Detcon DM-400IS - Manual (Page 4)

3.0 D ESCRIPTION
Detcon Model series DM-400IS, toxic gas sensors are designed to detect and continuously monitor for toxic gas in the
ppm range. Method of detection is by diffusion/adsorption requiring no moving parts. The sensor assembly consists of
an electrochemical fuel cell mounted in an Intrinsically Safe stainless steel and ABS plastic housing that includes an
integral rain-shield, a universal signal conditioning control transmitter circuit, a base connector board and an explosion
proof junction box.
Typical ranges of detection are 0-10ppm, 0-25ppm, 0-50ppm and 0-100ppm. Other ranges are available and all ranges are cov-
ered by this manual. To find out the specific gas type and range of detection of your sensor(s), refer to the label located on
the stainless steel sensor housing.
3.0.1 Sensor Technology
The sensors are electrolytic chemical cells. Each cell consists of three electrodes embedded in an electrolyte solution all
housed beneath a diffusion membrane. Sensitivity to specif ic target gases is achieved by varying composition of any
combination of the sensor components. Good specif icity is achieved in each sensor type. The cells are diffusion limited
via small capillary barriers resulting in long service life of up to 3 or more years. The fuel cell is packaged as a f ield
replaceable plug-in sensor via gold plated pins. Pre-amplif ier and intrinsically safe barrier circuits are epoxy potted in the
stainless steel housing and include the mating sockets for the sensor.
DM-400IS Toxic Gas Sensors PG.4
Construction of Electrochemical Sensor
Reference Electrode
Counter Electrode
Electrolyte Reservoir
Sensing Electrode
Diffusion Barrier