Sanwa PM33a Hybrid Digital Multimeter + Clamp Meter

1. Introduction

The Sanwa PM33a is a compact and lightweight hybrid digital multimeter and clamp meter designed for various electrical measurements. It combines the functions of a digital multimeter with a U-shaped current sensor, allowing for both direct contact measurements and non-contact current measurements. This manual provides essential information for the safe and effective use of your PM33a.

Figure 1: Sanwa PM33a Multimeter. The device features a tilt-up U-shaped CT sensor with a 10mm opening, and a storage space for the sensor on the back of the main unit. Test pins and caps are included, rated CAT.III 300V when attached and CAT.II 600V when unattached.

2. Safety Information

To ensure safe operation and service of the meter, follow these instructions. Failure to observe these warnings can result in severe injury or death.

• Always inspect the meter and test leads for damage before use. Do not use if damaged.
• Do not apply more than the rated voltage between terminals or between any terminal and ground.
• Use caution when working with voltages above 30V AC RMS, 42V peak, or 60V DC. These voltages pose a shock hazard.
• Do not operate the meter in explosive gas, vapor, or dust environments.
• Ensure the function switch is in the correct position for the measurement being performed.
• Disconnect the circuit power and discharge all high-voltage capacitors before measuring resistance, continuity, or diodes.
• When using the clamp sensor, ensure the circuit is de-energized if possible, or take appropriate safety precautions.
• Replace batteries immediately when the low battery indicator appears to ensure accurate readings.
• Adhere to the specified measurement categories (CAT.II, CAT.III) and voltage ratings.

3. Product Features

The Sanwa PM33a offers a range of features for versatile electrical testing:

• Lightweight Design: Approximately 160g for portability.
• Max/Min Value Hold: Capture and display the maximum and minimum measured values.
• U-shaped Current Sensor: Thin 7mm sensor for current measurement in confined spaces, capable of measuring at 0 and 180-degree angles.
• AC/DC Current Measurement: Measures up to 100A for both alternating and direct currents.
• Data Hold: Freeze the displayed measurement for easy reading.
• Auto Power Off: Conserves battery life.
• Digital Multimeter Functions: Includes voltage, resistance, capacitance, frequency, diode, and continuity tests.

4. Parts Identification

Familiarize yourself with the components of your Sanwa PM33a:

Figure 2: Labeled diagram of the Sanwa PM33a. Key components include the Display, MAX/MIN button, RANGE button, SELECT button, Power & Function switch, Hz/DUTY button, REL/ZERO button, DATA HOLD button, Test lead winding direction, Clamp sensor (when stored), Battery cover fixing screw, Battery cover, Test pin, Detachable test pin cap, Test probe (red), and Test probe (black).

1. Display: Shows measurement readings and indicators.
2. MAX/MIN Button: Toggles between maximum and minimum value hold.
3. RANGE Button: Manually selects measurement range (if not in auto-ranging mode).
4. SELECT Button: Toggles between functions within a rotary switch position (e.g., AC/DC voltage).
5. Power & Function Switch: Rotary switch to turn the unit ON/OFF and select measurement functions.
6. Hz/DUTY Button: Selects frequency or duty cycle measurement.
7. REL/ZERO Button: Activates relative measurement mode or zeros the display.
8. DATA HOLD Button: Freezes the current display reading.
9. Test Leads: Red and black leads for direct measurements.
10. Test Pins/Caps: Removable caps for test pins, affecting safety category rating.
11. U-shaped Clamp Sensor: For non-contact AC/DC current measurement.
12. Battery Cover: Located on the back, secured by a screw.

5. Setup

5.1 Battery Installation

The Sanwa PM33a requires two AAA batteries (included). To install or replace batteries:

1. Ensure the meter is turned OFF.
2. Locate the battery cover on the back of the unit (refer to Figure 2).
3. Use a suitable screwdriver to loosen the battery cover fixing screw.
4. Remove the battery cover.
5. Insert two AAA batteries, observing the correct polarity (+/-) as indicated inside the compartment.
6. Replace the battery cover and tighten the screw securely.

5.2 Test Lead Connection

The test leads are integrated into the meter and can be wound around the unit for storage. To prepare for measurement:

• Unwind the test leads from their storage position.
• Ensure the test pin caps are either attached or removed based on the measurement category required (CAT.III 300V with caps, CAT.II 600V without caps).
• Inspect the leads for any cuts, cracks, or damage before each use.

6. Operating Instructions

Turn the Power & Function switch to the desired measurement function. Use the SELECT button to toggle between AC/DC or other sub-functions if available within a single switch position.

6.1 Current Measurement (Clamp Function)

The PM33a's U-shaped clamp sensor allows for non-contact measurement of AC and DC currents up to 100A.

1. Turn the Power & Function switch to the CLAMP position.
2. Open the U-shaped clamp sensor.
3. Place the conductor (single wire) to be measured within the clamp opening. Ensure the clamp is fully closed around the conductor.
4. Read the current value on the display. The U-shaped sensor is particularly useful in tight spaces.

Figure 3: The U-shaped sensor in action, demonstrating its utility in confined areas like a circuit breaker panel. The clamp has a 10mm opening, measures AC/DC current up to 100A with an accuracy of ±(2.0%rdg + 5dgt), and a resolution of 0.1A.

6.2 Voltage Measurement (DCV / ACV)

1. Turn the Power & Function switch to the V position.
2. Use the SELECT button to choose between DCV (direct current voltage) or ACV (alternating current voltage).
3. Connect the red test lead to the positive (+) side of the circuit and the black test lead to the negative (-) or common side.
4. Read the voltage value on the display.

6.3 Resistance Measurement (Ω)

1. Ensure the circuit is de-energized and all capacitors are discharged.
2. Turn the Power & Function switch to the Ω position.
3. Connect the test leads across the component to be measured.
4. Read the resistance value on the display.

6.4 Capacitance Measurement

1. Ensure the capacitor is fully discharged before measurement.
2. Turn the Power & Function switch to the Capacitance position (often shared with Ω or Diode).
3. Connect the test leads across the capacitor terminals.
4. Read the capacitance value on the display.

6.5 Diode Test

1. Ensure the diode is disconnected from the circuit.
2. Turn the Power & Function switch to the Diode position.
3. Connect the red test lead to the anode and the black test lead to the cathode. A forward voltage drop will be displayed.
4. Reverse the leads. The display should show 'OL' (open loop) for a good diode.

6.6 Continuity Test

1. Ensure the circuit is de-energized.
2. Turn the Power & Function switch to the Continuity position (often shared with Ω or Diode).
3. Connect the test leads across the component or wire.
4. A continuous beep indicates a low resistance path (continuity).

Figure 4: Examples of checking various electronic components. This includes resistance measurement of electronic components, capacitance measurement of capacitors, diode polarity checks, and fuse continuity checks. Note: Alligator clips are optional accessories.

6.7 Frequency (Hz) / Duty Cycle (%) Measurement

1. Turn the Power & Function switch to the Hz/DUTY position.
2. Connect the test leads across the signal source.
3. Press the Hz/DUTY button to toggle between frequency and duty cycle display.
4. Read the frequency or duty cycle value on the display.

6.8 Special Functions (MAX/MIN, REL/ZERO, DATA HOLD)

• MAX/MIN: Press the MAX/MIN button to record and display the maximum and minimum readings during a measurement session. Press again to cycle through MAX, MIN, and current readings.
• REL/ZERO: Press the REL/ZERO button to store the current reading as a reference value and display subsequent measurements as a deviation from this reference. This is useful for nulling out lead resistance or comparing values.
• DATA HOLD: Press the DATA HOLD button to freeze the current reading on the display. Press again to release.

7. Maintenance

7.1 Battery Replacement

When the low battery indicator appears on the display, replace the batteries as described in Section 5.1. Always use two new AAA batteries of the same type.

7.2 Cleaning

Wipe the meter's casing with a damp cloth and a mild detergent. Do not use abrasives or solvents. Ensure the meter is completely dry before use. Do not immerse the meter in water.

7.3 Storage

If the meter is not used for an extended period, remove the batteries to prevent leakage and damage. Store the meter in a cool, dry place, away from direct sunlight and extreme temperatures.

8. Troubleshooting

If you encounter issues with your Sanwa PM33a, refer to the following common problems and solutions:

• No Display / Meter Does Not Turn On:
  • Check if the Power & Function switch is in an ON position.
  • Verify battery installation and polarity.
  • Replace batteries if they are depleted.
• Inaccurate Readings:
  • Ensure the correct function is selected for the measurement.
  • Check test lead connections for good contact.
  • Verify battery level; low batteries can affect accuracy.
  • Ensure the U-shaped clamp is fully closed around a single conductor for current measurements.
• 'OL' or 'OPEN' Displayed:
  • Indicates an open circuit or a value exceeding the meter's range.
  • Check test lead connections.
  • Ensure the component being measured is not open.
  • For resistance, continuity, or diode tests, ensure the circuit is de-energized.
• No Continuity Beep:
  • Ensure the meter is in continuity mode.
  • Check for an open circuit in the component or wire.

If the problem persists after attempting these solutions, contact Sanwa customer support for further assistance.

9. Specifications

The following table details the technical specifications of the Sanwa PM33a Hybrid Digital Multimeter + Clamp Meter.

Figure 5: Detailed specifications for the Sanwa PM33a, including measurement ranges, accuracy, and general characteristics.

General Specifications

• Display: 6600 counts
• Sampling Rate: 3 times/second
• Operating Temperature/Humidity: 5°C to 40°C, 80% RH (no condensation)
• Storage Temperature/Humidity: -10°C to 50°C, 70% RH (no condensation)
• Power Supply: AAA (LR03) battery x 2 (1.5V x 2)
• Power Consumption: Approx. 7mW
• Auto Power Off: Approx. 30 minutes
• Safety Standards: IEC61010 CAT.III 300V, CAT.II 600V
• EMC Standard: IEC61326 (EMC)
• Dimensions: 130(H) x 75(W) x 19.9(D) mm (excluding projections)
• Weight: Approx. 160g (including batteries)

Accessories

• Test Leads (integrated)
• AAA Batteries (x2)
• Instruction Manual

Optional Accessories

• Alligator Clip: CL-13a, CL-15a, CL-DG3a
• IC Clip: TL-9IC
• Carrying Case: C-DG3a

10. Warranty and Support

Sanwa products are manufactured under strict quality control. For warranty information, please refer to the warranty card included with your product or visit the official Sanwa website. For technical support, service, or inquiries regarding your PM33a, please contact your local Sanwa distributor or authorized service center.