Detcon DM-434B User Manual

Page 6

Linearity

± 0.5% FS

Output

Linear 4-20 mA DC

Input Voltage

11.5-28 VDC

Power Consumption

< 0.6 watts

Electrical Classification

Class I; Groups B, C, D; Div. 1.

Safety Approvals

CSA/NRTL (US OSHA Certified)

Sensor Warranty

2 year conditional

Field Wiring

Maximum loop load 650 ohms at 24 VDC

5.0 INSTALLATION

Optimum performance of ambient air/gas sensor devices is directly relative to proper application and
installation practice.

5.1 Field Wiring Table
Detcon Model DM-434B sensors are two wire loop powered. Wiring designators are + (+ power) and MA
(– power). Maximum single conductor resistance between sensor and controller is 10 ohms. Maximum
wire size for termination in the sensor assembly terminal board is 14 gauge.

AWG

Meters

Feet

240

800

360

1200

600

2000

900

3000

Note 1:

This wiring table is based on stranded tinned copper wire and is designed to serve as a reference only.

Note 2:

Shielded cable may be required in installations where cable trays or conduit runs include high

voltage lines or other sources of induced interference.

5.2 Sensor Location
Selection of physical 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 sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Maintenance access

Density

- Placement of sensors relative to the density of the target gas is such that sensors for the detection

of heavier than air gases should be located within 2-4 feet of grade as these heavy gases will tend to settle
in low lying areas. For gases lighter than air, sensor placement should be 4-8 feet above grade in open
areas or in pitched areas of enclosed spaces. Give consideration to easy access by maintenance personnel
as well as the consequences of close proximity to contaminants that may foul the sensor prematurely.

Leak Sources

- Most probable leak sources within an industrial process include flanges, valves, and tubing

connections of the sealed type where seals may either fail or wear. Other leak sources are best determined

Detcon Model DM-434B Oxygen Sensor PG.6