Detcon DM-534C - Manual (Page 5)

DM-534C Oxygen Sensor Assembly
DM-534C O2 Sensor Instruction Manual Rev. 1.4 Page 1 of 18
1.0 DESCRIPTION
Detcon MicroSafe™ Model DM534C, oxygen deficiency sensors are non-intrusive “Smart” sensors designed
to detect and monitor O2 in air over the range of 0-25%. One of the primary features of the sensor is its
method of automatic calibration which guides the user through each step via instructions displayed on the
backlit LCD. The sensor output is a standard 4-20 mA signal. The microprocessor-supervised electronics are
packaged as a plug-in module that mates to a standard connector board. Both are housed in an explosion proof
condulet that includes a glass lens. A 16 character alpha-numeric indicator is used to display sensor readings as
well as the sensor’s menu driven features via a handheld programming magnet.
1.1 Sensor Technology
The sensor technology is of the two-electrode, galvanic metal air battery type cell, which is housed as a field
replaceable plug–in module. The cell is diffusion limited and functions as a direct current generator
proportional to the amount of oxygen adsorption. The sensors are temperature compensated and show good
accuracy and stability over the operating temperature range -4° to +122° Fahrenheit. The sensor is warranted
for two years and has an expected service life of up to three years in ambient air at 20.9% oxygen.
Figure 1 Construction of Galvanic Cell
The control circuit is microprocessor based and is packaged as a plug-in field replaceable module, facilitating
easy replacement and minimum down time. Circuit functions include a basic sensor preamplifier, onboard
power supplies, microprocessor, back lit alpha numeric display, calibration and fault status LED indicators,
magnetic programming switches, and a linear 4-20 mA DC output.
Figure 2 Microprocessor Control Circuit