Korno MOT500-SF6 Online Infrared SF₆ Gas Detector

Overview

The Korno MOT500-SF6 is a fixed-installation, continuous-duty infrared gas detector engineered for reliable, long-term monitoring of sulfur hexafluoride (SF₆) concentrations in industrial and critical infrastructure environments. It operates on the principle of non-dispersive infrared (NDIR) spectroscopy — a well-established, interference-resistant optical method that exploits the characteristic absorption band of SF₆ near 10.55 µm. Unlike electrochemical or catalytic bead sensors, NDIR technology delivers inherent stability, minimal drift, and immunity to poisoning or sensor saturation under high-concentration exposure. The instrument is designed for integration into electrical substations, GIS (gas-insulated switchgear) rooms, SF₆ recovery and recycling facilities, and high-voltage equipment maintenance zones where trace leak detection, ambient safety compliance, and process gas integrity verification are mission-critical. Its robust die-cast aluminum housing, IP66-rated ingress protection, and certified Ex d IIB T4 Gb explosion-proof construction ensure safe deployment in Zone 1 hazardous areas per IEC 60079 standards — fully aligned with GB/T 3836.1–2021, GB/T 3836.2–2021, and GB/T 3836.31–2021.

Key Features

• High-stability NDIR sensing core with factory-calibrated reference cell and temperature-compensated signal processing
• Configurable measurement ranges: 0–100 ppm (leak detection), 0–1000 ppm (occupational exposure monitoring), up to 0–100% vol (pure gas handling)
• True T90 response time ≤20 seconds across all ranges, validated per ISO 12039 and IEC 62047-11 test protocols
• Dual-output architecture: simultaneous 4–20 mA (16-bit precision, ≤1 km cable run) and RS485 Modbus RTU (≤2 km, multi-drop capable)
• Expandable multi-gas platform: supports up to six independent sensor modules (e.g., O₂, CO, H₂S, CH₄) in a single enclosure with shared power and communication bus
• Three alarm levels (standard two-level, optional third) with programmable hysteresis, latching/non-latching modes, and dual relay outputs (250 VAC/30 VDC rated)
• Integrated diagnostics: real-time sensor health monitoring, zero/span validation flag, voltage supervision, and fault logging with timestamped event history

Sample Compatibility & Compliance

The MOT500-SF6 is optimized for continuous sampling of ambient air or process gas streams containing SF₆ in nitrogen, dry air, or CO₂ backgrounds. It accommodates diffusion, flow-through, and active pump-suction sampling configurations — enabling flexible deployment in confined spaces, ducts, or pressurized enclosures. All variants meet electromagnetic compatibility (EMC) requirements per GB/T 18268.1–2010 (IEC 61326-1) and environmental stress testing per GB/T 2423.1–2008 (cold), GB/T 2423.2–2008 (dry heat), and GB/T 2423.3–2016 (damp heat). The device is certified for use in Class I, Division 1 hazardous locations (Group B, C, D) and complies with functional safety guidelines relevant to SIL 2-capable systems when integrated with appropriate safety controllers (IEC 61508, IEC 61511). While not FDA 21 CFR Part 11-certified out-of-the-box, audit-ready data logs (with user ID, timestamp, and action type) support GLP/GMP-aligned QA documentation workflows.

Software & Data Management

Data acquisition and remote configuration are supported via Korno’s proprietary PC-based configuration tool (Windows 7–11 compatible) and optional web-enabled gateway firmware. The embedded Modbus RTU protocol enables seamless integration with SCADA, DCS, and PLC platforms (Siemens S7, Allen-Bradley ControlLogix, Yokogawa CENTUM VP). Optional TCP/IP and GPRS modules provide encrypted, time-synchronized transmission to cloud dashboards or on-premise servers using MQTT or HTTP(S) RESTful APIs. All analog and digital output events — including alarm triggers, calibration records, and sensor diagnostics — are timestamped with millisecond resolution and stored locally (non-volatile memory, ≥12 months at 1-min intervals). Remote firmware updates are supported over secure TLS 1.2 channels.

Applications

• Continuous SF₆ leak detection in GIS compartments and circuit breakers to prevent dielectric failure and regulatory non-compliance (IEC 62271-1, IEEE C37.122.1)
• Ambient concentration monitoring in substation control rooms to ensure occupational exposure limits (OELs) per ACGIH TLV® (1000 ppm TWA) and OSHA PEL (1000 ppm)
• Process gas purity verification during SF₆ recovery, purification, and refilling operations in utility maintenance depots
• Environmental compliance reporting for F-gas Regulation (EU No 517/2014) and EPA GHG Reporting Program (Subpart DD)
• Integration into fire suppression system interlocks where SF₆ displacement may indicate enclosure breach or inerting loss

FAQ

What is the recommended calibration interval for the MOT500-SF6?
Annual bump testing and full span calibration are recommended; however, field calibration frequency should be determined by risk assessment per ISO 17025 or internal QA procedures.
Can the instrument operate in high-humidity environments without condensation?
Yes — it is rated for ≤95% RH non-condensing operation. For sustained exposure above 85% RH or in dew-prone installations, optional heated sample line or Nafion™ dryer integration is advised.
Is third-party certification available for international hazardous area classification?
The CCRI24.8021X certificate covers Chinese national explosion-protection standards. For ATEX/IECEx recognition, Korno provides technical documentation packages supporting end-user submission to Notified Bodies.
How is zero drift compensated during long-term deployment?
The unit employs automatic baseline correction algorithms triggered during scheduled zero cycles (user-defined or timed), plus passive optical referencing to minimize thermal drift effects.
Does the MOT500-SF6 support HART communication?
No — it uses industry-standard 4–20 mA with digital overlay (HART is not implemented); however, RS485 Modbus RTU provides equivalent configurability and diagnostics.