News

Servo drivers are an important component of modern motion control and are widely used in industrial robots and CNC machining centers and other automated equipment. Especially, servo drivers used for controlling AC permanent magnet synchronous motors have become a research hotspot both at home and abroad. Currently, in the design of AC servo drivers, the widely adopted control algorithm is the three-loop control algorithm based on vector control, which includes current, speed, and position control. Whether the speed loop design in this algorithm is reasonable plays a crucial role in the entire servo control system, especially in the performance of speed control. [1]
In the speed closed-loop of the servo driver, the real-time speed measurement accuracy of the motor rotor is crucial for improving the dynamic and static characteristics of the speed loop. To achieve a balance between measurement accuracy and system cost, incremental optical encoders are generally used as the speed measurement sensors, and the commonly used speed measurement method is the M/T measurement method. Although the M/T measurement method has certain measurement accuracy and a wide measurement range, it has its inherent drawbacks, including: 1) At least one complete disc pulse must be detected within the speed measurement cycle, which limits the minimum measurable speed; 2) The two control system timer switches used for speed measurement are difficult to maintain strict synchronization, and in measurement scenarios with large speed changes, the speed measurement accuracy cannot be guaranteed. Therefore, the traditional speed loop design scheme using this measurement method is difficult to improve the speed following and control performance of the servo driver.

The selection of gas analysis instruments should follow the principle of “scenario-driven, on-demand matching” [5]. A systematic selection logic framework usually includes: first, clearly define the measurement target, including the types of gases to be measured, the range, accuracy, and stability requirements; second, define the application environment, such as high temperature, high humidity, high dust, corrosive media, or explosive hazardous areas; third, assess compliance requirements, confirm that the instrument and system need to meet national mandatory metrological certification (CPA), explosion-proof certification (Ex), and environmental monitoring standards (such as HJ series standards); finally, plan the full life cycle cost, covering purchase cost, installation and commissioning, regular calibration, consumable replacement, and maintenance and repair of long-term operation costs [4].
When comparing technical parameters, attention should be paid to the source and performance of core components (such as sensors, lasers, spectral core modules), and require the manufacturer to provide calibration or test reports issued by a third-party authoritative testing institution (such as provincial-level or above metrology institutes) based on relevant national verification regulations to verify key indicators such as accuracy [4-5]. For harsh working conditions, it is necessary to focus on the pre-treatment system design and practical cases provided by the manufacturer to ensure that the system includes efficient multi-level filtration, automatic backflushing, high-temperature heating, rapid cooling, and other targeted measures to ensure long-term online rate and stability [5].
Compliance is the bottom-line requirement for the application of gas analysis systems in highly regulated industrial and safety fields. The system and core instruments must comply with the national mandatory standards or certifications for the application field, such as equipment for explosive environments must obtain explosion-proof certificates, and CEMS for environmental monitoring must comply with HJ series standards and pass suitability tests. In addition, the system should have complete operation logs and calibration record functions to ensure that all monitoring data can be traced, meeting internal quality audits and external supervision requirements [5]. When purchasing, attention should be paid to whether the related products comply with the latest national standards, such as “GB12358-2024” which has more stringent requirements for the performance of gas detectors [9].
The long-term stable operation of the instrument relies on standardized maintenance and regular calibration. Calibration must use qualified and within-validity standard gases to ensure the traceability and reliability of measurement results [4] [8]. After the expiration of standard gases, qualified products must be purchased again, and it is strictly prohibited to continue using expired standard gases for monitoring. Such behavior is an illegal operation and will result in invalid monitoring data and may face penalties [8].

Gas analysis instruments are applied in the field of industrial process gas analysis in areas such as chemical engineering, metallurgy, power, and steel production, for monitoring indicators such as gas composition and calorific value. Typical products and technologies include the laser Raman spectroscopy gas analyzer LRGA-6000, in-situ laser process gas analyzer GasTDL-3100, and infrared gas analyzer Gasboard-3500, etc. [1].
In the environmental monitoring field, gas analysis instruments are used for smoke emission monitoring, greenhouse gas flux measurement, and emergency monitoring of sudden pollution incidents. Typical products and technologies include portable gas chromatographs, portable gas analyzers, and continuous emission monitoring systems such as the SERVOPRO 4900 analyzer [1-3] [6].
In the automotive/engine emission testing field, gas analysis instruments are used for actual road driving emission tests that meet standards such as Euro VI RDE, as well as engine research and certification tests. Typical products and technologies include the portable emission testing system Gasboard-9805, engine emission testing system Gasboard-9801, and full-flow dilution volumetric sampling system Gasboard-9802 [1].
In the safety protection field, gas analysis instruments are used in scenarios such as confined space operations, petrochemical inspections, gas maintenance, and fire emergency rescue. Typical products include four-in-one gas detectors that can simultaneously monitor combustible gases, oxygen, hydrogen sulfide, and carbon monoxide, as well as the S4200 electrochemical toxic gas detector [6] [9].
In the research and high-purity analysis field, gas analysis instruments are used for high-precision gas analysis in scientific research, air separation industries, semiconductor manufacturing, and other fields. Typical products and technologies include online process gas chromatographs, Fourier transform infrared spectrometers, trace oxygen analyzers, dew point meters, etc. [1] [4-5] [7].
Gas analysis instruments are also applied in other fields such as gas analysis of packaging container internal atmosphere, food safety testing, and composition analysis of oil and gas.

The laser Raman spectroscopy gas analyzer utilizes the Raman scattering effect and overcomes technical challenges such as weak characteristic signals, fluctuations in laser power and temperature to achieve gas analysis. The laser Raman spectroscopy gas analyzer can perform precise quantitative analysis of nearly 20 gas components including H2, N2, O2, CO, CO2, and CH4. [1]
The tunable semiconductor laser absorption spectroscopy technology is a technique that measures gas concentration by utilizing the wavelength tuning characteristic of semiconductor lasers and the selective absorption of the target gas by the laser. This technology has advantages such as high selectivity, fast response, no influence by moisture, and no drift. [1]
The non-dispersive infrared gas analyzer is based on the selective absorption of gases by infrared rays and can accurately identify and measure the concentration of target gases in complex production environments, effectively eliminating interference from other gases. [1]
The portable gas chromatograph inherits the core separation principle of traditional gas chromatography and achieves separation and detection by different components having different retention times in the chromatographic column. The portable GC realizes on-site rapid analysis through technologies such as micro-electromechanical systems (MEMS) and low-power design. [2]
Electrochemical sensors and catalytic combustion sensors are applied in gas detection.

Electrochemical gas analysis instruments
A type of chemical gas analysis instrument. It measures the gas components by detecting the changes in the amount of ions or current caused by chemical reactions. To improve selectivity, prevent the measurement electrode surface from contamination and maintain the performance of the electrolyte, a diaphragm structure is generally used. Common electrochemical analysis instruments include potentiometric electrolytic type and Galvanic cell type. The working principle of the potentiometric electrolytic type analyzer is to apply a specific potential to the electrode, and the measured gas will undergo electrolysis on the electrode surface. By measuring the potential applied to the electrode, the unique electrolytic potential of the measured gas can be determined, thereby enabling the instrument to have the ability to identify the measured gas. The Galvanic cell type analyzer electrolyzes the measured gas through the diaphragm and measures the formed electrolytic current to determine the concentration of the measured gas. By selecting different electrode materials and electrolyte to change the internal voltage on the electrode surface, selectivity for gases with different electrolytic potentials can be achieved.
Infrared absorption analyzer
An analyzer that works based on the characteristic that different component gases selectively absorb different wavelengths of infrared rays. Measuring this absorption spectrum can determine the type of gas; measuring the absorption intensity can determine the concentration of the measured gas. Infrared analyzers have a wide range of applications, not only for analyzing gas components but also for analyzing solution components, and they have high sensitivity, rapid response, and can provide online continuous indication, and can also form a regulation system. The detection part of the commonly used infrared gas analysis instruments in industry consists of two parallel and structurally identical optical systems.
In addition, gas analysis instruments include the following technical types: laser spectroscopy technology including tunable semiconductor laser absorption spectroscopy (TDLAS) and laser Raman spectroscopy (LRD) [1]. Chromatography technology such as portable gas chromatograph (Portable GC) [2]. Multi-parameter detection technology such as four-in-one gas detector [9]. Other technical principles include thermal conductivity analyzer, paramagnetic oxygen analyzer [6], Fourier transform infrared (FTIR) spectrometer [4-5], non-dispersive infrared spectroscopy (NDIR), and ultraviolet differential absorption spectroscopy (UV-DOAS) [1].

Gas analysis instruments are process analysis meters used to measure the composition of gases. In many production processes, especially those involving chemical reactions, merely relying on physical parameters such as temperature, pressure, and flow rate for automatic control is often insufficient. Due to the wide variety of analyzed gases and the diverse analytical principles, there are numerous types of gas analysis instruments. Commonly used ones include thermal conductivity gas analysis instruments, electrochemical gas analysis instruments, and infrared absorption analyzers, etc.

Generally, the power module is inserted into the first slot, numbered as 0, the PLC is inserted into the second slot, and various types of input/output modules are inserted into the remaining slots. The back of the I/O module rail is equipped with a printed circuit board with connectors, which can connect the various slots inserted into the I/O module. The top and bottom edges of the slots can make the inserted modules align in a straight line. The rail with I/O modules and the processor is called the local I/O rail; the rail with I/O modules, power supply, remote I/O communication card and installed away from the local I/O rail is called the remote I/O rail. The number of remote I/O rails depends on the number of variables that different processors can control. The communication between the remote I/O rail and the processor can be achieved in various ways, including coaxial cables, dual-axis cables, shielded twisted pairs, etc. If the distance is long and noise interference needs to be suppressed, optical fiber communication can be used.

The I/O modules can be classified into various types such as discrete, analog and special modules, and can be installed on rails or racks with multiple slots [1]. Meanwhile, Intel Xeon 6+ also includes up to 2 I/O modules with Intel 7 process technology [5].
These modules can be installed on rails or racks with multiple slots, with each module inserted into one of the slots. The number of slots ranges from 4, 8 to 12 [1]. In industrial control, to enable PLC to process analog quantities, an AD module is required to achieve the conversion between analog and digital quantities.

Let’s first take a look at what advantages servo motors have over other types of motors (such as stepper motors):
1. Precision: It achieves closed-loop control of position, speed, and torque; it overcomes the problem of step loss in stepper motors;
2. Speed: It has excellent high-speed performance, with the general rated speed reaching 2000 to 3000 revolutions per minute;
3. Adaptability: It has strong overload resistance and can withstand three times the rated torque, making it particularly suitable for occasions with sudden load fluctuations and requirements for rapid startup;
4. Stability: It runs smoothly at low speeds, and does not exhibit the step-like operation phenomenon similar to stepper motors at low speeds. It is suitable for applications requiring high-speed response;
5. Timeliness: The dynamic response time for acceleration and deceleration of the motor is short, generally within tens of milliseconds;
6. Comfort: Heat generation and noise are significantly reduced.
In simple terms: The ordinary motors you usually see will continue to rotate for a while after power loss due to their inertia, and then stop. However, servo motors and stepper motors stop and start immediately, with extremely fast responses. But stepper motors have the problem of step loss.
The application fields of servo motors are numerous. Any equipment that requires a power source and has precision requirements is likely to involve servo motors. Such as machine tools, printing equipment, packaging equipment, textile equipment, laser processing equipment, robots, automated production lines, etc., which have relatively high requirements for process accuracy, processing efficiency, and work reliability.

DC servo motors can be applied to spark machines, mechanical hands, precision machines and other equipment. Besides, servo motors are also commonly used in robots and industrial automation, lithium battery equipment, photovoltaic equipment, high-end CNC machine tools and small CNC CNC machine tools, etc. [4] It can be equipped with a 2500P/R resolution encoder and tachometer, and can also be equipped with a reduction gearbox, which helps improve the accuracy and torque output of mechanical equipment. Its speed regulation performance is good, and under the same weight and volume, the output power is usually higher than that of AC motors and stepper motors of the same specification. The torque fluctuation of the multi-stage structure is smaller.