1、 Technical performance

Conductivity measurement range: (0-199.9) μ s/cm; (200～1999)μs/cm ; (2.00～19.99)ms/cm ； (20.0～199.9)ms/cm ；
Resolution: 0.1/1 μ s/cm; 0.01/0.1ms/cm ；
Accuracy: Electrometer: ± 1.0% FS; Supporting: ± 1.5% FS
Temperature compensation: automatic or manual compensation for 10-50 ℃,
Basic configuration: DJS-1E (platinum black) electrode; 018 temperature electrode, 1408 μ s/cm conductivity standard calibration base; 4 DC1.5V batteries, No.7

1. Working conditions
Environmental temperature: 0-40 ℃ Relative humidity:<85%
Power supply: 4 No. 7 DC1.5V batteries
No significant vibration
There is no strong magnetic field interference other than the geomagnetic field.
Optional electrode specification constants: 0.1, 1, 10
Dimensions and weight: 180 × 80 × 30mm (length × width × height) 0.5 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 inversely proportional to the area A (cm2) of the plates. 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 a DC voltage generated by an oscillator to the electrode (the purpose of applying an 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, and detection, it is converted into a DC voltage, temperature compensation, etc., and finally converted into a digital signal by an A/D converter, which is 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
1. "Switch" - turn on the key, press the button to turn on and off the power.
2. "Calibration" - Calibration button. When in measurement mode, press the button to enter the instrument calibration mode.
3. "Function" - 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.
5. "Confirm" - Confirm button, when in calibration or parameter setting state, pressing the button indicates confirmation, and the instrument enters measurement mode after pressing the button.
4、 Conventional use of conductivity meter
1. Accurate conductivity
Press the "Calibration" button, and the "CAL" will flash, indicating that you have entered calibration mode. Insert the 1408 μ s/cm standard calibration head into the electrode holder at the back of the instrument, wait for the measurement value to stabilize, and then press the "Calibration" button. The LCD will flash "1408 μ s/cm", and after a few seconds, the "End" symbol will appear and return to the measurement mode. 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
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). Open the battery cover behind the instrument, install 4 1.5V batteries (pay attention to the positive and negative levels), press the "power on" button, turn on the power, and preheat for 5 minutes.
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) -84 μ s/cm; 1413μs/cm ； 12.88ms/cm ； 111.9ms/cm
CH(中国系列)—146.6US/CM； 1408μs/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 1408 μ s/cm. Using the conductivity electrode (K=1cm-1) provided with this instrument, the 1408 μ s/cm calibration solution can be used for calibration within a measurement range of less than 100ms/cm. Please refer to Table (1-1) for selection.
Table (1-1)

There are three calibration methods for the conductivity electrode of the instrument: standard solution calibration method, standard calibration seat 1408 μ s/cm, and constant setting method. The standard solution calibration method ensures accuracy as long as the standard solution is accurate. 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 (recommended). 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 coefficient varies for different types and concentrations of solutions. Users can refer to Table (1-2) and the data obtained in the experiment to set it in parameter setting P3.
Note: When 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)
1. Press the "Function" button to enter P1 mode of the instrument;
2. Press the "∧" or "∨" keys to select the standard solution series;
CH China Series USA Europe and America Series
3. Press the "Function" button to enter the next parameter setting or press "Confirm" to return to measurement mode;
(2) Electrode constant selection (P2)
1. Press the "Function Key" in P mode to enter P2 mode;
2. Press the "∧" or "∨" key to change the constant setting: 0.1 → 1 → 10;
3. Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;
The factory setting of P2 is K=1;
(3) Temperature compensation coefficient setting (P3)
Press the "Function" key in P2 mode to enter P3 mode;
2. Press 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;
3. Press 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)
1. Press the "Function" key in P3 mode to enter P4 mode, and the LCD will display the constant value of the previous calibration;
2. Press the "∧" or "∨" key to modify the size, and set it according to the constant value marked on the conductive electrode;
3. Press the "Function" button to enter the next parameter setting or press the "Confirm" button to confirm and return to measurement mode;
4. If constant setting is required for conductivity electrodes other than constant 1, such as using conductivity electrodes 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)
1. Press the "Function" key in P4 mode to enter P5 mode;
2. Press the "∧" or "∨" keys to select temperature units of ℃ or 0F;
3. Press 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)
1. Press the "Function" key in P5 mode to enter P6 mode;
2. Press 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. One portable microcomputer based conductivity meter host
2. One DJS-1E (platinum black) electrode
3.018 temperature electrode (optional model) 1 piece
4.1408 μ s/cm conductivity standard calibration base, 1 set
5.7V DC1.5V battery, 4 cells
6. One user manual
7. One product warranty card