CEM DT-859B 5-in-1 Multifunction Environment Meter

1. Introduction

The CEM DT-859B is a versatile 5-in-1 multifunction environment meter designed for professional and home use. It integrates the functions of a Sound Level Meter, Light Meter, Humidity Meter, Temperature Meter, and CFM/CMM Thermo-Anemometer into a single, portable device. This instrument is ideal for a wide range of applications including noise measurement in various environments, luminance assessment, environmental analysis, fume hood testing, and HVAC system assessment.

2. Product Overview

The DT-859B combines five key environmental measurement capabilities:

• Sound Level Meter: For measuring noise levels in factories, schools, offices, and homes, and for checking acoustics.
• Light Meter: For measuring luminance, fully cosine corrected for angular incidence of light. Utilizes a stable, long-life silicon diode.
• Humidity/Temperature Meter: Uses a humidity/semiconductor sensor and K-type thermocouple for accurate readings.
• CFM/CMM Thermo-Anemometer: Measures air velocity and flow, suitable for plant maintenance, environmental analysis, and HVAC systems.

Figure 2.1: CEM DT-859B Main Unit with All Probes Connected

Figure 2.2: Close-up of DT-859B Display and Control Buttons

Package Contents:

Figure 2.3: Package Contents

The package typically includes:

• DT-859B Main Unit
• Sound Level Probe
• Light Probe
• Humidity/Temperature Probe
• Anemometer Vane Probe
• K-Type Thermocouple
• Carrying Case
• User Manual
• Software CD (for data logging, if applicable)

3. Specifications

4. Setup

4.1 Battery Installation

The DT-859B requires a 9V battery (or specified equivalent). To install or replace the battery:

1. Locate the battery compartment cover on the back of the unit.
2. Open the cover by sliding or unscrewing it.
3. Insert the 9V battery, observing the correct polarity (+/-).
4. Close the battery compartment cover securely.

4.2 Connecting Probes

The DT-859B uses various external probes for its multifunctionality. Connect the desired probe to the corresponding port on the main unit. Ensure connections are firm to prevent inaccurate readings.

• Sound Level Probe: Connect the microphone probe to the designated audio input jack.
• Light Probe: Plug the light sensor probe into its dedicated port.
• Humidity/Temperature Probe: Connect the combined humidity and temperature sensor.
• Anemometer Vane Probe: Connect the anemometer vane to its input port.
• K-Type Thermocouple: For external temperature measurements, connect the K-type thermocouple to the appropriate input terminals.

Figure 4.1: Connecting the Humidity/Temperature Probe and K-Type Thermocouple

Figure 4.2: Connecting the Anemometer Vane Probe

5. Operating Instructions

5.1 Power On/Off

Press the Power button (usually a yellow button with a power symbol) to turn the device on. Press and hold the same button to turn it off.

5.2 Function Selection

Use the MODE button to cycle through the different measurement functions: Sound, Light, Humidity/Temperature, and Anemometer. The selected function will be indicated on the display.

5.3 Taking Measurements

Once a function is selected, position the corresponding probe in the environment to be measured. Readings will be displayed on the LCD screen.

• Sound Level: Point the microphone towards the sound source.
• Light: Position the light sensor to face the light source.
• Humidity/Temperature: Place the probe in the area where humidity and temperature are to be measured. For K-type temperature, ensure the thermocouple tip is in contact with the object.
• Anemometer: Hold the vane probe in the airflow, ensuring the airflow passes through the vane freely.

5.4 Data Hold Function

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

5.5 MAX/MIN/AVG Readings

Press the MAX/MIN/AVG button to cycle through the maximum, minimum, and average readings recorded since the function was selected or reset. Press and hold to reset the recorded values.

5.6 Unit Selection

Use the UNIT or SETUP button (refer to the specific button labels on your device, often combined with arrow keys) to change measurement units (e.g., °C/°F for temperature, m/s/ft/min/km/h/MPH/Knots for anemometer, CFM/CMM for air flow).

5.7 Backlight

The device features a backlight for visibility in low-light conditions. Press the Light Bulb button to activate or deactivate the backlight.

6. Maintenance

6.1 Cleaning

• Wipe the meter and probes with a dry, soft cloth.
• Do not use abrasives or solvents.
• Keep the light sensor, microphone, and anemometer vane free from dust and debris.

6.2 Battery Replacement

Replace the battery when the low battery indicator appears on the display to ensure accurate readings and proper operation. Follow the instructions in Section 4.1.

6.3 Storage

When not in use for extended periods, remove the battery and store the meter and its probes in the provided carrying case in a cool, dry environment, away from direct sunlight and extreme temperatures.

6.4 Sensor Care

• Sound Level Microphone: Avoid dropping or exposing the microphone to moisture.
• Light Sensor: Keep the dome clean and free from scratches.
• Humidity/Temperature Probe: Protect the sensor from physical impact and corrosive substances.
• Anemometer Vane: Ensure the vane rotates freely. Avoid touching the blades and protect them from damage.

7. Troubleshooting

8. Warranty & Support

The CEM DT-859B is covered by a manufacturer's warranty against defects in materials and workmanship. For specific warranty terms, technical support, or service inquiries, please refer to the documentation included with your product or contact the seller/manufacturer directly. Keep your purchase receipt as proof of purchase.