Extech SDL150 Dissolved Oxygen Meter SD Logger User Manual

1. Introduction

The Extech SDL150 is a Dissolved Oxygen Meter with an integrated SD card data logger. This device is designed for precise measurement of dissolved oxygen (DO) concentration and temperature in various applications. It records data directly onto an SD card in Excel format for easy transfer and analysis on a personal computer.

Key features include a dual backlit display, automatic temperature compensation, offset adjustment for relative measurements, and user-programmable sampling rates.

Figure 1: Extech SDL150 Dissolved Oxygen Meter and Probe. This image shows the main unit with its digital display and control buttons, connected to the dissolved oxygen probe.

2. Package Contents and Setup

2.1. Package Contents

Verify that all items are present and in good condition upon unpacking. The standard package includes:

• Extech SDL150 Dissolved Oxygen Meter
• Dissolved Oxygen Probe with built-in temperature sensor
• 6 x AA batteries
• SD card (2G capacity)
• Two spare replacement membranes for the DO probe
• Electrolyte solution for the DO probe
• Hard carrying case

2.2. Initial Setup

1. Battery Installation: Open the battery compartment on the back of the meter and insert the 6 AA batteries, observing correct polarity.
2. SD Card Insertion: Locate the SD card slot, typically on the side of the meter. Insert the provided 2G SD card until it clicks into place.
3. Probe Preparation:
   • Unscrew the protective cap from the dissolved oxygen probe.
   • Fill the probe's membrane cap with the supplied electrolyte solution. Ensure no air bubbles are trapped.
   • Carefully screw the membrane cap back onto the probe, ensuring the membrane is intact and free of damage.
4. Probe Connection: Connect the prepared DO probe to the designated input port on the top of the SDL150 meter.
5. Power On: Press the POWER button to turn on the device.

3. Operating Instructions

3.1. Basic Measurement

1. Calibration: Before first use and periodically thereafter, calibrate the dissolved oxygen probe according to the instructions in the full user manual (not provided here). This typically involves air calibration or zero-oxygen solution calibration.
2. Immersion: Immerse the DO probe into the sample solution. Ensure the membrane is fully submerged and free from air bubbles.
3. Reading Display: The dual backlit display will show the dissolved oxygen concentration (in mg/L or %) and the temperature (in °F or °C).
4. Units Selection: Use the FUNCTION button to cycle through different measurement units (mg/L, %, °F, °C) if applicable.

Figure 2: Extech SDL150 in a laboratory environment. The meter is shown measuring dissolved oxygen in a beaker, demonstrating its application.

3.2. Data Logging

• Manual Logging: Press the LOG button to manually store the current reading. The meter can store up to 99 manual readings.
• Automatic Logging:
  • Access the settings menu (refer to the full manual for specific button combinations) to set the desired sampling rate.
  • Once the sampling rate is set, activate automatic logging. The meter will record up to 20 million readings on the 2G SD card.
  • Data is stored in Excel-compatible format for easy transfer to a PC via the SD card.

3.3. Additional Functions

• Data Hold: Press the HOLD button to freeze the current display reading. Press again to release.
• Min/Max: Use the MIN/MAX button to view the minimum and maximum recorded values during a measurement session.
• Backlight: The display features a backlight for improved visibility in low-light conditions. Activate it using the dedicated backlight button (often indicated by a light bulb icon).
• Auto Power Off: The meter includes an auto power-off function to conserve battery life. This feature can typically be disabled or adjusted in the settings.
• Offset Adjustment: The offset adjustment function allows for zeroing the meter for relative measurements. Consult the full manual for detailed instructions on using this feature.

4. Maintenance

4.1. Probe Membrane and Electrolyte Replacement

The dissolved oxygen probe requires periodic maintenance, specifically the replacement of the membrane and electrolyte solution. This ensures accurate readings and extends the life of the probe.

1. Unscrew the membrane cap from the probe body.
2. Carefully remove the old membrane and discard it.
3. Rinse the probe tip and the inside of the new membrane cap with distilled water.
4. Fill the new membrane cap with fresh electrolyte solution, ensuring no air bubbles are present.
5. Gently screw the new membrane cap onto the probe body. Avoid overtightening.
6. Allow the probe to stabilize for a few minutes before use and perform a calibration.

4.2. Cleaning and Storage

• Meter Cleaning: Wipe the meter's exterior with a soft, damp cloth. Do not use abrasive cleaners or solvents.
• Probe Cleaning: After each use, rinse the probe tip with distilled water. Store the probe with its protective cap on, ideally with a small amount of electrolyte solution to keep the membrane moist, as specified in the full manual.
• Long-Term Storage: For extended storage, remove the batteries from the meter and ensure the probe is properly prepared as per the full manual's instructions. Store the unit and accessories in the hard carrying case in a cool, dry place.

5. Troubleshooting

This section provides general guidance for common issues. For detailed troubleshooting steps, refer to the comprehensive user manual provided with your Extech SDL150.

• No Power: Check battery installation and ensure batteries are not depleted. Replace if necessary.
• Inaccurate Readings:
  • Perform a calibration.
  • Check the probe membrane for damage or air bubbles. Replace the membrane and electrolyte if needed.
  • Ensure the probe is properly connected to the meter.
• SD Card Not Recording:
  • Verify the SD card is correctly inserted.
  • Check if the SD card is full. Transfer data to a PC and clear the card if necessary.
  • Ensure the logging function is activated and the sampling rate is set.

6. Specifications

7. Warranty and Support

For information regarding warranty coverage, technical support, or service, please contact Extech customer service. Refer to the official Extech website or the documentation included with your product for current contact details and warranty terms.

Manufacturer: Extech