GAOTek Conductivity Meter with Economy Portability (Data Storage) is designed using 3 point calibration mode and can be used in outdoor applications of accuracy 0.5 % F.S. It provides the expanded memory storage and recalls up to 50 readings. Users can transfer the stored data into their computer by USB communication interface. This economy portable conductivity meter functions continuously with multimode power scheme such as power adapter, battery and USB port. It is equipped with a clear LCD display used to display help message, measured values and mode indicators.
- Selectable temperature unit (°C or °F) meets different application requirements.
- Selectable cell constant (0.1/1/10) and temperature coefficient.
- Automatic Temperature Compensation provides accurate reading over the entire range.
- Help message as an operational guide that helps you quickly begin using the meter.
- Expanded memory stores and recalls up to 50 readings.
- Reset feature automatically resumes all parameters back to factory default settings.
- System menu allows setting the 7 parameters, including the number of calibration points, temperature unit, hold function, etc.
- Multimode power scheme (computer’s USB port, power adapter, battery).
- Economy portable conductivity meter is equipped with a large backlit LCD display.
- 1 to 3 points push-button calibration with automatic calibration solution recognition.
- Auto-Hold function freezes stable measured value for easy viewing and recording.
- Stored data can be transferred into computer by USB communication interface.
|Range||0 µS/cm~20.00 µS/cm, 200.0 µS/cm, 2000 µS/cm, 20.00 mS/cm, 200.0 mS/cm|
|Resolution||0.01, 0.1, 1|
|Accuracy||± 0.5 % F.S|
|Calibration Solutions||10 µS/cm, 84 µS/cm, 1413 µS/cm, 12.88 mS/cm, 111.8 mS/cm|
|Calibration Points||1 to 3 points|
|Range||32 °F ~ 221 °F (0 °C ~ 105 °C)|
|Resolution||32.18 °F (0.1 °C)|
|Accuracy||±0.9 °F, ±0.5 °C|
|Calibration Range||Measured value ±50 °F (±10 °C)|
|Calibration Points||1 point|
|Cell Constant||K=0.1, 1, 10 or User-Defined|
|Hold Function||Manual or Automatic|
|Temperature Coefficient||0.0 ~ 10.0 % / °C|
|Temperature Compensation||32 °F ~ 212 °F (0 °C ~ 100 °C), Manual or Automatic|
|Power Requirements||3×1.5 V AA Batteries|
|Normalization Temperature||77 °F (25 °C)|
|Power Off||Manual or Automatic (10 minutes after last key pressed)|
|Connector||6-pin Mini Plug|
|Memory||Stores up to 50 data sets|
|Output||USB Communication Interface|
|Battery Life||Approximately 150 hours (Turn off the backlit)|
|Dimension||6.69 in×3.34 in×1.18 in (170 mm×85 mm×30 mm)|
|Weight||0.66 lbs (300 g)|
- Conductivity Electrode
- Temperature Probe
- Conductivity Calibration Solutions (84 µS/cm, 1413 µS/cm, 12.88 mS/cm)
- AA Batteries
The conductivity meter is equipped with a clear and bright LCD display that is used to show measured value, mode indicator and message indicator. The following table describes the meaning of each indicator.
The meter has a succinct membrane keypad, names and symbols describe the each function key controls.
The device has 2 connectors for connecting the conductivity electrode and temperature probe. Listed in the below table are the details of these connectors.
|1||6-pin Connector||For connecting the conductivity electrode|
|2||Phone Jack||For connecting the temperature probe|
Inserting the Batteries
Before using the meter, insert three 1.5 V “AA” alkaline batteries into battery compartment, follow the procedure outlined below.
- Remove the battery cover from meter’s backside.
- Insert the batteries into the battery compartment, note polarity.
- Replace the battery cover into its original position. Installation is completed.
Connecting the Conductivity Electrode
Take out the conductivity electrode from the carrying case. Insert the 6-pin connector into corresponding connector socket. Ensure the connector is fully seated. After connection is completed, do not pull on the sensor cord. Always make sure that the connector is clean and dry.
Prior to Use
Soak the conductivity electrode for a few minutes in tap water to remove dirt and oil stains on the electrode.
- Press and hold the MEAS key for 3 seconds to turn on the meter, the display shows measured values, mode indicators and help messages.
- Press and hold the MEAS key for 3 seconds again, the meter will turn off.
- If you do not press any key for 10 minutes, the meter will turn off automatically.
The portable conductivity meter contains an integrated setup menu that allows you to customize each displayed option to meet measurement requirements.
Setting the Default Parameters
- Press and hold the key for 3 seconds to enter setup menu, the meter shows selected cell constant.
- Press orkey, the display successively shows 0.1, 1, 10 and USER.
- The “USER” option resembles the manual calibration function. User only need to input a constant value labeled on the sensor, the meter will use this value as a slope parameter to calculate measurement result. For more information, please refer to “Manual Calibration” section.
- Once the “USER” option is enabled, the CAL key will be invalid.
- Select the cell constant according to your sensor type, press ENTER key to confirm. The meter goes to calibration point selection mode, the display shows “CAL 1”.
- Press▲or▼key to select the number of calibration points, press ENTER key to confirm. The meter goes to temperature coefficient setting mode, the display shows “COE 2.1%”.
- Press▲or▼key to set temperature coefficient, press ENTER key to confirm. The meter goes to temperature unit selection mode.
- Press ▲or▼key to select the temperature unit (°C or °F), press ENTER key to confirm. The meter shows “HOLD/NO” indicating that the auto-hold function is disabled.
If the auto-hold function is enabled, the meter will automatically sense a stable endpoint reading and freeze it. If you disable this function, the meter allows user to freeze the reading by pressing the HOLD key.
- Press ▲or▼key to enable or disable the auto-hold function, press ENTER key to confirm. The meter shows “OFF/NO” indicating that the auto-off function is disabled.
- Press▲or▼key to enable or disable the auto-off function, press ENTER key to confirm. The meter shows “CLR/NO” indicating that do not clear all stored measured values.
- Press ▲or▼key to enable or disable the clear function, press ENTER key to confirm. The meter shows “RST/NO” indicating that do not reset meter.
- Press ▲or▼key to enable or disable the reset function, press ENTER key to confirm. The meter returns to measurement mode. Setting is completed.
EXIT THE SETUP MENU:
During the setup mode, press MEAS key, the meter will return to measurement mode immediately.
In order to get accurate measuring results, you need to enable the manual or automatic temperature compensation before measurement or calibration.
AUTOMATIC TEMPERATURE COMPENSATION:
Insert the connector of temperature probe into the meter’s phone jack.
The “ATC” indicator will show on the display, the meter is now switched to automatic temperature compensation mode.
MANUAL TEMPERATURE COMPENSATION:
- Do not connect the temperature probe to meter.
- Press the °C key to enter temperature setting mode.
- Press▲or▼key to set the temperature value of sample.
- Press ENTER key to confirm, the meter returns to measurement mode. Setting is completed.
Selecting the Conductivity Electrode
The device is capable of using the three types of conductivity electrode. Before calibration or measurement, you need to choose different sensors as per your sample concentration. The table below shows available sensor and its effective measuring ranges.
|SENSOR||MEASURING RANGES||CELL CONSTANT|
|CON-0.1||0.1 µS/cm~100 µS/cm||K=0.1|
|CON-1||0.01 mS/cm~10 mS/cm||K=1|
|CON-10||0.1 mS/cm~200 mS/cm||K=10|
Make sure that you selected the cell constant between 0.1, 1 or 10 in the setup menu. If the current option is “USER”, the automatic calibration function will be disabled (Refer to Setup Menu section).
In the automatic calibration mode, the meter allows up to 3 points calibration. To ensure higher accuracy, perform 3 points calibration or select a standard value close to the sample value you are measuring. The meter will automatically detect these conductivity standard solutions and prompt the user to calibrate the meter. When the calibration is completed, all new calibration values will automatically override existing data. The following table shows acceptable conductivity range of calibration solution for each measuring range.
|MEASURING RANGE||CALIBRATION SOLUTION RANGE||DEFAULT|
|0 µS/cm~20 µS/cm||7 µS/cm~17 µS/cm||10 µS/cm|
|20 µS/cm~200 µS/cm||70 µS/cm~170 µS/cm||84 µS/cm|
|200 µS/cm~2000 µS/cm||700 µS/cm~1700 µS/cm||1413 µS/cm|
|2 mS/cm~20 mS/cm||7 mS/cm~17 mS/cm||12.88 mS/cm|
|20 mS/cm~200 mS/cm||70 mS/cm~170 mS/cm||111.8 mS/cm|
SINGLE POINT CALIBRATION:
1.1 Rinse the conductivity electrode with distilled water, then rinse with a small amount of calibration solution.
1.2 Press CAL key, the meter enters the calibration mode.
1.3 Dip the electrode into the conductivity calibration solution, the display automatically shows current calibration standard (e.g., 1413 µS/cm).
1.4 Press ENTER key to confirm, the default calibration value begins flashing.
1.5 Press orkey to set each digit, press ENTER key to confirm. When the setting is completed, ensure that displayed value matches your calibration standard.
1.6 Press ENTER key to begin the calibration. Wait for the reading to stabilize, the display will show “END”. Single point calibration is completed.
2.1 Make sure that you have selected 2 or 3 points calibration in setup menu.
2.2 Repeat steps 1.1 to 1.6 above, when the first calibration point is completed, the display will show “CAL2”. The meter prompts you to continue with second point calibration.
2.3 Rinse the conductivity electrode with distilled water. Dip the electrode into the next calibration solution, the display automatically shows current calibration standard (e.g., 12.88 mS/cm).
2.4 Press ENTER key to confirm, the default calibration value begins flashing.
2.5 Press ▲or▼key to set each digit, press ENTER key to confirm. Wait for the reading to stabilize, the display will show “CAL3”. The meter prompts you to continue with third point calibration.
2.6 Repeat steps 2.3 to 2.5 above until the display shows “END”. The meter returns to measurement mode. Calibration is completed.
The conductivity meter provides a quick manual calibration mode that allows user to easily calibrate the meter.
- Record the cell constant value on the electrode (e.g., K=1.08).
- Press and hold the key for 3 seconds to enter setup menu.
- Press ENTER key to confirm, the display shows “1/CELL”.
- Press▲or▼key until the display shows “USER” (User-defined) option.
- Press ENTER key to confirm, the default value begins flashing.
- Press▲or▼key to set each digit according to previous record, press ENTER key to confirm until the setting values stop flashing.
- Press MEAS key to return to measurement mode. Setting is completed.
During the measurement mode, when automatic temperature compensation is enabled, if the temperature reading displayed differs from that of an accurate thermometer, you need to calibrate the meter.
- Make sure the connector of temperature probe is connected to the meter.
- Press °C key to enter the temperature calibration mode, the display shows current temperature reading.
- Press▲or▼key to set the temperature value.
- Press ENTER key to confirm. Calibration is completed.
EXIT THE CALIBRATION:
During the calibration process, press MEAS key, the meter will return to measurement mode.
- Rinse the conductivity electrode thoroughly with distilled water.
- Dip the electrode into the sample solution, stir the sensor gently.
- Wait for the reading to stabilize, record the measured value on the display.
The device contains two data hold modes. When the Auto-Hold function is enabled, the meter will automatically sense a stable endpoint reading and freeze it, “HOLD” indicator appears on the display. If the Auto-Hold function is disabled, press key, the meter will immediately freeze currently displayed value. Press the key again to resume measuring.
Storing and Recalling Data
The meter allows up to 50 data sets to be stored and recalled.
- In the measurement mode, press MI key to input measured value into the memory. “Memory” indicator appears on the display.
- If the meter memory is full, the display will show indicator “FULL”. To clear all stored data, please refer to “Setup Menu” section.
- Press MR key in the measurement mode, the meter alternately shows ID, temperature and measured value.
- Press▼key, the meter shows next data set.
- After the browsing, press MEAS key to exit the current mode.
Electrode Care and Maintenance
- Ensure that the conductivity electrode is thoroughly washed with distilled water after each use.
- If there is a build-up of solids inside the measurement area of the cell, these should be removed very carefully with a cotton bud soaked in solvent, taking care not to touch the metal parts of the inner cell.
How to prepare the conductivity standard solutions
Place AR potassium chloride reagent in a 50 mL beaker and dry in an oven for 3 to 5 hours at 221 °F (105 °C), then cool to room temperature in desiccator.
|84 µS/cm||Accurately weigh out 42.35 mg of KCL and dissolve in 1000 mL de-ionised water|
|1413 µS/cm||Accurately weigh out 745.9 mg of KCL and dissolve in 1000 mL de-ionised water|
|12.88 mS/cm||Accurately weigh out 7.45 g of KCL and dissolve in 1000 mL de-ionised water|
|111.8 mS/cm||Accurately weigh out 74.5 g of KC, and dissolve in 1000 mL de-ionised water|
Stir the solution until the reagent has thoroughly mixed. Preparation is completed.
How to calculate the temperature coefficient
To determine the temperature coefficient of sample solution use this formula:
- Press and hold the °C key for 3 seconds to enter temperature setting mode.
- Press ▲or▼key to set the temperature at 77 °F (25 °C).
- Dip the electrode into sample solution A.
- Record the temperature value TA and conductivity value CTA.
- Repeat the steps above, dip the electrode into same sample solution B. Make sure both sample solutions have about 41 °F (5 °C) to 50 °F (10 °C)
- Record the temperature value TB and conductivity value CTB.
- Calculate the temperature coefficient of sample solution according to the formula shown above.
- Enter the calculated temperature coefficient into the meter.