Detcon IR-642 - Manual (Page 9)

22 3A 16 10A
20 5A 14 20A
18 7A 12 25A
The RS-485 (if applicable) requires 24 gauge, two conductor, shielded, twisted pair cable between sensor and host
PC. Use Belden part number 9841. Two sets of terminals are located on the connector board to facilitate serial loop
wiring from sensor to sensor. Wiring designators are A & B (IN) and A & B (OUT).
3.5.2 Sensor Location
Selection of sensor location is critical to the overall safe performance of the product. Five factors play an important
role in selection of sensor locations:
(1) Density of the gas to be detected
(2) Most probable leak or generation sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Accessibility for routine maintenance
Density - Placement of sensors relative to the density of CO2 is such that sensors for the detection of CO2 should
be located within 2-4 feet of grade as CO2 will tend to settle in low lying areas.
Leak Sources - Most probable leak sources within an industrial process include f langes, valves, and tubing connec-
tions of the sealed type where seals may either fail or wear. Other leak sources are best determined by facility engi-
neers with experience in similar processes.
Ventilation - Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a
manner where the migration of gas clouds is quickly detected.
Personnel Exposure - The undetected migration of gas clouds should not be allowed to approach concentrated per-
sonnel areas such as control rooms, maintenance or warehouse buildings. A more general and applicable thought
toward selecting sensor location is combining leak source and perimeter protection in the best possible configuration.
Note: In all installations, the sensor element in SS housing points down relative to grade (Fig. 1). Improper sensor
orientation may result in false reading and permanent sensor damage.
3.5.3 Local Electrical Codes
Sensor and transmitter assemblies should be installed in accordance with all local electrical codes. Use appropriate
conduit seals. Drains & breathers are recommended. The sensor assemblies are designed to meet NEC and CSA
requirements for Class I; Groups B, C, D; Div. 1 environments.
3.5.4 Accessibility
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.9
EYS
Seal
Fitting
Drain
“T” Plug any unused ports.
Figure #1