Monthly Archives: July 2021

What does SCADA stands for?

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What does SCADA stand for?

SCADA is the abbreviation of Supervisory Control And Data Acquisition. Namely data acquisition and monitoring control system. SCADA system is also called monitoring configuration software, which is widely used in enterprise equipment management of equipment automatic operation.

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What does SCADA stand for?

What is a SCADA system?

SCADA is a data acquisition and monitoring control system. The scada system is a computer-based production process control and scheduling automation system. It can monitor and control the operating equipment on site. Because each application field has different requirements for scada, the development of scada system in different application fields is not exactly the same.

The scada system is the most widely used in the power system, and the technology development is also the most mature. It is one of the most important subsystems of the energy management system (EMS system). It has the advantages of complete information, improved efficiency, correct control of system operation status, accelerated decision-making, and can help quickly diagnose system fault status. Now it has become an indispensable power dispatcher. Missing tools.

The scada system plays an irreplaceable role in improving the reliability, safety and economic benefits of power grid operation, realizing the automation and modernization of power dispatching, and improving the efficiency and level of dispatching.

How does SCADA work?

The SCADA system deploys multiple software and hardware elements, allowing industrial organizations to: monitor, collect and process data.

Connect and control machines and equipment such as valves, pumps, motors, etc. through HMI (Human Machine Interface) software.

Log the event to a log file.

In the basic SCADA architecture, sensor or manual input information is sent to PLC (Programmable Logic Controller) or RTU (Remote Terminal Unit), and then sent to a computer with SCADA software.

SCADA software analyzes and displays data to help operators and other workers reduce waste and improve the efficiency of the manufacturing process.

An effective SCADA system can greatly save time and money. Many case studies have been published, highlighting the benefits and savings of using modern SCADA software solutions such as ignition.

What is SCADA used for?

The SCADA system has a wide range of applications, and it can be used in the fields of data acquisition, monitoring and control and process control in electric power, metallurgy, petroleum, chemical, gas, railway and other industries. Its functions mainly focus on four aspects: real-time collection of production data, process monitoring of production equipment, abnormal alarms of production equipment, data analysis, data reports and dashboard display. Its characteristics mainly reflect the following aspects.

  1. It supports more than 5000 communication protocols and meets the communication requirements of 99.99% of controllers and instruments on the market. Get through the automated hardware system and the information transmission of the information software system.
  2. Isolate office network IP and industrial equipment IP in hardware to avoid IP conflicts.
  3. Intuitive display of production dynamics, direct or indirect control of on-site equipment, to meet the needs of visual management.
  4. Perform statistical analysis of data and display it through the dashboard.

The SCADA system is centered on the data collected in the production process. It is related to the distribution of people, machines, materials, methods, environments, testing, and R&D. It is based on the data generated during the operation of production equipment. It is also a big Most companies are most concerned about.

Secondly, the SCADA system is aimed at the application needs of the above-mentioned manufacturing enterprises. At the same time, it will give play to its own unique advantages to bring improvements and benefits to the enterprise.

  1. Help companies collect all kinds of data in the production process in real time. Instead of manual operations, it also avoids certain losses caused by personnel errors. Not only improves work efficiency, but also enables real-time monitoring of production All abnormal data in the process provides another layer of guarantee for the quality of the product.
  2. The SCADA system provides the production data of each device, which makes the production situation intuitive and clear, and facilitates the analysis of the production situation by the management personnel of the enterprise, and at the same time helps the enterprise optimize the production, making the production plan more scientific and reasonable.
  3. Realize the digital and intelligent improvement of the management process of products, production schedule, production efficiency, quality information, equipment operation, etc., and optimize the digital management and control capabilities of the production process.
  4. During the company’s external publicity and visit, the company’s image and professionalism will be improved by explaining the application and advantages of the system for the company.

Extended reading: PID Controller Working Principle

The difference between SCADA, DCS and PLC

SCADA and DCS are a concept, and PLC is a product, the three are not comparable:

  1. PLC is a product, which can form SCADA, DCS;
  2. DCS is developed from process control, and PLC is developed from relay-logic control system;
  3. PLC is equipment, DCS and SCADA are systems.

In a narrow sense, DCS is mainly used for process automation. PLC is mainly used for factory automation (production line). SCADA is mainly used for wide-area needs. Such as oil fields, which stretch for thousands of miles of pipelines.

If they are unified from the perspective of computers and networks, the main reason for the differences lies in the application requirements. DCS often requires advanced control algorithms.

For example, in the oil refining industry, PLC requires high processing speed. Because it is often used in interlocking, even fail-safe systems. SCADA also has some special requirements. Such as vibration monitoring, flow calculation, peak and valley adjustment, and so on.

Therefore, you can simply think:

  • SCADA is the dispatch management layer
  • DCS is the plant management
  • PLC is the field device layer

Sino-Inst offers over controllers for Industrial data recording and analysis.

It is widely used in hydropower, tap water, petroleum, chemical, machinery, hydraulic and other industries to measure, display and control the pressure of fluid media on site.

A wide variety of controllers are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of controllers, located in China.

What is Modbus Protocol?

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What is meant by Modbus protocol?

Modbus Protocol is a serial communication protocol, which was published by Modicon company (now Schneider Electric) in 1979 for the use of programmable logic controller (PLC) communication. Modbus has become the industry standard (De facto) of communication protocols in the industrial field and is now a common connection method between industrial electronic devices.

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Modbus Protocol Features

The main reasons why Modbus is more widely used than other communication protocols are:

  • Published publicly and without copyright requirements
  • Easy to deploy and maintain
  • For suppliers, there are not many restrictions on modifying mobile local bits or bytes

Modbus allows multiple (approximately 240) devices to be connected on the same network to communicate. For example, a device that measures temperature and humidity and sends the results to a computer. In the data acquisition and monitoring control system (SCADA), Modbus is usually used to connect the monitoring computer and the remote terminal control system (RTU).

How does a Modbus work?

Modbus is a master/slave communication mode with a single master station. There can only be one master station on the Modbus network, and the master station has no address on the Modbus network. The address range of the slave station is 0-247, where 0 is the broadcast address. The actual address range of the slave station is 1-247. Modbus communication standard protocol can be transmitted through various transmission methods, such as RS232C, RS485, optical fiber, radio, etc.

Modbus has two serial transmission modes, ASCII and RTU. They define different ways of how data is packaged and decoded. Devices that support Modbus protocol generally support the RTU format. Both communication parties must support one of the above modes at the same time.

The above is the official definition, let’s use ordinary words to explain:

This is actually the communication protocol, and any protocol is similar. There are only two communication formats and communication specifications.

If you want, you can also define a communication specification yourself. Use PLC or VB language to process according to this specification defined by yourself. If the reliability exceeds Modbus, then your communication specification is the most popular!

The difference and connection between RS 485 and MODBUS

I often see RS485 and MODBUS written together, and Sino-Inst will talk to you about the difference and connection between RS485 and MODBUS.

RS485 is a physical interface, which is simply hardware.

MODBUS is an international standard communication protocol used to exchange data between devices of different manufacturers (usually for industrial purposes); the so-called protocol can also be understood as the “language” someone said above, or simply software.

Under normal circumstances, two devices transmit data through the MODBUS protocol: RS232C was first used as the hardware interface, (that is, the serial communication port (serial port) on an ordinary computer). There is also RS422, and there is also commonly used RS485. This interface The transmission distance is long, and it is often used in general industrial scenes.

The MODBUS protocol is divided into three modes: MODBUS RTU, MODBUS ASCII and the later developed MODBUS TCP.

The physical hardware interfaces used by the first two (MODBUS RTU, MODBUS ASCII) are serial (Serial) communication ports (RS232, RS422, RS485).

And MODBUS TCP is to conform to the development trend of the world today. Anything can be connected by Ethernet or Internet to transmit data.

The hardware interface of MODBUS TCP mode is the Ethernet (Ethernet) port, which is the network port generally used on our computer.

We categorize industrial networks into three categories: RS485 network, HART network and fieldbus network.

HART network

HART is a transitional bus standard proposed by Emerson. It mainly superimposes a digital signal on top of a 4-20 mA current signal.

The physical layer uses BELL202 frequency shift keying technology. In order to realize the functions of some smart meters. But this agreement is not a truly open standard, and you have to join his foundation to get the agreement. Part of the cost of joining the foundation.

The technology is mainly monopolized by several large foreign companies, and in the past two years, some domestic companies have started to do it again. But it has not yet reached the level of foreign companies.

Nowadays, a large part of smart meters are equipped with HART round cards and all have HART communication function.

But from the domestic point of view, this part of the function has not been really used, at most it is only used to set the parameters of the handheld communicator. The HART intelligent instrument has not played its due function, and it has not been connected to the Internet for equipment monitoring.

In the long run, due to the low communication rate of HART, the networking is difficult and other reasons. The procurement volume of HART instruments will experience a downward trend.

However, because HART instruments have a history of more than ten years, the number of instruments installed is very large. For some system integrators, there is still a lot of room for use.

Fieldbus network

Fieldbus technology is one of the hotspots of technology development in the field of automation today. Known as the computer local area network in the field of automation. Its appearance marks the beginning of a new era of automation control technology.

Fieldbus is a digital, serial, multi-station communication network that connects the instruments installed in the control site and the control equipment installed in the control room. The key symbol is the ability to support bidirectional, multi-node, bus-style all-digital communication.

In recent years, fieldbus technology has become a hot spot in the development of automation and instrumentation in the world. The appearance of the fieldbus network is a revolutionary change in the traditional control system structure. It is the automatic control system that is moving in the direction of intelligence, digitization, informationization, networking, and decentralization. Form a new type of network integrated fully distributed control system-Fieldbus Control System FCS (Fieldbus Control System).

However, various standards of current fieldbus exist in parallel and have their own areas of survival. There has not yet been a truly unified standard. The key is that we cannot see when a unified standard will be formed, and the technology is not mature enough.

In addition, the types of fieldbus instruments are still relatively small, and the room for selection is small, and the price is relatively high. From the perspective of end users, most of them are still on the sidelines. I want to wait until the technology is mature and consider it, but now there are few implementations.

RS485 network

RS485/MODBUS is a popular way of network layout. Its characteristic is simple and convenient to implement. And now there are many instruments that support RS485, especially in the oil industry.

RS485/MODBUS is simply dominating the world. Current instrument vendors have also switched to support RS485/MODBUS. The reason is simple, like the original HART instrument, it is very difficult and expensive to buy a conversion port. The RS485 conversion interface is much cheaper and has a wide variety.

At least in the low-end market, RS485/MODBUS will still be the most important networking method, and it will not change in the past two to three years.

Features of 4-20mA current loop and RS485 communication (Modbus RTU protocol) data acquisition

4-20mA current loop data acquisition characteristics

Use pressure, temperature transmitter and current acquisition module (RTU) or acquisition card on site for data acquisition and then communicate and transmit with the industrial computer. The data acquisition system using 4-20mA current loop instrument has the following characteristics:

  1. The construction is complicated, data cables need to be buried in advance, the number of cables is large, and the construction period is long
  2. The computer terminal needs a current acquisition card or a data acquisition module
  3. Complicated replacement and maintenance operations, troublesome expansion
  4. 4-20mA current loop data acquisition accuracy is low, and the error comes from 4-20mA output instrument and acquisition card (or data acquisition module)

RS485 communication (Modbus protocol) data acquisition characteristics

Use smart meters, transmitters, actuators, etc. with RS485 communication to directly communicate with the serial port of the industrial computer. The use of RS485 communication digital sensor meter network system has the following characteristics:

  1. The construction complexity is reduced, data cables need to be buried in advance, the number of cables is small, and the construction period is reduced
  2. The computer terminal only needs an isolated RS485/RS232 converter
  3. Easy to replace and maintain, and easy to expand
  4. High acquisition accuracy, eliminating the error of RTU, the system error only comes from the transmitter itself
  5. RS485 communication has good transmission stability and less network maintenance
  6. The cost of use is greatly reduced|
  7. The maximum communication distance of RS485 is 1200 meters

RS485 communication transmission of electromagnetic flowmeter Modbus protocol

The RS485 communication data transmission interface of the electromagnetic flowmeter is half-duplex. The standard rate is greater than 250kHz. The communication direction conversion time is 3.5us. Usually 16-way load can be connected. It can also be expanded to 32 channels. Standard shielded twisted pair cable is 1000m. Use master-slave multi-machine communication. When multiple electromagnetic flowmeters are interconnected. It can save signal lines and facilitate high-speed transmission.

RS-485 communication has good anti-noise interference. Long transmission distance and multi-station capability. Will not affect the synchronization of on-site and remote data due to PLC failure.

However, the electromagnetic flowmeter must have a 485 interface and support the MODBUS RTU protocol.

In order to maintain stability, it is better to use electromagnetic flowmeters of the same manufacturer and the same brand when communicating with multiple flowmeters.

RS485 is a kind of industrial data bus. The electromagnetic flowmeter has RS485 serial communication so that digital communication replaces the transmission of PLC analog signals and ordinary switch signals. The PLC simulation calculation is reduced, and the accurate data collection and transmission are realized.

RS485 precession vortex flowmeter

Precession vortex flowmeter is a new type of gas flowmeter. It can be used for the measurement of natural gas, propane, air, nitrogen and other gases.

The converter can output frequency pulse, 4 ~ 20mA analog signal, and has RS485 interface, can be directly connected to the computer network, transmission distance up to 1.2km;

Precession Vortex Gas Flowmeter, like vortex flowmeter, is a velocity flowmeter. The cost performance of the intelligent precession vortex flowmeter is higher than vortex flowmeter. The intelligent precession vortex flowmeter can only measure gas. Precession Vortex Gas Flowmeter can be made into an integrated temperature and pressure compensation. And can measure various gases. Such as compressed air, oxygen, biogas, natural gas, coal gas, etc.

RS485-communication-protocolDownload

Read more about Everything You Need To Know About Electronic Flow Meters

Guide: Magnetic Flowmeter Installation

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Magnetic flowmeters are mainly used to measure the flow of conductive media with good fluidity. Magnetic flowmeters are divided into insertion type and pipeline type. Pipeline electromagnetic flowmeter and insertion electromagnetic flowmeter has the same requirements for installation. There are also different places. Generally speaking, there are requirements for the external environment and installation methods.

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A magnetic Flow Meter is a flow meter that measures the flow of conductive fluids. Abbreviated as EMF, also called Electromagnetic flowmeters. It is a kind of Volumetric flow meter. A magnetic flow meter measures the velocity of conductive liquids moving through a pipe or conduit. In the wastewater treatment industry, a Magnetic Flow Meter is the best flow meter choice.

Electromagnetic flowmeters have been used for more than 50 years and have been widely used worldwide. The fields involve water/sewage, chemical, pharmaceutical, paper, food, and other industries.

  • Water / Wastewater Industry
  • Food and Beverage
  • Metals
  • Brewing, Distilling, and Wine makening
  • HVAC
  • Chemical
  • Pulp and Paper
  • Pharmaceutical
  • Mining, Mineral Processing

Extended reading: How to Select the Right Agriculture Flow Meter

Magnetic flowmeters use the principle of Faraday’s Law of Electromagnetic Induction to measure the flow rate of liquid in a pipe. In the magnetic flowmeter pipe parts, a magnetic field is generated and channeled into the liquid flowing through the pipe. 

Faraday’s Law states that the voltage generated is proportional to the movement of the flowing liquid. A conductor moving through a magnetic field produces an electric signal within the conductor. And the singal is proportional to the velocity of the water moving through the field. 

As fluid flows through the magnetic field, conductive particles in the fluid create changes. This variation is used to measure and calculate the velocity of water flow through the pipe. When the fluid moves faster, more voltage is generated. The electronic transmitter processes the voltage signal to determine the liquid flow.

To learn more about Magnetic Flow Meters, this video by Emerson gives a good explanation.
Video source: https://www.youtube.com/watch?reload=9&v=lRSjYjg9WRo

Read more about Everything You Need To Know About Electronic Flow Meters

The premise of using an electromagnetic flowmeter is that the liquid to be measured must be conductive and cannot be lower than the threshold (ie, the lower limit). If the conductivity is lower than the threshold value, measurement errors will occur until it cannot be used. The threshold value of general-purpose electromagnetic flowmeters is between 10-4~(5×10-6)S/cm, depending on the model. The general conductivity threshold is 5×10-6S/cm=5μS/cm. the

The conductivity of industrial water and its aqueous solution is greater than 10-4S/cm. The conductivity of acid, alkali and salt solution is between 10-4 and 10-1S/cm. There is no problem in use, and the low-grade distilled water is 10-5S/cm cm is also not a problem.

Petroleum products and organic solvents cannot be used if their conductivity is too low.

Some pure liquids or aqueous solutions have low conductivity and are considered unusable. However, in the actual work of electromagnetic flowmeters, there will be instances where they can be used because they contain impurities, which are beneficial to increase the conductivity.

For the aqueous solution, the conductivity in the data is measured in the laboratory with pure water. The actual aqueous solution may be mixed with industrial water. The conductivity will be higher than that found. It is also conducive to flow measurement.

Step 1: Magnetic Flowmeter Installation environment requirements

In order to make the electromagnetic flowmeter work stable and reliable, the following requirements should be paid attention to when choosing the installation location:

  1. Try to avoid ferromagnetic objects and equipment with strong electromagnetic fields (large motors, large transformers, etc.). In order to prevent the magnetic field from affecting the working magnetic field and flow signal of the sensor.
  2. Install in a dry and ventilated place as much as possible. Avoid sun and rain. The ambient temperature should be -20 ～ +60 ℃. The relative humidity is less than 85%.
  3. There should be ample space around the flowmeter. Easy to install and maintain.

Extended reading: Ultrasonic Insertion Flow Meter for Lined/Large Pipes

Step 2: Magnetic Flowmeter Installation Location selection

The electromagnetic flowmeter can be installed on a horizontal pipe or a vertical pipe.

  1. Choose a straight pipe section filled with liquid, such as the vertical section of the pipeline (flow direction from bottom to top is appropriate) or a liquid-filled horizontal pipe (the lowest point in the entire pipeline is appropriate). The position must ensure that the pipeline is always filled with the measured fluid . In the process of installation and measurement, there must be no partial full pipe.
  2. Select the place where the fluid flow pulse is small. That is, it should be far away from pumps, valves, elbows and other local resistance parts.
  3. When measuring two-phase (solid, liquid or gas, liquid) fluids, choose a place that is not easy to cause phase separation.
  4. Avoid negative pressure at the measurement site.
  5. The diameter or circumference of the side pipe is easy to measure, and the ovality should be small.
  6. Straight pipe length: The length of the straight pipe on the upstream side of the sensor installation pipeline should be greater than or equal to 10D, and the downstream side should be no less than 5D.
  7. There are two methods for inserting the insertion point of the plug-in electromagnetic flow sensor: one is to insert it on the central axis of the pipe under test, and the other is to insert it at 0.25D where the inner wall of the pipe is the pipe.
  8. Vertical installation: when the sensor is inserted into the pipe, the angle between the vertical diameter of the pipe section and the pipe section should be less than 5°, which is suitable for measuring clean media with small pipe vibration.
  9. Tilt installation: the angle between the axis of the sensor and the axis of the pipeline being measured is 45°. It is suitable for liquid flow measurement with large pipe diameter and other impurities in the measuring medium. This installation method has low water resistance and is not suitable for entanglement.

Step 3: Mounting flange for Magnetic Flowmeter Installation

A. Select the installation location and select the front and rear straight pipe sections of appropriate length. Cut the pipe section where the flowmeter is installed;
B. Weld a flange on each of the front and rear straight pipe sections. After adding gaskets at both ends of the sensor, connect the sensor to the flange with stud bolts (note that the direction of the arrow on the meter body should be consistent with the direction of fluid flow);
C. Weld the front and rear straight pipe sections of the sensor to the original pipe.

Note:

  1. When welding, ensure that the flange end face is perpendicular to the centerline of the pipeline;
  2. The place where the mounting hole pitch is larger is the meter rod mounting position. And the direction of the mounting holes of the two flanges should be the same;
  3. After the flange is welded, the pipeline should be cleaned up and there should be no welding slag and other sundries.

Extended reading: Magnetic Large Dia. Pipe Flow Meter

Step 4: Converter installation and connection cables

Power and signal wiring. Please refer to the product manual accompanying the goods.

The converter of the split electromagnetic flowmeter should be installed near the sensor where it is convenient for reading and maintenance. It can also be installed in the instrument room, and its environmental conditions can be much better than the sensor.

The distance between the converter and the sensor is limited by the conductivity of the measured medium and the signal of the signal cable. That is, the distributed capacitance of the cable, the cross-section of the wire, and the number of shielding layers. Use the information cable provided with the instrument by the manufacturer.

For liquids with lower conductivity and longer transmission distances, three-layer shielded cables are also specified.

The general instrument “Instruction Manual” gives the corresponding transmission distance range for liquids with different conductivity.

When a single-layer shielded cable is used for industrial water or acid-base liquids, the transmission distance is usually 100m.

In order to avoid signal interference, the signal cable must be worn separately in a well-grounded steel protection tube. Never put the signal cable and the power cord in the same steel pipe.

Guess you like: Insertion Magnetic Flow Meter-Large diameter online install

Special Magnetic Flowmeter Installation situation

For pipelines that do not allow flow interruption in the process, a bypass pipe should be installed and cleaned when the flow meter is installed. As shown in the figure, this device ensures continuous operation of the equipment system when the flow meter is withdrawn from use.

The inner diameter measured by the flowmeter should be consistent with the inner diameter of the pipe. If the inner diameter cannot be the same, the inner diameter of the pipe should be greater than the inner diameter of the flowmeter. And install a tapered tube or expansion tube with a cone angle not greater than 15 between them, as shown in the figure.

When the flowmeter is installed inclined or vertically, the flow direction should be from top to bottom, as shown in the figure.

All Magnetic Flowmeter Installations. It cannot be described in detail here. If you encounter problems with the Magnetic Flowmeter Installation. Please contact our engineers in time. We will guide the Magnetic Flowmeter Installation for you.

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Frequently
Asked
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Generally speaking, there will be an indication of the fluid flow direction on the main body of various flowmeters. When we install the flowmeter, just follow the instructions to install it.

Generally speaking, there are two principles for the installation direction of the flowmeter.

  1. Make sure to measure full of fluid. Because absolutely most of the flowmeters need to be in a full pipe state to ensure the measurement effect.
  2. Install according to the instructions of the flowmeter.

Electromagnetic flowmeters can be installed vertically. However, vertical installation needs to pay attention to the following aspects, whether it is installed at the water inlet or the water outlet. Standard installed in the middle of the vertical position where the water flows upwards. This installation complies with gravity.

If it is installed downstream, it will not be a full pipe, and the water flow from bottom to top is always full. This facilitates accurate measurement of the flow meter. The straight pipe section is required to be 10D in front and 5D in back to ensure the use and accuracy requirements of the electromagnetic flowmeter.

Electromagnetic flowmeter vertical installation requirements:

  1. Installed at the inlet of the pipeline (that is, upstream), so that the pipeline is always full.
  2. The electromagnetic flowmeter should be installed in the lower part of the horizontal pipeline, vertically upward. Avoid installing at high places and vertically downward positions in the pipeline.
  3. Requirements for straight pipe section: inlet/outlet straight pipe section: inlet ≥ 10×DN; water outlet ≥ 5×DN
  4. In order to facilitate the detection of the flowmeter, a bypass channel is set in the measuring pipeline.
  5. Grounding point requirements: In order to make the instrument work reliably, improve the measurement accuracy, and not be disturbed by strong external electromagnetic fields, the sensor should be well grounded, and the grounding resistance should be less than 10 ohms.

Generally speaking, there is no other cost to install a flow meter.
However, the actual situation needs to be determined according to the user’s pipeline situation.

The pump outlet flow meter should be installed after the pump outlet valve. But before regulating the valve. In this way, the regulating valve will not affect the measurement of the flowmeter.

The flowmeter is not allowed to be installed in front of the pump, because there will be negative pressure in front of the pump, which will affect the accuracy of the electromagnetic flowmeter. Therefore, the electromagnetic flowmeter must be installed behind the pump.

The installation distance depends on the length and width of your pipeline, and the flowmeter has certain requirements for the straight pipe sections before and after it. At least the straight pipe section in front of the flowmeter is 10 times the diameter of the flowmeter. The straight pipe section behind the flowmeter is 5 times the diameter of the flowmeter. The farther away from the straight pipe, the better.

More Flow Measurement Solutions

Sino-Inst offer over 50 Magnetic Flow Meters, with Best Price.

A wide variety of Magnetic Flow Meters options are available to you, such as free samples, paid samples.

About 13% of these are magnetic flow meter, 14% are Insertion Magnetic Flow Meter, 25% are Venturi flow meter, 13% are ultrasonic flow meter, and others are Liquid Turbine Flow Meters.

Electromagnetic flowmeters can be divided into insertion electromagnetic flowmeters and pipeline electromagnetic flowmeters. The Magnetic Flowmeter Installation methods of insertion electromagnetic flowmeters and pipeline electromagnetic flowmeters have the same place, but there are also differences.

First of all, what we need is that the shielded wire of the electromagnetic flowmeter cannot be routed together with the cable, because this will cause interference. Under normal circumstances, the parameters of the inner head of the electromagnetic flowmeter are set in advance, so no other adjustments are required.

Magnetic Flowmeter Installation should avoid places where the temperature rises and falls too much, and places where there are magnetic fields and strong vibration sources.

Sino-Inst is Magnetic Flow Meters supplier, located in China. Magnetic Flow Meters products are most popular in North America, Mid East, and Eastern Europe. The United States, and India, which export 99%, 1%, and 1% of Magnetic Flow Meters respectively.

For how to install the electromagnetic flowmeter, the details of Magnetic Flowmeter Installation, if you have any questions and ideas, please feel free to contact us.

Solvent flow meters

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The solvent flow meter is a flow meter that can measure solvent volume or mass flow. In the industrial production process, it is very important to accurately measure the amount of solvent. Solvents are divided into organic solvents and inorganic solvents according to their chemical composition. Solvents are commonly used raw materials in various industries such as coatings, paints, and dyes.

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Solvent refers to a substance that can dissolve other solids, liquids, gases, and other solutes. The most common solvent in our daily lives is water. Generally, the solvent has a low boiling point and is easy to volatilize, and the solvent cannot produce a chemical reaction to the solute. Solvents are generally colorless and transparent liquids with unique odors.

Solvents play a very important role in adhesives.

Organic solvents are a large class of organic compounds that are widely used in life and production. They have a small molecular weight and are liquid at room temperature. Organic solvents include many types of substances, such as paraffin, alkenes, alcohols, aldehydes, amines, esters, ethers, ketones, aromatic hydrocarbons, hydrogenated hydrocarbons, terpene olefins, halogenated hydrocarbons, heterocyclic compounds, nitrogen-containing compounds, and sulfur-containing compounds, etc. Etc. Most of them are toxic to the human body.

Solvents are generally found in paints, adhesives, lacquers, and cleaners. Commonly used organic solvents include DMF, cyclohexanone, acetonitrile, acetic acid, methyl acetate, ethyl acetate, isopropanol, vinyl acetate, cyclohexane, n-hexane, n-heptane, etc.

Organic solvents are a class of organic compounds that can dissolve some water-insoluble substances (such as grease, wax, resin, rubber, dyes, etc.). Its characteristic is that it is liquid at room temperature and pressure. It has greater volatility. In dissolution During the process, the properties of the solute and solvent are unchanged.

There are many types of organic solvents, which can be divided into 10 categories according to their chemical structure:

①Aromatic hydrocarbons: benzene, toluene, xylene, etc.;
②Aliphatic hydrocarbons: pentane, hexane, octane, etc.;
③ Alicyclic hydrocarbons: cyclohexane, cyclohexanone, toluene cyclohexanone, etc.;
④ Halogenated hydrocarbons: chlorobenzene, dichlorobenzene, dichloromethane, etc.;
⑤Alcohols: methanol, ethanol, isopropanol, etc.;
⑥Ethers: ether, propylene oxide, etc.;
⑦Esters: methyl acetate, ethyl acetate, propyl acetate, etc.;
⑧ Ketones: acetone, methyl butanone, methyl isobutyl ketone, etc.;
⑨Diol derivatives: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, etc.;
⑩Others: acetonitrile, pyridine, phenol, etc.

Read More about: Chemical Flow Meter Guide

Solvent flow meter – Oval Gear

An Oval Gear flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive Solvent fluids.

  • High measurement accuracy;
  • The installation pipeline conditions have no influence on the measurement accuracy;
  • Can be used for high-viscosity liquids;
  • Wide range;
  • The direct-reading meter can directly obtain the cumulative and total amount without external energy.
  • Clear and clear, easy to operate.

Extended reading: Mechanical flow meter types

Solvent flow meter – Turbine

Turbine flow meters are velocity flow meters, also called impeller flow meters. Can be used to measure the instantaneous flow and cumulative flow of Solvent liquids.

Turbine flowmeters are widely used in flow measurement: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas and cryogenic fluids. Turbine flowmeter signals can be divided into pulse signals or current signals (4-20mA). It is suitable for use with secondary display, PLC, DCS and other computer control systems.

Turbine Flow Meter reference price: USD 200-1700/pc.

Extended reading: non contact flow meter

Solvent flow meter – Electromagnetic

Magnetic Flow Meter is a flow meter that measures the flow of conductive Solvent fluids. Abbreviated as EMF, also called Electromagnetic flowmeters. It is a kind of Volumetric flow meter. A magnetic flow meter measures the velocity of conductive liquids moving through a pipe or conduit. In the wastewater treatment industry, Magnetic Flow Meter is the best flow meter choice.

  • Measures liquids or liquid slurries that have a minimum conductivity of 5 µS/cm.
  • Sanitary type, PTFE anticorrosive materials are optional.
  • Clamps, flanges, insertion installation are optional.
  • Battery powered optional.
  • Low cost.
  • DN 6 to DN2000
  • High precision: 0.5%, 0.2% optional

Extended reading: How to Select the Right Agriculture Flow Meter

Solvent flow meter – Gear

Gear flow meter is a micro digital positive displacement flow meter. Can measure very small flow rates and quantify small volumes of liquid. High and low-temperature resistance (-196℃-200℃).

The Gear flow meter for Microflow is made of stainless steel and is used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, grease, and other high-viscosity media. It can measure the viscosity of Fluid up to 10000Pa.s.

Generally speaking, we can choose a suitable flow meter according to the different characteristics of chemical solvents. For example, high-viscosity solvents are recommended to use gear flow meters. For example, for corrosive solvents, electromagnetic flowmeters can be used. If you need to reduce costs, you can choose a turbine flowmeter.

Of course, it needs to be based on our actual measurement conditions, such as the temperature of the medium, the temperature of the pipeline, the pressure, and so on. Select the appropriate flow meter to achieve accurate measurement.

Extended reading: Cylinder Gear flow meter for micro flow measurement.

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Extended Reading: Special Magnetic Flowmeter Installation situation

Sino-Inst, Manufacuturer for Solvent flow meters.

Sino-Inst’s Solvent flow meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.

RTD vs Thermocouple

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RTD vs Thermocouple- What is the difference? What are they used for?

Both RTDs and thermocouples are sensors used to measure heat such as Fahrenheit and Kelvin. Both thermocouple and thermal resistance belong to contact temperature measurement in temperature measurement. Although its role is to measure the temperature of the object the same. But their working principles and characteristics are different. Thermocouple is the most widely used temperature device in temperature measurement. Thermal resistance does not require compensation wires and is cheaper than thermocouples.

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As two major contact temperature sensors: thermocouple and thermal resistance. Their names differ by only one word and both can be used as sensors for measuring object temperature.

The choice of thermocouple or thermal resistance should be judged according to the measured object environment. Many people are not sure what to choose. Therefore, it is necessary to fully understand the difference between thermal resistance and thermocouple temperature sensor when choosing a temperature sensor.

RTDs stands for ‘Resistance Temperature Detectors’

Thermal resistance: no compensation wire is needed, the price is cheaper

The principle of temperature measurement of thermal resistance: based on the characteristics of the resistance of conductors or semiconductors that change with temperature.

Thermal resistance is one of the most commonly used temperature detectors in medium and low-temperature areas. The thermal resistance temperature measurement is based on the characteristic that the resistance value of the metal conductor increases with the increase in temperature for temperature measurement.

The advantage of thermal resistance: It can also transmit electrical signals remotely. High sensitivity and strong stability. Interchangeability and accuracy are better. However, power supply excitation is required. The temperature change cannot be measured instantaneously.

Disadvantages of thermal resistance: Although thermal resistance is widely used in industry. But because of his temperature measurement range, his application has been limited.

Industrial thermal resistance generally uses Pt100, Pt10, Cu50, Cu100, the temperature range of platinum thermal resistance is generally minus 200-800 degrees Celsius, and copper thermal resistance is minus 40 to 140 degrees Celsius.

Thermal resistors are mostly made of pure metal materials. At present, platinum and copper are the most widely used. In addition, materials such as nickel, manganese, and rhodium have now been used to make thermal resistors.

Thermal resistance does not require compensation wires and is cheaper than thermocouples.

Thermocouple: can transmit 4-20mA electrical signal far away

Thermocouple temperature measurement principle:

The principle of thermocouple temperature measurement is based on the thermoelectric effect. Connect two different conductors or semiconductors into a closed loop. When the temperature at the two junctions is different. The thermoelectric potential will be generated in the loop. This phenomenon is called the thermoelectric effect, also known as the Seebeck effect.

The thermoelectric potential generated in the closed-loop is composed of two kinds of electric potential. Thermoelectric potential and contact potential.

Thermoelectric potential refers to the electric potential generated by the temperature difference between the two ends of the same conductor.

Different conductors have different electron densities, so they generate different electric potentials.

The contact potential, as the name implies, refers to when two different conductors are in contact. Because their electron densities are different, a certain amount of electron diffusion occurs. The electric potential formed when they reach a certain equilibrium. The magnitude of the contact potential depends on the material properties of the two different conductors and the temperature of their contact points.

The advantages of thermocouples:
Wide temperature measurement range. The performance is relatively stable. At the same time, the structure is simple. The dynamic response is good. It can transmit 4-20mA electrical signals remotely. It is convenient for automatic control and centralized control.

Thermocouples currently used internationally have a standard specification. Internationally, thermocouples are divided into eight different divisions, namely B, R, S, K, N, E, J, and T. The lowest temperature can be measured at minus 270 degrees Celsius and the highest can reach 1800 degrees Celsius.

Among them, B, R, and S belong to the platinum series of thermocouples. Because platinum is a precious metal. So they are also called precious metal thermocouples and the remaining ones are called cheap metal thermocouples.

There are two types of thermocouples, common type, and armored type.

Ordinary thermocouples are generally composed of hot electrodes, insulating tubes, protective sleeves, and junction boxes. The armored thermocouple is a combination of thermocouple wire, insulating material, and a metal protective sleeve. A solid combination is formed by stretching.

But the electrical signal of the thermocouple needs a special wire to transmit, this kind of wire is called compensation wire.

Different thermocouples require different compensating wires, and their main function is to connect with the thermocouple to keep the reference end of the thermocouple away from the power supply so that the temperature of the reference end is stable.

Compensation wires are divided into two types: compensation type and extension type. The chemical composition of the extension wire is the same as that of the thermocouple being compensated. However, in practice, the extended wire is not made of the same metal as the thermocouple. Generally, a wire with the same electron density as the thermocouple is used instead.

The connection between the compensation wire and the thermocouple is generally very clear. The positive pole of the thermocouple is connected to the red wire of the compensation lead, and the negative pole is connected to the remaining color. Most of the general compensation wires are made of copper-nickel alloy.

Extended reading:  Tri Clamp Sanitary Thermometers

  1. Thermocouple English Thermocouple, abbreviated as TC, works on the principle of outputting a linear millivolt signal as the temperature changes. The instrument amplifies the signal and converts it into a temperature signal.
  2. Thermal resistance English Resistance abbreviation RTD working principle is: the resistance value changes linearly with temperature changes.
  3. The temperature transmitter can convert the thermocouple mV voltage signal or the resistance value signal of the thermal resistance into a 4-20mA standard signal for automation system control.
  4. Generally speaking, thermal resistance is cheaper than thermocouple.

Extended reading: RTD vs. Thermocouple: What’s the Difference, and Which Should You Use?

Here, we list some temperature measurement ranges of thermal resistance and thermocouple sensors, and the thermoelectric potential and thermal resistance values of 100°C.

Thermocouple

  • Platinum Guy 10-Platinum (Type S) (0-1300℃), T=100℃, E(100,0)=0.646mV.
  • Platinum Guy 13-Platinum (R type) (0-1300℃), T=100℃, E(100,0)=0.647mV.
  • Zhenming-Zhensi (K type) (0-1200℃) T=100℃E(100,0)=4.096mV.
  • Zhenming-Constantan (Type E) (-200-760℃), T=100℃, E(100,0)=6.319mV

Thermal resistance

  • Platinum thermal resistance (pt100) (-200-850℃), T=100℃, R=138.50Q
  • Copper thermal resistance, (Cu50) (-50-150℃), T=100℃, R=71.4Q.

RTD vs Thermocouple difference

A thermocouple is a sensor that measures temperature. It is a temperature sensor like a thermal resistance. But the main difference between thermocouple and thermal resistance lies in:

  1. The nature of the signal.

The thermal resistance itself is a resistance, and the change of temperature causes the resistance to produce a positive or negative resistance change; while a thermocouple produces a change in the induced voltage, which changes with the change of temperature.

  1. The temperature ranges detected by the two sensors are different.

The thermal resistance generally detects the temperature range of 0-150 degrees. The highest measurement range can reach about 600 degrees (of course, negative temperature can be detected).

The thermocouple can detect a temperature range of 0-1000 degrees (or even higher). Therefore, the former is low temperature detection, and the latter is high temperature detection.

  1. Different materials

From the material point of view, thermal resistance is a metal material. Metal materials with temperature-sensitive changes, thermocouples are bimetallic materials. Both two different metals.

Due to the change in temperature, a potential difference is generated at the two ends of two different metal wires.

  1. PLC modules are different

The thermal resistance corresponding to PLC and the input module of thermocouple are also different, this sentence is no problem. But generally PLC is directly connected to 4-20ma signal, and thermal resistance and thermocouple are generally equipped with transmitter before they are connected to PLC. If you connect to DCS, you don’t need to use a transmitter! The thermal resistance is the RTD signal, and the thermocouple is the TC signal!

  1. PLC also has thermal resistance module and thermocouple module, which can directly input thermal resistance and thermocouple signals.

6. Different prices

Thermocouples are available in J, T, N, K, S and other models. Some are more expensive than resistors, and some are cheaper than resistors. However, if the compensation wire is included, the comprehensive cost of the thermocouple is higher. Thermal resistance is a resistance signal, and thermocouple is a voltage signal.

  1. Different measurement principles

The principle of thermal resistance temperature measurement is based on the property of the resistance of the conductor (or semiconductor) that changes with temperature. The measurement range is minus 00 to 500 degrees. Commonly used are platinum resistance (Pt100, Pt10), copper resistance Cu50 (minus 50-150 degrees).

The principle of thermocouple temperature measurement is based on the thermoelectric effect to measure temperature. Commonly used are platinum rhodium-platinum (graduation number S, measuring range 0~1300 degrees), nickel chromium-nickel silicon (graduation number K, measuring range 0~900 degrees), nickel chromium-constantan (graduation number E, measuring range 0 to 600 degrees), platinum rhodium 30-platinum rhodium 6 (grading number B, measuring range 0 to 1600 degrees).

RTD vs Thermocouple, how to choose?

The selection of thermocouple should be based on comprehensive considerations such as the use temperature range, the required accuracy, the use atmosphere, the performance of the measurement object, the response time and the economic benefits.

  1. Selection of measurement accuracy and temperature measurement range
  • When the operating temperature is 1300~1800℃ and the accuracy is relatively high, the B-type thermocouple is generally used;
  • The accuracy is not high, and the atmosphere allows the use of tungsten rhenium thermocouples.
  • Tungsten rhenium thermocouple is generally used above 1800℃;
  • The operating temperature is 1000~1300℃, the accuracy is required and the high accuracy is available. S-type thermocouple and N-type thermocouple are available;
  • Generally use K-type thermocouple and N-type thermocouple below 1000℃;
  • Generally use E-type thermocouple below 400℃;
  • T-type thermocouples are generally used for measurement at 250°C and negative temperature. T-type thermocouples are stable and have high accuracy at low temperatures.
  1. The choice of atmosphere

S-type, B-type, and K-type thermocouples are suitable for use in strong oxidizing and weak reducing atmospheres. J-type and T-type thermocouples are suitable for weak oxidizing and reducing atmospheres. If a protective tube with better airtightness is used, the requirements for the atmosphere are not too strict.

  1. Choice of durability and thermal response

Thermocouples with larger wire diameters have better durability, but their response is slower. For thermocouples with large heat capacity, the response is slow. When measuring a temperature with a large gradient, in the case of temperature control, the temperature control is poor. It requires a fast response time and a certain degree of durability, so it is more appropriate to choose an armored couple.

  1. The nature and state of the measuring object to choose the thermocouple

The temperature measurement of moving objects, vibrating objects, and high-pressure vessels requires high mechanical strength. A chemically polluted atmosphere requires a protective tube. In the case of electrical interference, higher insulation is required.

Selection process: model-index number-explosion-proof grade-precision grade-installation and fixed form-protective tube material-length or insertion depth.

Related Products:

Sino-Inst, Manufacuturer for Temperature Transmitters, like: Armoured thermocouple, assembly thermocouple, explosion-proof thermocouple, etc.

Sino-Inst’s Temperature Transmitters, made in China, Having good Quality, With better price. Our Temperature measurement instruments are widely used in China, India, Pakistan, US, and other countries.

Grease Flow Meters

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What is a Grease Flow Meter?

Grease Flow meters are meters dedicated to measuring the volume or mass flow of industrial grease fluids.

The most common Grease Flow meters are elliptical gear flow meters, also called positive displacement flowmeters. There are turbine flow meters, gear flow meters, and so on. Industrial grease can be measured online. Including hydraulic oil, steam turbine oil, refrigeration oil, heat treatment oil and heat transfer oil, etc. In addition, there are greases with lubricating oil as base oil and thickening agent.

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More FlowMeters

Industrial Grease Flow meters are different from grease guns or grease meters. Industrial Grease Flow meters need to deal with more complex conditions. The pipe diameter can range from DN10 to DN200, or even larger. So how to choose the applicable Industrial Grease Flow meters? Let’s analyze it together.

Characteristics of industrial grease

What are the types of industrial grease?

Industrial greases mainly include hydraulic oil, gear oil, turbine oil, compressor oil, refrigeration oil, transformer oil, vacuum pump oil, bearing oil, metal processing oil (liquid), anti-rust grease, cylinder oil, heat treatment oil, and heat transfer oil.

Extended reading: High Temperature Flow Meter

In addition, there are greases with lubricating oil as base oil and thickening agent. The users of industrial lubricants are companies from all walks of life, and they use many varieties and large amounts.

The basic performance and main selection principle of industrial grease is viscosity. GB/T3141-94 is the ISO viscosity classification of industrial liquid lubricants, which is equivalent to the international standard ISO3448-1992 “Industrial Liquid Lubricants-ISO Viscosity Classification”.

So, when we choose an industrial grease flow meter, we first need to consider the viscosity of the grease. Then consider the flow range and temperature. And other special requirements of users.

Our commonly used industrial grease flow meters are oval gear flow meters, turbine flow meters, and gear flow meters. There is also a mass flow meter. Next, let’s discuss separately.

Grease Flow Meters-Oval Gear

Oval gear flowmeter is a volumetric meter for continuous or intermittent measurement and control of liquid flow in a pipeline.

Oval gear flowmeter, also known as positive displacement flowmeter. A positive displacement flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive fluids.

  • Volumetric Flow Meters
  • High measurement accuracy;
  • The installation pipeline conditions have no influence on the measurement accuracy;
  • Can be used for high-viscosity liquids;
  • Wide range;
  • The direct-reading meter can directly obtain the cumulative and total amount without external energy.
  • Clear and clear, easy to operate.

Therefore, we recommend that when the grease viscosity is high, you can first consider using an oval gear flowmeter.
Viscosity: 0.6—2mPa.s—200mPa.s—1000mPa.s-2000mPa.s.
Temperature: -20~+200℃

Extended reading: Sanitary Positive Displacement Flow Meter

Grease Flow Meters-Turbine

Turbine flow meters are velocity flow meters, also called impeller flow meters. Can be used to measure the instantaneous flow and cumulative flow of liquids and gases.

Turbine flowmeters are widely used in flow measurement: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas, and cryogenic fluids. Turbine flowmeter signals can be divided into pulse signals or current signals (4-20mA). It is suitable for use with secondary display, PLC, DCS, and other computer control systems.

Therefore, when measuring low-viscosity oils, such as diesel, edible oil, etc., we recommend that turbine flowmeters be considered first.

Extended reading: What Is Hydraulic Flow Meter?

Grease Flow Meters-Gear

Gear flow meter is a micro digital positive displacement flow meter. Can measure very small flow rates and quantify small volumes of liquid. High and low-temperature resistance (-196℃-200℃).

The Gear flow meter for Microflow is made of stainless steel and is used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, grease, and other high-viscosity media. It can measure the viscosity of Fluid up to 10000Pa.s.

  • High pressure resistance (1.0-45MPa)
  • High and low temperature resistance (-196℃-200℃)
  • Can measure various viscous media
  • High precision and repeatability
  • Pulse output/analog output optional
  • Wide range ratio (1:100)
  • Wide measuring range
  • Strong anti-corrosion and anti-fouling ability (acid and alkali)

Therefore, it is recommended to use Gear flow meters, when you need to measure grease in the following situations:High viscosity, low flow rate;Ultra-high temperatureUltra-low temperature;Small caliber;high pressure.

Extended Reading: Types Of Crude Oil Flow Meters

Grease Flow Meters-Mass

Mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density, temperature, and viscosity of the medium

Mass flow meter is a flow measuring instrument that measures the mass flow in the pipeline. The volume of a fluid is a function of fluid temperature and pressure and is a dependent variable. The quality of a fluid is a quantity that does not change with time, space temperature, and pressure. More about: What Is Mass Flow Rate?

The mass flow meter has high accuracy. But the price is expensive. Therefore, when you need high-precision measurement, you can choose to use a mass flow meter.

Extended reading: Fuel Flow Meter for Boat-Selection & Application

Tool: Volumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Find the most appropriate industrial grease flow meter from Sino-Inst for a variety of engineering and industrial purposes. Suitable for various fluids with different pressures and volumes. The choice of these depends on whether the volumetric or mass flow rate is to be measured. Grease flow meters offered on the site have wide minimum and maximum pressure ranges, which is considered to be a desirable quality as they can be used for a wider variety of fluids. These grease flow meters are highly accurate.

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Extended Reading: Guide and Selection for Diesel Fuel Flow Meters

Flow Meter K-Factor: What It Is and How to Calculate It

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Updated Apr 9, 2026 — Reviewed by Sino-Inst Engineering Team

The K-factor of a flow meter is the number of pulses the meter generates per unit volume of fluid. It is a calibration constant — determined at the factory or in the field — that converts raw pulse counts into an actual flow volume. Every pulse-output flow meter has a K-factor. Get it wrong, and your flow readings will be off by a fixed percentage regardless of flow rate. This guide explains what K-factor means, how to calculate it, and how to handle multi-point calibration for better accuracy.

Contents

What Is K-Factor in a Flow Meter

K-factor is the ratio of pulse output to volume passed through the meter. If a turbine flow meter generates 100 pulses for every liter of water, its K-factor is 100 pulses/liter. The flow computer or totalizer uses this number to convert accumulated pulses into volume.

K-factor is determined during calibration by passing a known volume of fluid through the meter at a controlled flow rate and counting the pulses generated. A well-calibrated meter will have a K-factor that stays relatively constant across its operating range. No meter is perfect — the K-factor typically varies by 0.5–2% across the meter’s turndown range, which is why some applications require multi-point calibration.

K-factor is specific to each individual meter, not just the meter model. Two turbine meters of the same model and size will have slightly different K-factors due to manufacturing tolerances. Always use the K-factor from the calibration certificate shipped with your specific meter.

K-Factor Formula and Units

The basic formula:

K = N / V

Where K is the K-factor (pulses per unit volume), N is the total number of pulses counted, and V is the total volume of fluid that passed through. Common units include pulses/liter, pulses/gallon, or pulses/m³.

To calculate instantaneous flow rate from frequency:

Q = f / K

Where Q is volumetric flow rate, f is pulse frequency (Hz, i.e., pulses per second), and K is the K-factor in pulses per unit volume. If K = 450 pulses/liter and the meter outputs 75 Hz, then Q = 75/450 = 0.167 liters/second = 10 L/min.

K-Factor for Turbine Flow Meters

Turbine flow meters spin a rotor in the fluid stream. Each rotation passes a blade past a magnetic pickup, generating one pulse per blade. A meter with a 6-blade rotor spinning at 500 RPM produces 3000 pulses per minute (50 Hz). The K-factor ties this pulse rate to the actual volume flowing through.

For liquid turbine meters, K-factor typically ranges from 50 to 2500 pulses/liter depending on meter size. Smaller meters have higher K-factors (more pulses per liter) because the rotor makes more revolutions per unit volume. A DN15 (½”) turbine meter might have K = 2200 pulses/liter. A DN100 (4″) meter might have K = 55 pulses/liter.

Turbine meter K-factor is affected by fluid viscosity. As viscosity increases, bearing friction becomes a larger fraction of the driving torque, and the rotor under-reads. Most turbine meters are calibrated on water. If you use one on a higher-viscosity fluid (glycol, light oil), the K-factor will shift and you need a viscosity correction curve from the manufacturer.

K-Factor for Vortex Flow Meters

Vortex flow meters work on the Kármán vortex street principle. A bluff body placed in the flow sheds vortices alternately from each side. The shedding frequency is proportional to flow velocity, related by the Strouhal number (St ≈ 0.27 for cylindrical bluff bodies in the relevant Reynolds number range).

The relationship: f = St × v / d, where f is vortex shedding frequency, St is the Strouhal number, v is flow velocity, and d is the bluff body width.

Unlike turbine meters, vortex meters have no moving parts. Their K-factor is primarily determined by the geometry of the bluff body and the pipe diameter. This makes the K-factor highly stable over time — it does not degrade with bearing wear. Vortex meter K-factor is also less affected by fluid viscosity and density, making it a good choice for flow measurement across different fluid conditions.

Multi-Point K-Factor Calibration

A single K-factor assumes linearity — that the pulses-per-volume ratio is the same at all flow rates. In practice, most meters have some non-linearity. A turbine meter might read 0.3% high at low flow and 0.2% low at high flow.

Multi-point calibration measures K-factor at 5–10 flow rates across the operating range. The flow computer stores these points and interpolates between them. This can reduce measurement uncertainty from ±1% down to ±0.15% or better.

Typical calibration points for a turbine meter: 10%, 20%, 30%, 50%, 70%, 100% of maximum flow. Each point is run at steady-state for enough time to accumulate at least 10,000 pulses. The calibration certificate will list K-factor values at each point, along with the deviation from the mean K-factor.

For custody-transfer applications (oil & gas, chemical billing), multi-point calibration is mandatory. The flow meter calibration process must follow ISO 4185 or API MPMS Chapter 4 procedures. Recalibration intervals depend on the application — typically every 1–3 years for custody transfer.

Calculation Examples

Example 1: Single K-Factor

A DN25 turbine flow meter has K = 1850 pulses/liter. Over 8 hours, the flow computer records 3,330,000 pulses. What is the total volume?

V = N / K = 3,330,000 / 1850 = 1800 liters (1.8 m³). Average flow rate = 1800 / 8 = 225 L/hr = 3.75 L/min.

Example 2: Frequency to Flow Rate

A vortex meter has K = 12.8 pulses/liter and currently outputs a frequency of 64 Hz. What is the instantaneous flow rate?

Q = f / K = 64 / 12.8 = 5.0 liters/second = 300 L/min = 18 m³/hr.

Example 3: Determining K-Factor from Calibration

During a gravimetric calibration, 500 kg of water (density 998 kg/m³) is passed through a meter, and 278,500 pulses are counted. K = 278,500 / (500/998) = 278,500 / 0.501 = 556 pulses/liter.

Common Mistakes with K-Factor Settings

Using the wrong units. K-factor can be expressed in pulses/liter, pulses/gallon, or pulses/m³. If the calibration certificate says 450 pulses/liter but you enter 450 into a flow computer configured for pulses/gallon, your readings will be off by a factor of 3.785. Always confirm the units match.

Using a generic K-factor. Some installers use the “typical” K-factor from the product datasheet rather than the individual calibration certificate. This can introduce 1–2% additional error right from day one.

Not recalibrating after process changes. If you switch from water to a 30% glycol solution, the viscosity change will shift the K-factor on a turbine meter. The same applies to significant temperature changes that alter fluid properties.

Ignoring the minimum flow rate. Below the manufacturer’s minimum flow rate, K-factor drops sharply. The rotor or vortex shedding becomes erratic. Readings below minimum flow are unreliable regardless of K-factor setting.

Sino-Inst offers pulse-output flow meters with factory-calibrated K-factors and optional multi-point calibration certificates.

Liquid Turbine Flow Meter

DN4–DN200 | ±0.5% accuracy | Pulse & 4-20mA output

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Vortex Flow Meter

DN15–DN300 | Steam, gas, liquid | ±1.0% accuracy

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Electromagnetic Flow Meter

DN3–DN3000 | ±0.2% accuracy | Pulse & 4-20mA output

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Frequently Asked Questions

What is a typical K-factor for a 1-inch turbine flow meter?

For a DN25 (1″) liquid turbine meter measuring water, K-factor is typically between 1500 and 2500 pulses/liter. The exact value depends on the manufacturer and the specific meter. Always use the K-factor from your individual meter’s calibration certificate.

Does K-factor change with temperature?

Indirectly. Temperature changes affect fluid viscosity and density. For turbine meters, higher viscosity (caused by lower temperature in most liquids) increases bearing drag and shifts the K-factor. Vortex meters are less affected because they have no moving parts. For high-accuracy applications, apply a temperature correction to the K-factor or use a multi-point calibration at the operating temperature.

How often should I recalibrate the K-factor?

For custody-transfer applications: every 1–3 years per API or ISO standards. For general process monitoring: every 3–5 years or when you suspect a shift. Turbine meters with bearings should be calibrated more frequently than vortex meters. If you notice a sudden change in K-factor, inspect the meter for damage, debris, or bearing wear.

What is the K-factor for an electromagnetic flow meter?

Mag meters also have a K-factor when configured with pulse output. However, since mag meters are inherently linear across their operating range, a single K-factor provides excellent accuracy. Typical values range from 1 to 10,000 pulses/liter depending on the configured scaling. The K-factor for a mag meter is set during commissioning and is very stable over time.

Can I use K-factor with 4-20mA output flow meters?

K-factor applies only to pulse outputs. For 4-20mA analog outputs, the equivalent concept is the span setting: 4 mA = zero flow, 20 mA = full-scale flow rate. Some flow computers accept both pulse and analog inputs and can calculate totalized volume from either signal, but the K-factor setting is only used for the pulse input.

What happens if I enter the wrong K-factor?

Your flow readings will have a fixed percentage error at all flow rates. If the true K-factor is 1000 pulses/liter but you entered 900, every reading will be 11.1% too high (the computer thinks each pulse represents a larger volume than it actually does). This error is constant and proportional — it does not vary with flow rate.

Need a flow meter with a factory-calibrated K-factor for your specific application? Contact our engineers for sizing assistance, multi-point calibration options, and pricing.

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What is a PID controller?

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What is a PID controller?

A PID controller is an instrument used in industrial control applications to regulate temperature, flow, pressure, speed, and other process variables. PID is the abbreviation for proportional integral derivative. PID controllers use a control loop feedback mechanism to control process variables and are the most accurate and stable controllers.

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What is meant by PID?

In the manufacturing process, if the equipment or space needs to be kept at a constant temperature, then PID is the best choice.
What is meant by PID?

P: Proportion, the input deviation is multiplied by a coefficient;
I: Integral, perform an integral operation on the input deviation;
D: It is differentiation, which performs a differential operation on the input deviation.

Mathematical description of PID:
u(t)=kp[e(t)+1/TI∫e(t)dt+TD×de(t)/dt].
Where
E(t) is the error signal;
U(t) is the output signal of the controller;
kp is the ratio coefficient;
TI is the integral time constant;
TD is the derivative time constant.

PID control is a kind of negative feedback control. Because in the feedback control system, the automatic regulator and the controlled object form a closed loop.

There are two possible situations when connected into a closed-loop: positive feedback and negative feedback.

The effect of positive feedback aggravates the imbalance of the inflow and outflow of the controlled object, resulting in system instability;

Negative feedback is to alleviate the imbalance, so as to correctly achieve the purpose of automatic control.

The instrument used in PID control is a PID regulator (also called a PID controller). Simply put, the PID control algorithm determines the price of the PID regulator. The temperature controller is also a kind of control algorithm that is more suitable for temperature control PID regulator. Its control algorithm is different from the regulator control algorithm commonly used for process control such as flow and pressure.

PID Controller Working Principle

PID controller, Promotion Integration Differentiation, that is, proportional-integral-derivative controller. It is mainly through the setting of three parameters Kp, Ki, and Kd. It is used to control the basic linearity and dynamic characteristics that do not change with time.

PID controller is based on the PID control principle to adjust the deviation of the entire control system. So that the actual value of the controlled variable is consistent with the predetermined value required by the process. Different control laws are applicable to different production processes. The corresponding control law must be selected reasonably. Otherwise, the PID controller will not achieve the expected control effect.

PID controller is a kind of feedback loop component that is very common in industrial control applications. This controller compares the collected data with a reference value. This difference is then used to calculate the new input value. The purpose of this new input value is to allow the system data to reach or maintain the reference value.

The PID controller can adjust the input value based on historical data and the occurrence rate of differences. This can make the system more accurate and more stable. It can be proved by mathematical methods. When other control methods lead to system stability errors or process repetitions, a PID feedback loop can keep the system stable.

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PID Temperature Controller Working Principle

Proportional integral derivative (PID) controllers can be used as a means to control temperature, pressure, flow, and other process variables. As the name suggests, PID controllers combine proportional control with additional integral and derivative adjustments. Help the equipment to automatically compensate for changes in the system.

Computer-controlled thermostat: Using PID fuzzy control technology* Use advanced digital technology to form a fuzzy control to solve the problem of inertial temperature error through the combination of Pvar, Ivar, and Dvar (proportional, integral, derivative).

Many manufacturers often encounter the problem of inertial temperature error in the process of using the thermostat. Suffering cannot be solved, relying on manual pressure adjustment to control the temperature.

PID controller Applications

The PID controller is the most widely used controller. There are many digital pid algorithms.
PID controllers are mostly used for temperature control. But there are other more advanced and lower-level programs.

The PID regulator used by the instrument ranges from tens of yuan to tens of thousands of yuan. The difference lies in IO precision, type, algorithm complexity, operation speed, and additional functions.

The PID algorithm used by PLC is also different. Usually simpler than meters.

In the field of temperature control, there are PID meters, smart fuzzy meters, fuzzy PID meters, and even industrial computers.

If the temperature control also needs to control the temperature rise curve, then a simple PID meter is not suitable. A set value generator is also needed, and most intelligent thermostats with this function are built-in.

  1. Classic PID control algorithm regulator

For example, the accuracy is 0.5%. The intelligent regulator is used for process control such as pressure, flow, and liquid level to achieve good control effects. The temperature control effect is not good when used for temperature control.

  1. Fuzzy control algorithm regulator

Such as accuracy of 0.3%. The fuzzy PID regulator is used for pressure, flow, liquid level, and other process control effects. It is best for temperature control in plastic/food/packaging machinery, heating furnaces, and other industries with a constant temperature effect of ±1℃. PID parameter self-tuning effect is excellent It is the classic PID control algorithm regulator. The price of the two is the same.

  1. Artificial intelligence control algorithm regulator

Such as an accuracy of 0.2%. This artificial intelligence regulator is suitable for all automatic control sites and can achieve very good control effects. The best constant temperature effect for temperature control is ±0.1℃. The effect of PID parameter self-tuning is better than the adjustment of classic PID control algorithms and fuzzy control algorithms The price is slightly higher. Product performance is no different from European and American products.

  1. Temperature controller

Such as an accuracy of 0.2%. The temperature controller is dedicated to the temperature control of various large lag working conditions (such as kilns, electric furnaces). The temperature is constant and does not fluctuate. The performance is not much different from that of Japanese island power products. The cost is lower.

Related measurement and control instruments

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Sino-Inst offers over 10 PID controllers for Industrial data recording and analysis.

It is widely used in hydropower, tap water, petroleum, chemical, machinery, hydraulic and other industries to measure, display and control the pressure of fluid media on site.

A wide variety of PID controllers are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of PID controllers, located in China.