1、 Displacement sensor Anti interference design of signal transmission channel
Grounding can eliminate the noise and voltage generated when the current flows through the ground wire. In addition to grounding the servo system, the signal shielding wire should also be grounded to prevent electrostatic induction and electromagnetic interference. If there is no proper grounding, a second may occur
This kind of interference phenomenon
(2) Pulling rope Displacement sensor Long line transmission of twisted pair shielded wire
The signal of displacement sensor will be affected by the interference factors such as electric field, magnetic field and ground impedance in the transmission process. The interference of electric field can be reduced by using grounding shield wire.
Compared with coaxial cable, twisted pair cable has higher wave impedance, stronger resistance to common mode noise, and can cancel the electromagnetic induction interference of each small link.
In addition, in the long-distance transmission process, the differential signal transmission is generally used to improve the anti-interference performance. The second, third and fourth interference phenomena can be effectively suppressed by using twisted pair shielded wire.
(3) Photoelectric coupling isolation measures
In the process of long-distance transmission, optocoupler can cut off the connection between control system and input channel, output channel and input and output channel of servo driver. If photoelectric isolation is not used in the circuit, external
The first kind of interference phenomenon occurs when the peak interference signal of the part will enter the system or directly into the servo drive device.
The main advantage of photoelectric coupling is that it can effectively suppress the peak pulse and various noise interference, so that the signal-to-noise ratio is greatly improved in the process of signal transmission. The main reason is: Although the interference noise has a large voltage amplitude, but the energy is small, only
It can form weak current, and the light-emitting diode in the input part of the optocoupler works under the current state. Generally, the on current is 10-15ma. Therefore, even if there is a high amplitude interference, it is suppressed because it can not provide enough current
2. Anti interference design of power supply system
(1) Using isolation transformer, considering that the high-frequency noise through the transformer is not mainly by the mutual inductance coupling of primary and secondary coils, but by the primary and secondary parasitic capacitance coupling, so the primary stages of the isolation transformer are separated by shielding layer to reduce the noise
Distributed capacitance to improve the ability to resist common mode interference.
(2) For example, the driving power supply and control power supply of linear displacement sensor are separated to prevent interference between devices
(3) Noise filter can also effectively suppress the interference of AC servo driver to other equipment. This measure can effectively restrain the above interference phenomena