YOKOGAWA vigilantplant DM8, User Manual

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<1. GENERAL>
1-12
IM 12T03A01-02E
1.4.3 Installation Area and Ambient Conditions
Model VD6DF density detector can be installed in hazardous area where specified gases are
present.
However, do not install the detector at the place where explosive gases may be continuously
present, and in which the gas concentration is continuous or for long period, equal to or more
than, the lowest gas explosion limit.
Environmental conditions at the installation site are very important to the detector.
Before installing the detector, check the temperature, humidity and altitude of the site.
The conditions shall not exceed the specified ranges. The temperature range (-10 to 50°C) in
indicated on the data plate, and the altitude shall be 1000 meters or less above sea level and the
relative humidity range 45 to 85 %.
1.4.4 External Wiring Work
External wiring for flameproof detector shall be carried out according to the flameproof metal
conduit wiring. For TIIS explosion-proof specifications, the flameproof packing type is used for
leading external cables.
1.4.5 Maintenance Procedure
Do not remove the detector cover in a hazardous area unless power is OFF. However, if detector
maintenance with power on is unavoidable, a gas detector check should first be made to
determine whether a hazardous atmosphere exits in the installation area.
1.4.6 Repairs
Regarding to repairs of flameproof detector, consults with service personnel.
The following points must be observed during repairs of flameproof detector.
The detector must be restored to their original conditions, electrically and mechanically to
maintain their flameproof properties.
WARNING
The gaps, path lengths and mechanical strength of enclosures are important factors in
establishing flameproof properties. Therefore, service staff should be careful not to damage point
surfaces and not to shock enclosures.
5th Edition : Dec. 11, 2015-00