Analox SDA-CO2 Carbon Dioxide Analyzer
| Brand | Analox |
|---|---|
| Origin | United Kingdom |
| Model | SDA-CO2 |
| Sensor Range | 0–5000 ppm and 0–2% CO₂ |
| Accuracy | ±25 ppm or ±1% of reading (0–5000 ppm) |
| Display | Full-color graphical LCD |
| Output Options | 4–20 mA, relay, Ethernet (protocol available on request) |
| Data Logging | Optional internal memory |
| Alarm | Configurable audio/visual alerts via front panel |
| Compliance | DNV, IMCA, Lloyd’s Register, ABS, ADCI |
| Sensor Type | Dual-beam NDIR (Non-Dispersive Infrared) |
| Mounting | Rack-mountable or panel-mountable |
| Replacement Sensor | Advanced digital 5S3 NDIR sensor |
| Legacy Compatibility | Direct drop-in replacement for Analox 5001 |
Overview
The Analox SDA-CO₂ Carbon Dioxide Analyzer is a purpose-engineered, dual-beam non-dispersive infrared (NDIR) gas analyzer designed for continuous, high-integrity monitoring of carbon dioxide concentrations in critical occupational and life-support environments—particularly saturation diving chambers, hyperbaric facilities, marine control rooms, and confined-space safety systems. Unlike single-beam NDIR architectures susceptible to drift from optical degradation or thermal fluctuation, the SDA-CO₂ employs a true dual-beam reference-compensated design: one beam passes through the sample cell while the other traverses a sealed, inert reference chamber. This architecture ensures long-term signal stability and minimizes zero-point drift, directly contributing to its extended sensor service life and reduced calibration frequency. The instrument operates on the fundamental principle of Beer–Lambert absorption spectroscopy at 4.26 µm—the characteristic CO₂ absorption band—enabling selective, interference-resistant detection without cross-sensitivity to water vapor, methane, or common hydrocarbons under standard operating conditions.
Key Features
- Dual-beam NDIR sensing platform with integrated temperature and pressure compensation for enhanced metrological robustness
- Advanced digital 5S3 sensor module—field-replaceable, pre-calibrated, and plug-and-play compatible with onboard diagnostics
- Full-color graphical LCD display with intuitive icon-driven menu navigation and real-time waveform visualization
- Front-panel configurable alarm setpoints with independent audio (piezo buzzer) and visual (LED strobe + on-screen alert) outputs
- Compact depth-optimized chassis suitable for 19″ rack mounting (2U height) or flush panel installation in control consoles
- Comprehensive analog and digital I/O: isolated 4–20 mA output, SPDT relay contacts (fail-safe configurable), and optional Ethernet interface supporting Modbus TCP or custom protocol implementation upon request
- Built-in data logging capability (optional) with timestamped CO₂ concentration records stored internally for post-event forensic analysis
Sample Compatibility & Compliance
The SDA-CO₂ is validated for use in ambient air, compressed breathing gas mixtures (including heliox and trimix), and recirculated chamber atmospheres at pressures up to 30 bar (gauge). It meets the stringent performance, documentation, and traceability requirements specified by DNV-RP-F103 (Recommended Practice for Saturation Diving Systems), IMCA D 022 (Guidance on Gas Monitoring in Diving Operations), Lloyd’s Register Rules for Offshore Units (Part 7, Chapter 8), ABS Guide for Building and Classing Submersibles, and ADCI Consensus Standards for Commercial Diving Operations. All units ship with UKAS-traceable calibration certificates, full factory test reports, and compliance documentation aligned with ISO/IEC 17025 principles. The analyzer supports GLP/GMP-aligned operational practices through audit-ready calibration logs, user-accessible firmware version tracking, and password-protected configuration settings.
Software & Data Management
While the SDA-CO₂ operates as a standalone, embedded-system analyzer with no external PC dependency, its Ethernet option enables integration into facility-wide SCADA or BMS platforms. When enabled, the unit transmits real-time CO₂ values, status flags (e.g., sensor fault, calibration due, alarm active), and diagnostic parameters (lamp intensity, detector voltage, ambient temperature) via configurable polling intervals. Data export formats include CSV-compatible ASCII streams and structured JSON payloads. Internal logging retains up to 30 days of 1-minute averaged data (expandable via optional SD card module). All configuration changes—including alarm thresholds, output scaling, and display brightness—are recorded with user ID, timestamp, and prior/post values to satisfy FDA 21 CFR Part 11 and EU Annex 11 electronic record integrity expectations.
Applications
- Saturation diving habitat atmosphere monitoring (primary CO₂ surveillance in bell and deck chambers)
- Hyperbaric medical treatment facilities requiring real-time CO₂ trending during recompression therapy
- Subsea control room environmental safety systems for offshore oil & gas platforms
- Confined-space entry programs in maritime, nuclear, and industrial infrastructure maintenance
- Research-grade CO₂ monitoring in simulated extraterrestrial or deep-sea habitat testbeds
- Legacy system modernization: direct mechanical, electrical, and functional replacement for discontinued Analox 5001 units without conduit or wiring modification
FAQ
What is the recommended calibration interval for the SDA-CO₂ in diving operations?
Per IMCA D 022 and DNV-RP-F103, initial calibration verification is required before first deployment; subsequent calibrations shall occur at least every 3 months—or after any event affecting sensor integrity (e.g., exposure to condensate, mechanical shock, or extreme over-range).
Does the SDA-CO₂ support automatic zero/span calibration?
No—it requires manual two-point calibration using certified span gas (e.g., 2000 ppm CO₂ in N₂) and zero gas (high-purity N₂ or synthetic air); however, the front-panel interface guides users through each step with real-time feedback.
Can the unit operate continuously at elevated pressure (e.g., 20 bar gauge)?
Yes—the analyzer housing and sensor assembly are rated for continuous operation at up to 30 bar gauge; sample gas must be pressure-regulated and filtered prior to inlet per Analox Application Note AN-SDA-004.
Is the 5S3 sensor compatible with older SDA-series instruments?
The 5S3 digital sensor is backward-compatible only with SDA-CO₂ units manufactured from 2019 onward; earlier SDA models require hardware retrofitting and firmware upgrade to support 5S3 communication protocols.
How is sensor lifetime defined, and what indicates end-of-life?
The dual-beam NDIR source has a nominal operational lifetime of ≥5 years under continuous duty; end-of-life is signaled by sustained lamp intensity decay below 70% of initial value, reported via diagnostic menu and logged alarm event.
