Encoders and working principle of the action: it is a kind of will spin displacement transformation into a sequence of digital pulse signal of rotating sensor, the pulse can be used to control the angular displacement, if encoder and article gear or spiral ball screw together, can also be used to measure linear displacement.
Encoder generated signals by several control for CNC, programmable logic controller, the control system, PLC to deal with. These sensors are mainly applied in the following aspects: machine tools, materials, motor feedback system and measurement and control equipment. In the transformation of the angular displacement ELTRA encoder used the optoelectronic scanning principle. Reading system is based on radial dividing the rotation of the disk, the dividing by the turn of the window and not pervious to light a window. This system with an infrared light source all vertical illuminate, the light is such an image on the plate surface onto the receiver, the receiver is covered with a layer of grating, called the collimator device, it has the same window and CD. The receiver's job is to feel the CD turn the output of light changes, and then will be converted into the light changes of electrical changes. In general, the rotary encoder can also get a speed signal, the signal to give feedback to the frequency converter, which regulates the frequency converter output data. Fault phenomena: 1, rotary encoder bad (no output), frequency converter can not work normally, which become running slow, and for a while inverter protection, shows "PG disconnect"... Joint action can be effective. To make the electrical signals to a higher level rise, and have no any interference of square wave pulsed, it must use electronic circuit to deal with. Encoder pg wiring and parameters vector frequency converter and encoder pg the connection between the way, must and model of the corresponding pg encoder. Generally speaking, encoder pg differential output model points, open collector output and the push-pull output three, its signal transfer mode must consider the pg card interface converter, so choose appropriate pg card types or set reasonable.
Encoder are generally classified into increment and absolute type, they have the biggest difference: in the incremental encoder, the position is from zero mark start of the pulse of the calculation to determine the number and type of absolute encoder position is the output of the readings of the code to determine. In a circle, every area of the output of the code reading is the only; Therefore, when the power supply when disconnected, absolute encoder is not with the actual type of position separation. If power through again, then position still is the current reading, effective; Don't like incremental encoders that, must go to look for zero mark.
Now the factory production series encoder is very full, normally, it is the special, such as elevators special encoder, machine tool special encoder, servo motor special encoder, etc, are all intelligent and coder, a variety of parallel interface can with other equipment communication.
Encoder is the angular displacement or linear displacement into electrical signal of a device. The former become code dish, the latter says yards feet. According to read the way encoder can be divided into contact and non-contact two. Contact output by brush, brush contact area or a conductive insulating area to say the state of the code is the "1" or "0"; Non-contact accept sensitive components is photosensitive components or magnetic susceptibility components, the photosensitive elements to pervious to light area and not pervious to light area to say the state of the code is the "1" or "0".
According to the work principle encoder can be divided into incremental and absolute type two kinds. Incremental encoder is to convert the electric signals of periodic displacement, again the electrical signals into a count pulse, with the number of pulse of the size of the displacement said. Of single channel absolute photoelectric shaft encoder every position corresponds to a certain digital code, so it shows only the value and measurement of the starting and the ending of the location, and measurement of the middle course have nothing to do.
Rotating incremental encoder to turns output pulse, through the count to know the position of equipment, when encoder fixed or power, rely on the count of the equipment to remember internal memory location. So, when power outages, encoders may not have any mobile, when to work, the output pulse coder process, also cannot have the interference and lost pulse, otherwise, the count of the equipment will offset zero memory, and the amount of the migration is never know, only the wrong production results appear to know. The solution is to increase the reference point, every reference point coder through, will reference position correction into count equipment memory location. In reference points before, is no guarantee that the accuracy of the position. Therefore, in industrial control of every operation first find reference points, boot methods for change. Such encoder is set by the code of the mechanical location decision, it from the power, the effects of the interference.
Absolute encoder mechanical position of the decision by the uniqueness of every position, it need not memory, no need to find a reference point, and don't count, when need to know what position, what you read its position. So, the anti-interference characteristics, data encoder reliability greatly improved.
Due to the absolute encoder has better in the positioning of incremental encoder, has been widely applied in industrial control positioning. Because of its high precision type absolute encoder, the output figures more, such as still using the parallel output, its each output signal must ensure that the connection is very good, for more complex conditions and isolation, some connection cables, thus to bring a lot of inconvenience and reduce the reliability, therefore, absolute encoder connection in output type, generally are chosen for serial output or main line output, the German production absolute resolver.by serial output the most commonly used is SSI (synchronous serial output).
Much circle absolute photoelectric encoder. Encoder manufacturers use the principle of the gears of a clock machinery, when center yards rotating, through the gear transmission another group code salver (or more sets of gear, much group code dish), in the lap of coding based on the number of laps to add code, to expand the encoder measuring range, such absolute encoder is called much circle type absolute encoder, it also is determined by mechanical position code, every position not to repeat the only coding, without having to memory. Much circle encoder another advantage is due to measurement range of big, rich practical use often more, so when installing the unnecessary difficult find, will be a middle position as a starting point, and greatly simplifies the installation and debugging of difficulty. Many laps absolute encoder in the length of the localization of the obvious advantages, has been more and more applied in industrial control positioning.