The loop (contact) resistance tester is meticulously crafted using high-power switching power supply technology and electronic circuitry. It serves as a testing instrument for high and low voltage switches, cables, wires, and weld contact resistance. The current adopts the 100A/200A DC recommended by the standard GB736, allowing the measurement of the resistance value of the test object under 100A/200A current conditions. This instrument features a compact size, light weight, strong anti-interference capability, high precision, user-friendly operation, and comprehensive protection functions.

1. High Current: Utilizing advanced switching power supply technology, it can continuously output high current for extended periods, overcoming the drawbacks of pulsed power supplies that provide instantaneous current. This effectively breaks through the oxide film on switch contacts, yielding excellent test results.

2. High Stability: Under severe interference conditions, the last digit of the LCD display remains stable within ±1 digit, ensuring stable readings and good repeatability.

3. High Precision: Employing dual-channel high-speed 16-bit Σ-Δ AD sampling and advanced digital signal processing technology, it achieves a high resolution of 0.01μΩ. It is one of the few contact resistance testers domestically that can achieve such resolution while maintaining exceptional stability, outperforming imported high-current micro-ohmmeters.

4. Intelligent: Equipped with an imported high-performance CPU, the system automatically switches ranges based on signal size during measurement, ensuring testing accuracy. The over-temperature protection circuit automatically stops current output when the instrument exceeds the set temperature, ensuring safe usage.

5. Superior Quality: Key components are entirely imported. A cleverly designed temperature compensation circuit effectively eliminates the impact of ambient temperature on measurement results. The use of connectors enhances vibration resistance.

6. Powerful Functionality: Current can be freely selected between 50A and 100A, and the test time can be set anywhere from 5s to 599s. This overcomes the limitations of similar instruments that cannot set measurement time or have excessively short continuous operation times, far surpassing the performance of other comparable devices.

7. User-Friendly Interface: Data input is facilitated through a rotary mouse, making it convenient and fast. Users can set the instrument's date and time, save measurement data in real-time, and print results instantly.

8. Multiple Communication Methods: It can communicate with a computer via an RS232 serial port (9-pin) or USB data cable, uploading measurement data for further analysis and processing by test personnel.

9. Ease of Use: The loop resistance tester is compact, lightweight, and portable.

Precautions:

1. Before turning on the power switch, adjust the current control knob counterclockwise to the "zero" position.

2. This instrument is equipped with over-current, over-voltage, and over-temperature protection functions, ensuring safe operation.

3. The instrument should be placed in a dry, well-ventilated indoor environment free from corrosive gases.