SG100-R Extended-Range Fixed CH4 Detector
Advanced fixed remote gas detection system designed for methane (CH₄) monitoring with extended distance capability between transmitter and sensor.
The SG100-R is a fixed gas detection system that separates the sensor from the transmitter by up to 1000 metres using RS485 communication. This remote-mount design is ideal when the measurement point is inside a duct, pipeline, confined space, or where gases are heavier than air - the sensor goes where the hazard is, while the transmitter stays at a convenient, safe location for display viewing and configuration.
Taking methane (CH₄) as an example, the system uses a catalytic combustion sensor to measure from 0 to 100%LEL with 1%LEL resolution. Outputs include 3-wire 4-20mA, RS485 Modbus, and three relays (low alarm, high alarm, fault alarm). Configuration is performed safely without opening the enclosure using a magnetic wand or optional remote control. The unit carries IECEx/ATEX certification (Ex db IIC T6 Gb), IP66/IP68 protection, and a rugged die-cast aluminium housing (SS316 optional). Comes complete with mounting bracket.
Why Remote Sensor Placement Matters
Traditional fixed detectors mount the sensor directly on the transmitter - but this doesn't work for every scenario. The SG100-R solves these challenges:
- Duct and pipeline installations - Place the sensor inside the airflow while the transmitter remains outside for easy access.
- Heavier-than-air gases - Gases like NH₃, H₂S, and H₂ tend to settle at low points. The sensor goes near the floor; the transmitter stays at eye level for safe reading.
- Hard-to-reach areas - Confined spaces, vessel heads, or elevated ductwork - access the sensor remotely without climbing or entering hazardous zones.
- Harsh sensor environments - If the measurement point is wet, dusty, or corrosive, the transmitter can be located in a cleaner area, extending its service life.
- Maximum separation distance: 1000 metres - powered and communicated via RS485 connection from the transmitter.
A Brief Note on Methane (CH₄)
Methane is the primary component of natural gas. It is colourless, odourless, and highly flammable. When its concentration in air reaches between 5% and 15% by volume, it becomes explosive. The Lower Explosive Limit (LEL) of methane is 5% VOL, defined as 100% LEL on the detector. Measuring 0-100%LEL directly indicates how close the atmosphere is to the explosive range.
Typical methane sources: Natural gas pipelines, landfills, coal mines, biogas plants, wastewater digesters, and oil refineries.
The SG100-R provides early warning of flammable leaks, especially in remote or difficult-to-access locations where conventional detectors cannot be easily installed or maintained.
Field Applications - Where the SG100-R Excels
- Duct pipelines - Monitor gas inside ventilation or exhaust ducts; sensor inside, transmitter outside.
- Heavy gas detection - NH₃, H₂, H₂S settle at low points; sensor at floor level, transmitter at comfortable viewing height.
- Confined space entry - Sensor inside tanks, vessels, or sewers; transmitter positioned safely outside for personnel monitoring.
- Landfills & biogas plants - Methane monitoring in collection wells and digesters.
- Natural gas compressor stations - Remote sensor in valve pits where access is restricted.
- Oil & gas refineries - Fugitive emission monitoring in hard-to-reach process areas.
- Wastewater treatment - Digester gas (methane) monitoring in tank headspaces.
- Coal mines - Remote sensing in return airways or goaf areas.
Product Images
Technical Specifications (CH₄, 0 -100%LEL)
| Parameter |
Value |
| Target Gas |
Methane (CH₄) |
| Detection Principle |
Catalytic combustion |
| Measuring Range |
0 - 100%LEL |
| Resolution |
1%LEL |
| Accuracy |
≤ ±2-5% FS (sensor-dependent) |
| Explosion-Proof Rating |
IECEx: Ex db IIC T6 Gb, Ex db ia IIC T6 Gb; ATEX: Ex db IIC T6 Gb, Ex db ia IIC T6 Gb |
| Ingress Protection |
IP66 / IP68 |
| Power Consumption |
<2.5W (toxic gas) / <4W (flammable gas) |
| Standard Outputs |
3-wire 4-20mA, RS485 Modbus |
| Relay Outputs |
3 relays (low alarm, high alarm, fault alarm) |
| Supply Voltage |
12-24V DC |
| Display |
LED |
| Operating Temperature (Catalytic) |
-40°C to +70°C |
| Operating Humidity |
0-95% RH (non-condensing) |
| Pressure Range |
86-106 kPa |
| Enclosure Material |
Die-cast aluminium (standard); SS316 (optional) |
| Cable Entries |
1 × 3/4 NPT (left) & 1 × M20 (right) |
| Dimensions |
157.8 × 128.8 × 69.6 mm |
| Weight |
1.0 kg |
| Warranty |
1 year |
Core Capabilities
- 1000-metre separation - Sensor and transmitter can be up to 1000m apart via RS485 - unmatched flexibility for difficult installations.
- Explosion-proof certified - IECEx and ATEX Ex db IIC T6 Gb - safe for Zone 1 and 2 hazardous areas.
- IP66/IP68 protection - Dust-tight, protected against powerful water jets, and submersible.
- Multiple output options - 4-20mA (3-wire), RS485 Modbus, plus three relays for external device control.
- Safe configuration - Magnetic wand (included) or optional remote control - no need to open the enclosure in explosive atmospheres.
- Local display - LED screen shows real-time gas concentration at the transmitter location.
- Durable construction - Die-cast aluminium housing; stainless steel 316 optional for corrosive sites.
- Easy installation - Mounting bracket supplied; standard cable entries (NPT and M20).
About the Manufacturer
Shenzhen YuanTe Technology Co., Ltd. (Safegas) - established in 2010, with over 16 years of experience in gas detection R&D, manufacturing, and sales. The company serves oil & gas, chemicals, environmental protection, electronics, municipal engineering, agriculture, and household appliances.
Key credentials:
- Certified under ISO9001, ISO45001, IECEx, ATEX, EMC
- Annual production capacity: >80,000 units
- Typical delivery: 5-7 working days
- 24/7 global after-sales support
- Product range includes portable detectors, fixed transmitters, gas analyzers, control panels, docking stations, and calibration accessories.
Frequently Asked Questions
Q1: How far can the sensor be from the transmitter?
A1: Up to 1000 metres using RS485 communication.
Q2: Can the SG100-R detect gases other than methane?
A2: Yes. It supports hundreds of sensor types - catalytic (flammables), IR (CO₂, CH₄), electrochemical (toxic), and PID (VOC). Contact us for specific gas configurations.
Q3: Does the transmitter have a display?
A3: Yes, an LED display shows real-time gas concentration at the transmitter location.
Q4: How do I adjust alarm setpoints without opening the enclosure?
A4: Use the supplied magnetic wand (non-intrusive) or the optional remote control - safe in hazardous areas.
Q5: What relays are provided?
A5: Three relays - low alarm, high alarm, and fault alarm. They can directly drive external horns, strobe lights, fans, or solenoid valves.
Q6: What is the protection rating?
A6: IP66 (dust-tight, protected against powerful water jets) and IP68 (submersible).
Q7: What is the warranty period?
A7: 1 year for the transmitter and sensor (sensor consumables may have shorter warranty depending on type).
Q8: Does the remote sensor need its own power supply?
A8: No. The transmitter powers the remote sensor via the RS485 connection.
Q9: Can I install the sensor inside a duct or pipeline?
A9: Yes. The remote sensor is designed for installation in ducts, stacks, or pipes - the transmitter remains outside in an accessible, safe location.
Q10: Is the SG100-R certified for explosive atmospheres?
A10: Yes. It holds IECEx and ATEX Ex db IIC T6 Gb certification for Zone 1 and Zone 2 hazardous areas.
Standard Package Contents
- Gas detector - 1 unit
- Magnetic wand - 1 piece
- User manual (English) - 1 copy
- Certificate of conformity / Warranty card - 1 copy
- Mounting bracket - 1 set
- Remote control - 1 piece
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