Outdoor Monitoring of Gas Limit Values

A global operating company in the chemical and fossil fuels industry designed a comprehensive early warning system for gas leakage detection. Twelve measuring stations are installed at intervals of 300 meters; each is equipped with an analog wind-direction and wind-speed sensor and four gas sensors. Two of the gas detectors use a 4 mA ... 20 mA signal for transmission, while the remaining two use the HART protocol. The early warning measuring stations are positioned on-site so that escaping gases are reliably detected before they disperse or dissipate.

All stations should be networked within the early warning system without any special cabling for the power supply or data communication. The solution for the wireless, digital transmission of data must offer the highest possible level of transmission security, even in ambient temperatures down to – 33 °C.

To integrate the sensors into the early warning system, five BULLET WirelessHART adapters are used for each measuring station: One unit each for the analog signals of the wind-direction and wind-speed sensors and the two 4  mA… 20 mA sensors, as well as an adapter that uses the multidrop feature to transmit the signals of the two HART transmitters. The WirelessHART adapters are engineered to provide a maximum level of ruggedness. The aluminum housing is extremely durable and easy to clean. It protects all inner electronic components against possible damage. A solar panel and battery supply the stations with power.

Self-sufficient wireless stations make it possible to set up a completely autonomous network. The high transmission security of the adapters guarantees a reliable, fail-safe connection of all measuring points within the early warning system. Escaping gases are detected and reported immediately. The multidrop operation of up to eight HART-compatible field devices on one BULLET WirelessHART adapter can help to lower network costs.

• Integration of wind and gas sensors into the early warning system
• Fail-safe data transfer via WirelessHART
• Rugged adapters with anti-static dome for demanding outdoor use
• Reliable leakage indication and alarm signaling