Yexsensor YEX-PHG-406 Series: Dual Output Industrial Online pH Sensor

In harsh industrial production and environmental monitoring, the corrosion resistance and signal stability of sensors are key to the success of the system. The YEX-PHG-406 series online pH sensor launched by Yexsensor not only inherits the brand's core patented reference technology but also introduces 316L stainless steel material and digital/analog dual output modes, providing a more robust and flexible choice for various complex industrial integration projects.

Core Technical Advantages: Stronger, More Stable, More Flexible

1. Patented Ultra-Long Life Reference System

The YEX-PHG-406 water quality pH sensor adopts Yexsensor's signature patented reference electrode design. The internal reference solution seeps forward at a very low rate through the microporous salt bridge under a pressure environment of ≥100KPa.

Anti-pollution performance: Forward seepage effectively prevents the penetration and pollution of external ions, ensuring that the reference potential remains stable for more than 20 months.

Multiplied service life: Compared with ordinary industrial electrodes on the market, the maintenance cycle is extended by 2-3 times.

2. Dual Output Modes: Compatible with Digital and Analog Systems

This series of sensors comes standard with RS-485 (Modbus RTU) digital output and supports optional 4-20mA analog current output (5-core wire design):

Digital integration: Direct access to distributed control systems (DCS) or IoT cloud platforms.

Analog adaptation: Compatible with traditional secondary instruments, recorders, or PLC systems that do not require complex communication protocols.

3. Multi-Material Housing, Adapted to Different Working Conditions

YEX-PHG-406-A (POM/ABS): Suitable for most municipal sewage, environmental monitoring, and conventional water treatment.

YEX-PHG-406-S (316L Stainless Steel/POM): Designed for environments with mechanical impact, high pressure, or specific chemical corrosion, providing superior structural strength.

YEX-PHG-406 Water Quality pH Sensor Widely Applicable Environments

1. Industrial Chemical Reaction Process Control
   In the neutralization reaction and chemical synthesis processes of acid, alkali, and salt solutions, the dual high-impedance differential amplifier of YEX-PHG-406 can effectively resist common-mode interference generated by stirring motors, ensuring precise and real-time measurement results.

2. Harsh Environment Water Quality Monitoring
   Whether in high-salinity seawater environments or biochemical sewage with high protein content, the sensor's patented microporous salt bridge can effectively prevent clogging and maintain stable readings.

3. Smart Water Affairs and Remote Monitoring
   Relying on RS-485 bus communication, integrators can easily achieve multi-node networking and grasp the pH dynamics of each node in the pipeline network or treatment process in real time.

YEX-PHG-406 Water Quality pH Sensor Technical Performance Parameters

Installation and Electrical Connection Instructions

Installation Angle Requirements

To ensure normal pressure of the internal liquid and electrochemical balance of the sensor:

Prohibited: Inverted or horizontal installation.

Tilted installation: The installation angle should be tilted more than 15 degrees from the horizontal plane to prevent air bubbles from adhering to the glass sensing membrane surface.

5-Core Twisted Shielded Wire Wiring Definition

• Red wire: Power positive (12～24V DC)

• Black wire: Power ground (GND)

• Blue wire: RS-485 A

• White wire: RS-485 B

• Yellow wire: 4-20mA current output (optional function, only for optional models)

Safety Tips: Please carefully check the wire sequence before powering on. All wiring points must be waterproofed, and it is recommended that the user cable has anti-corrosion capability to prevent penetration of acid and alkali mist.

YEX-PHG-406 Water Quality pH Sensor Maintenance, Care and Calibration Guide

Daily Maintenance Methods

• Window protection: Clean the glass membrane with deionized water before and after use. Never scratch it with hard objects.

• Terminal drying: Check whether the wiring terminals are dry. If contaminated, wipe with anhydrous alcohol and blow dry.

• Glass membrane recovery: If sediment forms on the sensor glass membrane due to long-term use, it can be washed with very dilute hydrochloric acid.

Storage Requirements

When not in use: Clean and insert into a protective sleeve containing 3mol/L potassium chloride (KCl) solution. Never store dry, otherwise the glass membrane will fail.

Calibration Steps

• Zero point calibration: Use pH=6.86 standard solution. After the value stabilizes, write the calibration command.

• Slope calibration: According to the nature of the on-site liquid to be measured, choose pH=4.00 (acidic) or pH=9.18 (alkaline) standard solution for two-point calibration.

Common Questions and Answers (FAQ)

Q1: What are the advantages of YEX-PHG-406-S compared to model A?

A1: The S model adopts a 316L stainless steel housing, which has stronger resistance to mechanical impact and specific corrosion resistance. It is suitable for industrial pipeline installations with higher pressure or harsher physical environments.

Q2: Can the sensor output both RS-485 and 4-20mA at the same time?

A2: Yes. If your model is equipped with the current output function, the sensor can provide both digital communication and analog signals simultaneously to meet the needs of different control systems.

Q3: Why do I need to blot the moisture with filter paper before measurement?

A3: This is to prevent the cleaning water from diluting or contaminating the solution to be measured, thereby ensuring the most accurate and fastest response when switching measurement samples.

Q4: Under what circumstances does the electrode need to be replaced?

A4: When the electrode still cannot reach the calibration value after standard maintenance and calibration, or the response time is abnormally slow (more than 5 minutes), it indicates that the glass membrane has aged or the reference system has failed, and the sensor needs to be replaced.

Q5: What does the reference solution forward seepage for 20 months mean?

A5: This means that Yexsensor's patented structure can continuously provide a stable reference potential for the electrode for more than 20 months, significantly reducing reading drift and frequent calibration caused by depletion of the reference solution.

Q6: How far can the RS-485 signal be transmitted?

A6: In a standard industrial environment, RS-485 can transmit stably up to 1200 meters. For 4-20mA analog signals, the transmission distance is affected by the cable resistance, and it is recommended to control it within a few hundred meters.

Q7: Can the pH glass membrane be brushed with a brush?

A7: It is strictly prohibited to use hard brushes or any hard objects to contact it. The glass membrane is extremely fragile, and mechanical damage will cause permanent damage to the sensor. If there is scale, please refer to the manual and use a chemical dilution solution for cleaning.

Q8: Why is it not recommended to calibrate the sensor arbitrarily?

A8: Yexsensor sensors are precisely calibrated before leaving the factory. Since the accuracy of on-site standard solutions is greatly affected by the environment, non-standard calibration under unnecessary conditions may introduce measurement errors.

Quality Assurance and Service

• 72-hour aging test: Ensure long-term stability of each product under harsh working conditions.

• Quality assurance: Strictly implement quality inspection procedures; unqualified products will never leave the factory.

• Packing list: Sensor (1 pc), instruction manual, certificate of conformity, 5-meter shielded cable. 100% complete, no deletions, zero omissions.