Where are the sources of analog sensor interference?

The primary source of disturbance that mimics sensors:

1) Electrostatic induction.

Electrostatic induction is also called capacitive coupling because there is parasitic capacitance between two branch circuits or components, so that the charge in one divergence is transmitted to the other divergent path through the parasitic capacitance.

2) Electromagnetic induction.

When there is mutual inductance between two circuits, the transition of current in one circuit is coupled to the other circuit through the magnetic field, a scene called electromagnetic induction. For example, transformers and coils leakage magnetic flux, energized parallel wires, etc.

3) Leakage current induction.

Because the internal components of the electronic circuit, such as the bracket, binding post, printed circuit board, capacitor internal medium or shell, etc., are poorly insulated, especially because the humidity of the sensor is high, the insulation resistance of the insulator decreases, and the leakage current is added, which will cause disturbance. This is especially true when leakage current flows into the input stage of the measurement circuit.

4) RF agitation.

First of all, the disturbance of the start-up and operation abort of large-scale power equipment and the disturbance of higher harmonics. Such as the disturbance of the thyristor rectifier system.

5) Other disturbances.

In addition to the above disturbances, the on-site safe production monitoring system is also susceptible to mechanical disturbance, thermal disturbance and chemical disturbance due to the poor task condition of the system. The information here is provided to you free of charge by Jiangsu Jinhu Aotemei Automation Instrument Factory, hoping to bring greater help to those who need it.

The interference of the sensor is basically caused by high-frequency interference;

Generally, the interference is 150kHz 100MHz, which requires a reasonable selection of anti-interference filter products;

Our company has filters for this frequency band, which are also customized for several large sensor companies;

For specific product needs, you can call the mobile phone number sold by the company above, hoping to help.

Static electricity, as well as interference sources generated by strong electrical wiring in a trunking.

The interference of sensors and instruments in the field operation is varied, and the specific situation is analyzed on a case-by-case basis, and it is the principle of anti-interference to take different measures for different interference. This flexible strategy is undoubtedly contradictory to universality, and the solution is to adopt a modular approach, in addition to the basic components, for different operating occasions, the instrument can be equipped with different options to effectively resist interference and improve reliability. Before further discussing the selection of circuit components, circuits, and system applications, it is necessary to analyze the sources and types of interference that affect the accuracy of analog sensors.

Unexpected transient interference occurs mainly during the operation of electrical equipment, such as closing or opening, etc., and sometimes occurs at the moment when lightning occurs or radio equipment is working.

Interference can be roughly divided into 3 aspects:

a) locally generated (i.e. unwanted thermocouples);

b) coupling within the subsystem (i.e., the path problem of the ground wire);

c) Externally generated (interference from BP power supply frequencies).

In applications, the following major interference phenomena are commonly encountered:

1) When the command is issued, the motor rotates irregularly;

2) When the signal is equal to zero, the value of the digital display table jumps randomly;

3) When the sensor is working, its output value is inconsistent with the signal value corresponding to the actual parameters, and the error value is random and irregular;

4) When the measured parameter is stable, the difference between the value output by the sensor and the signal value corresponding to the measured parameter is a stable or periodically changing value;

5) The equipment (such as monitors, etc.) that shares the same power supply with the AC servo system is not working properly.

There are two main types of channels for interference to enter the positioning control system: signal transmission channel interference, which enters through the signal input channel and output channel associated with the system; Interference in the power supply system.

The signal transmission channel is the way for the control system or driver to receive feedback signals and send out control signals, because the pulse wave will have delay, distortion, attenuation and channel interference on the transmission line, so in the transmission process, long-line interference is the main factor. There is internal resistance in any power supply and transmission line, and it is these internal resistance that causes the noise interference of the power supply, if there is no internal resistance, no matter what kind of noise will be absorbed by the power supply short circuit, and no interference voltage will be established in the line; In addition, the AC servo drive itself is also a strong source of interference, which can interfere with other equipment through the power supply.