SIGAS SA-TR96/91 Embedded Oxygen Analyzer
| Brand | SIGAS |
|---|---|
| Model | SA-TR96/91 |
| Detection Principle | Electrochemical & Frequency-Modulated Ion Current |
| Measurement Range | 0–10 ppm to 0–25% O₂ (selectable) |
| Accuracy | ±1% FS (0–1000 ppm and above), ±3% FS (0–100 ppm), ±5% FS (0–10 ppm) |
| Repeatability & Stability | ±1% FS (≥100 ppm), ±1.5% FS (0–100 ppm), ±2.5% FS (0–10 ppm) |
| Response Time (T90) | <60 s at 25°C |
| Recovery Time (20.94% → 10 ppm) | ≤60 min |
| Operating Pressure | 35–210 kPa (absolute), flow-controlled at 1.0–1.5 L/min (recommended: 1.2 L/min) |
| Ambient Temp. | 0–45°C |
| Humidity | <80% RH |
| Power Supply | 85–264 VAC, 50/60 Hz, <20 VA |
| Output Signals | Isolated 4–20 mA (configurable to 0–20 mA / 0–1 V / 0–5 V / 0–10 V / 1–5 V) |
| Communication | RS485 (standard), RS232 (optional) |
| Gas Inlet | 1/8″ stainless steel |
| Enclosure Dimensions | 144 × 144 × 251 mm (L×W×D) |
| Mounting Hole Pattern | 136 × 136 mm |
| Sensor Lifetime | >2 years (typical use) |
| Analyzer Lifetime | >5 years (typical use) |
| Compliance | Designed for continuous industrial gas monitoring per IEC 61000-6-2/6-4 EMI immunity & emission requirements |
| Certifications | CE-marked |
Overview
The SIGAS SA-TR96/91 Embedded Oxygen Analyzer is a compact, field-deployable electrochemical gas analyzer engineered for high-reliability continuous oxygen monitoring in industrial process streams and inerted environments. It employs dual-sensing methodology—electrochemical cell detection augmented by frequency-modulated ion current technology—to deliver stable, low-drift measurements across an exceptionally wide dynamic range: from trace-level oxygen (0–10 ppm) up to full-scale 25% O₂ concentration. Unlike optical or paramagnetic analyzers, this platform leverages galvanic electrochemical cells optimized for long-term stability under variable pressure and background gas composition—including N₂, Ar, He, H₂, and hydrocarbon mixtures. Its architecture integrates real-time pressure compensation, over-pressure protection, and over-range cutoff logic to preserve sensor integrity during transient process excursions. Designed for integration into OEM systems or standalone panel-mount deployment, the SA-TR96/91 meets the functional safety expectations of continuous emissions monitoring (CEM), inert gas blanketing verification, and purity assurance workflows.
Key Features
- Electrochemical sensing core with optional frequency-modulated ion current enhancement for improved linearity and reduced cross-sensitivity in complex matrices
- Full-range programmable measurement: user-selectable spans from 0–10 ppm to 0–25% O₂ via intuitive on-device menu navigation
- Integrated pressure compensation algorithm that dynamically corrects for absolute sample pressure deviations (35–210 kPa), ensuring metrological consistency independent of upstream regulator drift
- Dual-stage over-protection system: automatic pneumatic isolation upon detection of out-of-spec pressure (210 kPa) or oxygen concentration exceeding user-defined upper limit
- Modular test chamber design enabling field replacement of electrochemical sensors without specialized tools or calibration recalibration
- Tempered glass overlay on 128×64 dot-matrix LCD display provides IP65-rated front-panel ingress protection and mechanical impact resistance
- MDT (Maintenance Due Timer) function displays cumulative sensor operating hours and recommends service intervals based on runtime and exposure history
- Configurable analog output: isolated 4–20 mA standard, with software-selectable alternatives including 0–20 mA, 0–1 V, 0–5 V, 0–10 V, or 1–5 V
- Two SPST relay outputs rated at 24 VDC / 0.2 A for local alarm staging or interlock signaling
- Tactile membrane keypad with enhanced lifecycle rating (>1 million actuations) and moisture-resistant sealing
Sample Compatibility & Compliance
The SA-TR96/91 is validated for use with nitrogen, argon, helium, hydrogen, and hydrocarbon-based carrier gases. When deployed in CO₂-, H₂S-, SO₂-, NOₓ-, or NH₃-containing streams, prior consultation with SIGAS application engineering is required to assess potential electrochemical interference and recommend appropriate filter configurations or alternative sensor chemistries. The analyzer complies with IEC 61000-6-2 (immunity) and IEC 61000-6-4 (emission) standards for industrial electromagnetic compatibility. While not intrinsically safe or ATEX-certified, its enclosure design satisfies general-purpose indoor/outdoor mounting requirements per IEC 60529 (IP65 equivalent for front panel). It supports GLP-aligned operational documentation through timestamped event logging (power cycles, alarm triggers, sensor replacements) and is compatible with FDA 21 CFR Part 11–compliant data acquisition systems when paired with validated SCADA or DCS interfaces.
Software & Data Management
Configuration and diagnostics are managed locally via the integrated LCD interface and tactile keypad. No proprietary PC software is required for routine operation. All setup parameters—including zero/span values, alarm thresholds, pressure compensation coefficients, and analog output scaling—are stored in non-volatile memory with write-protection options. RS485 Modbus RTU protocol (standard) enables bidirectional communication with PLCs, HMIs, or central monitoring servers; RS232 is available as an optional interface for legacy serial integration. Event logs record timestamps for critical events: sensor replacement, power failure, pressure fault, oxygen over-range, and manual calibration actions. These logs support audit-ready traceability for quality systems governed by ISO 9001, ISO 14001, or pharmaceutical GMP Annex 11 frameworks.
Applications
- Air separation plant (ASP) purge gas purity verification downstream of molecular sieves
- Semiconductor fabrication: ultra-high-purity (UHP) N₂ and Ar blanket gas monitoring in diffusion furnaces and CVD chambers
- Metal welding: real-time verification of inert shielding gas integrity (e.g., Ar/He blends) in TIG/MIG processes
- Food packaging: residual O₂ quantification in modified atmosphere packaging (MAP) lines prior to seal integrity testing
- Petrochemical refining: oxygen leak detection in closed-loop hydroprocessing reactors and catalyst regeneration off-gas streams
- Inert gas blanketing of storage tanks containing flammable liquids or reactive chemicals (per NFPA 56 and API RP 2510)
- Pharmaceutical lyophilization: chamber headspace O₂ monitoring during primary drying and backfill cycles
FAQ
What background gases are compatible with the SA-TR96/91 without requiring additional filtration?
Nitrogen, argon, helium, hydrogen, and saturated hydrocarbon mixtures (e.g., methane, propane) are fully supported. CO₂, H₂S, SO₂, NOₓ, and NH₃ require pre-filtration or sensor chemistry customization—contact SIGAS technical support with your specific matrix.
Can the analyzer operate continuously at elevated sample temperatures beyond 45°C?
No. The specified maximum sample temperature is 45°C. For higher-temperature streams, a cooled sample probe or heat exchanger must be installed upstream to condition gas to ≤45°C before entering the analyzer.
Is field calibration possible without sending the unit to a service center?
Yes. Zero and span calibration can be performed in situ using certified calibration gases and the built-in menu-driven procedure. Calibration certificates and traceability documentation are maintained in device memory.
Does the 4–20 mA output support HART protocol?
No. The analog output is a standard isolated current loop only. HART functionality is not implemented; digital communication relies exclusively on RS485/RS232.
How often is sensor replacement recommended under typical operating conditions?
Electrochemical sensors are rated for ≥2 years of continuous operation in clean, non-corrosive gas streams. MDT (Maintenance Due Timer) tracking on the display provides proactive notification based on actual runtime and exposure profile.
