DDS-22C laboratory high-precision desktop conductivity detector

Preface

Thank you for purchasing the product developed and produced by our companyDDS-22C desktop microcomputerType conductivity meter.

This instrument is mainly used to measure the conductivity of various liquids. When paired with an electrode with a specification constant of 0.1, the conductivity of pure water or high-purity water can be measured. It can be widely used in light industry, chemical industry, food, medicine, health, energy, environmental protection, as well as education and research departments.

The instrument is controlled by a microcomputer and has high accuracy; Good stability; High reliability; Easy to operate; Easy to maintain.

This user manual will provide complete guidance on installation and useDDS-22C desktop microcomputerType conductivity meter. At the same time, the maintenance, upkeep, and related precautions of the instrument were also introduced. Please read this User Manual carefully so that you can better use our company's products and improve your work efficiency.

Instrument registration:

Before using this instrument, please take a few minutes to fill out the user registration card attached to this<<user manual>and mail or email it to our company, so that our after-sales engineers can provide you with technical support and other after-sales services more effectively.

Technical Services:

During the warranty period of the instrument, if there are any quality issues, please contact the distributor or our sales department in a timely manner. We will solve it seriously and quickly for you.

If you encounter any problems while using this instrument, please refer to this "User Manual". If it cannot be resolved, please feel free to consult our after-sales service department at any time. We will be enthusiastic and provide timely service for you.

1Technical performance

1. Working conditions

lEnvironmental temperature: 5-35 ℃ Relative humidity:<85%

lPower supply: 220V ± 10% 50Hz ± 1Hz

lNo significant vibration

lThere is no strong magnetic field interference other than the geomagnetic field.

2. Main technical indicators

lMeasurement range: Conductivity:(0～199.9)μs/cm ；(200～1999)μs/cm ；

(2.00～19.99)ms/cm ；(20.0～199.9)ms/cm ；

lResolution: 0.1/1 μ s/cm; 0.01/0.1ms/cm ；

lAccuracy:Electrometer: ± 1.0% FS; Supporting: ± 1.5% FS

lTemperature compensation range: 0-50 ℃ (manual temperature compensation)

lTemperature coefficient: 2.0%/℃

lOptional electrode specification constants: 0.1, 1, 10

lData storage: 50 sets

lStorage contents: number, measurement value, measurement unit, and temperature value

lPower supply: DC9V adapter

lDimensions and weight: 220 × 200 × 80mm (length × width × height) 0.7 kg

2、 Instrument working principle

In an electrolyte solution, charged ions move and transfer current under the action of an electric field. Its conductivity is represented by the electrical conductivity G, which is the reciprocal of the resistance. That is, G=1/R

The method for testing conductivity can be to insert an electrode composed of two metal plates into a solution to form a conductivity cell and measure the resistance between the two plates. According to Ohm's Law, the resistance value is proportional to the distance L (cm) between the plates and the area A (cm) of the plates²）Inversely proportional. That is, R=ρ· L/A

If ρ is the resistivity and its reciprocal is the conductivity, expressed in K, then K=1/ρ

For a certain electrode, the ratio of the effective distance L between the electrode plates to the area A of the plates is called the electrode constant of this electrode, represented by J, that is, J=L/A

According to the above formulas, we can obtain:

G=K/J means K=G · J

The unit of conductivity G is Siemens, and the unit symbol is S.

1S＝10³ms＝10⁶μS

The commonly used units for conductivity K are mS/cm and μ S/cm.

The method of testing conductivity with this instrument is to apply an AC voltage generated by an oscillator to the electrode (the purpose of applying AC voltage is to avoid polarization of the electrode), generate a current in the conductivity cell, which is proportional to the conductivity of the measured solution. After current voltage conversion, amplification, detection, conversion to DC voltage, temperature compensation, etc., it is finally converted into a digital signal by an A/D converter and displayed on a microcomputer. The entire process is controlled and processed by a microcomputer.

3、 Basic Instrument Description

1. Instructions for instrument operation buttons

The instrument has a total of 6 operation keys

1Switch "- the power button is used to turn on and off the power supply.

2Calibration "- calibration button. When in measurement mode, press the button to enter the instrument calibration mode.

3Function "- Function keys, enter parameter setting modes P1, P2, P3

4∧, ∨ "- increase and decrease keys.

a、 In the measurement state, when manually compensating for temperature, press the button to increase or decrease the temperature value. Short press once to change 0.1 ℃, and long press to quickly change the temperature.

b、 When in parameter setting state, press the key to change the number or ON/OFF state.

5Storage/Extraction "- The storage and extraction buttons are used for storing and extracting measured values.

6Confirm "- Confirm button, when in calibration or parameter setting state, pressing the button indicates confirmation, and the instrument enters measurement mode after pressing the button.

2. Storage, extraction, and clearing of measurement information

storageDuring the testing process, if a measurement value needs to be stored, simply press the "Save/Extract" button. At this time, the "STORE" character and storage number (1, 2, 3, 4-25) will appear on the display screen, indicating that the measurement value has been stored under this number and will immediately return to normal display mode. This instrument can store 25 measurement values. If more than 25 are stored, the first stored measurement value will be replaced sequentially.

extractPress and hold the "Save/Extract" button for a few seconds, and release it when the "RECALL" character and storage number appear on the display screen. The measurement value will then be displayed on the screen, showing the last stored number and measurement. Press the * key again to display the storage number and measurement value in sequence. Short press the confirm button to exit and extract the program, the RECALL character disappears, and the instrument returns to normal display mode

clean upIn the "RECALL" state, press and hold the confirm button for 5 seconds to clear all stored data.

4Conventional use of conductivity meter

Select the appropriate electrode according to the measured solution, insert the electrode plug into the socket, align the groove of the plug with the convex groove of the socket, press the top of the plug, and hear a "click" sound. (Plug out: Pinch the plug and pull it out). Insert the power adapter into a 220V AC power supply, plug the output head into the DC9V socket of the instrument, press the "power on" button, turn on the power, and preheat for 10 minutes.

1. Accurate conductivity

Press the 'Calibration' button, 'CAL' will flash, indicating the entry into calibration mode, and switch to 1408μs/cmInsert the standard calibration head into the electrode holder at the back of the instrument, wait for the measurement value to stabilize, then press the "Calibration" button, and the LCD display will flash "1408μs/cm”After a few seconds, the "End" symbol will be displayed and the measurement mode will return. Calibration can be repeated until the measurement value is stable and accurate.

Attention: The instrument has been calibrated before leaving the factory and can generally be used directly.

2. Conductivity measurement

Wash and spin dry the conductive electrode, place it in the solution, stir and let it stand still. Wait for the measured value to stabilize, which is the conductivity value of the solution.

3. Important note

There are two calibration solution series stored in this instrument. Please set them in parameter settings P1;

USA (European and American series) -84μs/cm ；1413μs/cm ；12.88ms/cm ；111.9ms/cm

CH (China Series) -146.6 US/CM; one thousand four hundred and eightμs/cm ；12.85ms/cm ；111.3ms/cm

This instrument has a unique calibration function, which can select a calibration solution for calibration based on the principle of the conductivity of the water sample and the calibration solution being as close as possible. The commonly used calibration solution is 1408μs/cmUse the conductivity electrode (K=25px) provided with this instrument^-1）Using 1408μs/cmCalibration solution can be used for calibration, with a range of less than 100ms/cmUsed within the measurement range. Please refer to Table (1-1) for selection.

Table (1-1)

The calibration methods for conductivity electrodes in instrument settings include standard solution calibration method and standard calibration seat1408μs/cmThere are three methods: constant setting method and standard solution calibration method. As long as the standard solution is accurate, it can ensure accuracy. If users are accustomed to using the constant setting method, which is based on the constant value marked on the conductive electrode, the sample holder calibration method is an innovative invention of our company, which is very convenient and fast to use. The three calibration methods can be freely selected without affecting each other.

The temperature compensation coefficient set by the instrument at the factory is 2.0%/℃, but the conductivity temperature coefficients of various types and concentrations of solutions are different. Users can refer to Table (1-2) and the data obtained in the experiment to set them in parameter setting P3.

pay attention toWhen the temperature compensation coefficient is set to 0.00, which means there is no temperature compensation during instrument testing, the measured value of the instrument is the conductivity value at that temperature

Table (1-2)

For other parameter settings of the instrument, please refer to Table (1-3)

4. Parameter settings

List of Conductivity Test Parameter Settings (1-3)

Table (1-3)

(1) Selection of Conductivity Calibration Solution Series (P1)

1Press the "Function" button to enter P1 mode of the instrument;

2Press the "∧" or "∨" keys to select the standard solution series;

CH China Series USA Europe and America Series

3Press the "Function" button to enter the next parameter setting or press "Confirm" to return to measurement mode;

(2) Electrode constant selection (P2)

1Press the 'function key' in P mode to enter P2 mode;

2Press the "∧" or "∨" key to change the constant setting: 0.1 → 1 → 10;

3Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;

4The factory setting of P2 is K=1;

（3）Temperature compensation coefficient setting (P3)

1Press the "Function" key in P2 mode to enter P3 mode;

2Press the "∧" or "∨" key to change the numerical range: 0.00-99.9; Long press the "∧" or "∨" key to quickly change;

Note: When the number is set to 0.00, it indicates that there is no temperature compensation;

3Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;

The factory setting for P3 is 2.0%;

（4）Electrode constant setting (P4)

1Press the "Function" key in P3 mode to enter P4 mode, and the LCD will display the constant value of the previous calibration;

2Press the "∧" or "∨" keys to modify the size, and set it according to the constant value marked on the conductive electrode;

3Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;

4If constant setting is required for conductivity electrodes other than constant 1, such as using a conductivity electrode with constant 10.3, first enter constant setting P2 to set constant "10", and then enter P4 mode to set the constant value to 10.3;

(5) Temperature unit selection (P5)

1Press the "Function" key in P4 mode to enter P5 mode;

2Press the "∧" or "∨" keys to select the temperature unit ℃ or⁰F；

3Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;

(6) Restore factory settings (P6)

1Press the "Function" key in P5 mode to enter P6 mode;

2Press the "∧" or "∨" key to select "On", which means to restore the factory settings mode, and return to the measurement mode after 2 seconds;

5、 Precautions

1. The instrument has been calibrated on the conductive electrodes before leaving the factory, and users can generally use it directly.

2. Under normal usage, it is recommended to calibrate once a month; Newly purchased conductive electrodes and conductive electrodes that have been used for a period of time should be calibrated. 3. Keep the conductive electrode clean. Before and after measurement, rinse the electrode with pure water and shake dry. It is best to rinse the electrode with the tested solution.

4. The surface of the induction rod of the conductive electrode is coated with a layer of metal platinum black to reduce electrode polarization and expand the range. Therefore, the surface of the platinum black electrode cannot be wiped, and can only be cleaned by shaking in water to avoid damaging the platinum black coating; Warm water containing detergent can be used to clean organic contaminants on electrodes, or alcohol can be used for cleaning.

5. The conductive electrode should be immersed in pure water to prevent the inerting of platinum black. If the platinum black coated electrode is found to be malfunctioning, it can be immersed in a 10% nitric acid solution or 10% hydrochloric acid solution for 2 minutes, then rinsed clean with pure water before measurement. If the situation does not improve, the platinum black should be re plated or a new conductive electrode should be replaced.

When the instrument malfunctions, please set P6 to "On" to restore the instrument to its factory settings before calibration and testing.

6、 Complete set of instruments

1.DDS-307 One desktop microcomputer conductivity meter

2. One DJS-1E (platinum black) electrode

3.1408 μ s/cm conductivity standard calibration base, 1 set

1 4.9V power adapter

5. One set of electrode holder and electrode clamp

6. One user manual

7. One product warranty card

8. One copy of product qualification certificate