2013年10月27日星期日

Capacitance weighing sensor's faults

No matter what the sensor has its own advantages and disadvantages, the weighing sensor is the same, it is mainly used to quality signals into electrical signals, the advantages of capacitance sensor is low power consumption, low cost, what are the disadvantages of it, we come to understand in detail. Disadvantages: high output impedance, low load capacity
Capacitance Cooling Temperature Sensor capacity by the electrode geometry restriction very difficult to do, generally tens to hundreds of micro method, even only a few micro method. Therefore, the output impedance capacitive weighing sensor is high, so the load capacity is poor, vulnerable to outside interference produced unstable phenomenon, serious and even unable to work. We must take shielding measures properly, to design and the use of inconvenience. Capacitance sensor also requires insulation resistance value is extremely high, otherwise the insulation performance of part as bypass resistance and affect the instrument, so we should also pay special attention to the surrounding environment such as temperature, cleanliness, etc.. If the use of high frequency power supply, can reduce the output capacitance weighing sensor resistance, but the high frequency amplifier, sensor than low frequency complex, and the effect of parasitic capacitance, is not easy to ensure the stability of the work. Two shortcomings: the output characteristics of output characteristics of nonlinear capacitance weighing sensor is nonlinear, although the use of differential type to improve, but can not be completely eliminated.Engine Coolant Temperature Sensor for other types of only ignores the edge effect of electric field, the output characteristics is linear. Additional capacitance or the edge effect will be directly superimposed sensor capacitor, the output characteristics of nonlinear. Disadvantages: three parasitic capacitance effect of initial capacitor capacitance weighing sensor is small, and the lead capacitance, electronic circuit connected with the sensor and the electronic circuit of the stray capacitance and inside Coolant Temperature Sensor plate and the surrounding conductors capacitors and other so-called missing large parasitic capacitance, not only reduces the sensitivity of the sensor, and the capacitance is often random variation the instrument, work is not stable, influence the accuracy of measurement. So the cable selection, installation, connection method has strict requirements. For example, with good shielding property, its small distributed capacitance of high frequency electric wire as the lead, lead is thick and short, to ensure the instrument stray capacitance is small and stable and so on, otherwise it can not guarantee the high measurement precision. It should be pointed out that, along with the material, technology, electronic technology, especially the rapid development of technology, the capacitance weighing sensor has been developing and constantly overcome shortcomings. The capacitance sensor is becoming a high sensitivity, high precision, low pressure sensor in dynamic, and some special measurement has a promising.

2013年10月24日星期四

Pressure sensor is how negative

Pressure sensor vacuum is how ? Pressure sensor is used to measure the negative pressure and vacuum , regular contact with the negative pressure of the pressure sensor will find generally negative pressure sensor measuring the negative pressure of the maximum range is -100kpa or is -0.1 MPA. But there are very few manufacturers say can be measured to -300kpa even lower, which in the end is how it happened ? Fact, this is two different angles analysis . Studied physics knows vacuum pressure -100kpa, so that the general Camshaft Positioning Sensor measures the pressure is the lowest -100kpa is the basis of this , so the market is basically the lowest negative Auto Temperature Sensor can measure -100kap, that - 300kpa sensor is how it happened ?-300kpa fact not refer to atmospheric pressure , and physical stress on both a reference, you can understand , in a sealed box filled 300kpa high pressure gas , which sets stood a vacuum boxes , we use negative Crankshaft Positioning Sensor placed outside the big box to measure the pressure inside a small box , which would show a -300kpa, so that -300kpa pressure is produced . It is not with reference to atmospheric pressure . Understand this concept we chose negative pressure sensor can be helpful, so we do not choose the wrong pressure sensor , which is why we often help customers choose the pressure sensor when the first use of the environment will ask him to ask his range how much. Only then will not choose the wrong pressure sensor.

How to choose the flow sensor

Flow sensor how to choose ? Information technology is a major force in the computer, communications technology, then there is a sensor , the sensor market promising, with advances in technology , increased levels of automation , our special attention to development of sensors . Test procedures and standards are flow sensor flow meter can accurately measure of protection. In many areas of the economy , the flow of accurate measurements have become very important , for example: environmental monitoring , health care , security , and trade settlement and so on. Why do you want to develop a Engine Temperature Sensor ? Now , product type flow sensor has been increasing, and almost every year there will be a number of new sensors for your choice . These sensors have their own economic and technical characteristics. Therefore, consumers should be generous to accept their presence , so you can successfully promote the great advances in technology . However, the new sensors are not necessarily mature technology , a lot of new products out of the technology was not mature enough , but not to promote technological progress, so that either improve them or let them social outcasts . Some flow sensor is not sufficient in many occasion in experiments conducted in the laboratory, but only some of the experiments on the market . In fact, these sensors , there are still many unknown factors, but does not have the national conditions of some of the technical regulations . Therefore, Positioning Sensor should be prohibited extensive promotion and application , otherwise , it brings the community is definitely a bad influence. According to the nature of the flow sensor standard classification , can be divided into the following categories . Method Standard : Engine Water Temperature Sensorcalculation method, detection methods , test methods and performance assessment methods, etc. ; basic standards : Some basic parameters of the sensor specifications , models, naming, and in the measurement process jargon ; product standard : it provides sensor technology requirements, acceptance of rules , test methods and product categories , in addition , there are proper installation and use requirements, etc. There are some standard that only the correct installation and use of technology, which is the product of the nature of the standard product applications .

Why do you want to develop a standard sensor

Why do you want to develop a standard sensor ?Now, the type of product flow sensor has been increasing, and almost every year there will be a number of new sensors for your choice . These sensors have their own economic and technical characteristics. Therefore, consumers should be generous to accept their presence , so you can successfully promote the great advances in technology . However, the new sensors are not necessarily mature technology , a lot of new products out of the technology was not mature enough , but not to promote technological progress, so that either improve them or let them social outcasts . Some flow sensor is not sufficient in many occasion in experiments conducted in the laboratory, but only some of the experiments on the market . In fact, Crankshaft Positioning Sensor , there are still many unknown factors, but does not have the national conditions of some of the technical regulations . Therefore, such sensors should be prohibited extensive promotion and application , otherwise , it brings the community is definitely a bad influence. According to the nature of Crankshaft Sensors standard classification , can be divided into the following categories . Method Standard : Some Camshaft Position Sensor calculation method, detection methods , test methods and performance assessment methods, etc. ; basic standards : Some basic parameters of the sensor specifications , models, naming, and in the measurement process jargon ; product standard : it provides sensor technology requirements, acceptance of rules , test methods and product categories , in addition , there are proper installation and use requirements, etc. There are some standard that only the correct installation and use of technology, which is the product of the nature of the standard product applications .

Speed ​​sensor is a sensor measuring the speed of the object

Speed ​​sensor is to measure the speed of an object 's sensor, which is very useful in the field of robotics , incremental displacement per unit time is speed . Including line speed and angular speed , corresponding to the wire speed sensor and an angular velocity sensor , we are collectively referred to as the speed sensor. Digital speed sensor performance are: ( 1 ) number of pulses and resolution. Digital speed sensor output is a pulse signal , the number of output pulses per revolution Shaft Position Sensor resolution. ( 2 ) frequency modulation. Constant when the sensor is rotated, the frequency modulation is offset relative to the center frequency swing . ( 3 ) frequency response. Sensor output pulses are frequency dependent , above a certain frequency response , the sensor output pulse waveform deterioration , the error is too large, the sensor malfunction . Typically , the maximum frequency response of Engine Water Temperature Sensor is large, can meet the requirements. ( 4 ) the moment of inertia . Moment of inertia of Coolant Temperature Sensor dynamic characteristics of the system have a greater impact, and starting the drive motor directly affects the output of the sensor , therefore , the rotational inertia of the sensor should meet the dynamic requirements of the drive system .

The performance of all kinds of different digital sensors , should be based on different applications

The performance of all kinds of different digital sensors , should be based on different applications , use of different digital speed sensors. Several major applications are presented . 1 , analog DC motor speed control DC motor speed control analog feedback with analog voltage and frequency in two ways. The former DC tachometer generator as a Engine Coolant Sensor , because the DC tachometer generator inherent defect, so that people consider using other types of speed sensor as a speed feedback . Wherein the speed feedback element is a magnetic sensor via digital speed F / V conversion , and filtered into a DC level back to the comparing circuit for controlling the rotational speed . The speed control method is not only simple , reliable, and low cost.
2, the DC motor incremental motion control with high precision for complex control applications requires the use of incremental motion control methods to meet system requirements. Incremental motion control only controls the speed of movement , but also for positioning control and frequent starts and stops acceleration and deceleration control . The speed feedback system with digital Coolant Temperature Sensor output digital signal that can achieve these various control requirements. Incremental movement of the DC motor speed control system in the encoder sensor digital Camshaft Position Sensor. Speed ​​digital speed sensor output signal is fed to the comparison circuit and a regulating circuit , to meet the fast high-precision servo control, and requirements for wide speed control , which is often used in modern incremental movement speed feedback method . 3, the phase lock servo motor speed control system is controlled by the speed feedback to regulate due to mechanical loads or changes in the environment caused by such speed deviation . This method of control is to regulate the nature of the case of a difference , speed accuracy is not high, although the number may be used to improve the accuracy of incremental control , but still can not meet the high precision speed control requirements. The lock-in technique for speed control , can achieve synchronous motor control is achieved without droop . Lock-in technique to compose for servo controlling the phase lock servo control system, which phase lock loop is determined by the reference frequency generator , an encoder , a phase frequency comparator , a low pass filter, amplifier and DC motors and other components.

2013年10月20日星期日

What point load cell selection

Choose to use the load cell should first consider the use of the actual needs , in addition to meet the measurement accuracy and the main technical performance , but also taking into account economic and practical aspects. Load cell due to the different structure and elastomeric properties of different strain gauges used , while in measurement accuracy and Cooling Temperature Sensor will be different, and different manufacturing processes , production costs will be very different , the price is consequent different so to the actual needs of considering applications to choose the appropriate load cell. With the widespread use of anomalies and failures have also occurred , checked judge , mainly human error . Here's fault generated links , causes, phenomena analysis and countermeasures from the selection, transportation, installation , use, maintenance, overhaul several ways to illustrate.