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Loop powered signal isolator is one type of signal isolator with a power supply module. The function of the loop powered signal isolator is to isolate the current source signal input to the loop powered isolator and output a DC signal that is isolated from and proportional to the input signal.
Loop powered signal isolators use the signal current in the input loop to power the meter (take out some energy of input signal inside the isolator to drive the isolator), without any external power supply.

Correct selection of the frequency converter or frequency changer is crucial for the normal operation of electronic control system for mechanical equipment. To buy the frequency converter, according to the type of mechanical equipment, load torque characteristics, speed regulation range, static speed accuracy, starting torque and the requirements of the use environment, and then choose the suitable frequency converter.
Before selecting the frequency converter (AC power supply), we should firstly make clear the input mode of load, it is three phase or single phase? Secondly, determine the load characteristics, such as resistive load, inductive load, capacitive load, mixed load. Since different load characteristics will cause different inrush currents when the load starts, the influence of inrush current must be considered when buying the frequency converter, otherwise converter will not output normally.

As a matter of fact, the main function of the series reactor is to restrain the higher harmonic or limit the switching surge, prevent the harmonic wave from endangering the capacitor, avoiding the excessive amplification and resonance generation of the access of the capacitor to the power grid harmonic. As to the increasingly automatic life, the harmonic problem of the power system is becoming increasingly serious. We have to take measures to process the harmonic, because a too high harmonic will seriously affect the normal operation of the device and electrical system.

Solid state relays (SSRs) have plenty of types and models, so its input control methods and control circuits are numerous accordingly. The common characteristics of solid state relay (SSR) lie in the small drive current or drive voltage, namely, the on-off the SSR can be controlled by just inputting a small signal. If it is required to realize effective and reliable control, its input signal should reach a given value. As to the requirement to the working current of the input loop, it is recommended to switch on when the value is 5-10mA and switch off when the value is lower than 1mA. As to the requirement of the working voltage of the input terminal, it is generally no lower than 3V in switch on, and lower than 1V in switch off. Of course, because of the different product characteristics and different manufacturers, the requirement to the input current or resistance value is also different. Therefore, in using and designing the circuit, the selection and design can be conducted according to the specification and operation occasions on the basis of solid state relay (SSR) type. The following text introduces some basic methods and circuits of SSR input control.

Load capacity of soft starter mainly refers to the overload capacity. Due to different working system, actual load capacity of soft starter is also different. For example, the soft starter generally bears a current of 2~4 times of rated current at starting process, and the duration is within 60s. For long-term working systems, the soft starter actually works under short-term overload during starting process. But for short-term working systems, the soft starter actually works under long-term overload during starting process. Thermal capacity of power semiconductor devices (thyristors) is very small, so the overload capacity of devices mainly depends on the overload capacity of power conductor devices and heat dissipation capacity of soft starters.

Image sensor is an important part of the industrial camera. According to difference of the original, it can be divided into CCD and CMOS sensors. In the last 25 years of the last century, CCD technology has been leading the trend of the imaging sensor. It is a high-resolution and high-quality image sensor which can be integrated on a very small chip. However, in recent years, with the rapid development of the semiconductor manufacturing technology, the size of the integrated transistor is becoming smaller and smaller, and the performance is much better. CMOS image sensor obtains rapid development in the recent years, and it seems CMOS image sensor has overtaken CCD image sensor. CMOS provides the performance on a par with CCD in the mid-end and low-end applications, and has a significant advantage in price. With the development of technology, CMOS will also occupy a space in the high-end application field. This paper makes a detailed explanation to the difference between CCD and CMOS image sensors in the industrial camera.

Output line reactor is also called as the motor reactor. It is mainly used in the industrial automation system, especially occasions with frequency converter, to extend the valid transmission distance of the frequency converter, effectively restrain the transient high voltage in switching on/off the IGBT module of the frequency converter. It is suitable for compensating the distributed capacitance, restraining the output harmonic current, effectively protecting the frequency converter and improving the power factor, with an expectation to reduce the pollution of the harmonic current generated by the rectification unit to the power grid.

Have you ever though why your motor has a shorter service life than that of others? Let us tell you, your motor may need a soft starter. Generally, the motor shall adopt a soft starter as soon as its power exceeds 20hp (15kW), otherwise it will affect the use and operation of other equipment in power grid and damage the motor. Why should the soft start controller be used? What are the benefits of using motor soft starter?

One of the other manufacturing reasons for the high noise of the reactor lies in the insufficient clamp force of the iron core. The low iron core fastening force will increase the operation noise of the reactor. As the experience indicates, when the pressure intensity of the iron core clamp force is 0.8~1.2MPa, the noise of the reactor is the lowest. In addition to this, the compression screw and clamp nut of the iron core sheet should be equipped with an additional lock net, preventing from the looseness of the nut caused by the vibration of the iron core sheet in operation, so as to result in the high noise degree.

With the three-phase reactor, in regulating the speed of the original power frequency excitation, the establishment of the feedback voltage maintains the excitation current in the excitation coil to be in a rather small amplitude, which will basically not exceed the maximum value. It can reach the maximum value unless it is in full-speed operation status. The three-phase reactor is widely used in the elevator, wind power generation, solar power generation, railroad engine, metro, machine tool, welding machine, industrial washing machine, airplane, ship, electromechanical laboratory of the university and other fields.

The problem why the frame loss of the industrial camera occurs is indeed caused by the blockage of the material channel, so it is unable to be processed by the technology. Therefore, when the new images are collected, the former image might be forced to be abandoned, or the new image will probably be forced to be abandoned. Generally speaking, the frame loss of the industrial camera is not related to the transmission interface adopted by the industrial camera. For USB, 1394, GigE, or camera-link, the poorly designed driving program or industrial camera hardware is the true reason of frame loss. In order to solve this problem, the designers are required to conduct precision design to every link of the driving program and industrial camera hardware material transmission.

Industrial camera is a key component in the machine vision system. Its most essential function is to convert the optical signal into the ordered electrical signal of the small-size high-definition industrial camera. In the machine vision system, the lens of the industrial camera are equivalent to the eyes of human beings. Its main function is to focus the targeted optical images on the photo surface of the image sensor (industrial camera). All image information of the visual system treatment can be obtained from the lens of industrial camera. The lens quality of the industrial camera will directly affect the entire performance of the visual system. As an image device, the lens of industrial camera usually constitute a complete image collecting system with the power source and camera. Therefore, the lens selection of the industrial camera is restrained by the entire system requirement. Generally, it can be analyzed and considered as the following aspects.

In PLC control system, we mostly use DC proximity sensors. And in DC circuit, the proximity sensors used include 2-wire proximity sensor, 3-wire proximity sensor and 4-wire proximity sensor. And they can be further divided into NPN type and PNP type. Generally, people in the United States and Japan usually use NPN proximity sensor, while in the Europe use the PNP proximity sensor.
The difference of NPN proximity sensor and PNP proximity sensor lies in the conduction situation. NPN proximity sensor belongs to the low level conduction and PNP proximity sensor belongs to the high level conduction. In other words, signal of the NPN proximity sensor flows from the load to the proximity sensor, while that of the PNP proximity sensor flows from the proximity sensor to the load.
We will take FX3U PLC and S7-200 PLC as examples to explain how is the NPN proximity sensor and PNP proximity sensor connected to PLC.

Three phase asynchronous motor has many advantages, but also has two fatal weaknesses: one is the poor starting performance, the other is poor speed control performance. With the development of power semiconductor technology and application of high power transistors in industrial control field, two typical products greatly improve the two weaknesses of asynchronous motors: Variable Frequency Drive and Soft Starter. The VFD improves the speed control performance of asynchronous motors, while the soft starter improves the starting performance of asynchronous motors.
With various functions such as soft start, soft stop, pump control and timed low speed operation, the 3 phase motor soft starter has incomparable advantages over traditional reduced voltage starter in power equipment control in the industrial and civil construction fields.

When we get a pressure transducer, it's necessary to do detection for it. The easiest way to test a pressure transducer is to connect it to a display instrument directly. And check whether the display value changes with the pressure. If it is ok. We have to do further detection for the pressure transducer.

In the visual inspection of industrial machine, there are usually projects requiring to capture the objects in high-speed movement. However, the ordinary industrial camera will probably problems of vague or deformed pictures, thus failing to reach the project requirements of the customers. At this time, high-performance industrial camera is required to solve such problems. Then, we will illustrate it by taking the high-speed image capturing of the industrial camera as an example.

Generally, DCS system treats the current higher than 20.2mA or less than 3.8mA as a fault, and the pressure transducer also has fault current settings. For example, it can set the fault current of pressure transducer to 3.6mA or 22.8mA, or setting as needed and related to failure alarm setting. When the output current of pressure transducer is less than 4mA or greater than 20mA, it refers to the common saying that the instrument display is below zero or the instrument display is maximum. In this case, the fault is analyzed and judged in excess of the range. When checking the over-range fault of pressure transducer, firstly check the components related to the process, whether the process parameters have significantly changed, whether the instrument sampling valve and connecting pipes are normal, whether the connecting line or safety grille is faulty or damaged. Then check the pressure transducer itself, whether its range is selected correctly, whether the measuring diaphragm and circuit board break.

Solid state relay, SSR in short, is the non-contact switch constituted by the microelectronics circuit, discrete electron device and power electronics power device. The isolation device is used to realize the isolation of the control terminal and load terminal. The input terminal of the solid state relay adopts the tiny control signal, thus realizing the direct driving of the high-current load.
Then, we will mainly introduces the faults of the solid state relay burnout. How to test the SSR if it is damaged or not? What is the reason of the solid state relay burnout and how to deal with?

The lightning stroke discharging between the cloud layer and earth is constituted by one or several individual lightning. Every lightning carries several currents with very high amplitudes and short duration. One typical lightning discharging shall include two or three lightning. There is about an interval of 1/20 second between two lightnings. Most lightning currents drop in the scope of 10, 000~100, 000 Amp, and its duration is generally lower than 100ms.
Because of the operation of high-capacity equipment and frequency conversion equipment in the power supply system, an increasingly serious interior surge problems have been generated. We conclude it into the influence of transient overvoltage (TVS). Any power equipment has the allowed scope of power supply voltage. Sometimes, even very narrow overvoltage impact might damage the equipment power supply or entire equipment. The destructive effect of transient overvoltage (TVS) is just like this. In particularly, as to some sensitive microelectronics devices, some very low surge impacts will probably case fatal damage.

As the common part of the electrical device, both the surge protection device and lightning arrester have the function of preventing from over-voltage, especially preventing from the lightning over-voltage. However, the two have great differences.

• Different voltage level from the perspective of application field
• Different protecting objects
• Different insulation level or withstand voltage level
• Different installation position