Ground Reference And Supply Offset Simulator

1. Basic Understanding of Equipment

1.1 Product Overview

The LIS-OFFSET-10V10A Ground Reference and Supply Offset Simulator employs a four-quadrant bipolar power supply architecture with constant-voltage/constant-current dual modes, with a maximum output of ±10V/±10A and a bandwidth of 100 kHz. It is specifically designed for ground reference and power supply offset testing in automotive electronics, simulating potential difference conditions where multiple power supplies and ground paths coexist in a vehicle, and verifying the operational reliability of in-vehicle ECUs and components under potential offset conditions.

1.2 Applicable Standards

Standard Number	Standard Title
GB/T 28046.2-2019, Clause 4.8	Environmental Conditions and Tests for Electrical and Electronic Equipment in Road Vehicles—Part 2: Electrical Loads
ISO 16750-2:2023, Clause 4.8	Road Vehicles—Environmental Conditions and Testing for Electrical and Electronic Equipment—Part 2: Electrical Loads
Ford EMC-CS-2009.1, Clause 18.0	Electromagnetic Compatibility Specification for Automotive Electrical and Electronic Components
BMW GS 95024 Section 5.1	Electrical and Electronic Components in Motor Vehicles – Requirements and Tests
Nissan 28400	Automotive Electrical and Electronic Component Test Specification
FMC1278 CI 210	Automotive Electrical and Electronic Test Standard

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 surrounding area; use of the equipment in dusty, flammable, or 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 cables as short as possible and route them in parallel to minimize the impact of parasitic parameters; route signal and power cables separately to avoid cross-interference.

2.4 Operational Safety Guidelines

Wear insulated protective gear; before testing, ensure that all connections are secure and that there are no exposed conductors; Do not connect or disconnect test cables during testing to avoid arc burns; do not touch the DUT, test fixtures, or output terminals while the output is active to prevent the risk of electric shock from potential differences; if you hear unusual noises, smell an odor, or see smoke, immediately disconnect the power; during prolonged continuous testing, ensure the equipment is properly ventilated for heat dissipation.

2.5 Precautions for the Device Under Test (DUT)

All input and output ports of the DUT must be connected to representative analog vehicle loads and networks to simulate real-world vehicle operating conditions; the DUT must be configured in operating mode 3.4 as specified in ISO 16750-1, and its functional status must be monitored throughout the test; When multiple internal ground pins of the DUT are internally connected, the offset voltage must be applied simultaneously to all connected ground pins.

3. Equipment Overview

3.1 Front Panel

See Figure 3-1.

Number	Note
①	Device Power Switch: Press briefly to turn on; press and hold to turn off.
②	10.1-inch Capacitive Touchscreen
③	USB1 port: Used by LISUN engineers for device debugging; users do not need to use it
④	USB 2.0 port, which can be used to connect a mouse to control the touchscreen, or to connect a USB flash drive to upgrade the software or update database files
⑤	Output connector—pay attention to polarity

3.2 Back Panel

See Figure 3-2.

Number	Note
①	Power cord receptacle and fuse; ensure the input power supply is properly grounded
②	Circuit breaker, main power switch for the input power supply for equipment
③	Protective ground terminal: If the input power supply does not have a reliable ground connection, this terminal must be connected separately to ground.
④	Output jacks—pay attention to polarity; these function the same as the front-panel output jacks.
⑤	RS485 port/LAN port, which can be connected to a computer to use the host software (for backup purposes). The host software offers the same functionality as the touchscreen; please contact us if needed.

4. Introduction to the Touchscreen Program

This device is essentially a four-quadrant bipolar power supply. For information on using the four-quadrant bipolar power supply program, please refer to the LIS-APS Operating Instructions. These instructions cover only the operations required when using the device as a Ground Reference and Supply Offset Simulator.

See Figure 4-1.

Number	Note
①	Set to CV (Constant Voltage)
②	Output impedance is set to 0
③	Set the offset voltage
④	Click to enable/disable the offset voltage output

5. Ground Reference and Power Supply Offset Test

5.1 Verification of Test Conditions

Verify the DUT specifications: Confirm whether it is a 12V or 24V system; Verify the number and pin definitions of the DUT’s power and ground pins;
verify the auxiliary power supply: an external base power supply (typically 13.5 V for 12 V systems and 28 V for 24 V systems);
Verify the DUT load: Connect the DUT inputs and outputs to corresponding simulated loads to simulate the actual vehicle wiring harness network;
Verify test standard requirements: Confirm the hold time for each test condition, the operating mode required for the DUT, and the criteria for passing the test.

5.2 Hardware Wiring

See Figure 5-1 for the standard wiring diagram (taken from ISO 16750-2:2023, Figure 18).

The LIS-OFFSET-10V10A is a single-channel device that must be used in conjunction with your LIS-AP device. Refer to Figure 5-2 for the wiring diagram; be sure to observe the polarity indicated in the diagram when making connections.

Number	Note
①	Auxiliary Power Supply
②③	LIS-OFFSET and LIS-AP have the same function and are used to simulate power supply offset and ground offset. ② is used to simulate the power supply offset Uoffset1, and ③ is used to simulate the ground (GND) offset Uoffset2.
④	DUT

5.3 Explanation of the Standard Test Matrix for ISO 16750-2-2023

The table below lists the eight test conditions specified in the standard; typically, each condition must be maintained for 30 to 60 seconds to observe the DUT’s operating status.

Test Conditions: Case	Power Supply Offset DC Output (Uoffset1)	Ground Offset DC Output (Uoffset2)	Test Description
Case 1	0 V	1V	1 V GND offset, no power supply offset
Case 2	1V	1V	1 V GND offset, +1 V supply offset
Case 3	-1V	1V	1 V GND offset, –1 V supply offset
Case 4	0 V	-1V	‑1V GND offset, no power supply offset
Case 5	1V	-1V	‑1V GND offset, +1V power supply offset
Case 6	-1V	-1V	-1V GND offset, -1V power supply offset
Case 7	1V	0 V	No GND offset, +1V supply offset
Case 8	-1V	0 V	No GND offset, -1V supply offset

When the DUT has multiple independent power supply pins and multiple independent ground pins, each set of power-ground loops must undergo a complete repetition of all 8 test cases; if multiple GND pins within the DUT are internally interconnected, the offset voltage must be applied simultaneously to all interconnected ground pins; All input and output load networks must match those of the actual vehicle; no no-load testing is permitted.

5.4 Evaluation of Test Results

Level	Definition of Standards
Class A	During and after testing, all functions met the design specifications; there were no abnormalities and no out-of-tolerance conditions.
Class B	Functioned normally during testing, with only brief instances of parameters exceeding tolerance limits; automatic recovery from stress relief; storage function must be Grade A.
Class C	The test procedure allows for functional failures; normal operation is automatically restored after the offset voltage is removed.
Class D	Failed during testing; after the stress is removed, manual reset or a power cycle is required to restore operation.
Class E	Permanent damage; hardware needs to be repaired or replaced

Note: Clause 4.8 of ISO 16750-2:2023 does not itself specify which class the DUT must meet, but this test typically mandates Class A.

6. Daily Maintenance and Care of Equipment

6.1 Daily Cleaning

6.1.1 Cleaning Schedule and Procedures

After each use: Clean the touchscreen surface and remove dust from the device panel;

Weekly: Clean the equipment housing and vent filters;

Monthly: Clean dust from inside the equipment (to be performed by a professional).

6.1.2 Cleaning Methods

Wipe the exterior with a clean, soft, lint-free cloth; use a dedicated screen cleaner for the touchscreen; clean the vents with a soft-bristled brush and a vacuum cleaner if necessary; do not use corrosive solvents such as acetone.

6.2 Periodic Inspections

Check the power cord for damage or wear; check that the ground connection is secure; check that the fan is operating normally; check that the buttons and touchscreen are responsive; check the terminal blocks for oxidation or loose connections.

6.3 Storage and Handling

6.3.1 Long-Term Storage Requirements

Storage Conditions: Temperature -10°C to +50°C, humidity ≤85%; Clean the equipment and apply dust protection before storage; Power on the equipment once every 3 months, running it for at least 30 minutes each time; Avoid stacking or applying heavy pressure to prevent the panel from warping.

6.3.2 Precautions for Handling

Unplug all external cables before moving the device; use the original packaging and ensure it is properly cushioned and protected; keep the device upright during transport and avoid vigorous shaking; when lifting, grip the bottom and sides of the device—do not lift by the panel.

6.4 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. The specific calibration interval may be determined by the user based on frequency of use, environmental conditions, and quality system requirements.

7. Troubleshooting and Resolving Common Problems

Fault Symptoms	Possible Causes	Procedure
The device won’t turn on	The input power supply main power switch on the back 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-On	System freeze, loose ribbon cable	If the problem persists after restarting, disconnect the power, open the device’s casing, and check whether the touchscreen ribbon cable is loose.
Test Stopped Automatically Midway	Over-temperature protection triggered; overcurrent/overvoltage protection triggered	Check whether the equipment’s ventilation is obstructed and whether the ambient temperature is too high; check the DUT for short circuits or overloads.
USB Flash Drive Not Recognized	USB drive format is incompatible or has too much storage capacity	Use a FAT32-formatted USB drive with a capacity of no more than 32 GB; if that still doesn’t work, try a different USB drive.
No voltage/current after output is enabled	DUT Wiring Abnormality, Protection Function Triggered	After disconnecting the output, verify that the DUT is wired correctly and that there are no open circuits or short circuits; check for any overvoltage, overcurrent, or overtemperature warnings, and retry after resolving the issue.
Abnormal Output Voltage/Current Accuracy	Improper output resistance settings; long-term lack of calibration	Verify that the source impedance parameters meet the test requirements; contact a third-party metrology organization to perform calibration.