2104B2081 HONEYWELL

The Searchline Excel operates by projecting a continuous, intense infrared (IR) beam from the Transmitter (2104B2081) to a separate Receiver unit, which is typically mounted up to 120 meters away. If a flammable hydrocarbon gas cloud (like methane, propane, or ethylene) passes through the beam path, it absorbs a portion of the IR energy. The Receiver detects this reduction in signal and interprets it as a gas concentration, reporting the measurement in LEL.m (Lower Explosive Limit meter). The 2104B2081 is specifically the Transmitter designated for Medium Range applications.

Product Specifications

• Product Type: Medium Range Transmitter, part of the Searchline Excel Open Path Infrared Gas Detector

• Detection Principle: Infrared (IR) absorption

• Gas Detected: Flammable hydrocarbon gases (e.g., Methane, Ethane, Propane, Butane, Pentane, Ethylene, Propylene)

• Path Length (Range): Medium Range is $40 \text{ to } 120 \text{ meters}$ ($130 \text{ to } 390 \text{ feet}$)

• Output Signal: The complete system (Transmitter + Receiver) outputs a standard $4 \text{ to } 20 \text{ mA}$ DC analog signal, corresponding to $0 \text{ to } 5 \text{ LEL.m}$, and a Modbus RS485 digital output for multi-drop communication.

• Speed of Response: Very fast, with T90 less than 3 seconds under normal conditions, providing early warning.

• Operating Temperature: $-40^{\circ}\text{C}$ to $+65^{\circ}\text{C}$ ($-40^{\circ}\text{F}$ to $150^{\circ}\text{F}$)

• Enclosure Material: 316 Stainless Steel, providing excellent corrosion resistance.

• Ingress Protection (IP Rating): IP66 and IP67 for superior protection against dust and water.

• Certification: ATEX certified for safe use in hazardous, potentially explosive atmospheres (e.g., Exd IIC T5).

Product Advantages

• Wide Area Coverage: Open Path detectors cover a large linear area, significantly increasing the probability of detecting a gas leak compared to single point detectors, often requiring fewer devices overall.

• High Reliability in Harsh Conditions: The robust 316 stainless steel enclosure and heated optics prevent the buildup of condensation, ice, or snow. The patented optical design provides $100\%$ solar immunity, preventing false alarms from sunlight, arc welding, or flare stacks.

• Immunity to Poisons: As an infrared-based detector, it is immune to catalytic poisons that can permanently disable traditional catalytic bead sensors.

• Fault Detection and Self-Diagnostics: The system features integral self-diagnostics with distinct fault signals (e.g., $2.5 \text{ mA}$ for beam blocked, $3 \text{ mA}$ for dirty optics, $0 \text{ mA}$ for fault), ensuring no unrevealed failure modes.

• Tolerance to Misalignment and Obscuration: Its coaxial optical design offers resilience to vibration, duct flex, minor misalignment, and partial beam obscuration, helping to keep the system online and operational.

Important Considerations (Precautions)

• Line of Sight: The fundamental requirement for an Open Path detector is a clear, unobstructed line of sight between the Transmitter (2104B2081) and its paired Receiver unit. Any permanent blockage will prevent proper operation.

• Alignment: Although the design is robust, initial alignment of the Transmitter and Receiver must be performed accurately, usually with a high-power rifle telescope and a specialized handheld interrogator tool, to guarantee optimal performance.

• Field Wiring: All field wiring, especially in hazardous locations, must comply with the certified standards (ATEX, UL, CSA) and local electrical codes. The use of appropriate cable glands and junction boxes is mandatory.

• Installation Height: The system should be mounted at a height appropriate for the target gas (e.g., near the ground for heavier-than-air gases like propane, or near potential leak sources).

Product Applications

The 2104B2081 Medium Range Transmitter, as part of the Searchline Excel system, is widely used for continuous flammable gas monitoring in large, open, and hazardous industrial areas where leaks are a major risk.

• Oil & Gas (Onshore and Offshore): Monitoring perimeters, pipelines, storage tanks, drilling rigs, and offshore platforms.

• Petrochemical and Chemical Processing: Detecting hydrocarbon leaks across open process areas, compressor stations, and bulk chemical storage facilities.

• Refineries: Covering processing units and loading racks where large gas clouds could quickly form.

• Power Generation: Monitoring areas around gas turbines and fuel storage facilities.

• LNG/LPG Terminals: Providing early warning for potential leaks in expansive storage and transfer areas.