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YEX-S1PRO-MLSS Online Sludge Concentration Sensor | YexSensor
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YEX-S1PRO-MLSS Online Sludge Concentration Sensor | YexSensor

YEX-S1PRO-MLSS Online Sludge Concentration Sensor | YexSensor

Brand: YexSensor

Model: YEX-S1PRO-MLSS

Output: RS-485 (Modbus RTU protocol) / Optional 4-20mA, select one

Power: 12-24 VDC

IP Rating: IP68

Range: Sludge concentration and temperature

Description: Online MLSS sensor for aeration tanks and return sludge monitoring, using optical measurement, RS-485 Modbus and a rugged 316L IP68 housing.

Products Description

YEX-S1PRO-MLSS Online MLSS-A-Online-Sludge-Concentration-Sensor.html">Sludge Concentration Sensor: Stable Online Sludge Concentration Monitoring for Industrial Water Quality Projects

YEX-S1PRO-MLSS Online Sludge Concentration Sensor Product Introduction

YexSensor YEX-S1PRO-MLSS belongs to the YexSensor S1 PRO stainless-steel sensor series. It is designed for continuous sludge concentration monitoring in natural water, industrial water, laboratory water, municipal wastewater and automated water quality systems. The sensor outputs sludge concentration and temperature for easier process evaluation and remote data acquisition.

The product uses optical scattering method, 316L stainless steel + ABS housing and NPT 3/4 thread installation. It supports RS-485 Modbus communication, with optional 4-20mA output available according to project integration requirements.

For sludge concentration applications, the most important engineering concerns are stable readings, clear parameter interpretation and low-maintenance integration. YEX-S1PRO-MLSS addresses these needs by combining optical scattering method, +/-5% of reading; temperature +/-0.1 C; linearity 0.999 R2 accuracy performance, 30 s response behavior and RS-485 Modbus communication in one compact probe.

S1 PRO Series Positioning and Engineering Advantages

The S1 PRO series is positioned as the upgraded high-accuracy stainless-steel sensor line. Compared with standard plastic-housing sensor configurations, this series highlights higher measurement accuracy, 316L stainless steel structure, IP68 protection, automatic temperature compensation, digital Modbus integration and optional analog output. It is suitable for system integrators who need stable field deployment, compact wiring and precise parameter reading.

The sensor is suitable for projects where sludge concentration and temperature must be sent continuously to a PLC, RTU, data logger or cloud gateway. Digital Modbus data reduces signal attenuation over distance, while optional 4-20mA output keeps the product compatible with older analog control panels. This dual integration path helps engineering teams standardize cabinet wiring without sacrificing site flexibility.

Core Technical Highlights

  • 316L stainless steel + ABS housing: The robust housing supports demanding field installation while keeping the probe compact for tanks, pipes and immersion points.

  • High-accuracy temperature channel: Temperature accuracy reaches +/-0.1 C, supporting reliable compensation and more stable sludge concentration data.

  • RS-485 / 4-20mA output options: Standard RS-485 Modbus output supports PLC, RTU, data logger and IoT gateway integration, while optional 4-20mA can be selected for analog systems.

  • Designed: Designed for high-concentration sludge process points up to 20000 mg/L.

  • 316L: 316L stainless steel housing supports demanding wastewater installation.

Wide Application Scenarios and System Integration Solutions

YEX-S1PRO-MLSS Online Sludge Concentration Sensor can be integrated into PLC, SCADA, RTU and water quality IoT systems. The product is suitable for repeated online measurement points where offline sampling is slow, data continuity is weak, or on-site wiring space is limited.

  1. Aeration Tank Mlss
    Used for continuous online sludge concentration monitoring; it provides continuous online data for system control, alarms and historical trend analysis.

  2. Return Sludge Monitoring
    Used for continuous online sludge concentration monitoring; it provides continuous online data for system control, alarms and historical trend analysis.

  3. Secondary Sedimentation Tank
    Used for continuous online sludge concentration monitoring; it provides continuous online data for system control, alarms and historical trend analysis.

  4. Wastewater Plant Automation
    Used for continuous online sludge concentration monitoring; it helps operators follow process change, discharge fluctuation and treatment efficiency in real time.

For engineering contractors, this means the same product can be used across new monitoring stations, retrofit control panels and OEM water quality cabinets. The digital output simplifies data mapping, while the stainless-steel construction helps improve long-term reliability in outdoor and industrial environments.

Engineering Selection, Interference and Project Acceptance

Measurement Meaning and Selection Boundary

MLSS is a laboratory mass concentration, while the online sensor infers concentration optically. Site-specific sludge characteristics determine the strength of the correlation. Provide the minimum and maximum MLSS, sludge color and particle characteristics, aeration intensity, installation location, cleaning access and laboratory sampling method.

Installation Risk and Data Quality

Bubbles, rags, biological coating, changing floc size, dark industrial solids and non-representative tank zones can affect optical response. Correlate the online signal with well-mixed grab samples from the same location.

System Integration and Alarm Design

Map the primary measurement, temperature and communication status as separate engineering tags. Configure process high/low alarms independently from communication-loss, out-of-range and rate-of-change alarms. Filtering should be limited to what the process response permits so a real step change is not hidden.

Commissioning and Acceptance

Record the sensor model, range, unit, output option, device address, baud rate and reference method. Compare simultaneous online and reference results at representative conditions, then function-test alarms, historical trends and any control interlock from probe to HMI. Acceptance should cover the complete measurement loop rather than only the local probe value.

YEX-S1PRO-MLSS Online Sludge Concentration Sensor Technical Performance Specifications

ItemSpecification
Product modelYEX-S1PRO-MLSS
Measured parameterssludge concentration and temperature
Measuring range0-20000 mg/L
Accuracy+/-5% of reading; temperature +/-0.1 C; linearity 0.999 R2
Response time30 s
Measuring principleoptical scattering method
Power supply12-24 VDC, approx. 0.4 W
CommunicationRS-485 (Modbus RTU protocol) / Optional 4-20mA, select one
Housing material316L stainless steel + ABS
Protection gradeIP68
Temperature compensationAutomatic temperature compensation
Cable5 m four-core shielded cable by default
InstallationImmersion installation, NPT 3/4 thread
Operating environment0-50 C, non-freezing; pressure < 0.2 MPa
Cleaning configurationOptional self-cleaning function for sludge and high-fouling processes.

Installation Guidance and Electrical Connection Instructions

Installation Position Recommendations

The sensor can be installed by immersion, or mounted in a pipe or tank through the NPT 3/4 thread. For electrochemical and optical sensors, avoid upside-down or horizontal installation when the application requires a stable liquid contact surface. Keep the measuring area fully immersed and avoid strong bubbles or sediment impact where possible.

Electrical Wiring

Connection reference: 1-red power positive, 2-black power negative, 3-green 485B, 4-yellow 485A, 5-optional 4-20mA output. Wire colors may vary by batch, so the connector mark or pin number should be used as the final reference.

Maintenance, Care and Calibration Guide

At least one third of the sensor should be inserted into the measured liquid so the measuring end is fully covered. Keep wiring terminals, measuring surface and aviation connector clean. Clean the measuring surface with a soft brush and avoid scratching optical windows, electrodes or membranes.

The sensor is calibrated before delivery. Calibration is not recommended unless necessary. If long-term use causes data drift, perform zero or slope calibration according to the communication protocol and site standard solution.

Frequently Asked Questions

Q1: What does YEX-S1PRO-MLSS measure, and what decision can the data support?

A1: YEX-S1PRO-MLSS uses optical scattering and absorption for high-range sludge concentration for continuous sludge concentration sensor monitoring. It is intended to support aeration tanks, return activated sludge, sludge thickening, membrane bioreactors and industrial biological treatment. Define whether the signal will be used for display, alarm, process comparison, automatic control or compliance screening, because each purpose requires different limits and verification.

Q2: What measurement limitation should engineers understand before specifying this sensor?

A2: MLSS is a laboratory mass concentration, while the online sensor infers concentration optically. Site-specific sludge characteristics determine the strength of the correlation.

Q3: What information is required to select the correct range and configuration?

A3: Provide the minimum and maximum MLSS, sludge color and particle characteristics, aeration intensity, installation location, cleaning access and laboratory sampling method.

Q4: Which site conditions can interfere with the reading?

A4: Bubbles, rags, biological coating, changing floc size, dark industrial solids and non-representative tank zones can affect optical response. Correlate the online signal with well-mixed grab samples from the same location.

Q5: Where should the sensor be installed?

A5: Choose a continuously wetted and representative point after adequate mixing. Avoid dead zones, direct chemical-injection impact, sediment accumulation and locations where bubbles collect. Keep the sensing area fully immersed and follow the NPT 3/4 mounting and orientation requirements in the supplied manual.

Q6: How should RS-485 Modbus be commissioned with a PLC or SCADA system?

A6: Verify 12-24 VDC power, A/B polarity, device address, baud rate, register order, engineering unit and decimal scaling. Create a separate communication-status alarm so a frozen or missing value is not interpreted as normal water quality. Acceptance should compare the probe display, PLC register and HMI value across the complete loop.

Q7: When should optional 4-20mA be selected?

A7: Choose RS-485 Modbus when digital values, multiple channels, diagnostics or multidrop networking are required. Choose the optional 4-20mA configuration for an existing analog-only controller or a conventional point-to-point loop. The output options are selected according to the order; confirm the mapped parameter and full-scale value before production.

Q8: What maintenance and verification routine is recommended?

A8: Inspect the sensing surface, cable, seals and connector; remove deposits using the method stated in the manual and avoid scratching optical windows, membranes or electrodes. Compare the stabilized online result with the agreed site reference after commissioning, process changes or cleaning. Recalibrate only after installation, reference-method and fouling effects have been excluded.

Quality Assurance and After-sales Service

YexSensor is committed to providing an excellent product experience.

Strict quality inspection: Each product goes through a standardized inspection process and 72-hour aging test to help ensure a defect rate below 2%.

One-year warranty: A one-year after-sales warranty is provided from the date of sale, excluding man-made damage or improper use.

Cable configuration: A 5-meter four-core shielded cable is the standard cable configuration.

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