The working principle and function of the elevator encoder - News - Global IC Trade Starts Here Free Products

Programmable Package SG-8018CA(SG7050C) 0.67M~170M

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The working principle and function of the elevator encoder: it is a rotary sensor that converts the rotational displacement into a series of digital pulse signals. These pulses can be used to control the angular displacement if the elevator encoder is combined with a gear bar or a screw screw. It can also be used to measure linear displacement.
After the elevator encoder generates an electrical signal, it is processed by the number control CNC, the programmable logic controller plc, the control system, and the like. . The angular displacement conversion in the ELTRA elevator encoder uses the principle of photoelectric scanning. The reading system is based on the rotation of a radial indexing disk consisting of alternating light transmissive windows and opaque windows. The system is illuminated entirely by an infrared source such that light projects the image on the dish onto the surface of the receiver, which is covered by a layer of grating, called a collimator, which has the same window as the disc. The job of the receiver is to sense the change in light produced by the rotation of the disc and then convert the change in light into a corresponding electrical change. In general, a rotary elevator encoder can also obtain a speed signal that is fed back to the frequency converter to adjust the output data of the frequency converter. Fault phenomenon: 1. When the rotary elevator encoder is bad (no output), the inverter can't work normally, it becomes very slow, and the inverter protects for a while, and the “PG disconnect” is displayed... the joint action can work. To raise the electrical signal to a higher level and produce a square wave pulse without any interference, this must be handled by an electronic circuit. The connection between the elevator encoder pg wiring and the parameter vector inverter and the elevator encoder pg must correspond to the model of the elevator encoder pg. In general, the elevator encoder pg model is divided into three types: differential output, open collector output and push-pull output. The signal transmission mode must take into account the interface of the inverter pg card, so choose the appropriate pg card model or set it properly. .
Elevator encoders are generally divided into incremental and absolute types, which have the biggest difference: in the case of incremental elevator encoders, the position is determined by the number of pulses calculated from the zero mark, and the absolute elevator encoder The position is determined by the reading of the output code. In one lap, the output code reading for each position is unique; therefore, the absolute elevator encoder is not separated from the actual position when the power is turned off. If the power is turned back on, the position reading is still current and valid; unlike the incremental elevator encoder, it is necessary to look for the zero mark.
Now the elevator encoder manufacturers produce a full range of products, generally dedicated, such as elevator-specific elevator encoders, machine-specific elevator encoders, servo motor-specific elevator encoders, etc., and elevator encoders are intelligent There are various parallel interfaces that can communicate with other devices.
An elevator encoder is a device that converts an angular displacement or a linear displacement into an electrical signal. The former becomes the code wheel and the latter is called the code ruler. According to the reading mode, the elevator encoder can be divided into contact type and non-contact type. The contact type uses a brush output, and a brush contacts the conductive area or the insulating area to indicate whether the state of the code is "1" or "0"; the non-contact receiving sensitive element is a photosensitive element or a magnetic sensitive element, and when the photosensitive element is used The light transmissive area and the opaque area indicate whether the state of the code is "1" or "0".
According to the working principle, the elevator encoder can be divided into two types: incremental and absolute. The incremental elevator encoder converts the displacement into a periodic electrical signal, which is then converted into a counting pulse, and the number of pulses is used to represent the magnitude of the displacement. Each position of the absolute elevator encoder corresponds to a certain digital code, so its indication is only related to the start and end positions of the measurement, regardless of the intermediate process of the measurement.
The rotary incremental elevator encoder outputs a pulse when rotating, and its position is known by the counting device. When the elevator encoder is not moving or power is off, the internal memory of the counting device is used to remember the position. In this way, after the power failure, the elevator encoder can not have any movement. When the caller works, the elevator encoder can not interrupt and lose the pulse during the output pulse. Otherwise, the zero point of the counting device will be offset, and this The amount of offset is unknown, and only the wrong production results will be known. The solution is to increase the reference point, and the elevator encoder corrects the reference position into the memory position of the counting device every time the reference encoder passes. Before the reference point, the accuracy of the position cannot be guaranteed. For this reason, in the industrial control, there are methods such as finding a reference point for each operation, and starting to change the zero. Such an elevator encoder is determined by the mechanical position of the code wheel, and it is not affected by power outages and interference.
The absolute elevator encoder is unique in each position determined by the mechanical position. It does not need to be memorized, there is no need to find a reference point, and it is not necessary to count all the time, when to know the position, and when to read its position. In this way, the anti-jamming characteristics of the elevator encoder and the reliability of the data are greatly improved.
Since absolute elevator encoders are significantly superior to incremental elevator encoders in positioning, they have been increasingly used in industrial positioning. Due to its high precision, the absolute elevator encoder has a large number of output bits. If parallel output is still used, each output signal must ensure that the connection is good. For more complicated working conditions, it must be isolated and the number of connecting cable cores is large. This brings a lot of inconvenience and reduces reliability. Therefore, the absolute elevator encoder is usually a serial output or a bus type output in the multi-digit output type. The most commonly used serial output of the absolute elevator encoder produced in Germany is SSI. (synchronous serial output).
Multi-turn absolute elevator encoder. Elevator encoder manufacturers use the principle of watch gear machinery. When the center code wheel rotates, another set of code wheels (or sets of gears, multiple sets of code disks) can be driven by gears to increase the number of turns on the basis of single-turn coding. The coding to expand the measuring range of the elevator encoder, such an absolute elevator encoder is called a multi-turn absolute elevator encoder, which is also determined by the mechanical position code, and each position code is unique and does not need to be memorized. Another advantage of the multi-turn elevator encoder is that due to the large measuring range, the actual use is often more affluent, so that it is not necessary to find a zero point during installation, and an intermediate position is used as a starting point, which greatly simplifies the difficulty of installation and debugging. . The multi-turn absolute elevator encoder has obvious advantages in length positioning and has been increasingly used in industrial control positioning.