CEM DT-337+

Contents

CEM DT-337+ Compact Digital Clamp Meter User Manual

Model: DT-337+ | Brand: CEM

1. Introduction

The CEM DT-337+ is a compact, high-precision digital clamp meter designed for a wide range of electrical measurements, including AC/DC current, voltage, resistance, frequency, capacitance, and temperature. Its auto-ranging capability and small jaw size make it ideal for various applications, including automotive repair, HVAC, and general electrical diagnostics. This manual provides essential information for safe and effective use of your DT-337+ clamp meter.

Front view of the CEM DT-337+ Clamp Meter, showing the display, dial, and buttons.
Figure 1: Front view of the DT-337+ Clamp Meter.

2. Safety Information

Always adhere to safety precautions when using any electrical testing equipment. Failure to do so may result in injury or damage to the meter or equipment under test.

  • Ensure the meter is in good working condition before use.
  • Do not attempt to measure voltages or currents exceeding the meter's specified maximum limits.
  • Wear appropriate personal protective equipment (PPE), such as safety glasses and insulated gloves.
  • Avoid working alone in hazardous electrical environments.
  • Always disconnect power to the circuit before making resistance, capacitance, or diode measurements.
  • The meter is designed to safety standard IEC 61010-2-032: CAT III 600V and pollution degree 2. Adhere to these ratings.

3. Product Overview

The DT-337+ is a compact clamp meter with a small jaw size, making it suitable for measurements in confined spaces. It features a large backlit display for easy reading and a rotary dial for function selection.

3.1 Components

  • Clamp Jaws: For non-contact AC/DC current measurement.
  • Rotary Function Switch: Selects measurement functions (e.g., A~, V~, V-, Ω, CAP, Hz, TEMP, Diode, Continuity).
  • LCD Display: Shows measurement readings, units, and function indicators.
  • ZERO Button: Used for zeroing DC current readings.
  • AUTO POWER OFF Button: Toggles auto power off feature.
  • HOLD Button: Freezes the displayed reading.
  • MODE Button: Selects between AC/DC, or other sub-functions within a range.
  • RANGE Button: Manually selects measurement range (disables auto-ranging).
  • COM Input Jack: Common terminal for test leads.
  • VΩCAPHz Input Jack: Input terminal for voltage, resistance, capacitance, and frequency measurements.
  • Test Leads: For voltage, resistance, capacitance, diode, and continuity measurements.
  • Carrying Case: For storage and transport.
Packaging contents of the CEM DT-337+ Clamp Meter, including the meter, carrying case, test leads, batteries, and user manual.
Figure 2: Included accessories and packaging.

4. Setup

4.1 Battery Installation

The DT-337+ requires batteries for operation. Ensure the meter is powered off before installing or replacing batteries.

  1. Locate the battery compartment cover on the back of the meter.
  2. Use a screwdriver to loosen the screw(s) securing the cover.
  3. Remove the battery compartment cover.
  4. Insert the required batteries, observing the correct polarity (+ and -) as indicated inside the compartment.
  5. Replace the battery compartment cover and tighten the screw(s).

Note: The product is shipped without batteries. Please use appropriate batteries as specified in the manual or product packaging.

5. Operating Instructions

5.1 Power On/Off and Auto Power Off

  • To power on the meter, rotate the function switch from the 'OFF' position to any desired measurement function.
  • To power off the meter, rotate the function switch back to the 'OFF' position.
  • The meter features an Auto Power Off function to conserve battery life. It will automatically power off after a period of inactivity. This feature can typically be toggled using the 'AUTO POWER OFF' button.

5.2 AC/DC Current Measurement (Clamp Function)

CEM DT-337+ Clamp Meter measuring current on a wire within an electrical panel.
Figure 3: Measuring current with the clamp jaws.
  1. Rotate the function switch to the '80A' or '4A' AC/DC current range.
  2. Press the 'MODE' button to select between AC (~) or DC (-) current measurement if necessary.
  3. For DC current measurement, press the 'ZERO' button to zero the display before clamping onto the conductor.
  4. Open the clamp jaws by pressing the trigger.
  5. Enclose only one conductor with the clamp jaws. Ensure the jaws are fully closed.
  6. Read the current value on the LCD display.

5.3 AC/DC Voltage Measurement

  1. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  2. Rotate the function switch to the 'V~' (AC Voltage) or 'V-' (DC Voltage) position.
  3. Connect the test leads across the circuit or component to be measured.
  4. Read the voltage value on the LCD display.

5.4 Resistance Measurement

  1. Ensure the circuit under test is de-energized.
  2. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  3. Rotate the function switch to the 'Ω' (Resistance) position.
  4. Connect the test leads across the component to be measured.
  5. Read the resistance value on the LCD display.

5.5 Capacitance Measurement

  1. Ensure the capacitor is fully discharged before measurement.
  2. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  3. Rotate the function switch to the 'CAP' (Capacitance) position.
  4. Connect the test leads across the capacitor.
  5. Read the capacitance value on the LCD display.

5.6 Frequency Measurement

  1. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  2. Rotate the function switch to the 'Hz/%' (Frequency/Duty Cycle) position.
  3. Connect the test leads across the signal source.
  4. Read the frequency value on the LCD display. Press 'MODE' to switch to Duty Cycle if available.

5.7 Diode Check

  1. Ensure the circuit under test is de-energized.
  2. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  3. Rotate the function switch to the Diode symbol position.
  4. Connect the red test lead to the anode and the black test lead to the cathode of the diode.
  5. The display will show the forward voltage drop. Reverse the leads to check for open circuit.

5.8 Continuity Check

  1. Ensure the circuit under test is de-energized.
  2. Insert the black test lead into the 'COM' jack and the red test lead into the 'VΩCAPHz' jack.
  3. Rotate the function switch to the Continuity symbol position.
  4. Connect the test leads across the component or circuit path.
  5. A continuous beep indicates continuity (resistance below threshold).

5.9 Data Hold Function

Press the 'HOLD' button to freeze the current reading on the display. Press it again to release the hold function and resume live measurements.

6. Maintenance

6.1 Cleaning

Wipe the meter with a damp cloth and mild detergent. Do not use abrasives or solvents. Keep the input terminals free of dirt and moisture.

6.2 Battery Replacement

When the battery indicator appears on the display, replace the batteries promptly to ensure accurate measurements. Refer to Section 4.1 for battery installation instructions.

6.3 Storage

If the meter is not used for an extended period, remove the batteries to prevent leakage and damage. Store the meter in its carrying case in a cool, dry place.

7. Troubleshooting

  • Meter does not power on: Check battery installation and ensure batteries are not depleted.
  • No reading or 'OL' displayed: The measurement range may be exceeded, or the circuit is open. Try a higher range or check connections.
  • Inaccurate readings: Ensure test leads are properly connected, batteries are fresh, and the correct function is selected. External electromagnetic interference can also affect readings.
  • Display is dim: Replace batteries.

8. Specifications

The following tables detail the features and technical specifications of the DT-337+ model, along with comparisons to DT-338 and DT-339 where applicable.

8.1 Features Comparison

Table comparing features of DT-337, DT-338, and DT-339 models, including jaw size, resolution, True RMS, temperature function, AC/DC current, safety standard, display counts, auto power off, data hold, peak/max/min hold, relative functions, capacitance, frequency, and flashlight.
Figure 4: Features comparison for DT-337, DT-338, and DT-339.
Features DT-337 DT-338 DT-339
Small jaw size 0.5˝ 0.8˝ 0.7˝
1mA high resolution * * *
True RMS AC clamp-on multimeter * *
Type K Temperature function * *
Digital clamp tester for AC/DC current measurement * * *
Providing wide measuring range from very small to large current * * *
Designed to safety standard IEC 61010-2-032: CAT III 600V and pollution degree 2 * * *
Display counts 4000 4000 5000
Auto power off & Data hold function * * *
Peak hold, Max/Min hold and Relative functions * Max/Min
Advanced functions include Capacitance, Frequency * *
Flashlight *

8.2 Electrical Specifications

Table of detailed electrical specifications for DT-337, DT-338, and DT-339 models, including max range, resolution, and basic accuracy for current, voltage, resistance, frequency, % duty, capacitance, temperature, diode check, and continuity check.
Figure 5: Electrical Specifications for DT-337, DT-338, and DT-339.
Function Max Range Max. Resolution Basic Accuracy DT-337 DT-338 DT-339
Current AC 80A 1mA ±(2.5%+5d) * * *
Current DC 80A 1mA ±(2.5%+4d) * * *
Voltage AC 400mV~600V 0.1mV ±(2.0%+4d) * * *
Voltage DC 400mV~600V 0.1mV ±(1.5%+3d) * * *
Resistance 400Ω~40MΩ 0.1Ω ±(1.5%+2d) * * *
Frequency 5Hz~10MHz 0.001Hz ±(1.2%+3d) * * *
% Duty 5%~99.9% 0.10% ±(1.2%+3d) *
Capacitance 40mF 0.001nF ±(3.5%+10d) 100uF * 500.0uF
Temperature (-20ºC~+760ºC) 0.1ºC ±(2.0%+3ºC) * *
Temperature (-4ºF~+1400ºF) 0.1ºF ±(2.0%+3ºF) * *
Diode Check Test current of 0.3mA, Open circuit voltage 3.0V (338) * * *
Continuity Check Threshold 50Ω * * *

8.3 General Specifications

  • Dimensions (HxWxD): 210mm x 70mm x 37mm
  • Weight: 200g
  • Safety Rating: IEC 61010-2-032: CAT III 600V, Pollution Degree 2
  • Battery Included: No
  • Semi-finished product: No
  • High-concerned chemical: None

9. User Tips

  • Zeroing DC Current: Always remember to press the 'ZERO' button before measuring DC current with the clamp jaws to ensure accurate readings, especially for small currents.
  • Single Conductor Rule: For accurate current measurements, ensure only one conductor passes through the clamp jaws. Measuring multiple conductors will result in a net current reading, which may be zero if currents are balanced.
  • Backlight: Utilize the display backlight in dimly lit environments for better readability.
  • Auto-Ranging vs. Manual Ranging: While auto-ranging is convenient, for faster measurements or specific troubleshooting, manually selecting a range using the 'RANGE' button can sometimes be more efficient.

10. Warranty and Support

For warranty information, technical support, or service inquiries, please contact your point of purchase or the manufacturer directly. Keep your purchase receipt as proof of purchase.

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