14mm Hollow Encoder

Rotary encoder anti-interference principle, how to judge is the encoder interference?

Rotary encoder is a precision electronic components, the use of environmental requirements to anti-jamming, today to take you to understand the rotary encoder anti-jamming system design principles, how to determine whether the encoder itself failure? Or interference.

Rotary encoder anti-interference system design principle

Rotary encoder is a rotary displacement sensor, which is rotated into a series of digital pulse signals can be used to control the angular displacement. Then rotary encoder in the motion control system how to interfere with anti-jamming design? Signal transmission channel: shielded twisted pair transmission, the signal will be affected by the electric field, magnetic field and the impedance of the interference factors in the transmission process. Compared with coaxial cable, although the frequency band is poor, but the impedance is large, strong anti-common-mode noise, so that every small part of the electromagnetic interference can be offset against each other. Photocoupling isolation measures in long-distance transmission, photocoupler can cut off the control system and the circuit connection between the input channel as well as the output channel and the input and output channels of the servo drive. The main advantage of opto-coupling is that peak pulses and noise disturbances can be effectively suppressed, thereby greatly improving the signal-to-noise ratio (SNR). Although the noise voltage is large, but the energy is small, only weak current, and light-emitting diode photocoupler input part of the work in the current state, the general conduction current of 10-15mA, so even if it can not provide enough current is suppressed, so the interference is very large. Power system anti-interference design: the implementation of power supply group, for example, will be implemented motor drive power supply and control power supply to prevent interference between devices. The use of isolation transformers, taking into account the mutual inductive coupling of high-frequency noise does not depend on the early stages through the secondary coil of the transformer, but begins between the primary and secondary auxiliary parasitic capacitance coupling, so the transformer isolation and shielding isolation, reduce capacitance to improve the ability to resist common mode interference. Noise filters are effective in suppressing interference to other AC servo drives.

In many cases it is the rotary encoder is not bad, but only the cause of the interference, resulting in a bad waveform, leading to inaccurate counting.

Rotary encoder is a precision component, this is mainly because of the encoder around the interference is more serious, for example: whether there is a large motor, welding machine frequent start-up caused by the interference, and whether the power line and the same pipeline transmission and so on.

Select what kind of output on the anti-jamming is also very important, the general output with reverse signal anti-jamming to be better, i.e., A + ~ A-, B + ~ B-, Z + ~ Z-, which is characterised by the addition of power supply 8 wires, rather than 5 wires (common zero). With the reverse signal in the cable transmission is symmetrical, interference is small, in the receiving device can also be added to the judgement (for example, the receiving device's signal using A, B signal 90 ° phase difference, read level 10, 11, 01, 00 four states, counted as a valid pulse, this scheme can effectively improve the system's anti-jamming properties (counting is accurate)).

How to judge whether the encoder itself fault?

1, exclude (move away, shut down, isolate) the source of interference.

2、To judge whether it is the cumulative error of the mechanical gap.

3, determine whether the control system and encoder circuit interface mismatch (encoder selection error);

1,2,3 method of solving the test after the failure phenomenon excluded, then the preliminary judgement, if not excluded must be further analysed.

Determine whether the encoder itself is a simple method of failure is to exclude the method.

The specific method of elimination is: to replace the encoder with a same model up, if the failure phenomenon is the same, can be basically ruled out is the problem of encoder failure, because the two encoders at the same time there is a failure of small probability of events may be very small, can be viewed as 0. If you change the same type of encoder up, the failure phenomenon is immediately ruled out, it can be basically ruled out is the failure of the encoder.

Guangdong KKG electronic products specialising in the production of rotary encoders for 15+ years, rotary encoder model complete selection, the old factory, according to customer demand for size, precision, pulse, etc. to customize the product. KKG electronic research and development production of rotary encoders in a magnetic encoder, cost-effective than the photoelectric encoder, magnetic encoder performance is not easy to be affected by the impact of dust and condensation; its structure is simple and compact, no contact, Long life, high and low temperature resistance, vibration resistance, fast response time and lower cost. Find rotary encoder manufacturers to find KKG Electronics.