Automotive Transient Emission Test System

1. Basic Understanding of Equipment

1.1 Model Classification

LISUN Model	LIS-TEMI-50A	LIS-TEMI-100A	LIS-TEMI-150A
DUT Capacity	80 V/50 A	80 V/100 A	80 V/150 A
Product Name	Automotive Transient Emission Test System (Power Cables)
Monitoring Interface	N-type 1:1 coaxial terminal output
Resistors in Parallel	[Rs]: Open circuit, 10 Ω, 20 Ω, 40 Ω, 120 Ω
Trigger Method	Automatic, One-Time, External Trigger
Mode Selection	Mechanical switches, electronic switches
Instrument Grounding Connection Methods	Banana Plug Cables ≤ 10 mm
Artificial Mains Network Parameters
Frequency	0.1 MHz–100 MHz
Capacitance	0.1 μF
Impedance	5 μH||50 Ω, conforms to the impedance curve specified in ISO 7637-2
DC Resistance	<5 mΩ
Electronic Switch Specifications
Start and Stop Times	0.01–99.99 s + (10% + 10 ms)
Operating Hours	300 ns + 20% @ load 50 μH/0.6 Ω
Transient Protection Voltage	440 V
Mechanical Switch Specifications
Start and Stop Times	0.01–99.99 s + (10% + 10 ms)
Contact Points	High-purity silver, with no contact inhibition
Action Time	Close: 20 ms; Open: 10 ms

1.2 Applicable Standards

ISO 7637-2, “Road Vehicles—Electrical Disturbances Caused by Conduction and Coupling—Part 2: Electrical Transients Conducted Along Power Lines,” Clause 4.3, Appendix B

GB/T 21437.2-2021 “Road Vehicles—Test Methods for Electromagnetic Disturbances Caused by Conduction and Coupling in Electrical/Electronic Components—Part 2: Conducted Transient Emissions and Immunity Along Power Lines,” Clause 4.3, Appendix B

1.3 Application Scenarios

The LIS-TEMI Series Automotive Transient Emission Test System is a power line transient conducted emission test bench specifically designed for the research and development of in-vehicle electrical and electronic components. It is used to evaluate the level of voltage transient disturbances generated by the device under test (hereinafter referred to as DUT) during power on/off transitions and to verify whether the product complies with relevant automotive electromagnetic compatibility standards.

The system simulates the impedance characteristics of vehicle wiring harnesses using an artificial network. Combined with high-precision switching modules and adjustable shunt resistors, it can perform two types of transient emission Test: slow pulses (millisecond-level) and fast pulses (microsecond-level). It is widely used by automotive parts manufacturers and third-party testing laboratories for electromagnetic compatibility (EMC) research and development as well as compliance verification.

1.4 Core Testing Capabilities

1.4.1 Slow-Pulse Transient Emission Test

For voltage transient disturbances in the millisecond range and slower, this test is suitable for DUTs with inductive loads driven by internal switches, and simulates slow transient disturbance emission Test caused by the vehicle ignition switch or a relay opening.

1.4.2 Fast-Pulse Transient Emission Test

Designed for fast voltage transient disturbances in the microsecond-to-millisecond range, Test is suitable for DUTs without internal switches and simulates fast transient disturbance emissions caused by high-speed switching operations.

2. Precautions for Use

2.1 Environmental Requirements

Ambient temperature: 23 °C ± 5 °C; relative humidity: 45–75%, non-condensing; altitude: ≤2000 m; no strong vibrations or electromagnetic interference in the vicinity; use of the equipment in dusty or flammable and explosive environments is strictly prohibited.

2.2 Power Supply Requirements

Input power supply: AC 220 V ±10%, 50 Hz; Input power: ≤1 kW; The power supply must be reliably grounded, with a grounding resistance of ≤4 Ω; It is recommended to use a voltage-stabilized power supply to prevent power grid fluctuations from affecting test accuracy.

2.3 Wiring Principles

Use power cables with the specified wire gauge to prevent overheating under high current conditions; keep Test as short as possible and route them in parallel to minimize the effects of parasitic parameters; ensure the DUT (Device Under Test) enclosure is reliably connected to the equipment’s protective ground; and route signal and power cables separately to avoid cross-interference.

2.4 Operational Safety Guidelines

Wear insulated protective gear; Test testing, ensure that all connections are secure and that there are no exposed conductors; do not touch or plug in or unplug any wiring harnesses or cables during Test; if you hear unusual noises, smell an unusual odor, or see smoke, immediately turn off the power.

3. Equipment Overview

3.1 System Hardware Components

3.1.1 Host Computer

See Figure 3-1.

Number	Note
①	Main Control and Manual Network, including a touchscreen and an N-type monitoring interface
②	Mechanical switch with an N-type monitoring interface
③	Electronic Switch, with N-Type Monitoring Interface

3.1.2 Accessories

See Figure 3-2.

Number	Note
①	Power Cord
②③	100mm Standard Connecting Cable
④	200mm Standard Connecting Cable

3.2 Introduction to the Touchscreen Program

See Figure 3-3.

Number	Note
①	Switch Mode Selection: To switch between electronic and mechanical switches, the setting must match the hardware of the switch module actually connected.
②	Parallel resistance options: 10 Ω, 20 Ω, 40 Ω, 120 Ω, or open circuit. If “open circuit” is selected, the customer may connect a parallel resistor of any other value.
③	Settings for Connection Duration (On/Off)
④	Pulse Count Setting
⑤	DUT Power Supply Control: Controlling the DUT’s Power Supply Output
⑥	Operational Control, Start/Stop Pulse Test

4. Procedures for Automotive Electronic Transient Emission Testing

4.1 Preparation of the Test Environment

4.1.1 Site and Grounding Requirements

Tests must be conducted in an Electromagnetic Shielding Cabinet or a laboratory with a stable electromagnetic environment to prevent external electromagnetic interference from affecting the Test results.

Place a metal grounding plate with a thickness of ≥2 mm; the plate must be large enough to cover all Test equipment and the DUT, and it must be securely connected to the laboratory grounding system, with a grounding resistance of ≤4 Ω.

Artificial networks and switch modules are placed directly on the metal ground plane. The DUT’s connection cables must be routed parallel to the ground plane at a height of 50 mm ± 5 mm above it.

4.1.2 Electromagnetic Environment Requirements

The test area must be located away from sources of strong electromagnetic interference, such as high-power motors, variable-frequency drives, and high-frequency transmitting equipment.

During testing, avoid turning high-power laboratory equipment on or off to prevent power grid fluctuations from interfering with Test.

4.1.3 Preparation of Auxiliary Equipment

Digital Oscilloscope: Minimum sampling rate of 2 GS/s, bandwidth of 400 MHz, and input sensitivity of at least 5 mV/division; power on 30 minutes in advance to allow for warm-up; voltage probes: must be suitable for the test voltage range, have proper bandwidth matching, have the attenuation ratio set correctly, and be calibrated in advance.

DUT DC power supply or battery: The output voltage and current must meet the DUT’s rated operating requirements, and the voltage regulation accuracy must be ≤±0.5%.

Insulated support block: 50 mm ± 5 mm thick, used to raise the DUT and prevent direct contact with the ground plate.

4.2 Test Plan Approval

Test Type Selection

Select the Test type based on the DUT type and Test standard requirements: For DUTs with internal mechanical/electronic switches that drive inductive loads, select Test slow-pulse test; for DUTs without internal switches, select Test fast-pulse test.

Type Testing / Test: Use mechanical switches for slow pulses and electronic switches for fast pulses; there is no need to Test using both types of switches.

Parameter Settings

Parameters	Slow Pulse	Rapid Pulse
Resistors in Parallel	Typical values are 10Ω, 20Ω, 40Ω, and 120Ω. For special operating conditions, you can select the “open circuit” setting and connect an external resistor with a custom resistance value. For 12V automotive systems, 20Ω to 50Ω is commonly used; for 24V systems, 40Ω to 120Ω is commonly used.
Connection Duration	DUTs are typically inductive loads with internal switches, and their current rise time is relatively long; the turn-on time is usually set to 500 ms to 5 s, depending on the time it takes for the DUT load to reach steady state.	DUTs are typically resistive or slightly inductive loads without internal switches; they reach steady state faster, so the turn-on time can be appropriately shortened—usually set to 100 ms to 1 s—though the core principle remains ensuring stable DUT operation.
Duration of Disconnection	Inductive loads take a long time to demagnetize; the turn-off time is typically set to be at least as long as the turn-on time, usually ranging from 500 ms to 10 s, to ensure the load is fully reset.	The load energy is low, demagnetization is fast, and the disconnection time can be set to ≥100 ms; it is also necessary to ensure that the load is fully reset.
Number of pulses	Since the contact state varies slightly each time, Test typically performed 10 to 100 times.	High waveform consistency; typically Test to 50 times

4.3 Wiring Methods

4.3.1 Wiring Diagram for the Slow-Pulse Test

See Figure 4-1 for the wiring diagram.

Connect the LIS-TEMI as shown in Figure 4-2. From left to right: DUT DC power supply or battery, 100-mm standard connecting cable, mechanical switch, main control unit and manual network, 200-mm standard connecting cable, and DUT.

4.3.2 Wiring Diagram for the Rapid Pulse Test

See Figure 4-3 for the wiring diagram.

Connect the LIS-TEMI as shown in Figure 4-4. From left to right: DUT DC power supply or battery, 200-mm standard connection cable, master controller and manual network, electronic switch, 100-mm standard connection cable, and DUT.

4.4 Evaluation of Test Results

Determination is based on the following three rules; if all are met, Test is considered passed.

Rules for Determination	Compliance Statement
Transient Emission Amplitude	The peak values of the positive transient voltage and the negative transient voltage must be tested separately, and both must meet the limit requirements.
Process Requirements	The DUT functioned normally throughout Test
Final Inspection Requirements	No permanent damage was found after Test

5. Daily Maintenance and Care of Equipment

5.1 Daily Use and Maintenance

5.1.1 Clean before and after each use

Before Use: Wipe the device’s surface, screen, and ports with a dry, soft cloth to remove dust and stains. Do not use corrosive cleaning agents.

After use: Clean the Test bench, organize the cables, and place dust covers over the device ports to prevent dust from entering the interior.

Screen Cleaning: Gently wipe the screen with a dedicated screen-cleaning cloth, and avoid scratching the touchscreen with hard objects.

Routine Visual and Interface Inspections

Before each use, check the following: the equipment housing for deformation, dents, or rust; the power and signal connector pins for bending, oxidation, or looseness; the power cable and standard Test cables for damage or aging, and the plugs for deformation; and the grounding terminal for a secure connection and signs of oxidation.

5.2 Long-Term Storage and Maintenance

Storage Environment Requirements

Storage temperature: -10°C to 50°C; relative humidity: ≤70%, no condensation; storage environment: dry, well-ventilated, dust-free, free of corrosive gases, and away from direct sunlight and heat sources; the equipment must be stored in its original packaging and placed on a raised surface to prevent moisture exposure.

5.2.2 Preprocessing Before Storage

Clean the equipment thoroughly to remove surface dust and stains; place dust caps over all ports, and neatly organize and bundle the cables to prevent kinks; disconnect all external connections and place a dust bag over the equipment; place desiccant inside the packaging to prevent moisture damage.

5.2.3 Requirements for Periodic Power Supply During Long-Term Storage

If the equipment is stored for more than 3 months, remove it from storage, plug it in, and let it warm up for 1 hour to remove internal moisture. After plugging it in, perform Test to ensure the equipment is operating normally. Replace the desiccant regularly to ensure the storage environment remains dry.

5.3 Calibration Interval Requirements

To ensure the measurement accuracy and operational reliability of the equipment, it is recommended that it be sent periodically to a qualified third-party metrology laboratory for calibration. The recommended calibration interval is 12 months. Users may determine the specific calibration interval based on frequency of use, environmental conditions, and quality system requirements.

6. Troubleshooting and Resolving Common Problems

Failure Symptoms	Possible Causes	Procedure
The device won’t turn on	The input power supply main power switch on the rear panel is not turned on, or the fuse has blown.	Turn on the input power supply switch located at the power cord receptacle on the back of the device; check the fuse, and if it has blown, replace it with a fuse of the same rating.
Touchscreen Malfunction After Power-Up	System freeze, loose ribbon cable	If the problem persists after restarting, disconnect the power, then follow our instructions to remove the device casing and check whether the touchscreen ribbon cable is loose.
Switch Mode Failure	Incorrect Switch Module Connection	Please verify that the switch type selected on the touchscreen matches the type of switch actually connected.
Pulse Output Abnormality	Switch Mode Error, Parallel Resistance Range Error, DUT Malfunction	Verify that the switch mode selected on the touchscreen matches the switch module that is actually connected; verify that the appropriate parallel resistor setting is used; verify that the DUT operates normally after the switch is turned on.
Unusual Noise When Operating the Switch	Contact oxidation and ablation; DUT voltage and current out of limits	If severe ablation due to oxidation occurs, replace the parts; do not exceed the load capacity under any circumstances.