CLEAN DO5000 Dissolved Oxygen Controller

Overview

The CLEAN DO5000 Dissolved Oxygen Controller is an industrial-grade online analyzer engineered for continuous, high-stability measurement and process control of dissolved oxygen (DO) in water and aqueous solutions. It operates on the polarographic electrochemical principle—utilizing a Clark-type membrane-covered sensor where oxygen diffuses through a selective gas-permeable membrane and undergoes reduction at a cathode, generating a current proportional to DO concentration. This method delivers robust performance across variable temperature, salinity, and pressure conditions typical in municipal wastewater treatment, boiler feedwater monitoring, cooling tower management, and bioprocess fermentation systems. The DO5000 integrates real-time signal conditioning, dual analog outputs, digital communication, and programmable relay logic into a single compact panel-mount unit compliant with international environmental and industrial automation standards.

Key Features

• Polarographic DO sensing architecture with optional replaceable membrane caps (CS4551, CS4751, CS4763, CS4773 electrodes) supporting 0–40 ppm range and field-serviceable maintenance
• Dual isolated 4–20 mA current outputs, each independently configurable for DO (% sat or mg/L), temperature, or relay status—with 1% FS accuracy and load capability up to 500 Ω
• RS-485 interface with galvanic opto-isolation and native MODBUS RTU protocol support, enabling bidirectional configuration, data polling, and integration into SCADA, DCS, or PLC-based control networks
• IP65-rated front panel enclosure ensuring reliable operation in humid, dusty, or splash-prone environments including outdoor pump stations and chemical dosing skids
• Configurable digital filtering coefficients to suppress electrical noise and stabilize readings in electrically noisy industrial settings—critical for EMI-rich plant floors or near VFDs
• Manual atmospheric pressure and salinity compensation functions to correct for site-specific operational variables affecting oxygen solubility
• Three programmable relays: two SPST control relays (2.5 A @ 230 VAC) for DO-driven actuation (e.g., air blower start/stop, chemical dosing), plus one user-defined function relay for cleaning cycles or alarm escalation
• Temperature measurement via integrated TH22k thermistor input (−5.0 to 105.0 °C), with automatic or manual temperature compensation applied to DO calculations per ISO 5814 and ASTM D888 conventions

Sample Compatibility & Compliance

The DO5000 is designed for continuous monitoring of aqueous streams in compliance with standard methods for dissolved oxygen analysis, including EPA Method 360.1, ISO 5814:2012 (Electrochemical probe method), and ASTM D888-22 (Standard Test Methods for Dissolved Oxygen in Water). Its polarographic sensor design ensures compatibility with low-conductivity boiler feedwater (≥5 µS/cm), municipal effluent, activated sludge basins, and recirculating cooling systems. The controller meets CE marking requirements for electromagnetic compatibility (EN 61326-1) and safety (EN 61010-1). While not intrinsically safe, it supports installation in non-hazardous Zone 2 areas when paired with appropriate barrier-protected electrode cabling. All firmware operations maintain traceable audit trails suitable for GLP-aligned water quality laboratories.

Software & Data Management

No embedded PC software is required for basic operation—the DO5000 features an intuitive menu-driven interface with English/Chinese language toggle and context-sensitive prompts. Configuration is performed locally via membrane keypad or remotely via MODBUS RTU commands (Function Codes 03h, 06h, 10h). Data logging is externalized to host systems; however, the device supports cyclic polling of real-time DO (% sat, mg/L), temperature (°C), and relay states at user-defined intervals (1–300 s). When integrated with supervisory systems compliant with FDA 21 CFR Part 11, the DO5000’s deterministic response time (<100 ms for analog output update) and MODBUS register mapping enable full electronic record integrity—including timestamped setpoint changes, calibration events, and fault alarms—without requiring proprietary drivers.

Applications

• Wastewater treatment plants: Aeration basin DO control to optimize energy use and nitrification/denitrification efficiency
• Power generation: Monitoring dissolved oxygen in boiler feedwater and condensate return lines to prevent corrosion per ASME PTC 19.11 guidelines
• Food & beverage processing: Ensuring consistent DO levels in CIP rinse water and product contact streams
• Pharmaceutical water systems: Supporting USP purified water and WFI specifications during distribution loop surveillance
• Aquaculture and hatchery operations: Maintaining species-specific DO thresholds in recirculating aquaculture systems (RAS)
• Industrial cooling towers: Preventing microbiologically influenced corrosion (MIC) through real-time DO trending and automated biocide dosing triggers

FAQ

What sensor types are compatible with the DO5000?
The DO5000 is designed for use with CLEAN’s polarographic DO electrodes (CS4551, CS4751, CS4763, CS4773), all featuring replaceable membrane caps and electrolyte reservoirs optimized for 0–40 ppm measurement.
Does the DO5000 support automatic temperature compensation?
Yes—via built-in TH22k thermistor input; users may select either automatic or manual temperature entry depending on installation constraints.
Can the relay outputs be configured for fail-safe operation?
Each relay supports configurable activation modes (NO/NC), hysteresis settings, and delay timers—enabling fail-closed or fail-open logic per IEC 61511 functional safety practices.
Is MODBUS RTU configuration supported without a PC?
Basic parameter setup (e.g., DO units, relay thresholds) is possible via front-panel navigation; advanced MODBUS register mapping requires a serial master device or terminal emulator.
What is the recommended calibration frequency?
Field calibration using air-saturation (100% point) and zero-oxygen (sodium sulfite) solutions is advised per ASTM D888—typically every 7–30 days depending on fouling risk and regulatory requirements.