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1.1 Flameproof flammable gas detector
This version of
Xgard
is a Flameproof gas detector, designed to detect
flammable gas present in ambient air, at concentrations not exceeding
the Lower Explosive Limit (LEL) of the target gas for which it is calibrated.
Xgard
Type 3 operates using pellistors as part of a 3wire Wheatstone
Bridge (WB) circuit, and must be connected to a suitable control card.
The detector is certified
II 2 GD EExd IIC T6 for operation up to 50°C
(120°F),
II 2 GD EExd IIC T4 for operation up to 80°C (176°F), and is
suitable for use in Zone 1 and Zone 2 hazardous areas.
Electrical connections to the detector are made via the terminal block on
the PCB shown below.
Diagram 8:
Xgard
Type 3 PCB layout
(Shown with PCB cover removed).
1. Introduction
Xgard Type 3
Supple
mental
external
grounding
terminal
(earth)
Internal
grounding
terminal
(earth)
