Shanghai Jingpu Mechanical & Electrical Co., Ltd
(@Q)
1, what is the absolute value
"Absolute value" means that the measured position value is independent of the previous measurement count and is the absolute position value for the measurement origin.
It is different from the "relative value", the relative value is a relative moving position value relative to the previous measurement position, and the "absolute value" is called "absolute" every time the normal measurement is independent of any other measurement relationship.
2, what is the absolute value coding
Absolute value coding refers to the absolute coding of all mechanical positions within the measurement range (sensor) that have a unique correspondence with the mechanical position origin in the measurement range. The measurement at any time does not depend on the history of the previous measurement. . Even if you don't move, you can directly output a unique absolute code.
The fundamental of absolute value coding, the first is to obtain complete position information independent of the movement and previous history comparison, and each position is unique, and the second is independent of the previous reading (including various memory modes). The internal does not need to be accumulated by the counter. The unique signal value can be measured and output without moving the position and without knowing the position of the previous reading.
3. What is the difference between "absolute" and "absolute value coding"?
The fundamental difference is that the "absolute" name is focused on measuring the "absolute" position output mode of the receiving device relative to the external origin position, while the "absolute value encoding" is focused on measuring the internal coding form of the sensor, in its range The interior is uniquely "absolutely encoded" for all positions of the origin position. As the "encoder" should be based on the principle of internal code reading to determine its name.
In fact, depending on the count, whether it is internal battery memory, external battery, or even low-power Wiegand effect counting, it is “counting†and can no longer be called “absolute value codingâ€. Relative to the "absolute" of the receiving device.
4. What is an absolute value single-turn encoder?
In the 360-degree measurement range, the data encoding of each output position is absolute and unique within a 360-degree single circle, and position information is obtained without relying on rotation and previous data. After rotating more than 360 degrees, the data loops again from 0.
For example, GAS60 series single-turn encoder of Shanghai Jingpu (GEMPLE)
Optical multi-channel absolute value single-turn encoder code disc form
The number of bits of the single-turn absolute encoder is represented by the N-order number of 2, and the 8-bit number has 256 code positions. The 10 bits are 1024, 12 bits 4096, 13 bits 8192, 14 bits 16384. 16-bit 65536, the highest number of digits currently is the 25-bit single-turn absolute encoder from HEIDENHAIN, Germany.
5, what is the absolute value multi-turn encoder
Absolute multi-turn encoders, in their measurement range, not only have "absolute value coding" within 360 degrees of a single turn, but also have a unique absolute code that does not depend on the multi-turn value of the counter after more than 360 degrees. It is generally similar to the clockwise minute hand and hour hand principle.
The multi-turn absolute encoder is based on the number of bits in a single turn and the number of turns in the multi-turn. The resolution and the number of measurements are measured. The multi-turn is usually 4096 laps, and the small amount can reach 16384 laps and 65536 laps (16 bits). The absolute multi-turn encoder of the GMX425 series can reach 12-bit 4096 laps, and the special requirements can reach 16384 laps and 65536 laps.
For example, GEMPLE's GAX60 series of absolute multi-turn encoders, mechanical absolute value multi-turn encoders as shown below
Clock gear type absolute multi-turn encoder
6. What is the electronic "absolute"?
The electronic "absolute", although the data that can be supplied to the outside is also output in the same absolute value, but the internal absolute encoding of each position is not dependent on the rotary motion of the encoder and the previous reading. Compared with the memory preservation, the obtained position information, similar to a tape recorder or a laser CD, must be rotated by a tape or rotated by a disc to organize the collection of complete information and output, which requires "moving up" or "moving a small part". Obtaining a similar absolute information output, called "dynamic" data scanning absolute, while some rely on battery, super capacitor memory data, or more advanced low or no power Wiegand effect readings and register readings with capacitors, which The way in which a class can output the stored position information without moving it is called a "static" electronic absolute.
Whether it is "static" or "dynamic" electronic "absolute", it is not the position information obtained by the internal absolute value encoding, so it should not be called "absolute encoder". The name of the encoder should be determined by its internal encoding and reading principle, rather than just looking at the output signal.
7. What is the problem with the "electronic absolute" encoder compared to the "true absolute value" encoder?
The internal working principle of the electronic absolute encoder is dependent on the positional information obtained by comparing the motion reading with the previous memory data, so that compared with the "true absolute value encoder", there will be three parts of the possibility of error. :
The first is the cumulative count of readings after exercise. This part may be affected by various internal and external electrical environment interference factors or the device's small probability of failure factors. It is different from absolute value coding. Absolute value coding is due to position information. It always exists, even if the one-time small probability reading fails, it does not affect the accuracy of the next reading. The electronic failure through the reading count may affect the accumulation of the next reading. This error cannot be judged separately, and the information output in time and at each position continues; and the reading after power failure It relies on battery, capacitor power supply, or Wiegand effect. It has very small power generation energy storage power. Because of its limited power supply, its anti-interference is worse, and the reading frequency is low. When the fast rotary encoder or external is large Under the influence of interference, it is very likely that there is no time to count the accumulated or interfered with the reading error, and the continuation is cumulative.
The second is the accumulation of memory, which is limited by power, or due to problems with memory energy components, such as battery power loss, capacitance and Wiegand effect storage capacity, storage data Distortion of the coupled data of the capacitor, distortion of the data collected by the stored data, low temperature failure of the battery, high temperature explosion of the battery, memory energy and life of the data memory, etc., etc., affecting its memory data and again Whether the acquisition is likely to be distorted.
The third is that the speed response is limited and the data is processed and decoded. Because it is based on the integrated decoding of the motion reading and the internal registration data, the speed response is limited, the carry synchronization processing, fast motion reading In the case of various factors such as processing and interference effects, the reprocessing and decoding of the two sets of data still have the possibility of error, and this kind of error is different from the true absolute encoding, and it cannot be judged if it is wrong (or need Then use the auxiliary sensor to compare and judge), and the error continues in time and position.
In summary, the electronic absolute encoder, in principle, because it is not absolutely coded at each position, once an error occurs, it will affect the next reading and continue to the accuracy of subsequent readings, and the possibility of such errors Always present, just in terms of probability size to reflect the manufacturer's technical level. In principle, it is not an "absolute value coding" encoder. Its application should be extremely careful to avoid situations that cause more damage due to errors, such as safety monitoring.
8. What is the watch gear type absolute multi-turn encoder?
Rotating the single-turn absolute encoder to measure the coded lines of the optical code disc in rotation to obtain a unique set of codes. When the rotation exceeds 360 degrees, the code returns to the origin, so that the absolute code is not unique. In principle, such an encoder can only be used for measurements within a range of 360 degrees of rotation, called a single-turn absolute encoder.
Real multi-turn absolute encoder: The encoder manufacturer uses the principle of watch gear machinery to add a set of mechanical gear set code discs. When the center code disc rotates, another set of gear discs (or sets of gears) is driven by gears. , multiple sets of code discs), on the basis of single-turn coding, increase the number of turns of the code to expand the measurement range of the encoder, this way is similar to the second, minute and time of the mechanical timepiece, also known as the absolute encoder Called
Clock gear type absolute multi-turn encoder, this kind
Real multi-turn absolute encoder, for multi-turn values, the same is determined by the mechanical position of the code, each position code is unique and does not repeat, without memory.
9. What is an electronic multi-turn "absolute encoder"?
The unicyclic code disc uses the principle of absolute value, such as the absolute value of the optical multi-code channel single-turn or the magnetoelectric absolute value single-turn encoder, and the multi-turn measurement uses the electronic counting accumulation and registration method, which is called "electronic type". Multi-turn absolute encoder", but called "absolute value coding" is not serious and deceptive, this is partial absolute value coding, the complete full-stroke measurement range can not be counted as absolute value, but partial increment Counting.
The electronic multi-turn absolute encoder has the use of the last reading to determine the value of the circle without using the battery. The movement angle after the power failure has a certain range limit; there are also built-in batteries or external batteries to record the number of turns, and the battery capacity is limited. In the case of power failure memory ring value; there is currently a battery-free Wiegand effect (no power pulse generation and counting) to record the circle value, but still belong to the electronic multi-turn encoder.
Electronic multi-turn encoders still have the possibility of reading, registering, and re-reading errors. Once this possibility cannot be found and compensated, it needs to be corrected by comparison with other auxiliary sensors. In addition, the electronic multi-turn encoder is after power failure. The rotation angle and speed are limited.
10. What is the Wiegand effect encoder?
There are some electronic multi-turn encoders whose multi-turn counting is based on the principle of the Wiegand effect.
in
on
In the 1960s, John Wiegand discovered that there are large differences between the inner core and the outer layer through properly treated magnetic wires.
Sex
Under certain conditions, two state transitions can be produced. This effect is called the Wiegand effect, and the wire similar to this feature is called Wiegand. Magnetic sensor made of such wire
, when the NS changes in the magnetic field, can generate spikes without power supply, Wiegand sensor
Has a high operating temperature (up to 200
°C
), can output high pulse voltage (up to 5~6V) without any external power supply, and can directly interface with the computer. Therefore, it has been applied in many occasions.
. The sensor made by this principle is called “Wiegand Sensorâ€. This sensor requires almost no power supply, and even the spikes it generates can be stored with capacitors. The Wiegand sensor internally counts and peaks tiny energy stored by the capacitor. As early as the 1990s, the products were produced, but the technical conditions at that time were very unstable. In recent years, the emergence of low-power electronic components has made this product mature to the market, but its reliability is limited. It can only be used for counting the number of turns, (since the number of rounds is small, the frequency is low, the reliability factor reflects the low probability of occurrence), and the single-turn code disk uses an absolute value code (for example, the principle of magnetoelectricity).
The counting of the Wiegand principle is still an electronic multi-turn encoder. It is also flawed. Because the signal generated by “self-generation†is weak, it is easy to be disturbed by surrounding electrical noise, and the counting read and registration are still interfered. The possibility of error, and once the error is disturbed, the original position is lost and cannot be retrieved. Care must be taken for applications where the surrounding electrical environment is relatively clean and not suitable for applications where lifting, engineering and various electrical environments are complex. If the stored energy is limited, the counting anti-interference after power failure is poor, the counting response is not fast enough, and the anti-interference is poor when the power is cut off and the power is switched. In short, it is not a complete absolute value encoding, and can no longer be called an "absolute multi-turn encoder". It is indicated in the foreign sample data as a single-turn absolute value, and the multi-turn Wiegand effect "electronic" multi-turn of. If you deliberately ignore Wiegand's "electronic" content, it is called "absolute multi-turn encoder", deliberately confused with the higher cost and more reliable mechanical absolute encoder, with less serious commercial deception Sexual suspicion.
11, what is the full-stroke multi-turn absolute encoder
The interior of the measuring sensor encoder is absolute coded throughout the measuring stroke. This is relative to some measurements where the partial absolute value encoding portion is counted differently, or more than a stroke requires the refresh starting point to be re-measured as an absolute value difference. Because the measurement range of the gear-type absolute multi-turn encoder is limited by the internal mechanical gear set, the absolute value of the coded circle value is limited, such as 4096 (12-bit), 16384 (14-bit), etc., or economical. 64 laps, 16 laps, this specifies the measurement loop value travel, and confirms that it is encoded and used in absolute value within this measurement stroke, called the full-stroke absolute encoder. The use of full-stroke multi-turn coding is used within this range depending on the number of encoder turns provided. The sensor is out of travel and is re-used from the starting point.
12. What are the absolute value single-turn encoders?
GEMPLE offers optical and magnetoelectric absolute single-turn encoders;
GEMPLE will provide the market with higher optical and magnetoelectric hybrid absolute encoders as needed.
13. What are the absolute multi-turn encoders?
GEMPLE's multi-turn absolute encoders are currently available on the market for mechanical full-stroke absolute value coding, with no internal electronic counting principle and battery.
(In the future, GEMPLE will also provide some absolute value coding + electronic counting encoder according to market needs, but it will definitely indicate its electronic counting characteristics.)
14, what is a smart encoder?
The intelligent encoder is the invention patent of GEMPLE. Its encoder has built-in 32-bit smart chip MCU, and has a setting software Easypro, which can be connected to the computer. An intelligent encoder integrates digital RS485 output and analog current.
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20mA output, for encoder applications, such as angle measurement, length measurement, speed measurement, electronic cam switch output, overspeed and low speed output switch, etc., can be directly output and applied through intelligent settings, for signal RS485 Set baud rate, address and resolution for signal 4
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20mA can be set to zero, full scale, direction of rotation, and current calibration. In addition, digital signals can be converted into various fieldbuses, Ethernet, wireless, etc. as needed. From then on, the encoder has entered the era of intelligence, providing a sensor base for angle, length and speed for intelligent management of plant equipment and the Internet of Things.
Easypro software interface
15, what is the analog signal output of the absolute encoder
The absolute encoder is internally digitally encoded, but the output can be output as an analog signal using digital-to-analog conversion (ADC), such as current 4
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20mA or voltage 1
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5V. For example GMS412. LB---single circle absolute value 4
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20mA output; GAX60. LB, multi-turn absolute value 4
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20mA output and so on.
16, why the analog semaphore value of the absolute encoder can not start from "0"?
The signal analog value of the absolute encoder cannot start from 0, because if the output 0, it is impossible to judge whether the signal is turned on, whether the encoder works normally, and the 0 signal is easily subject to external interference and is slightly moved, and it is impossible to judge the position value. It is still moving or disturbing. Therefore, the current signal 4
-
20mA starts at 4mA, the voltage signal 1-5V starts from 1V, the output of 0-10V, the position base point starts from 2V.
17, GEMPLE's absolute encoder has which signal output absolute encoder is optional?
The remaining output signal requirements can be communicated to GEMPLE for collaborative production.
Shanghai Jingpu Electromechanical Co., Ltd. adheres to the German absolute encoder and absolute multi-turn encoder technology, and forms a “design principle zero-error design†at the product design stage to ensure “zero error†in the design. To ensure the reliability guarantee of absolute encoder products, tens of thousands of sets have been used stably and reliably for more than 5 years in various industrial projects at home and abroad, which is the guarantee of high quality.
For more applications, please contact Shanghai Jingpu Electromechanical Co., Ltd.
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