POS Machine EMC Testing

POS Machine EMC testing, or electromagnetic compatibility testing, is an important process to ensure that a POS machine operates normally in an electromagnetic environment without causing interference to other devices. Below is a related introduction:

Purpose of Testing

1. Ensure Stable Operation: To ensure the POS machine operates stably in various electromagnetic environments, such as near other electronic devices or wireless signal sources. The goal is to avoid issues like system crashes, data errors, or communication interruptions, ensuring smooth payment transactions.

2. Reduce External Interference: To prevent electromagnetic radiation, conducted interference, and other emissions from the POS machine during operation from interfering with other nearby electronic devices, such as mobile phones, computers, or other payment terminals. This avoids affecting the normal use of these devices.

3. Comply with Regulatory Standards: To meet domestic regulations such as CCC certification and international standards such as CE certification, ensuring the POS machine can be legally sold and used in the market.

Testing Items

1. Electromagnetic Interference (EMI) Testing

 - Conducted Emissions (CE): Primarily tests electromagnetic interference signals transmitted from the POS machine through power lines, signal lines, etc., to the outside. The test frequency range is usually 150kHz - 30MHz.

 - Radiated Emissions (RE): Measures the electromagnetic interference emitted by the POS machine in the form of electromagnetic waves through space. The test frequency generally ranges from 30MHz - 1GHz.

 - Harmonics: Tests the harmonic currents produced by the POS machine during operation to assess its impact on the power grid. It must comply with standards such as IEC 61000-3-2.

 - Flicker: Examines voltage fluctuations and flicker caused by the POS machine during operation, following standards such as IEC 61000-3-3.

2. Electromagnetic Immunity (EMS) Testing

 - Electrostatic Discharge Immunity (ESD): Simulates static discharge from humans or objects to the POS machine, testing its immunity to electrostatic impact. Test voltage is typically ±4kV for contact discharge and ±8kV for air discharge.

 - Radiated RF Electromagnetic Field Immunity (RS): Tests the stability of the POS machine's operation in an RF electromagnetic field environment. The frequency range is generally 80MHz - 1000MHz or higher, with a typical test level of 3V/m.

 - Conducted RF Immunity (CS): Tests the POS machine’s resistance to RF interference conducted through power lines, signal lines, etc. The test voltage is generally 3V.

 - Electrical Fast Transient/Burst Immunity (EFT): Simulates the impact of fast transient pulses generated by various electrical devices during switching operations. Pulse voltage is usually ±1kV.

 - Surge Immunity (Surge): Simulates the impact of surge shocks generated by lightning or power grid switching operations on the POS machine. Surge voltage requirements are typically line-to-line ±1kV and line-to-ground ±2kV.

 - Voltage Dips, Short Interruptions, and Voltage Variations Immunity (DIP): Tests the POS machine’s ability to withstand power voltage dips, short interruptions, or voltage variations.

Testing Standards

- International Standards: Common international standards include en55032, EN55035. If the POS machine is to be exported to regions like Europe, these standards must be met.

Testing Process

1. Preparation: The manufacturer must submit detailed technical information about the POS machine, such as product manuals, circuit diagrams, PCB layouts, etc., to the testing organization. This helps the testing body understand the product's features and functionality, allowing them to determine the testing plan.

2. Sample Testing: The POS machine sample is placed in a professional electromagnetic compatibility testing laboratory. Using specialized testing equipment such as anechoic chambers, receivers, signal generators, and electrostatic discharge simulators, various EMC test items are conducted according to relevant standards and specifications.

3. Result Evaluation: After the testing is completed, the testing organization evaluates the POS machine's EMC performance based on the test data and standard requirements, determining if it meets the relevant standards.

4. Report Issuance: If the POS machine passes the test, the testing body will issue an EMC test report, confirming that the product's electromagnetic compatibility meets the required standards. If the product fails the test, the testing organization will point out the issues and provide suggestions for improvements. The manufacturer must make the necessary modifications to the product and retest it.