SF6 gas density controller 8739

About
Trafag, based in Switzerland, supplies precise, maintenance-free instruments designed for monitoring the density of SF6 and alternative insulation gases. Measurement uses an absolute-pressure reference gas principle and a patented oscillating quartz sensor. The hybrid design integrates both principles in a single instrument, enabling direct gas density measurement and providing switching contacts plus Modbus communication.

Main features

• Large dial for easy readability
• Up to four galvanically separated circuits
• Fully temperature compensated
• Suitable for indoor and outdoor installation
• Compatible with SF6 and a wide range of alternative mixed insulation gases

Technical Data
Product code: 8739
Designation: Hybrid Gas Density Monitor 8739 with switching contacts and Modbus output
Measuring range:

• 0 ... 1300 kPa abs. @ 20°C
• 0 ... 60 kg/m3

Measuring principle:

• Monitor: Absolute-pressure reference gas measuring system
• Sensor: Oscillating quartz

Output signal:

• Monitor: Floating change-over contact (SPDT)
• Sensor: RS485 / Modbus (RTU)

Ambient temperature: -40°C ... +80°C
Product category: Gas density monitoring
Applications: Medium voltage technology

Specifications

• Product code: 8739
• Model designation: Hybrid Gas Density Monitor 8739
• Measuring ranges: 0 ... 1300 kPa abs. @ 20°C; 0 ... 60 kg/m3
• Measuring principles: Absolute-pressure reference gas measuring system (monitor) and oscillating quartz (sensor)
• Outputs: SPDT switching contacts (monitor) and RS485 / Modbus RTU (sensor)
• Temperature compensation: Fully temperature compensated
• Operating ambient temperature: -40°C to +80°C
• Installation: Suitable for indoor and outdoor applications
• Compliance: Compatible with SF6 and alternative mixed insulation gases