1. Introduction
The RuoShui 4090A/C 4091C series are high-precision benchtop digital LCR meters designed for accurate measurement of inductance (L), capacitance (C), and resistance (R). These instruments offer a basic accuracy of 0.1% and a measurement frequency up to 100KHz, making them ideal for laboratories, factories, and electronic hobbyists. Key features include a 3.5-inch color display, automatic identification, data recording, data hold, and USB connectivity for computer communication.
2. Safety Information
Please read and understand all safety instructions before operating the device. Failure to follow these instructions may result in electric shock, fire, or damage to the instrument.
- Ensure the correct voltage is selected (AC 200-240V 50-60Hz) and use the provided three-core power cord.
- Do not operate the instrument in wet or damp conditions.
- Do not open the instrument casing unless you are qualified service personnel.
- Replace fuses only with the specified type (AC 250V 500mA).
- Always connect test leads properly to avoid short circuits or incorrect readings.
3. Package Contents
Verify that all items listed below are included in your package:
- Digital LCR Meter (Main Unit)
- Three-core Power Cord
- Four-terminal Pair Kelvin Test Cable
- Product Manual (this document)
- Fuse
4. Setup
4.1 Adjusting the Handle
The instrument is equipped with an adjustable handle for convenient positioning. To adjust, hold the handles on both sides of the main unit, pull them outward, and then rotate the handle to the desired position.
4.2 Front and Rear Panel Overview
Familiarize yourself with the front and rear panel components before making any connections.
- Front Panel: 3.5-inch display, Power switch key, Ground port, Test clip jacks (H sense, L sense, H force, L force), Basic measurement function keys (LEVEL, FREQ, RANGE, SPEED, SET, ENTER, ANULL, CAL, AUTO/COMP, COMPARE, SAVE, TOL%, HOLD, DCR, MAX, MIN, AVG), Switch key, Arrow keys.
- Rear Panel: Voltage jack (AC 200-240V 50-60Hz, Fuse: AC 250V 500mA), Voltage selection switch, RS232 interface, HANDLER interface, USB interface.
4.3 Power Connection
- Ensure the voltage selection switch on the rear panel matches your local power supply (AC 200-240V).
- Connect the provided three-core power cord to the voltage jack on the rear panel and then to a grounded power outlet.
- Press the Power switch key on the front panel to turn on the instrument.
4.4 Test Lead Connection
Connect the four-terminal pair Kelvin test cable to the corresponding test clip jacks (H sense, L sense, H force, L force) on the front panel. Ensure a secure connection for accurate measurements.
4.5 Computer Connection (Optional)
The LCR meter supports communication with a computer via RS232 or USB interfaces. The RS232 communication interface supports the SCPI communication protocol. The Handler interface supports comparator sorting and list scanning.
To connect:
- Connect a standard USB cable from the instrument's USB interface to your computer.
- Alternatively, connect an RS232 cable from the instrument's RS232 interface to your computer.
- Install the necessary drivers and software (not provided in this manual, refer to manufacturer's website or included software CD if applicable) for communication.
5. Operating Instructions
5.1 Display and Navigation
The 3.5-inch TFT (True Color) LCD provides a 5 1/2 digit resolution and a dual parameter display. It supports both English and Chinese interfaces. Use the arrow keys and 'SET' / 'ENTER' buttons for menu navigation and parameter adjustment.
5.2 Basic Measurement Functions
The front panel features dedicated keys for various measurement functions:
- LEVEL: Adjusts the test signal level.
- FREQ: Selects the test frequency.
- RANGE: Manually selects the measurement range or enables auto-ranging.
- SPEED: Adjusts the measurement speed (Fast, Medium, Slow).
- ANULL: Performs null adjustment.
- CAL: Initiates calibration.
- AUTO/COMP: Toggles between auto-comparison mode.
- COMPARE: Activates comparison function.
- SAVE: Saves measurement data.
- TOL%: Sets tolerance percentage for sorting.
- HOLD: Holds the current measurement reading.
- DCR: Selects DC Resistance measurement mode.
- MAX/MIN/AVG: Displays maximum, minimum, or average values.
5.3 Measurement Speed Selection
The instrument offers three measurement speeds to suit different testing requirements:
- FAST: 10 times/second
- MID: 5 times/second
- SLOW: 2 times/second
5.4 Correction and Screening Functions
- Correction Function: Supports Open Circuit Correction and Short Circuit Correction for improved accuracy.
- Screening Function: Allows for component sorting based on tolerance. The tolerance range is -100% to +100%, with fixed points at 10%, 25%, and 50%. It features five gear sorting, indicating three gear qualified, one gear failed, and one ancillary gear.
6. Maintenance
6.1 General Care
- Keep the instrument clean and dry. Use a soft, damp cloth for cleaning the exterior. Do not use abrasive cleaners or solvents.
- Store the instrument in a stable environment, away from extreme temperatures, humidity, and strong electromagnetic fields.
- Protect the display from scratches or impact.
6.2 Fuse Replacement
The instrument is equipped with a fuse box for protection. If the instrument fails to power on, the fuse may need replacement.
- Ensure the instrument is powered off and disconnected from the main power supply.
- Locate the fuse box next to the voltage jack on the rear panel.
- Carefully open the fuse compartment.
- Replace the old fuse with a new one of the specified rating: AC 250V 500mA.
- Close the fuse compartment securely.
7. Troubleshooting
This section provides solutions to common issues. If the problem persists, contact customer support.
- Instrument does not power on: Check power cord connection, ensure voltage selection switch is correct, and verify the fuse (refer to Section 6.2).
- Inaccurate readings: Ensure test leads are properly connected, perform open/short circuit correction, check for external interference, and verify component connection.
- No computer communication: Check USB/RS232 cable connections, ensure correct drivers are installed on the computer, and verify communication settings.
8. Specifications
The following table details the technical parameters for the RuoShui 4090C model (100K type). Specifications may vary slightly for other models (4090A, 4091C).
| Parameter | Description |
|---|---|
| Model | 4090C (100K type) |
| Test frequency(Hz) | 16 points (100, 120, 200, 400, 800, 1k, 2k, 4k, 8k, 10k, 15k, 20k, 40k, 50k, 80k, 100k) |
| Display method | 3.5 inch LCD screen display |
| Display digits | Main parameter: 5 bits, Secondary parameter: 5 bits |
| Parameter | Main parameter: L/C/R/Z, Secondary parameter: X/D/Q/ESR/θ |
| Range(L) | 0.01μH ~ 9999H |
| Range(C) | 0.01pF ~ 9999μF |
| Range(R) | 0.0001Ω ~ 99.99MΩ |
| Basic accuracy | 0.1% |
| Measurement Display Speed | Fast (10 times/sec), Medium speed (5 times/sec), Slow speed (2 times/sec) |
| Internal Bias | 0mV-1500mV adjustable, 1mV step |
| Test level | 100mV, 300mV, 600mV, 1000mV, 1500mV, 2000mV |
| Correction Function | Open circuit correction, short circuit correction |
| Screening function | Tolerance range: -100% ~ +100%, with fixed points of 10%, 25% and 50%. Five gear sorting, three gear qualified, one gear failed, one ancillary gear |
| Communication Interface | Standard configuration: USB, RS232 (or 485), Handle interface; Optional: GPIB, USB Host |
| Others | Support DCR, electrolytic capacitor measurement mode, adjustable backlight brightness, optional in English and Chinese |
9. User Tips
- For the most accurate measurements, always perform open and short circuit corrections before testing, especially when changing test frequencies or ranges.
- Utilize the data hold function (HOLD button) to freeze readings on the display for easier recording.
- When measuring small components, ensure the Kelvin test cables are properly connected to minimize lead inductance and resistance effects.
- Experiment with different measurement speeds (FAST, MID, SLOW) to balance between measurement time and precision for your specific application.
10. Warranty and Support
For warranty information, technical support, or service inquiries, please contact the Ruoshui Victor Instrument Store or your authorized dealer. Keep your purchase receipt as proof of purchase.