ASI's fast response gas sensor products provide the highest frequency response of any commercially available photoionization gas sensor. The miniPID sensor is best suited to studies that require exceptionally fast response time in a small package. The digitalPID sensor is best suited to large outdoor tests that require many sensors synchronized in time and being controlled from a single location.
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miniPID
Fast-Response Concentration Sensor
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The miniPID photo-ionization detector combines small size, fast response, and high sensitivity in an easy-to-use, competitively priced package. The sensor has a true frequency response of 330 Hz with 10-90% rise time of 0.5 msec. The detection limit is 50 ppb (parts per billion) propylene in air and the full-scale measurement range is 1000 ppm. The sensor head contains the detection cell, electrometer, RF-excited UV lamp and lamp control circuitry.
The easy-to-use controller has on/off switches for instrument and pump power, a three position switch for gain range selection, and a potentiometer for setting the zero. LEDs provide indication of power, pump, and lamp status. A front-panel display provides fast-response indication of the output signal from the sensor.
The miniPID has been used successfully during concentration fluctuation field trials at U.S. Army Dugway Proving Ground and during wind tunnel studies at the University of Utah. The sensor has proven to be easy-to-use, reliable, and robust. More recently the miniPID has been used by neuroscientists performing olfactory studies.
The digitalPID digital photo-ionization detector combines fast response, high sensitivity and micro-processor control in an easy-to-use package. The sensor has a frequency response of 50 Hz and a detection limit of 40 ppb (parts per billion) propylene in air. The sensor is self-contained and only requires a 12 volt battery or AC adapter for power. A built-in micro-processor allows all functions of the sensor (on/off, gain, zero and data transmission) to be remotely controlled through either the RS-232 or RS-485 communications interface. A 20-bit charge-digitizing analog-to-digital converter provides precision conversion of the sensor output.
Easy-to-use DPID control software provides the functions required for control, data retrieval, and calibration of up to 48 sensors. Data can be displayed on the computer screen in real-time while data logging is underway. The DPID software uses a real-time version of the Linux operating system and comes installed and ready-to-use on a dedicated PC.
One hundred digitalPID sensors have been constructed for U.S. Army Dugway Proving Ground. These sensors have been used successfully at Dugway Proving Ground for concentration fluctuation field trials and biological field trials. In addition the sensors have been used for dense gas dispersion studies at the Nevada Test Site. In all of these trials the sensors have proven to be easy-to-use, reliable and robust.