ATAGO CM-ISα Series Intrinsically Safe Online Refractometer for Continuous 24-Hour Monitoring

Overview

The ATAGO CM-ISα Series Intrinsically Safe Online Refractometer is an industrial-grade optical process analyzer engineered for continuous, real-time measurement of refractive index and derived concentration (e.g., % Brix, % w/w, nD) in hazardous environments. Based on the critical angle principle, the instrument employs a high-stability LED light source and precision sapphire prism interface to measure total internal reflection at the prism–process fluid boundary. This non-invasive, no-moving-parts design eliminates sampling delays, fouling risks, and calibration drift associated with offline methods. The CM-ISα operates unattended for 24/7 monitoring in Zone 0/20 classified areas—fully compliant with IECEx and ATEX intrinsically safe requirements—making it suitable for chemical synthesis reactors, solvent recovery units, fermentation broth lines, and pharmaceutical crystallization vessels where explosion risk coexists with stringent process control demands.

Key Features

• Intrinsically safe architecture certified to IECEx ia IIC T4 Ga and ATEX II 1G Ex ia IIC T4 Ga—enabling direct installation in gas Group IIC (e.g., hydrogen, acetylene) and dust Zone 20 environments without additional barriers.
• Sapphire prism sensor with 316L stainless steel body ensures long-term chemical resistance against aggressive solvents, acids, alkalis, and high-purity aqueous streams.
• Fast dynamic response (< 5 s T90) supports closed-loop concentration control in PID-regulated processes such as evaporation endpoint detection or dilution blending.
• Dual-output capability: isolated 4–20 mA analog signal with HART 7 protocol support for field configuration and diagnostics, plus RS-485 Modbus RTU for integration into DCS/SCADA systems.
• Temperature-compensated measurement using integrated Pt100 RTD (±0.2 °C accuracy) referenced to ISO 21748 and ASTM D1218 standards for refractive index correction.
• Robust mechanical design: IP67-rated sensor head withstands washdown, vibration, and ambient temperature fluctuations; transmitter housing rated IP65 for panel or wall mounting.

Sample Compatibility & Compliance

The CM-ISα accommodates homogeneous liquid streams—including aqueous solutions, organic solvents, glycol mixtures, syrupy food intermediates, and sterile bioprocess broths—with suspended solids content < 0.5 % v/v and particle size 10,000 mPa·s), or fluids containing abrasive particulates. Regulatory alignment includes compliance with IEC 61508 SIL2 for functional safety applications, adherence to FDA 21 CFR Part 11 data integrity requirements when paired with ATAGO’s optional data logging software, and conformity with GMP/GLP documentation practices for pharmaceutical and food-grade installations. Calibration traceability follows NIST-traceable sucrose standards per ISO 5725.

Software & Data Management

Configuration and diagnostic functions are accessible via ATAGO’s dedicated PC-based setup utility (CM-ConfigTool), supporting parameter adjustment (e.g., Brix range, temperature compensation curve, damping factor), firmware updates, and event log export. When integrated with a validated historian system, the CM-ISα meets ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available) for audit-ready data retention. Optional HART-enabled handheld communicators allow field-level verification without process interruption. All configuration changes generate timestamped audit trails with operator ID logging—essential for 21 CFR Part 11 compliance in regulated manufacturing.

Applications

• Continuous sugar concentration monitoring in juice evaporation and syrup blending lines (ISO 21748-compliant Brix reporting).
• Real-time solvent concentration tracking in API crystallization and extractive purification steps.
• In-line control of glycol concentration in HVAC chillers and antifreeze formulation tanks.
• Monitoring of acid/base concentration during neutralization reactions in fine chemical batch reactors.
• Concentration validation in sterile filtration skids and buffer preparation systems for biologics manufacturing.
• Endpoint detection in vacuum distillation columns processing flammable hydrocarbons (e.g., ethanol, acetone).

FAQ

What hazardous area classifications does the CM-ISα support?
It is certified for Zone 0 (gas) and Zone 20 (combustible dust) per IEC 60079-0/-11 and EN 60079-0/-11, covering Group IIC gases including hydrogen and acetylene.
Can the CM-ISα be calibrated in-situ without removing the sensor?
Yes—zero and span calibration can be performed online using certified reference liquids (e.g., distilled water and NIST-traceable sucrose standards) while maintaining process flow.
Is temperature compensation automatic and configurable?
Yes—the built-in Pt100 RTD provides real-time fluid temperature input, and the compensation algorithm follows either default polynomial coefficients or user-defined tables aligned with ISO 21748 Annex C.
Does the device support validation documentation for pharmaceutical use?
Full IQ/OQ documentation templates, calibration certificates, and FAT/SAT protocols are available upon request to support GMP validation under EU Annex 11 and USP .
How is sensor fouling mitigated in high-fouling applications?
Optional air-purge collars and ultrasonic cleaning modules (sold separately) can be mounted adjacent to the prism face to maintain optical clarity during extended operation in sticky or precipitating streams.