1. Introduction
The LUTRON MO-2002 is a high-precision benchtop miliohm meter designed for accurate resistance measurements across a wide range. Utilizing a four-wire measurement technique, it ensures precise readings, especially for very low impedance values. This manual provides essential information for the safe and effective operation, maintenance, and troubleshooting of your MO-2002 Miliohm Meter.
2. Safety Information
WARNING:
- This instrument contains no user-serviceable parts. Do not attempt to open or repair the device. All servicing should be performed by qualified personnel only.
- Ensure the correct power supply voltage (AC110V or AC220V, 50/60Hz) is used as specified for your unit.
- Observe all safety precautions when working with electrical circuits.
- The device is rated CAT II 240V. Do not use it for measurements exceeding this rating.
3. Key Features
- Wide measuring range: 0.01mΩ to 20KΩ across 7 selectable ranges.
- Four-wire measurement technique for high accuracy, especially for low impedance values.
- Integrated high/low range alarm with audible (beeping) and visual (LED) indications.
- Built-in overload protection for enhanced durability and safety.
- Benchtop design for stable and convenient operation.
- Clear digital display for easy reading of measurement results.
4. Specifications
4.1 General Specifications
| Parameter | Value |
|---|---|
| Measurement Range (Test Current) | 20 mΩ (1A DC) / 200 mΩ (1A DC) / 2Ω (100mA DC) / 20Ω (10 mA DC) / 200Ω (1 mA DC) / 2KΩ (100μA DC) / 20KΩ (10μA DC) |
| Alert Settings | Alarm setting, upper and lower setting values can be set by LED. Buzzer alarm sound. |
| Operating Temperature | 0 ~ 50°C |
| Operating Humidity | Lower than 80% R.H. |
| Working Power Supply | AC110V±15%, 50/60Hz or AC230V±15%, 50/60Hz (as specified for your unit) |
| Working Power Fuse | 200mA/250V, Size 5*20mm dia. |
| Physical Dimensions | 280 x 210 x 90 mm |
| Weight | Approximately 2.2 kg |
| Display Type | Digital Only |
| Certification | CE |
| Battery Included | Yes (Internal, not user-serviceable) |
4.2 Measurement Range and Accuracy
| Range | Resolution | Road Voltage | Test Current | Accuracy |
|---|---|---|---|---|
| 20 mΩ | 0.01 mΩ | About 2.7 VDC | 1A | ±(0.2% + 6 digits) |
| 200 mΩ | 0.1 mΩ | About 3.3 VDC | 1A | ±(0.2% + 4 digits) |
| 2Ω | 1 mΩ | About 3.5 VDC | 100mA | |
| 20Ω | 0.01Ω | About 4.1 VDC | 10 mA | |
| 200Ω | 0.1Ω | About 4.5 VDC | 1 mA | |
| 2KΩ | 0.001KΩ | About 4.5 VDC | 100μA | |
| 20KΩ | 0.01KΩ | About 4.5 VDC | 10μA |
4.3 Open Circuit Voltage
| Range | Open Circuit Voltage |
|---|---|
| 20 mΩ | About 2.7 VDC |
| 200 mΩ | About 3.3 VDC |
| 2Ω | About 3.5 VDC |
| 20Ω | About 4.1 VDC |
| 200Ω | About 4.5 VDC |
| 2KΩ | About 4.5 VDC |
| 20KΩ | About 4.5 VDC |
5. Package Contents
Upon unpacking, please verify that all items listed below are present and in good condition:
- LUTRON MO-2002 Miliohm Meter (1 unit)
- Power Cord (1 pc)
- 4-wire Test Clamp (Kling clamp) (1 pair)
- Operating Instructions (1 copy)
6. Setup
- Placement: Place the MO-2002 meter on a stable, flat surface, away from strong electromagnetic fields, direct sunlight, and excessive heat or moisture.
- Power Connection:
- Ensure the power switch on the rear panel is in the "OFF" position.
- Connect the provided power cord to the AC inlet on the rear panel of the meter.
- Plug the other end of the power cord into a suitable AC power outlet (AC110V or AC220V, 50/60Hz, depending on your unit's specification).
- Test Lead Connection:
- Identify the four input terminals on the front panel: FORCE+, SENSE+, SENSE-, FORCE-.
- Connect the 4-wire test clamps to these terminals. Typically, the red leads connect to FORCE+ and SENSE+, and the black leads connect to SENSE- and FORCE-. Ensure a secure connection.
7. Operation
- Power On: Flip the power switch on the rear panel to the "ON" position. The display should illuminate.
- Range Selection:
- Use the range selection buttons on the front panel (e.g., 20mΩ, 200mΩ, 2Ω, 20Ω, 200Ω, 2KΩ, 20KΩ) to select the appropriate measurement range.
- Start with a higher range if the resistance value is unknown to avoid overloading the meter. Adjust downwards for better resolution.
- Connecting to the Device Under Test (DUT):
- Ensure the DUT is de-energized and safe to test.
- Connect the 4-wire test clamps to the points on the DUT where resistance is to be measured. The FORCE leads inject current, and the SENSE leads measure the voltage drop, minimizing lead resistance errors.
- Taking a Measurement:
- Once the DUT is connected and the range is selected, the resistance value will be displayed on the digital screen.
- Allow a few seconds for the reading to stabilize.
- Comparator Function (Hi/Lo Alarm):
- The MO-2002 features a comparator function with Hi/Lo alarm settings.
- Use the "Comparator Set" knobs (HI and LO) to set the upper and lower resistance thresholds.
- When a measurement falls outside these thresholds, the corresponding HI or LO LED will light up, and the buzzer will sound (if enabled).
- This feature is useful for production line testing or quality control to quickly identify out-of-spec components.
- Power Off: After use, disconnect the test leads from the DUT, then turn off the meter using the power switch.
8. Maintenance
- Cleaning: Wipe the meter's exterior with a soft, dry cloth. Do not use abrasive cleaners or solvents.
- Storage: Store the meter in a cool, dry place, away from direct sunlight and extreme temperatures.
- Calibration: For continued accuracy, periodic calibration by a qualified service center is recommended.
- Fuse Replacement: If the meter fails to power on, check the power fuse located on the rear panel. Replace it only with a fuse of the same type and rating (200mA/250V, 5x20mm dia.). Ensure the meter is disconnected from the power supply before attempting fuse replacement.
9. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Meter does not power on. | No power from outlet, faulty power cord, blown fuse. | Check power outlet, inspect power cord, replace fuse (see Maintenance section). |
| Inaccurate or unstable readings. | Poor connection of test leads, incorrect range selected, external interference, meter out of calibration. | Ensure test leads are securely connected to both meter and DUT. Select appropriate range. Move meter away from strong electrical noise sources. Consider professional calibration. |
| HI/LO alarm constantly active. | Comparator thresholds set incorrectly, DUT resistance outside expected range. | Adjust HI/LO comparator settings. Verify the actual resistance of the DUT. |
| "OL" or "OVERLOAD" displayed. | Resistance value exceeds the selected range. | Select a higher measurement range. |
10. User Tips
- Always use the 4-wire Kelvin connection method for critical low-resistance measurements to eliminate the resistance of the test leads from the measurement.
- For highly inductive loads, allow sufficient time for the reading to stabilize.
- When measuring very low resistances, ensure good contact between the test clamps and the material being measured to prevent contact resistance from affecting readings.
- Regularly check the test leads for any signs of damage or wear, as this can impact measurement accuracy.
11. Warranty and Support
LUTRON products are manufactured to high-quality standards. For warranty information, technical support, or service inquiries, please contact your local LUTRON distributor or the point of purchase. Please have your model number (MO-2002) and purchase details ready when contacting support.
