METRIA M51 Benchtop Conductivity or TDS Meter Instruction Manual

METRIA M51 Benchtop Conductivity/TDS Meter

The METRIA M51 Benchtop Conductivity/TDS Meter is a device used for measuring the conductivity and total dissolved solids (TDS) of a liquid sample. The meter is equipped with an easy-read LCD display that shows the measured values and mode icons. It comes with standard components including the METRIA M51 Conductivity/TDS Meter, Electrode Arm, CON-1 Conductivity Electrode, TP-10K Temperature Probe, and a DC9V Power Adapter.

Introduction
Thank you for selecting the METRIA M51 becnhtop Conductivity/TDS meter. This manual provides a step-by-step guide to help you operate the meter, please carefully read the following instructions before use.

Unpacking

Before unpacking, ensure that the current work environment meets following conditions.

• The relative humidity is less than 80 %.
• Ambient temperature is greater than 0°C and less than 60°C.
• No potential electromagnetic interference.
• The following list describes the standard components of the meter. After the unpacking, please check all components are complete. If any are damaged or missing, please contact nearest distributor.

Display
The METRIA M51 Conductivity/TDS meter is equipped with an easy-read LCD display that used to show the measured values and mode icons. The following table describes the function of each icon. INDEX:

Keypad
The meter has a succinct membrane keypad, names and symbols describe the each function key controls.

Connectors

INDEX

Usage Instructions

1. Unpack the device and check all the components to ensure they are complete and undamaged. If any components are missing or damaged, contact the nearest distributor.
2. Install the electrode holder by inserting the connecting rod into the circular hole on the base plate of the electrode holder and swiveling the electrode arm 90 degrees. If the electrode arm automatically rises or falls, adjust the screws until it is at the desired position.
3. Connect the conductivity electrode to the left or right side of the electrode arm by inserting it and hooking up the cable. Insert the 6-pin connector into the connector socket labeled COND. Ensure that the connector is clean and dry.
4. Place the temperature probe into the circular hole of the electrode arm and insert the phone plug to the connector socket labeled ATC. Ensure that the connector is fully seated.
5. Before plugging in the power adapter, ensure that its voltage matches the local main voltage. Insert the connector to the power socket. The meter is now ready for use.
6. To measure conductivity or TDS, turn on the device and select measurement mode icon on the keypad. Dip the conductivity electrode into the liquid sample and wait for the reading to stabilize. The LCD display will show the measured value and mode icons.
7. To calibrate the device, select calibration mode icon on the keypad and follow the instructions in the user manual.
8. To change the settings of the device, select setup mode icon on the keypad and follow the instructions in the user manual.
9. To lock the measured value, select hold icon on the keypad.
10. After use, clean the conductivity electrode and temperature probe according to the instructions in the user manual.

Installing the Electrode Holder

Take out the electrode arm from the packaging. The base plate of the electrode holder has a circular hole, the electrode arm has a connecting rod. Insert the connecting rod into the circular hole and swivel the electrode arm 90o. Electrode holder is now ready to swing into desired position.

Adjustment of electrode arm
After installation, if the electrode arm automatically rises or falls, you need to adjust the screws until arm locate at any position.

1. Remove the plastic cover from the electrode arm.
2. Use the screwdriver to tighten the screw moderately.
3. Insert the plastic cover to previous position. Installation is completed.

Connecting the Electrode

1. Take out the conductivity electrode from the packaging. Follow the steps below to place the electrode into left or right side of the electrode arm.
2. Insert the 6-pin connector into the connector socket labeled COND. After the connection is completed, DO NOT pull on the cable. Always make sure that the connector is clean and dry.

Connecting the Temperature Probe

1. Place the temperature probe into the circular hole of the electrode arm.
2. Insert the phone plug to the connector socket labeled ATC. Ensure the connector is fully seated.

Connecting the Power Adapter

1. Before plugging in the power adapter, ensure that its voltage matches the local main voltage.
2. Insert the connector to the power socket. The meter is now ready for use.

Prior to Use
Soak the conductivity electrode for a few minutes in tap water to remove dirt and oil stains on the electrode.

Switching the Meter On and Off

• Press the Meas key to switch on the meter, the display shows the measured values.
• Press and hold the Meas key for 5 seconds, the meter will switch off.
• To enable the Auto-Power Off feature, please refer to chapter SETUP MENU.

Setup Menu

The METRIA M51 Conductivity/TDS meter contains an integrated setup menu that is used to customize the displayed option to meet measurement requirements. The following table describes the functions of the menu items.

MENU| DESCRIPTION| OPTIONS| DESCRIPTION| DEFAULT|
---|---|---|---|---|---

|

Set the cell constant to match connected electrode.

|

| K=0.1|

K=1

|
| K=1|
| K=10|
| User-Defined|

|

Set the number of calibration points.

| | 1 point|

1 point

|
| 2 points|
| 3 points|
| Set the linear temperature compensation coefficient.| | Range: 0.0~10.0%/°C| 2.1/°C|
| Set the TDS conversion factor.| | Range: 0.1~1.0| 0.5|
|

Set the default temperature unit.

| | Degrees Celsius|

°C

|
| Degrees Fahrenheit|
| When  the  option  is  enabled,  the  meter  will| | Enable| |
automatically| Disable|
| Disable|
sense a stable reading and lock the measurements.| |
| When  the  option  is  enabled,  the  meter  will| | Enable| |
automatically| Disable|
| Disable|
switch off if no key is pressed within 3 hours.| |

| When the option is enabled, all of the calibration data and| |

Enable

| |
selected parameters will back to factory default| | Disable|
| |
settings,| Disable| |
the meter must be recalibrated.| | |

Setting a default option

1. In the measurement mode, press and hold the key for 3 seconds to enter the setup menu.
2. Press the UP or DOWN key select the desired option.
3. Press the Enter key to confirm and move to the next menu item.
4. Repeat the steps above until the meter returns to the measurement mode. Setting is completed.

• If the USER is selected, the user only need to input a constant value labeled on the electrode for calibration. The meter will use this value as a slope parameter to calculate the measurement results. For more information, please refer to chapter MANUAL CALIBRATION. Note, once the “USER” is enabled, the Cal key will invalid.
• If you want to exit the setting, press the Meas key.

Temperature Compensation
For better accuracy, we recommend the use of either a sensor with a built-in or a separate temperature probe for the calibration or measurements.
Automatic Temperature Compensation
Connect the temperature probe to the meter (Refer to page 5 “Connecting the Temperature Probe”). The ATC icon immediately appears on the display, the meter is now switched to the automatic temperature compensation mode.

Manual Temperature Compensation
If the meter does not detect a temperature probe, the °C icon will show on the display indicating that the meter is switched to the manual temperature compensation mode. To set the temperature value of sample, follow the steps below.

1. Press the oC key to enter the temperature setting mode.
2. Press the UP or DOWN key to modify the temperature value.
3. Press the Enter key to confirm.

Press the or UP or DOWN key once, the setting value will increase or decrease by 0.1. Press and hold the UP or DOWN key, the setting value will increase or decrease by 1.

Selecting the Conductivity Electrode
The METRIA M51 C onductivity /TDS meter is capable of using the 3 types of conductivity electrodes. Prior to the calibration and measurement, you need to select the different sensors as per your sample concentration. The table below shows available elect rode and its effective measuring ranges.

Automatic Calibration
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 chapter SETUP MENU The meter allows 1 to 3 points calibration in the automatic calibration mode. To ensure higher accuracy, we recommend that you 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 the acceptable conductivity range of standard solution for each measuring range.

Single point calibration

1. Make sure that you have selected 1 point calibration in the setup menu.
2. Rinse the conductivity electrode with distilled water, then rinse with a small amount of standard solution.
3. Press the Cal key, the display shows “CAL1” and waits for recognizing the standard solution.
4. Place the electrode into the conductivity standard solution, the meter automatically shows current calibration standard (e.g., 1413μS/cm).
5. Press the Enter key, the default calibration value begins flashing
6. Press the ◄ or ► key to set the calibration value, press the Enter key to confirm and move to next digit. When the setting is completed, ensure that displayed value matches your calibration standard.
7. Press the Enter key, the meter begins the calibration, the Calibration icon will continuously flashing. Wait for the reading to stabilize, the display will show END. Single point calibration is completed.

Multi-point calibration

1. Ensure that you have selected 2 or 3 points calibration in the setup menu.
2. Repeat steps 1.2 to 1.7 above, when the first calibration point is completed, the display will show “CAL2”. The meter prompts you to continue with second point calibration.
3. Rinse and place the electrode into the standard solution, the display automatically shows current calibration standard (e.g.,12.88mS/cm).
4. Press the Enter key, the default calibration value begins flashing.
5. Press the ◄ or ► key to set the calibration value, press the Enter key to confirm and move to next digit. When the setting is completed, press the Enter key, the meter begins the calibration, the Calibration icon will continuously flashing.
6. Wait for the reading to stabilize, the display will show “CAL3”. The meter prompts you to continue with third point calibration.
7. Repeat the steps 2.3 and 2.5 above until the meter returns to the measurement mode. Calibration is completed.

Manual Calibration
The meter provides an easy manual calibration mode. If the conductivity standard solution is not ready, you are able to use this method for calibration.

1. Record the cell constant value on the conductivity electrode (e.g., K=1.01).
2. Press and hold the key for 3 seconds to enter the setup menu.
3. Press the Enter key, the display shows “CELL/1”.
4. Press the ◄ or ► key until the display shows “CELL/USER” (User-defined) option.
5. Press the Enter key, the default value begin flashing.
6. Press the ◄ or ► key to set each digit according to previous record.
7. Press the Enter key to confirm until the setting values stop flashing.
8. Press the Meas key to return to the measurement mode. Calibration is completed.

Exit the calibration
During the calibration process, press the Meas key, the meter will exit the calibration and return to the measurement mode.

Temperature Calibration
During the measurement process, if the temperature reading displayed differs from that of an accurate thermometer, the meter needs to be calibrated.

1. Connect the temperature probe to the meter and place into a solution with a known accurate temperature.
2. Press the oC key to enter the temperature setting mode.
3. Press the UP or DOWN key to set the temperature value.
4. Press the Enter key, the meter returns to the measurement mode. Calibrating is completed.

Switching the Measurement Mode

1. In the conductivity measurement mode, press the Mode key until the display shows “TDS”. The meter is now enters to the TDS measurement mode.
2. Press the Mode key again, the meter returns to the conductivity measurement mode.

Conductivity and TDS Measurements

1. Rinse the conductivity electrode thoroughly with distilled water.
2. Place the electrode into the sample solution, stir the electrode gently.
3. Record the measured value when the reading is stable.

Auto-Hold
The METRIA M51 Conductivity/TDS meter contains an Auto-Hold function. If enabled, the meter will automatically sense a stable reading and lock the measurements, the HOLD icon appears on the display. If disabled, press the key, the meter will immediately lock the displayed value. Press the Meas key to resume measuring.

Electrode Care and Maintenance

• DO NOT touch the measurement area of electrode and always make sure that is clean.
• If there is a build-up of solids inside the measurement area, 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. After the solids are removed, the electrode must be recalibrated.

Troubleshooting

| Electrode dried out| Soak the conductivity electrode in tap water for 10 minutes.
Measured value is out of range| Check the electrode whether dirty or broken.

| Electrode does not suit the current sample| Replace the conductivity electrode.
Setting value does not match calibration

solution

|

Reset the calibration value or check the calibration solution.

Electrode is broken| Replace the conductivity electrode.

Specifications

Conductivity

| Model| METRIA M51
---|---|---
Range| 0.01~20.00, 200.0, 2000µS/cm, 20.00, 200.0mS/cm
Accuracy| ±1% F.S
Resolution| 0.001, 0.01, 0.1, 1
Calibration Points| 1 to 3 points
Calibration Solutions| 10µS/cm, 84µS/cm,1413µS/cm,12.88mS/cm,111.8mS/cm

TDS

| Range| 0~10.00, 100.0, 1000ppm, 10.00, 100ppt (Max. 200ppt)
Accuracy| ±1% F.S
Resolution| 0.01, 0.1, 1
TDS Factor| 0.1~1.0 (Default 0.5)

Temperature

| Range| 0~105°C, 32~221°F
Accuracy| ±1°C
Resolution| 0.1°C
Calibration Points| 1 point

General

| Temperature Compensation| 0~100°C, 32~212°F, Manual or Automatic
Temperature Coefficient| 0.0~10.0%/°C
Cell Constant| K=0.1, 1, 10
Normalization Temperature| 25°C
Connector| 6-pin
Display| LCD (135 × 75mm)
Power Requirements| DC9V, using AC adapters, 220VAC/50Hz
Dimensions| 210 (L) × 205 (W) × 75 (H)mm
Weight| 1.5kg

Addendum 1: Preparation of Conductivity Standard Solutions
Place AR potassium chloride reagent in a 50ml beaker and dry in an oven for 3 to 5 hours at 105°C, then cool to room temperature in desiccator.

water.
1413µS/cm| Accurately weigh out 745.9mg of KCL and dissolve in 1 litre deionised water.
12.88mS/cm| Accurately weigh out 7.45g of KCL and dissolve in 1 litre deionised water.
111.8mS/cm| Accurately weigh out 74.5g of KCL and dissolve in 1 litre deionised water.

Stir the solution until the reagent has thoroughly mixed. Preparation is completed.

Addendum 2: How to calculate the temperature coefficient
To determine the temperature coefficient of sample solution use the formula below:

Where:
TC Temperature coefficient
CTA Conductivity at Temperature A
CTB Conductivity at Temperature B
TA Temperature A
TB Temperature B

1. Press and hold the o C key for 3 seconds to enter the temperature setting.
2. Press the UP or DOWN key to set the temperature to 25 C.
3. Place the electrode into the sample solution A and record the temperature value T A and conductivity value C TA
4. Condition the sample solution and electrode to a temperature that is about 5 C to 10 C different from T A . Record the temperature value T B and conductivity value C TB
5. Calculate the temperature coefficient according to the formula above.

Addendum 3: How to calculate the TDS conversion factor
To determine the TDS conversion factor use the formula below:

Where:
Actual TDS: value from the high-purity water and precisely weighed NaCl or KCL reagent.
Actual Conductivity : the meter measured the conductivity value.
For example: dissolve 64g of potassium chloride reagent in 1 liter of distilled water. If its conductivity value is 100mS/cm, then TDS conversion factor is 0.64.

Hazardous Substance Statement

METRIA Instruments is committed to the reduction and eventual elimination of all hazardous substances in both the manufacturing process and finished products we supply. We have an active manufacturing and procurement program to minimize and eliminate the use of harmful heavy metals such as cadmium, lead, mercury and the like. New technologies and design parameters are also promoting these efforts and we expect to have little or no such materials in our product in the coming years. We welcome our customer suggestions on how to speed up these efforts.

Warranty

The warranty period for meter is one year from the date of shipment. Above warranty does not cover the sensor and calibration solutions. Out-of-warranty products will be repaired on a charged basis. The warranty on your meter shall not apply to defects resulting from:

• Improper or inadequate maintenance by customers.
• Unauthorized modification or misuse.
• Operation outside of the environmental specifications of the products.
• For more information, please contact the nearest authorized distributor.

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