ATAGO CM-800α-EG Online Ethylene Glycol Concentration Meter

Overview

The ATAGO CM-800α-EG Online Ethylene Glycol Concentration Meter is a precision industrial refractometer engineered for continuous, real-time monitoring of ethylene glycol (EG) concentration in liquid process streams. It operates on the principle of critical-angle refractometry—measuring the refractive index of the sample at the interface between synthetic sapphire prism and process fluid—and converts it into EG mass percentage using a calibrated polynomial algorithm traceable to NIST-standard reference solutions. The instrument simultaneously calculates and displays freezing point temperature based on the measured EG concentration and temperature, enabling predictive freeze-protection management in cooling, heat-transfer, and deicing systems. Designed for permanent installation in piping loops or tank sidestreams, the CM-800α-EG features a robust, sanitary-grade wetted path constructed entirely from corrosion-resistant SUS316L stainless steel and optical-grade synthetic sapphire—ensuring long-term stability in aggressive chemical environments including glycol-water mixtures, brines, and industrial antifreeze formulations.

Key Features

• High-stability LED light source emitting at ~589 nm (near sodium D-line), optimized for refractive index measurement consistency across thermal drift
• Automatic Temperature Compensation (ATC) integrated over 5–100°C, eliminating manual correction and ensuring accuracy under dynamic process conditions
• Real-time dual-output capability: primary EG concentration (% w/w) and derived freezing point (°C/°F), both updated every ~1 second (configurable from 0.5 to 10 s intervals)
• IP67-rated enclosure with hermetically sealed optical interface, suitable for humid, washdown, or outdoor installations without additional housing
• Dual analog and digital outputs: isolated 4–20 mA current loop (HART-compatible wiring) for PLC/DCS integration, plus RS-232C serial interface supporting ASCII-based data streaming of refractive index (nD), EG %, freezing point, and temperature
• Factory-calibrated with certified EG reference standards; calibration verification protocol supports in-situ validation using zero-point (pure water) and span-point (known EG standard) checks

Sample Compatibility & Compliance

The CM-800α-EG is validated for direct measurement of aqueous ethylene glycol solutions ranging from 0.0 to 90.0% w/w—covering common applications such as automotive antifreeze (typically 30–60%), HVAC glycol loops (20–50%), aircraft deicing fluids (40–85%), and industrial heat-transfer media. It maintains accuracy in turbid or mildly colored solutions due to its collimated beam geometry and sapphire prism’s high transmission efficiency. The device complies with IEC 61000-6-2 (EMC immunity) and IEC 61000-6-4 (EMC emission) standards. Its construction materials meet FDA 21 CFR 177.2400 (indirect food contact) and ASTM A276 Type 316L requirements. While not intrinsically safe, it may be deployed in Class I, Division 2 hazardous locations when installed with appropriate barrier systems per NEC Article 500.

Software & Data Management

Data output via RS-232C is configurable through front-panel menu or remote command set (e.g., “READ” returns full parameter string: “nD=1.3842,EG=42.3%,FP=-28.1°C,T=32.5°C”). No proprietary software is required for basic integration; standard Modbus RTU mapping (via optional converter) enables compatibility with most SCADA platforms. For audit-ready environments, the unit supports timestamped output logging when paired with external data loggers compliant with 21 CFR Part 11—though native electronic record functionality is not embedded. Calibration history, configuration settings, and error logs are accessible via serial interface and retained across power cycles.

Applications

• Real-time concentration control in EG blending stations for automotive coolant manufacturing
• Freeze-point assurance in district heating/cooling networks using glycol-based secondary loops
• In-process monitoring during aircraft deicing fluid reclamation and reuse operations
• Quality verification in pharmaceutical clean steam condensate systems where glycol traces must remain below specification limits
• Preventive maintenance support in metalworking fluid recirculation circuits where glycol degradation affects corrosion inhibition
• Validation of concentration stability in solar thermal plant heat-transfer fluids operating above 120°C

FAQ

What is the maximum allowable process pressure for the CM-800α-EG?

The sensor is rated for continuous operation up to 1.0 MPa (145 psi) at 20°C; pressure rating decreases linearly to 0.6 MPa at 160°C per ASME B31.3 guidelines.
Can the unit measure propylene glycol (PG) concentration?

No—the CM-800α-EG uses an EG-specific calibration curve. ATAGO offers the CM-800α-PG variant for propylene glycol applications, with identical hardware but distinct firmware and calibration coefficients.
Is cleaning-in-place (CIP) compatible?

Yes—SUS316L body and sapphire prism withstand repeated exposure to 2% NaOH and 1% HNO₃ CIP solutions at ≤80°C; mechanical scrubbing or ultrasonic cleaning is not recommended.
How often is recalibration required?

Under stable operating conditions, annual verification against traceable standards is sufficient; more frequent checks are advised following maintenance events, composition changes, or after exposure to particulate-laden streams.
Does the device support HART communication?

Not natively—but the 4–20 mA output is HART-enabled when wired through a compatible smart transmitter or DCS I/O card with HART multiplexing capability.