in heat dissipation. Yes, but a heat dissipation and pressure induction pipe must be installed in front of it. Only needle valve, the valve must be closed before gas supply, and then open the needle valve after the steam pressure in the gas supply pipe is stable (quick opening valves such as ball valves cannot be used), because the steam has a large vibration at the beginning, which is commonly known as resonance or air hammer phenomenon. This pressure ratio The real steam supply pressure will be dozens of times greater, which will damage the diaphragm of the pressure transmitter. After the air pressure in the pipe is stable, slowly open the needle valve so that the pressure transmitter can measure the pressure. Do not open it too much. The principle is as mentioned above. It mainly prevents the air hammer phenomenon that occurs during use. We also have pressure transmitters customized for measuring steam pressure, mainly for air hammer and resonance, but heat dissipation still requires a section of pipe in front. Do you know the buffer pipe dedicated to the pressure gauge? It is best to use it in the pressure transmitter. Adding this buffer tube in front of the transmitter not only buffers the impact of air hammers in the pressure, but also dissipates heat. But the buffer is only a part of the anti-resonance impact. As I mentioned earlier, this is still very important and must be paid attention to! Once the steam is stopped and the supply is resumed during use, customers sometimes forget the process of closing and opening the valve (or even unwilling to perform this process), so it is best to use our customized pressure transmitter, but remember that the needle valve must not be opened too large. As long as it can pass steam in, the pressure can change. The transmitter can measure the real pressure, so that the needle valve can also play the role of pressure buffering and damping. The extension length of this section of the needle valve and pipe is generally about one meter, and there must be no leakage in this section of the pipeline (leakage will bring heat over and cannot dissipate heat). If the steam temperature is relatively low, around 120 degrees Celsius, you can also directly use a pressure transmitter with a radiator (I will send you a picture later), but be careful that the temperature generally does not exceed 120 degrees Celsius. The above content is provided by Huan Gong Instruments. Huan Gong Instruments specializes in the production of pressure transmitters, pressure sensors, temperature transmitters, temperature sensors, liquid level transmitters, liquid level sensors, input liquid level transmitters, pressure controllers, differential pressure transmitters, wind pressure sensors, etc. If you encounter questions related to instruments, you can contact us. Our professional technology will answer your questions. Tel: 0574-62723633!

Transmitter wiring and adjustment   The wiring principle of the transmitter is as shown in the figure. Terminal 4 is connected to the positive terminal of the 24V power supply, and terminal 3 is the 4~20mA current output terminal. This terminal returns to the negative terminal of the 24V power supply through the load resistor R1.   Terminals 1 and 2 are connected to the thermal resistor, or 2 is connected to the positive thermocouple, and 1 is connected to the negative thermocouple. The transmitter has zero point and range adjustment potentiometers to facilitate the user to make micro adjustments.   Temperature transmitter calibration method:   ·When used in explosive hazardous locations, please pay attention to the explosion-proof mark and protection level; ·The installation environment of the mechatronic temperature transmitter must be within -20-+70℃. When the ambient temperature is too high, the SBWZ/R signal converter and display module can be installed separately from the thermal resistor or thermocouple. Our factory is equipped with an explosion-proof box for separately installing the transmitter.   ·Before powering on, please carefully check the positive and negative polarity of the power supply. Do not connect it incorrectly, otherwise it may cause unknown consequences.   ·The SBW signal converter module is potted and cured with epoxy resin to enhance its shock-proof performance and is moisture-proof, anti-corrosion and moisture-proof.   ·The temperature transmitter needs to be calibrated after six months of use. Environmental Instruments specializes in the production of pressure transmitters, pressure sensors, temperature transmitters, temperature sensors, liquid level transmitters, liquid level sensors, input liquid level transmitters, pressure controllers, differential pressure transmitters, wind pressure sensors, etc. If you encounter any questions related to instruments, you can contact us. Our professional technology will answer your questions. Tel: 0574-62723633!   a. Calibration method of thermal resistance temperature transmitter   ·Equipment requirements: One digital voltmeter;   ·Connect according to the system connection method;   ·According to the sensor and measuring range indicated on the transmitter nameplate, enter the corresponding resistance value so that the output is 1V and 5V (the zero-point potentiometer and full-scale potentiometer can be adjusted respectively);   ·Input each resistance value according to the tenth decimal point of the measuring range, and check whether each temperature output meets the accuracy range; ·Test according to the technical indicators in the instruction manual, and it should meet the technical requirements.   b. Thermocouple temperature transmitter calibration method   ·Equipment requirements: One digital voltmeter;   ·Connect according to the system connection method;   ·According to the sensor and measuring range indicated on the transmitter nameplate, enter the corresponding resistance values so that the outputs are 1V and 5V respectively (the zero-point potentiometer and full-scale potentiometer can be adjusted separately);   ·Input each potential value according to the tenth decimal point of the measuring range, and check whether each temperature output meets the accuracy range; ·Test according to the technical indicators in the instruction manual, and it should meet the technical requirements.

What are the characteristics of a temperature transmitter? How to calibrate the temperature transmitter error?   The series thermocouple and thermal resistance temperature transmitter is a field-mounted temperature transmitter unit in the series instrument. It is used in conjunction with industrial thermocouples and thermal resistors. It adopts a two-wire transmission method (two wires serve as common transmission lines for power input and signal output). It converts industrial thermocouple and thermal resistance signals into 4-20mA and 0-10mA output signals that are linear with the input signal or temperature signal.   The main features of the temperature transmitter are as follows:   1. The SBWZ temperature transmitter adopts a silicone rubber or epoxy resin sealing structure, so it is shock-resistant and moisture-resistant, and is suitable for installation and use in harsh on-site environments.   2. The SBWZ temperature transmitter is installed in the junction box of thermocouples and thermal resistors and can directly output 4-20mA and 0-10mA output signals. This not only saves the user the cost of using compensation wires, but also improves the anti-interference ability during long-distance signal transmission;   3. The SBWZ temperature transmitter has a wide range of applications. It can not only form an integrated on-site installation structure with thermocouples and thermal resistors, but can also be installed as a functional module in testing equipment and used on instrument panels;   4. The thermocouple transmitter has the function of automatic compensation of cold end temperature, high accuracy, low power consumption, wide operating environment temperature range, and stable and reliable operation;   5. The intelligent temperature transmitter can adjust the display direction of the transmitter according to the actual needs of the user, and display the medium temperature, sensor value changes, output current and percentage measured by the transmitter;   6. The intelligent temperature transmitter can communicate with the host computer through the HART modem or perform remote information management, configuration, variable monitoring, calibration and maintenance functions with the handheld device and PC on the model, graduation number and range of the transmitter. Environmental Instruments specializes in the production of pressure transmitters, pressure sensors, temperature transmitters, temperature sensors, liquid level transmitters, liquid level sensors, input liquid level transmitters, pressure controllers, differential pressure transmitters, wind pressure sensors, etc. If you encounter any questions related to instruments, you can contact us. Our professional technology will answer your questions. Tel: 0574-62723633!   The temperature measuring elements used in the temperature transmitter include thermocouples and thermal resistors, and their wire systems are divided into three types: two-wire system, three-wire system, and four-wire system. Despite the above differences, the test content and principles are the same.   1. Requirements for the standard device. Since the calibration work is being carried out, it can generally be carried out based on the existing equipment conditions and referring to the temperature transformer operating instructions. However, in order to ensure the quality of calibration, there should be certain requirements for the calibration system (i.e. the standard device). According to convention, the error of the standard device should be less than 1/5 of the allowable error of the measured temperature transformer, and for the O.1 level measured temperature transformer should be less than 1/3 of its allowable error. In addition, the uncertainty and repeatability of the entire set of standard devices should also meet the requirements.   Regarding the temperature transmitter adjustment method, the general method of temperature transmitter adjustment:   Comprehensive adjustment method.   This method is to adjust the temperature measuring element and the temperature transformer together. It relies on changing the temperature of the temperature field of the constant temperature equipment to measure the output adjustment points and the number of forward and reverse cycles of the thermostat (similar to the analog adjustment method), and then calculates the indication error of the temperature transformer. The adjustment result of this method is the comprehensive result of the temperature transformer and the temperature measuring element. This method can be used to test the S series integrated temperature transformer with temperature measuring element, and is rarely used for rack-mounted and wall-mounted temperature transformers.

HG-L300 ultrasonic liquid level transmitter has the characteristics of safety, cleanliness, high precision, long life, stability and reliability, easy installation and maintenance, etc. It is suitable for various fields such as acid, alkali, salt, anti-corrosion, high temperature, etc. This instrument can be connected to the display meter or various DCS systems through 4~20mA or RS485 (Modbus protocol or other customized protocols) to provide real-time liquid level data for industrial automation operations.   Application range of ultrasonic liquid level transmitter     Water plants, sewage treatment plants, urban water supply Pools, wells, mines, culverts, water tanks Industrial pools, oil pools Hydrogeology, reservoirs, rivers, oceans Features of ultrasonic liquid level transmitter The circuit design uses high-quality power modules starting from the power supply part, and imported high-stable and reliable components are selected, which can completely replace the same type of foreign imported instruments. Sonic intelligent technology software can perform intelligent echo analysis without any debugging or other special steps. This technology has the functions of dynamic thinking and dynamic analysis. The sonic intelligence technology of this product greatly improves the accuracy of the instrument. The liquid level accuracy reaches 0.3%, and it can resist various interference waves. This instrument is a non-contact instrument and does not come into direct contact with liquid, so the failure rate is low. The instrument provides a variety of installation methods, and users can fully calibrate the instrument through this manual. All input and output lines of the instrument are protected against lightning and short circuit. Ultrasonic liquid level transmitter technical parameters   Ultrasonic liquid level transmitter dimensions   Ultrasonic Liquid Level Transmitter Selection Guide

A friend asked how to test whether the temperature transmitter of an environmental engineering instrument can still be used normally if it has not been powered on for a long time. Let me tell you how to test whether the temperature transmitter can still be used normally offline!       The simplest method is to directly connect the temperature transmitter/flow meter to the secondary meter and see if there is any numerical value displayed. The same is true for the pressure transmitter/flow meter. Just add some pressure and see;   If you want to be more precise, this is it - on-site inspection is a bit more difficult. It is easy to check whether it is good or bad, but it is difficult to check whether it is accurate. If you are under pressure, you can make your own pressurizing device and get a standard table for comparison. The temperature transmitter can be unplugged on site and the current can be measured. If the flow meter has been stored for several years, it is recommended to send it back to the manufacturer for recalibration.   If there is no secondary display instrument, there should be a multimeter. The temperature transmitter/pressure transmitter directly measures the 4-20mA current, and the thermal resistor directly measures the resistance between lines.   If the above secondary display instruments and multimeters are not available, then there is nothing you can do!   Yuyao Huangong Instrument Factory specializes in the production of temperature transmitters, liquid level transmitters, differential pressure transmitters, and supporting secondary display instruments. Product 0574-62723632/0574-62723633

What is a smart temperature transmitter   The intelligent temperature transmitter uses a highly integrated microcontroller chip, which has high integration, high precision, high linearity, strong anti-interference ability, and simple adjustment and verification. Thermal resistance and thermocouple signals can be input. After being processed by the instrument, the transmitter outputs single-channel, dual-channel, and up to three-channel linear voltage or current signals that are isolated from each other. Provide electrical isolation between input, output, and power supplies.   Principle and function of intelligent temperature transmitter   1. The temperature transmitter converts physical measurement signals or ordinary electrical signals into standard electrical signal outputs or devices that can be output through communication protocols. Temperature transmitter is an instrument that converts temperature variables into a transmittable standardized output signal. It is mainly used for the measurement and control of temperature parameters in industrial processes. The current transmitter converts the measured main circuit AC current into a constant current loop standard signal and continuously transmits it to the receiving device.   2. The temperature current transmitter converts the signal of the temperature sensor into a current signal, and then connects it to the secondary instrument, so that the corresponding temperature can be displayed.   3. Temperature transmitter technology is very mature and is very common in various factories. It can be mainly used in on-site temperature measurement process control in petroleum, chemical industry, chemical fiber; textile, rubber, building materials; electric power, metallurgy, medicine; food and other industrial fields; it is especially suitable for computer measurement and control systems, and can also be used in conjunction with instruments.

Using the principle of static pressure measurement: when the liquid level sensor is put into a certain depth in the liquid to be measured, the pressure formula on the liquid surface of the sensor is: Ρ = ρ.g.H + Po where: P: The pressure on the liquid surface of the transmitter ρ: Density of measured liquid g: local gravity acceleration Po: Atmospheric pressure on the liquid surface H: Depth of the transmitter into the liquid At the same time, the pressure of the liquid is introduced into the positive pressure chamber of the sensor through the gas-guiding stainless steel, and then the atmospheric pressure Po on the liquid surface is connected to the negative pressure chamber of the sensor to offset the Po on the back of the sensor. Let the pressure measured by the sensor be: ρ.g.H. Obviously, by measuring the pressure P, the liquid level depth can be obtained.   Features: ◆Good stability, long-term stability of full scale and zero position can reach 0.1%FS/year. Within the compensation temperature range of 0 to 70°C, the temperature drift is less than 0.1% FS and less than 0.3% FS within the entire allowable operating temperature range. ◆Equipped with reverse protection and current limiting protection circuit, the transmitter will not be damaged if the positive and negative poles are reversed during installation. In case of abnormality, the transmitter will automatically limit the current to within 35MA. ◆Solid structure, no moving parts, high reliability and long service life. ◆Easy to install, simple in structure, economical and durable.   Main technical parameters: Process: Diffused silicon, ceramic capacitor, sapphire capacitor optional. Split integrated type is optional, range: 0---0.5---200 meters, output: 4---20mA (2-wire system) power supply: 7.5---36VDC. It is recommended that the 24VDCCBM-2100/CBM-2700 input hydrostatic level meter is reliable and anti-corrosion and has a ceramic measuring unit probe for level measurement of clean water, sewage and salt water. GY500 input split type liquid level transmitter adopts diffused silicon piezoresistive core, 316 all stainless steel structure, and the shell adopts isolation and explosion-proof design. This input type liquid level transmitter is mainly suitable for liquid level measurement and control in rivers, groundwater levels, reservoirs, water towers and containers, etc. The circuit adopts signal isolation amplification, frequency cutoff interference design (strong anti-interference ability, lightning protection), overvoltage protection, current limiting protection, impact resistance, anti-corrosion and other designs. ] Main technical parameters: b] Measuring medium: water, oil and other liquids Pressure type: gauge pressure, absolute pressure (no requirement, default gauge pressure)] b] Range: 0~300m intermediate range optional Comprehensive accuracy: 0.1%FS Output signal: 4~20mA (two-wire system), 0~5V, 1~5V, 0~10V (three-wire system) Power supply voltage: 12~36VDC Medium temperature: -30~60℃ Ambient temperature: -40~85℃ Zero temperature drift: ≤±0.05%FS℃ range temperature drift: ≤±0.05%FS℃ compensation temperature: 0~70℃ Safety overload: 150%FS limit overload: 200%FS sampling frequency: ≤2ms Load capacity: (current type) 250~1425Ω (voltage type) ≥2KΩ Sealing grade: IP68 Long-term stability: 0.1%FS/year Vibration impact: Within the mechanical vibration frequency of 20Hz ~ 1000Hz, the output change is less than 0.1% FS. Mechanical connection (threaded interface): input type (submersible type)] Product size (mm): b]   Invest in split level transmitter ⊙Select high-precision, isolated sensitive components imported from the United States, with reliable performance ⊙Gauge pressure or absolute pressure measurement ⊙Wide measuring range: 1mH2O～200mH2O ⊙Output: 4～20mA or 0～5V ⊙Power supply voltage: 24VDC (12~36VDC), mV output type is powered by constant current 1.5mADC or constant voltage 12VDC ⊙High accuracy, better than 0.2%F.S ⊙100% waterproof and moisture-proof, protection grade IP68 ⊙Complete circuit functions, easy to adjust

1. Pressure level gauge: There are two types of pressure-type liquid level meters: bottom-mounted type and input type. They mainly measure the liquid by measuring the pressure at the bottom of the liquid: P=h×γ, γ represents the specific gravity. If it can be installed on the bottom side of the container, the bottom-mounted type, that is, an ordinary pressure transmitter, is generally used; if the liquid level is measured in culverts, wells, pools, etc., because the bottom-mounted type cannot be installed, a plunge-type liquid level transmitter is required. The sensor is put into the bottom of the liquid, and then the atmospheric pressure is introduced into the sensor through a gas cable for compensation for measurement.   2. Magnetic flip liquid level gauge: Magnetic flip level gauges can be divided into reed tube type and magnetic resistance type. They both use a magnetic steel float ball in the tube to attract the nearest reed tube or magnetic resistance, and then measure the height of the liquid level based on the resistance value corresponding to the attraction position.   3. Ultrasonic liquid level meter The measurement is carried out through the emission and reflection time of ultrasonic waves. The disadvantage is that when encountering bubbles, dust and other substances, ultrasonic waves will also be reflected back, causing measurement errors.   4. Radar level gauge It is measured by the time it takes for the radar electromagnetic wave to be emitted and reflected back. The radar wave has strong penetrating power and can penetrate bubbles, so it has strong anti-interference ability. The disadvantage is that the price is relatively high.   5. Float level gauge The principle is the same as that of the magnetic flap, except that the floating ball is outside the stainless steel tube, and the reed switch or magnetic resistance is inside the stainless steel tube. This is more intuitive, but it is not suitable for media with high viscosity and tiny particles.   6. Tuning fork level gauge The tuning fork level gauge uses a pair of piezoelectric crystals installed on the tuning fork base to make the tuning fork vibrate at a certain resonance frequency. When the tuning fork of the tuning fork level gauge comes into contact with the measured medium, the frequency and amplitude of the tuning fork will change. These changes in the tuning fork level gauge are detected and processed by the intelligent circuit and converted into electrical signals.   7. Radio frequency admittance level meter Radio frequency admittance is a technology for measuring liquid level developed from capacitive type. It is anti-sticking. It is a new measurement technology that is more reliable, more accurate and more adaptable than capacitive type. Admittance is the reciprocal of impedance in electricity. It is composed of resistance, capacitance and inductance. The radio frequency admittance level meter is based on the circuit of the capacitive level meter and adds an oscillator buffer circuit and an AC conversion chopper drive circuit. Through the unique circuit and sensor structure, the changes in admittance are perfectly converted into electrical signals. Maintenance-free, strong anti-interference ability, can overcome the influence of steam, foam and stirring on measurement   8. Magnetostrictive level gauge When the sensor of the magnetostrictive liquid level gauge is working, the circuit part of the sensor will excite a pulse current on the waveguide wire. When the current propagates along the waveguide wire, a pulse current magnetic field will be generated around the waveguide wire. There is a float outside the sensor rod of the magnetostrictive liquid level meter. This float can move up and down along the rod as the liquid level changes. There is a set of permanent magnetic rings inside the float. When the pulse current magnetic field meets the magnetic ring magnetic field generated by the float, the magnetic field around the float changes, causing the waveguide wire made of magnetostrictive material to generate a torsional wave pulse at the position of the float. This pulse is transmitted back along the waveguide wire at a fixed speed and is detected by the detection mechanism. Pass the test