Water quality sensor online monitoring PH sensor PH transmitter KWS750 Signal output: RS-485 (Modbus/RTU protocol)

1. Introductory

Hydrogen ion glass electrode and reference electrode were used to form a galvanic cell. In the process of ion exchange between hydrogen ions in the glass film and the measured solution, the concentration of hydrogen ions in the solution was detected by measuring the potential difference between the electrodes, so as to measure the PH value of the measured liquid.

PH sensor, commonly known as PH probe, is composed of glass electrode and reference electrode. The glass electrode consists of a glass support rod, a glass film, an internal reference solution, an internal reference electrode, an electrode cap, and a wire. The reference electrode has a known and constant electrode potential, and calomel or silver/silver chloride electrodes are commonly used. Because the PH value is related to temperature, it is generally necessary to add a temperature electrode for temperature compensation to form a three-pole composite electrode.

Used for environmental water quality monitoring, acid/alkali/salt solution, chemical reaction process and industrial production process, it can meet the requirements of online pH measurement for most industrial applications.

2. Technical Specifications

3. Dimensional Drawing

Note:The sensor connector is M16-5 core waterproof joint male head.

4. Installation and Electrical Connection

4.1 Installation

Note: The sensor should not be installed upside down or horizontally when installed, at least at an angle of 15 degrees or more.

4.2 Electrical Connection

a) Red line - power cord (12 ~ 24V)

b) Black line - ground (GND)

c) Blue line - 485A

d) white line - 485B

e) bare wire - shielded wire

After wiring is completed, it should be carefully checked to avoid incorrect connections before powering up.

Cable specification: Considering that the cable is immersed in water (including sea water) for a long time or exposed to the air, the cable has certain corrosion resistance. The outer diameter of the cable is Φ6 mm and all interfaces are waterproof.

5. Maintenance

5.1 Use and Maintenance

When measuring the pH sensor, it should be cleaned in distilled water (or deionized water), and the filter paper should be used to absorb moisture to prevent impurities from being introduced into the liquid to be tested. 1/3 of the sensor should be inserted into the solution to be tested.

The sensor should be washed when not in use, inserted into a protective sleeve with a 3.5 mol/L potassium chloride solution, or the sensor inserted into a container with a 3.5 mol/L potassium chloride solution.

Check if the terminal is dry. If it is stained, wipe it with absolute alcohol and dry it. Avoid long-term immersion in distilled water or protein solution and prevent contact with silicone grease. With a longer sensor, its glass film may become translucent or with deposits, which can be washed with dilute hydrochloric acid and rinsed with water. The sensor is used for a long time. When a measurement error occurs, it must be calibrated with the meter for calibration.

When the calibration and measurement cannot be performed while the sensor is being maintained and maintained in the above manner, the sensor has failed. Please replace the sensor.

Standard Buffer pH Reference Table

The actual reading and standard of the instrument sometimes have an error of ±1 words.

5.2 Calibration

Note: The sensor has been calibrated before leaving the factory. If the measurement error is not exceeded, it should not be arbitrarily calibrated.

a) Zero Calibration

Use 250 mL of distilled water in a measuring cylinder, pour into a beaker, add a packet of calibration powder with pH=6.86, stir evenly with a glass rod until the powder is completely dissolved, configure the solution with pH=6.86, put the sensor into the solution, wait for 3 ～5 minutes, after the value is stable, see if the displayed value is 6.86. If not, you need to perform zero calibration. Refer to the appendix for the calibration instructions.

b) Slope Calibration

For acidic solution: Take 250 mL of distilled water in a measuring cylinder, pour into a beaker, add a packet of calibration powder with pH=4.00, stir evenly with a glass rod until the powder is completely dissolved, and configure the solution to pH=4.00; In the solution, wait for 3 to 5 minutes. After the value is stable, see if the value is 4.00. If not, the slope calibration is required. Refer to the appendix for the calibration instructions.

For alkaline solution: Take 250 mL of distilled water in a measuring cylinder, pour into a beaker, add a packet of calibration powder with pH=9.18, stir evenly with a glass rod until the powder is completely dissolved, and configure the solution to pH=9.18; In the solution, wait for 3 to 5 minutes. After the value is stable, check if the display is 9.18. If not, the slope calibration is required. Refer to the appendix for the calibration instructions.

6.Quality and Service

6.1 Quality Assurance

• The quality inspection department has standardized inspection procedures, advanced and perfect testing equipment and means, and strictly in accordance with the regulations, to do 72-hour aging test and stability test on the product, and not to allow one unqualified product to leave the factory.
• The receiving party directly returns the product batch with a failure rate of 2%, and all the costs incurred are borne by the supplier. The reference standard refers to the product description provided by the supplier.
• Guarantee the quantity of goods and the speed of shipment.

6.2 Accessories and Spare Parts

This product includes:

• 1 sensor
• Calibration powder 3 packs
• 1 copy of the manual
• 1 certificate

6.3 After-sales Service Commitment

The company provides local after-sales service within one year from the date of sale, but does not include damage caused by improper use. If repair or adjustment is required, please return it, but the shipping cost must be conceited. Damaged on the way, the company will repair the damage of the instrument for free.

Photograph

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