Gas Detection 13 New Smart Sensor Technology
Alphasense (UK), the leading gas sensor manufacturer for safety and industrial markets, launches new smart sensor technology for its electro-chemical sensors. The AFE (Analogue Front End) is a programmable device for use in micro power electro-chemical sensing applications. It is intended to be used with the sensor, creating a “smart sensor”. It is designed for three-electrode single gas sensors and for two electrode oxygen sensors. This device provides all of the functionality for detecting changes in gas concentration based on a delta current at the working electrode, and generates an output voltage proportional to the cell current.
Transimpedance gain is user programmable through an I2C® compatible interface from 3.4kOhm to 440kOhm
making it easy to convert current ranges from 5µA to 650uA full scale. Optimised for micro-power applications, the AFE works over a voltage range of 2.7V to 5.5 V. The cell voltage is user selectable using the on board programmability. A temperature sensor is embedded and it can be power cycled through the interface, the output of this temperature sensor can be read by the user through the ‘Out’ pin. Together with the coefficients stored in the on
board EEPROM, this information can be used to compensate for the sensor sensitivity drift over temperature. Additionally user controlled sensor test will be implemented. The tests the sensor for proper connection (all 3 terminals) as well as proper function.
Depending on configuration, total current consumption for the device can be less than 10µA running, for power savings transimpedance amplifier (TIA) can be turned off and instead a load impedance equivalent to the TIA’s inputs impedance is switched in.
Arthur Burnley, Sales & Marketing Director commented, “We are continually developing new technologies especially with respect to electronics and have been working with Semi- conductor manufacturers to provide Smart Sensor Technology that will ease the development and reduce time to market for OEM’s and system builders by providing a ‘smart’ interface to our electro-chemical sensors. This is a further example of developments making a positive contribution to the protection of life in challenging environments. Supporting our customers is one of our highest priorities and the Alphasense team has many decades of design, Manufacturing and Application experience. We are not only improving our products continuously, but also our internal procedures and processes to ensure we offer the highest possible levels of Customer Support”
Reader Reply Card No. Simple Explosive Gas Detector uses Catalytic Gas Sensors
The Mini-Agis from Arel Electronics (Turkey) is a pocket sized explosive gas meter designed as a handy, easy to use spot-checking instrument for HVAC Engineers needing to locate or detect flammable gas escapes in non-hazardous areas such as dwellings, commercial buildings, RV’s and pleasure boats. With %LEL and %Volume settings for both LPG and Natural Gas, the Mini-Agis benefits from simple one button operation and the use of an industrial standard catalytic gas sensor, rather than the semiconductor based sensors often seen in similar low-cost instruments, resulting in more reliable measurements and greater sensor stability.
Measuring 45mm X 100mm X 27mm and weighing just 122g, the Mini-Agis can make over 200 flammability measurements before its two AA batteries need replacing, and to maximise battery life the instrument switches itself off automatically if left unused for longer than 6 minutes.
Reader Reply Card No.
Fluorescent Optical Oxygen Sensor Makes a World of Sense
SST Sensing Ltd (UK) has adapted a proven and reliable oxygen sensing technology and developed this into a miniaturised oxygen sensor aimed at OEMs. The technology, packaged in a small 'can style' housing, uses fluorescence quenching by oxygen to determine the oxygen content in a given environment. The sensor incorporates a temperature sensor which removes the need for external hardware or software temperature compensation.
An optional pressure sensor allows the sensor to report the oxygen concentration as well as the oxygen partial pressure. The standard ‘can’ style sensor provides an RS232 output, SST Sensing's Evaluation Board allows customers to trial the product and provide a variety of outputs (RS232 and 0-10V and 4-20mA and Modbus) and their Industrial Board provides the output specifically to match customer’s requirements (RS232 or RS485 or 0-5V or 4-20mA).
Connection to the host microcontroller is by a simple two-wire interface and requires no ancillary components like amplifiers, A-to-Ds and temperature sensors. This saves on both design time and bill of material cost.
The gas temperature and the gas pressure (in models with built-in pressure sensor) can also be sent to the host.
A stabilisation process performed during manufacture removes initial short-term sensor drift ensuring the long-term stability of the product.
Unlike standard electrochemical sensors, LuminOx contains no hazardous materials and is fully RoHS compliant.
Used for many years in complex, high value instrumentation products, LuminOx technology is proven to be robust and accurate. SST uses a unique formula to ensure stability and long life, in a significantly smaller package than previously available. Data from trials using this technology in high-value instruments showed a drift of less than 0.3% O2 in ten years without re-calibration.
LuminOx’s non-consumptive sensing principle means that shelf-life issues associated with electrochemical sensors are non-existent.
Sensors measuring 0-300mbar O2 partial pressure and 0-25% vol. O2 are currently available, fully calibrated, from SST Sensing’s factory in Scotland.
LuminOx is a complimentary addition to SST’s current Zirconia oxygen sensing product portfolio. Reader Reply Card No. 37
Baby_125x180_eng_0812.indd 1 Reader Reply Card No. 38 22.08.12 17:19 Great endurance, small dimensions
• top reliability – tested for 4,000 hours non-stop • steady performance thanks to a newly developed valve unit • long battery life due to extremely low power consumption • adjustment by means of customised configuration • problem-free use also in Ex-certified devices
Gardner Denver Thomas GmbH
Benzstraße 28 D-82178 Puchheim, Germany
Fon: +49 89 80900-0 Fax: +49 89 808368
www.gd-thomas.com
The New Miniature Gas Pump 1010
36 35
For moments like this we provide maximum reliability.
www.envirotech-online.com IET September / October 2012
4,000 hrstested
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