Why Absolute Encoders? With a description of the advantages

Why absolute encoders? What are its advantages? Take a look below!

1, the absolute position is not lost characteristics: absolute encoder as a position confirmation tool with absolute position is not lost, can ensure that in the system if the power supply failure or in the case of power failure in the system also occurs in the case of movement, the true position value of the system will not be lost. Absolute value encoder code value" with the measured "position" corresponds to the only, with "power failure memory" function, no rotary measurement of accumulated errors, in "a cycle of "It is superior to incremental encoders in the field of measurement and control, and the range can be adjusted by adding a front reduction gearbox. Absolute encoders are particularly suitable for applications where continuous reading of position is not required, such as satellite tracking antennas, where checking the position at intervals is sufficient.

2, flexible programmable features: absolute encoder without system zero, can be based on point-to-point position reference, to establish the position programming, rather than based on the system starting zero position. Encoder installation installed after the reduction gear, such as the shaft end of the winch wire rope reel or the last section of the reduction gear shaft end, this method has no gear back and forth clearance, the measurement is more direct, higher accuracy, this method is generally measured over long distances positioning, such as a variety of hoisting equipment, feeding trolley positioning. In addition the microprocessor interface module is the designer can program a number of operating parameters including resolution.

3, safety features: in some applications, the lack of position may lead to mechanical damage or injury to the operator control personnel. Absolute encoders allow the system to be calibrated for position at the moment of power-up.

4, better anti-electrical noise performance: absolute encoder is through the non-stop reading of the coded signal to determine the position, by the electrical noise generated by the surge pulse will not accumulate, accurate position signal can be obtained in the next reading.

5, long-distance transmission characteristics: synchronous serial interface is very suitable for long-distance transmission. The parallel data generated by the encoder is converted into a serial signal, which is very suitable for high-speed and long-distance transmission, and the distance can be as far as 1200 meters.

6, single-turn and multi-turn absolute encoders are available: absolute single-turn encoders are suitable for short travel motion control, position positioning within a single turn of the encoder shaft; while absolute multi-turn encoders are suitable for long distance and complex position positioning applications.

Based on the above advantages and practical applications of absolute encoders, there are basically three reasons for choosing absolute encoders:

1. The problem of moving the system out of power.

2. Anti-interference problem of signal transmission.

3. CPU resource issues for subsequent input device reading.

1, the system power failure to move the problem: we all understand that the absolute value of a single turn can be added through subsequent equipment, then the power outage can move half a circle, most of them with a holding brake or screw can be realized, and multi-turn absolute value if you want to go over the 4096 circle, but also through the subsequent equipment to add a circle, then the power outage can be moved to 2048 circles, which can meet the vast majority of the application.

2, signal transmission anti-interference problems: for this understanding is not too many people, sometimes by the incremental encoder anti-interference problem is a big headache, also did not think of absolute value encoder can be changed, generally change the absolute value of a single-turn can be, as long as the time of continuous interference is not more than a half-turn of the time, the absolute value of the signal is still in the position, you can get the correct reading. Encoder installation high-speed end installation: installed in the power motor shaft end, this method has the advantage of high resolution, due to the multi-turn encoder has 4096 turns, the number of motor rotation turns in this range, you can fully use the full range and improve the resolution, the disadvantage is that the movement of the object through the deceleration gears, back and forth there is a gear lash error, generally used for unidirectional high-precision control and positioning, such as rolling rolls in the roll gap control. In addition, the encoder is directly mounted on the high-speed end, the motor jitter must be small, otherwise it is easy to damage the encoder. That way, anti-jamming problems single-turn, multi-turn is almost the same.

3, the subsequent input device CPU resources: even fewer people know about this problem. The use of incremental encoders, especially high-resolution incremental encoders, follow-up equipment must be read continuously, if it is multi-axis, the CPU may be fully occupied, can not engage in other processing work, the actual results of the error rate increases greatly. The absolute value encoder, as long as the sampling time to meet the requirements, single-turn in the rotation of half-turn, multi-turn in the rotation of 2048 turns, what time to read, what time to read, freeing up a large number of CPU time to do something else, this is the European servo with the absolute value of the real advantage.

According to the advantages of absolute encoders and the above three reasons, depending on your actual needs, whether you need to use absolute encoders, and can determine whether to use a single-turn or multi-turn.