POINT TYPE GENERAL MONITORS COMBUSTIBLE GAS INTELLIGENT SENSOR S4000CH II LEL CH4

POINT TYPE GENERAL MONITORS COMBUSTIBLE GAS INTELLIGENT SENSOR S4000CH II LEL CH

General Monitors S4000CH II LEL CH

The S4000CH II LEL CH is a state-of-the-art, microprocessor-based point-type intelligent sensor designed for the continuous monitoring of combustible gases in ambient air. It is part of General Monitors’ premier SafetyNet and Modbus product families, representing a significant evolution from the previous S4000 series with enhanced features for performance, safety and ease of maintenance.

Core Function & Purpose

• Detection: Continuously measures the concentration of combustible gases and expresses it as a percentage of the Lower Explosive Limit.
• Primary Goal: To provide early warning of potentially explosive atmospheres, allowing for timely corrective action to prevent fires or explosions in industrial settings

Key Intelligent Features & Technology 

1. Advanced Microprocessor: Enables digital communication, self-diagnostics, and field programmability.
2. Dual-Wavelength Infrared Sensor:
   • This is the defining technology for this model. It uses two specific wavelengths of infrared light to detect combustible gases.
   • One wavelength is absorbed by the target gas, while the other is not.
   • This design makes it highly resistant to contamination, poisoning, and changes in ambient conditions that can plague catalytic bead sensors. It is also immune to sensor poisoning from silicones, lead, and sulfur compounds.
3. HART & Modbus Communication Protocols:
   • HART: Allows for two-way digital communication over the standard 4-20 mA analog signal line. Enables remote configuration, calibration, and diagnostics using a HART communicator or compatible host system.
   • Modbus RTU: Provides direct digital connectivity to PLCs, DCS, or Safety Controllers supporting the Modbus protocol, allowing for multiple variables to be transmitted.
4. Extensive Diagnostics:
   • Continuously monitors sensor health, optical path integrity, and electronics.
   • Provides specific fault messages on connected displays or host systems.

Typical Applications

• Oil & Gas Platforms and Refineries
• Chemical and Petrochemical Plants
• Gas Compression and Transmission Stations
• Fuel Storage and Dispensing Facilities
• Paint Booths and Solvent Processing Areas
• Any classified hazardous area requiring robust, low-maintenance gas detection.

Physical & Environmental Specifications

• Enclosure: Robust, corrosion-resistant stainless steel housing.
• Protection Rating: Typically IP66/IP67, suitable for harsh outdoor/indoor environments.
• Hazardous Area Certifications:
  • ATEX / IECEx: Ex db IIC T6 Gb / Ex tb IIIC T85°C Db.
  • cULus: Class I, Div 1, Groups B,C,D Class II, Div1, Groups E, F, G, Class III.
• Operating Temperature: Wide range -40°C to+70°C .
• Output: 4-20 mA analog plus simultaneous digital HART/Modbus signal.

User Benefits

• High Reliability & Safety: Reduced false alarms and failsafe operation.
• Lower Total Cost of Ownership: Long sensor life, infrequent calibration, and minimal maintenance.
• Ease of Use: Remote calibration and monitoring via HART reduce the need for physical access in hazardous areas.
• Flexibility: Compatible with General Monitors’ SIL 2 rated control modules and most third-party control systems via 4-20 mA or Modbus.