Economic grade and standard industrial grade of encoder

An encoder is a device that compiles and converts a signal (such as a bit stream) or data into a signal form that can be used for communication, transmission and storage. Encoders can be roughly divided into commercial grade and chip grade, economic grade, standard industrial grade, and various special industrial grades according to their usage.

　　 Encoder is a device that compiles and converts signals (such as bit streams) or data into signal forms that can be used for communication, transmission and storage. Encoders can be roughly divided into commercial grade and chip grade, economic grade, standard industrial grade, and various special industrial grades according to their usage.

►Commercial and chip level

　　 For example, the encoder inside the printer and the magnetic card machine has a simple structure, and many shells do not have it. There is almost no need to talk about temperature, dustproof, waterproof and electromagnetic compatibility, and the price is extremely cheap. Chip level: The price is very low. At present, some foreign semiconductor chip manufacturers provide, or simply packaged by downstream manufacturers, without shell or simple shell, power supply and signal only simple processing, suitable for the manufacturer's secondary circuit development, the receiving line distance encoder should not exceed 50cm. Some flowmeter and valve ESC manufacturers choose this level. The protection and electromagnetic compatibility anti-interference of this type of encoder should be taken into account by the secondary development manufacturer. If you don't understand it, it is easier to cause damage.

►Economy and Industrial

The economical grade has simple packaging and simple processing, and is suitable for stand-alone equipment, such as embroidery machines. However, the economical grade is characterized by its economical efficiency compared with industrial grades. Its design and material selection are positioned on economical benefits and are not suitable Large-scale equipment, assembly lines and engineering projects, and industrial-grade design, material selection and testing are all done in accordance with standard industrial requirements, suitable for various industrial equipment, assembly lines and engineering projects. The typical difference between the two levels can be seen from the appearance and parameters The differences seen on the table are as follows:

　　1 bearing

The economical shaft bearings are single bearings, (some of the chip-level bearings do not use ball bearings), and some economical bearings are fixed by clips on the outside. You can see the circlip (as shown in the figure below). Some are smarter and add a part to the front After covering the circlip, the single bearing is used for a period of time, due to the single force support, the accuracy is naturally difficult to guarantee, and the sealing performance is also poor. The industrial grade has a double ball bearing structure, multiple balanced support points, and the shaft has high precision, impact resistance, and tightness. The double-bearing structure requires high machining accuracy and installation accuracy of the shaft, because if the accuracy is not enough, due to the interaction of the two bearings, there will be a feeling of "stuck" when turning, so you can feel the shaft when you turn it. To the precision of the shaft. The strange thing is that for some encoders with nominal "high precision" bearings, the bearings are also single-bearing methods, and their "high precision" will be revealed sooner or later under long-term use.

　　 2 shell package

The economical housing packaging relies on three screws to fix (if there are three screws on the outer diameter of the encoder housing, the outer circle is slightly deformed and not round due to the screw jacking, which will affect the sealing performance). The grade shell is not fixed by screws, and the seal is a one-time seal with an extruded + O-ring seal. Some users think that there is no dust and water vapor in the working environment, how can it be damaged? In fact, when the encoder is in use, there must be a change between startup and shutdown. Due to the temperature difference between thermal expansion and contraction, the internal and external air pressure is different. Encoders with poor protection levels will produce "breathable" water vapor. The optical components and electrical circuits are damaged due to the accumulation of time, which affects the use or damages the encoder. Typically, it is inaccurate or unstable for a period of time. However, some encoders have problems when used at higher temperatures, which are thought to be temperature problems, but in fact they are airtight problems.

　　3 temperature levels

The economic grade is generally only minus 10°c～60°c, and generally does not exceed 70°c, while the industrial grade working temperature is generally minus 20°c～70°c, and the good one is minus 25°c～80°c of. The temperature grade actually reflects the grade of the internal parts selected. Everyone should know that the temperature of general civilian-grade electronic parts is mostly 55°c or 60°c, and the price of premium industrial-grade parts above 70°c is often It will be more than twice as expensive, and different grades are not only a temperature problem, but also the failure probability reflected in use. The wide range is not only applicable to these extreme temperature ranges, but also has good resistance to temperature shock fluctuations. Some users think that the operating environment cannot reach these temperature limits, 55°C is enough, but they ignore the damage to the device that may be caused by temperature shock fluctuations such as power-on and shutdown, and the failure probability of the internal chip.

　　4 output signal and power

　　 The most economical output is PNP or NPN with open collector. There is no polarity protection and short circuit protection for power and signal. Open collector output is unilateral unbalanced. Anti-interference and signal long-distance transmission are inferior, and it is not suitable to use in some working conditions, especially engineering type. The industrial-grade output is push-pull (taking into account both PNP and NPN), or differential drive balanced output, or other standard industrial signals. For example, for SSI signals, some economical grades are also marked as SSI, but the SSI that is not standard industrial grade RS422 is found to be wrong when you buy it and connect it; the industrial grade power supply is 10-30Vdc, and the long-distance voltage drop attenuation does not affect the signal line. Often with short circuit protection. Many industrial field power supplies will be unstable for a short period of time. Wide power supply is very important to ensure that the encoder is not affected. Polar short-circuit protection can prevent the encoder from being damaged by wrong wiring and accidents during engineering and maintenance.

　　5 Electromagnetic compatibility

The economical electromagnetic compatibility level is not very high, and there is basically no special design for this purpose, while the industrial electromagnetic compatibility EMC generally has to reach level two or above, (must have testing standards and provide testing certificates), including surge, rapid pulse group, Standard tests such as static electricity, these indicators are related to the stable operation of the encoder in a complex electrical environment.

　　 6 internal parts

　　The internal parts cannot be seen from the appearance and the parameter table. The industrial-grade ones are often integrated, highly modular, chip-on-board welding, and three-proof processing.

　　7 Program testing and standards and final cost

For standard industrial encoders, due to the structural design and the selection of parts, the cost of parts may be several times more than the cost of economical encoders. In addition, the inspection procedures and standards are higher than that of economical encoders. Therefore, industrial encoders The cost is much higher than economical.

　　Various types of special industrial use grades: such as explosion-proof grades, automotive electronics grades, high temperature grades (greater than 100 degrees), water immersion resistance grades, heavy load grades, etc.