What are Pressure Transducer EMC/EMI/EMS

pressure transducer and the measured object are in a disturbed environment at the same time, and inevitably suffer from external interference. Electromagnetic interference will cause hazards such as misuse, loss of information, leakage, equipment failure, and damage, etc. So, what should we do in the face of this situation? It requires consideration of the electromagnetic compatibility of the pressure transducer. Electromagnetic compatibility refers to the ability of equipment and systems to function properly in an electromagnetic environment and does not constitute unacceptable electromagnetic interference to other equipment in the environment.
Electromagnetic compatibility can be expressed by the formula: EMC=EMI+EMS.

EMC Electromagnetic Compatibility	EMC is electromagnetic compatibility, which is a capability of the device. It allows the pressure transducer to perform its function in an electromagnetic environment without creating intolerable interference in its environment.
EMI Electromagnetic Interference	EMI is electromagnetic interference. It refers to any electromagnetic energy that can interrupt, hinder, reduce or limit the effective performance of the pressure transducer.
EMS Electromagnetic Susceptibility	EMS is electromagnetic susceptibility. It refers to the undesired response degree of a pressure transducer, subsystem, or system when exposed to electromagnetic radiation.

Sources of electromagnetic interference include interference noise generated by the emission source and interference noise experienced by the receiving source.

• The reason for the emission source generating interference noise

1. The recessive frequency of the emission source.
2. Mixed wave and amplitude modulation interference generated by the emission source to the receiving source.
3. Improper amplitude modulation output of the source.
4. Local oscillation noise of the receiver.
5. Derived noise of clock signal transmission.
6. Noise generated by motor devices such as motor relays.
7. Noise from power systems such as spark corona.
8. Lightning and lightning strikes.

• The reason for the receiving source feeling the interference noise

1. The RF frequency of the receiving source is improperly selected, which cause noise penetrating into the interference.
2. Mixed wave and amplitude modulation interference.
3. The noise of the power line is coupled to the receiving source, causing interference.
4. The electronic box cabinet is poorly isolated and infiltrates into the receiving source, causing interference.

The frequency bands for electromagnetic interference are classified as follows.

Interference Type (classified by frequency band)	Frequency Range	Typical interference source
Power frequency and audio interference	50Hz and its harmonics	Power line Electric traction system Cable broadcast
Very low frequency interference	30kHz and below 30kHz	Lightning, etc.
Carrier interference	10kHz-300kHz	High-voltage DC transmission high order harmonic AC transmission high order harmonic
RF, video interference	300kHz-300MHz	Industrial, scientific, medical equipment Internal combustion engine, electric motor Lighting appliances
Microwave interference	300MHz-100GHz	Microwave oven Microwave relay communication Satellite communication transducer

Among various pressure transducers, especially piezoelectric pressure transducers and capacitive pressure transducers are susceptible to interference. The interference methods for the pressure transducer are start with the structure.
Improve the structure of the pressure transducer to avoid the introduction of interference to a certain extent. It can be done as follows. Integrate the signal processing circuit with the sensitive components of the pressure transducer, that is, integration. In this way, the signal that needs to be transmitted is enhanced, thereby improving the anti-interference ability. At the same time, because it is an integrated structure, it reduces the introduction of interference. The integrated pressure transducer has the characteristics of compact structure and strong function, which is beneficial to improve anti-interference ability. For intelligent pressure transducers, anti-interference measures such as digital filtering, timing self-calibration, and characteristic compensation can be taken in software from various aspects.