Available Available for application review and quotation
Water Quality & Organic Carbon Series
Model C620TUR

Model C620TUR Online Turbidity Analyzer

Continuous 0-4000 NTU turbidity monitoring with 850 nm infrared scattered-light measurement, a self-wiping immersion sensor, local display, and plant outputs.

Brand: Blue Dragon Technology Supply & support: Blue Dragon Technology
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Product Overview

Purpose-built measurement, clearly presented.

The Model C620TUR provides continuous turbidity measurement across a 0-4000 NTU sensor range using an infrared scattered-light measurement system and a motor-driven self-wiping optical window. The standard package combines the immersion sensor, local controller/transmitter, 10 m cable, mounting bracket, replacement rubber scrapers, and plant communication functions.

The system is designed for wastewater, process-water, surface-water, intake, clarifier, filter, settling, discharge, utility-water, and other industrial water applications where continuous solids-related turbidity trends, alarms, and process visibility are required. The self-wiping sensor reduces routine fouling, while one-point verification and calibration support site quality-control programs.

Distinctive Capabilities

  • Flexible poolside, railing, tank, channel, basin, or project-specific immersion mounting
Performance & Technical Data

The measurement method and the values that matter.

How it measures

Measurement Principle

An 850 +/-10 nm infrared light source illuminates the process water. Suspended particles scatter the incident light, and an optical detector positioned at approximately 90 degrees to the source measures the scattered-light intensity. The signal is processed into a turbidity value displayed in NTU or FTU. A motor-driven rubber wiper periodically cleans the quartz optical window to reduce deposit buildup.

Measurement Range0-4000 NTU
Accuracy+/-2% of measured value
Repeatability+/-2%
Analysis TimeLess than 60 seconds, excluding process transport effects
Measurement ParametersTurbidity
Process Temperature0-45 °C; no freezing

Complete Technical Data

Standard sensor configuration
Self-wiping immersion turbidity sensor
Measurement units
NTU or FTU
Optical method
850 +/-10 nm infrared, approximately 90-degree scattered-light measurement
Resolution
0.01-0.1 NTU
Maximum process pressure
0.4 MPa
Maximum local flow velocity
2.5 m/s
Sensor body
SUS316L stainless steel
Optical window
Quartz
Wiper / scraper
Motor-driven rubber wiper
Sensor sealing
No separate O-ring in the standard sensor configuration
Cable-jacket material
PUR
Sensor protection
IP68 / NEMA 6P (manufacturer rating)
Sensor dimensions
Approximately Ø60 x 261 mm for the standard automatic-cleaning stainless-steel configuration
Sensor weight
Approximately 1.65 kg
Standard sensor cable
10 m; up to 50 m maximum for this Blue Dragon configuration
Controller supply
100-240 VAC, 50/60 Hz; optional 24 VDC
Controller power consumption
4 W nominal
Controller dimensions
144 x 144 x 104 mm
Controller weight
Approximately 0.9 kg
Controller front protection
IP65 (manufacturer rating)
Analog output
One active, isolated 4-20 mA output; maximum load 500 ohm
Digital communication
RS485, Modbus RTU
Relay outputs
Three outputs; maximum 5 A at 250 VAC or 5 A at 30 VDC
Data history
Up to 1000 records with automatic overwrite when full
Trend display
Local waveform display
Data export
USB-based CSV export on current-production controllers; supplied interface and firmware govern
Calibration
One-point / factor calibration for the standard configuration
Recommended calibration interval
Approximately every six months, adjusted for fouling, criticality, and site quality plan
Standard warranty
12 months, subject to the sales contract
Availability
Available for application review and quotation
Industrial Use

Applications and industries.

Typical Applications

Municipal and industrial wastewater treatmentProcess-water and water-treatment monitoringSurface-water and raw-water intake monitoring where the range and matrix are suitableClarifier, filter, settling, and treatment-process trend monitoringIndustrial discharge, utility-water, and plant-water monitoringHigh-solids or fouling-prone water streams where automatic wiping reduces optical-window depositsTurbidity & Suspended Solids Monitoring

Industries Served

Chemical ProcessingEnvironmental Monitoring & ComplianceFood & BeverageMetals, Mining & MaterialsOil & GasPetrochemicalsPower GenerationPulp & PaperRefiningWater & Wastewater
Engineering & Integration

Built for specification, installation, and long-term operation.

Practical information for selecting the measurement point, installing and wiring the immersion sensor, integrating plant signals, establishing calibration and cleaning intervals, and maintaining reliable turbidity measurement.

Standard system0-4000 NTU self-wiping immersion sensor, local controller, 10 m PUR cable
Process limits0-45 °C, no freezing; <=0.4 MPa; <=2.5 m/s local velocity
Plant integrationIsolated 4-20 mA, RS485 Modbus RTU, and three relay functions
Calibration basisOne-point factor calibration with certified or traceable turbidity standard

System Configuration

  • StandardLocal controller/transmitter with display, configuration, calibration, alarm, history, and waveform functions
  • Standard10 m PUR-jacketed sensor cable, L-shaped mounting bracket, four replacement rubber scrapers, operation manual, and certificate of conformity
  • Optional24 VDC controller power, extended cable up to 50 m, mounting hardware, instrument enclosure, sample chamber, communication accessories, and turbidity standards
  • Application DependentOther body materials, cleaning arrangements, or flow-through installations are supplied only when specifically stated on the order
  • StandardC620TUR local controller/transmitter with self-wiping SUS316L immersion turbidity sensor and 10 m PUR-jacketed cable
  • StandardL-shaped mounting bracket, four replacement rubber scrapers, operation manual, and certificate of conformity

Sensor & Sample Interface

Reliable turbidity measurement depends on representative immersion, stable mounting, and freedom from trapped bubbles or local process disturbances.

  • StandardInstall at a representative, well-mixed point with the optical face continuously submerged
  • StandardMaintain clearance around the optical window and wiper and prevent the sensor from striking walls, pipes, or structures
  • Application DependentAvoid dead zones, sediment beds, entrained gas, foam, heavy fibre accumulation, and locations where the sensor can become exposed at low level
  • Application DependentBubbles, particle size and shape, colour, process stratification, and large solids can affect the indicated value or stability
  • Application DependentFlow-through use requires a specifically supplied sample chamber and a representative, controlled sample arrangement

Installation & Utilities

Install the controller and sensor within the confirmed environmental, process, and electrical limits and provide safe service access.

  • StandardPanel-mount controller, 144 x 144 x 104 mm, with IP65 front protection and clearance for terminals, cable bend radius, and ventilation
  • StandardProvide an accessible external disconnect, correctly rated overcurrent protection, protective earth, and separation of mains from signal wiring
  • Application DependentProtect the controller from direct spray, condensation, corrosive vapour, excessive vibration, and direct sunlight
  • Application DependentCable routing must avoid abrasion, heat, chemical attack, sharp bends, tensile load, and water entry at terminations

Controller & Communications

The controller provides local indication and common industrial outputs for monitoring, alarms, and control-system integration.

  • StandardRS485 Modbus RTU with 4800, 9600, or 19200 baud; default controller address 4 and default format 9600 baud, 8N1
  • StandardThree relay functions support high alarm, low alarm, and a cleaning-related output; contacts are rated up to 5 A at 250 VAC or 5 A at 30 VDC
  • StandardLocal simulation functions support 4-20 mA and relay commissioning checks
  • Application DependentUse interposing relays for inductive, high-current, or safety-related loads and confirm fail-safe logic in the project cause-and-effect
  • Application DependentRecord the actual device address, output scaling, alarm setpoints, and supplied firmware during commissioning

Calibration & Quality Control

  • StandardUse a certified or traceable turbidity standard reasonably close to the normal process concentration where practical
  • StandardClean the quartz window, remove bubbles, shield the calibration vessel from strong light, and allow the reading to stabilise before calibration
  • StandardVerify after sensor replacement, major cleaning, wiper service, cable repair, or unexplained drift
  • Application DependentEstablish site-specific comparison and acceptance procedures because particle properties, bubbles, colour, and installation can affect online turbidity response
  • Application DependentCurve calibration and two-point calibration are not approved field procedures for the standard C620TUR configuration

Cleaning & Maintenance

The automatic wiper reduces normal fouling but does not eliminate inspection, manual cleaning, or replacement of wear components.

  • StandardInitial wiper guidance is 720-1440 minutes for clean process water, 60-240 minutes for typical wastewater, and 15-60 minutes for rapid-fouling service
  • StandardReplace the rubber wiper when hardened, cut, permanently deformed, or no longer cleaning effectively; quarterly replacement is a conservative starting interval
  • StandardTypical wiper life is approximately three to six months depending on solids, abrasiveness, and cleaning frequency
  • StandardDo not force or rotate the motor-driven wiper arm by hand
  • StandardInspect the PUR cable, cable entry, housing joints, mounting bracket, output, alarms, and protective earth as part of routine maintenance

Interferences & Application Considerations

The standard C620TUR is intended for general-purpose, non-hazardous industrial locations and must be reviewed against the process matrix and installation conditions.

  • StandardSafe-area installation only; the standard configuration has no ATEX or IECEx approval
  • StandardDo not exceed 0.4 MPa process pressure, 2.5 m/s local velocity, or the 0-45 °C sensor-temperature range; do not expose the sensor to freezing conditions
  • Application DependentReview compatibility for strong acids, hydrofluoric acid, concentrated sulfuric acid, hot high-chloride service, strong oxidants, aggressive refinery wastewater, solvents, and unknown mixtures
  • Application DependentThe C620TUR should not be positioned as a low-level drinking-water compliance turbidity instrument; below 50 NTU, the available qualification is based on standard-solution comparison rather than supplied water-sample comparison data
  • Application DependentNo ISO 7027, EPA, NSF, or MCERTS compliance claim is made for the standard C620TUR
  • StandardDo not use an unverified online reading as the sole basis for a safety-critical shutdown, custody-transfer decision, or regulatory compliance decision
Application Review

Application Engineering Notes

Measurement location

Select a representative, well-mixed point and keep the optical window submerged. Avoid entrained gas, foam, sediment beds, direct impact from large debris, severe local stratification, vibration, and contact between the sensor and vessel wall.

Low-range applications

The C620TUR is designed for industrial online turbidity measurement. Applications below 50 NTU require suitable standards and an application-specific comparison plan; drinking-water compliance use should be confirmed against the applicable method and regulatory requirements.

Calibration and verification

Clean and inspect the sensor before changing calibration. Use a certified or traceable standard, record the before and after readings, and investigate bubbles, fouling, poor mixing, cable faults, or installation effects before applying a large correction factor.

Supply scope

The standard system includes the controller/transmitter, self-wiping immersion sensor, 10 m cable, L-shaped bracket, four replacement rubber scrapers, operating manual, and certificate of conformity. Optional items include 24 VDC controller power, extended cable, mounting hardware, instrument enclosure, sample chamber, communication accessories, and turbidity standards.

Project Delivery

Project Integration & Support Scope

Blue Dragon reviews the measurement objective, interfaces, documentation, commissioning, and lifecycle requirements as part of project configuration. The scope below identifies the principal items to confirm before order placement.

Measurement Objective
Continuous industrial turbidity monitoring for wastewater, process water, intake and surface water, treatment processes, utility water, filtration performance, and discharge monitoring.
Signal Outputs
The standard controller provides one active isolated 4-20 mA output, RS-485 Modbus RTU, and three relay functions for high alarm, low alarm, and cleaning-related logic.
Data Integration
The controller supports local indication, waveform display, up to 1000 historical records, current-production USB CSV export, 4-20 mA and Modbus connection to PLC, SCADA, DCS, or historian, and local output simulation for commissioning.
Alarms & Diagnostics
High and low turbidity alarms, cleaning output, output simulation, local history, and controller status are available. Fail-safe logic, interposing relays, actual firmware, device address, scaling, and alarm setpoints must be recorded during commissioning.
Documentation
The package may include the product sheet, operation manual, controller and sensor wiring, Modbus information, mounting and sample-chamber details, calibration guidance, certificate of conformity, and FAT or SAT records as ordered.
Commissioning Support
Commissioning can include installation review, representative-location check, sensor and wiper inspection, baseline and standard verification, 4-20 mA simulation, relay testing, Modbus checks, alarm setup, cleaning interval review, operator training, and handover records.
Lifecycle Support
Lifecycle support covers optical-window cleaning, rubber-wiper replacement, sensor and cable inspection, calibration or verification, controller troubleshooting, spare scrapers and parts, repairs, and long-term technical assistance.
Online Analyzer Configuration

Sample System & Online Analyzer Readiness

Reliable online measurement depends on the process interface as well as the analyzer. Confirm the following application data before final configuration and quotation.

Sample Type & Phase
Wastewater, process water, intake water, surface water, treated water, utility water, or another aqueous stream requiring industrial turbidity monitoring. The standard configuration uses a self-wiping immersion sensor.
Measurement Range
Confirm expected normal and maximum turbidity, alarm points, required resolution, reporting units, and process or compliance objective. The standard range is 0-4000 NTU with 0.01-0.1 NTU resolution; the product is not positioned as a low-level drinking-water compliance instrument.
Sample Conditions
Provide temperature, pressure, local velocity, solids loading, particle size and shape, color, bubbles, foam, oil or grease, fibres, chemicals, fouling tendency, and risk of freezing. The standard limits are 0-45 degrees C, 0.4 MPa, and 2.5 m/s.
Sample Handling
Define direct immersion or a specifically supplied flow-through chamber, representative mixing, mounting, clearance around the optical face and wiper, cleaning access, cable routing, drain or return, and protection from debris or wall contact.
Installation Area
Confirm tank, channel, basin, pipe, sample chamber, indoor or outdoor location, controller environment, front-panel mounting, cable length, maintenance access, safe-area requirements, and protection from spray, condensation, corrosive vapor, vibration, and sunlight.
Utilities
Provide 100-240 VAC, 50/60 Hz for the standard controller or the ordered 24 VDC option, protective earth, external isolation and overcurrent protection, sample presentation, cleaning access, communication cabling, and drain or return for any flow-through arrangement.
Response Requirement
Define whether the analyzer supports filtration control, treatment-process monitoring, high-turbidity alarm, discharge monitoring, or trending. The published response is less than 60 seconds, excluding process transport and mixing effects.
Integration Requirement
Confirm 4-20 mA lower and upper scaling, RS-485 Modbus address and baud rate, high and low alarm setpoints, cleaning relay behavior, interposing relays where needed, PLC or SCADA tags, historian requirements, and fail-safe logic.
Commissioning Requirement
Verify the representative measurement location, continuous submersion, bubbles and solids, sensor and wiper operation, standard verification, output simulation, relay functions, Modbus communication, alarm setpoints, cleaning interval, firmware record, operator training, and handover documentation.
Operational Visibility

Alarm & Diagnostic Matrix

The C620TUR controller provides dedicated high, low, and cleaning-related relay functions together with local status, history, output simulation, 4–20 mA, and RS-485 Modbus RTU.

Project Setpoint means the limit is selected for the ordered application. Recommended severity is generic website guidance; the site alarm philosophy is final.

High turbidity

Process Severity: Critical
Trigger / Basis
Measured turbidity reaches the configured high Project Setpoint.
Instrument Response
The high-alarm relay operates as configured; the local value, 4–20 mA output, and Modbus data remain available.
Operator Response
Confirm the process condition, sensor immersion, bubbles, solids, window condition, and comparison method before process action.
Reset & Ownership
The DCS or PLC owns process action. Setpoint, delay, relay logic, latching, and reset are project configured.

Low turbidity

Process Severity: Advisory
Trigger / Basis
Measured turbidity reaches the configured low Project Setpoint.
Instrument Response
The low-alarm relay operates as configured and the controller continues reporting the measured value.
Operator Response
Check process conditions, sensor position, bubbles, fouling, calibration, output scaling, and whether low monitoring is required for the application.
Reset & Ownership
Normally DCS or PLC owned; final alarm use and reset follow the project alarm philosophy.

Cleaning cycle active

Maintenance Severity: Status
Trigger / Basis
The configured automatic cleaning interval calls for a wiper cycle.
Instrument Response
The cleaning-related output operates according to the controller configuration while the motor-driven wiper cleans the quartz window.
Operator Response
No action is normally required; confirm cycle completion and review the interval if deposits remain.
Reset & Ownership
Controller owned. External indication or permissive logic is project configured and must not be treated as a universal process trip.

Optical window or wiper service required

Maintenance Severity: Warning
Trigger / Basis
Inspection, drift, unstable measurement, or failed verification indicates fouling or ineffective wiping.
Instrument Response
Automatic cleaning may continue but cannot restore an acceptable optical condition.
Operator Response
Clean the quartz window without scratching it, replace a hardened or damaged rubber wiper, and verify operation and response.
Reset & Ownership
Operator maintenance owned. Return to service only after visual inspection and an acceptable verification.

Result invalid or out of range

Measurement Quality Severity: Warning
Trigger / Basis
The reading is outside the configured 0–4000 NTU measurement range or is invalid because of sensor or process conditions.
Instrument Response
Local status and plant outputs indicate an unavailable, unstable, or implausible measurement according to controller behavior.
Operator Response
Check immersion, bubbles, foam, solids, sensor position, cable, window, range, and controller status.
Reset & Ownership
Instrument status originates locally; data-quality and fail-safe handling belong to the DCS or PLC configuration.

Calibration or verification failed

Quality Control Severity: Warning
Trigger / Basis
One-point factor calibration or comparison with the approved standard fails the site acceptance criterion.
Instrument Response
The result must not be accepted as verified until the cause is resolved.
Operator Response
Clean the window, remove bubbles, protect the standard from strong light, confirm standard value and stability, and repeat the approved procedure.
Reset & Ownership
Quality-system owned. Return to service requires an accepted verification and recorded as-left result.

Sensor, cable, or controller fault

Analyzer Severity: Critical
Trigger / Basis
The controller cannot obtain a valid sensor signal or identifies a sensor, cable, wiper, or controller condition.
Instrument Response
The measurement and associated outputs become unavailable or invalid according to the supplied controller status.
Operator Response
Inspect power, sensor cable, terminations, water entry, mechanical damage, wiper freedom, and the active controller diagnostic.
Reset & Ownership
Controller owned; external fail-safe action and reset follow the approved I/O and cause-and-effect.

4–20 mA signal fault

Integration Severity: Warning
Trigger / Basis
The receiving system detects a missing, invalid, or non-updating active isolated 4–20 mA signal.
Instrument Response
Local measurement can remain available while the analogue plant signal is unavailable.
Operator Response
Use the local output simulation, then check lower and upper scaling, loop load, polarity, terminals, cable, and DCS input.
Reset & Ownership
The DCS or PLC owns loop-fault alarming and reset; the controller owns the simulated and measured output.

Modbus communication loss

Integration Severity: Warning
Trigger / Basis
RS-485 Modbus RTU data stops updating or the controller does not answer the master.
Instrument Response
Local display and measurement can remain available while remote digital data is stale or absent.
Operator Response
Confirm device address, baud rate, 8N1 format, polarity, termination, shielding, register selection, and master setup.
Reset & Ownership
The receiving system owns communication-loss alarming and stale-data handling.

Controller power loss

Utility Severity: Critical
Trigger / Basis
The configured 100–240 VAC or optional 24 VDC supply is lost.
Instrument Response
Local indication, sensor processing, relays, analogue output, history, and Modbus become unavailable.
Operator Response
Verify safe isolation, supply, external disconnect, protective devices, earth, wiring, and controller condition before restart.
Reset & Ownership
The receiving system owns loss-of-signal action; restart follows the approved commissioning and alarm-test procedure.
Technical Resources

Product Documents

Product Sheet first, followed by the Brochure, Manual, and any additional technical documents.

PDF

Product Sheet

Technical product sheet covering the C620TUR system configuration, 0-4000 NTU range, infrared scattered-light method, self-wiping sensor, plant outputs, installation data, and applications.

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Application Engineering

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