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8013741/16LH/V1-7/2020-04| SICK
O P E R A T I N G I N S T R U C T I O N S | MCS300P Ex
Subject to change without notice
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PRODUCT DESCRIPTION
2.3.1
Function of the pressurized enclosure
2.3.1.1
Purpose
The pressurized enclosure prevents an explosive atmosphere from being created inside the
enclosure. To this purpose, the gas analyzer enclosure is filled with a protective gas. Apart
from that, it also ensures the gas pressure inside the gas analyzer enclosure is higher than
the ambient air pressure.
2.3.1.2
Functionality during operation
The pressurized enclosure system functions in “leakage compensation” operating mode: A
protective gas pressure is created in the gas analyzer enclosure after pre-purging has
completed. If the protective gas pressure drops below the minimum pressure set, protective
gas feed is activated until the rated pressure is reached again.
2.3.2
Safety functions
For MCS300P Ex category 3G
An alarm will sound on Ex control unit FS840 to alert the operator and must be evaluated
(operator responsibility
→
Pressurized enclosure system F840 Manual) when the
pressurized enclosure is not in the correct operating state (malfunction),
For MCS300P Ex category 2G
●
The enclosure is pre-purged automatically before commissioning. The main power
supply for the gas analyzer is switched on automatically after pre-purging has
completed.
●
The main power supply of the gas analyzer is switched off automatically when the
pressurized enclosure is not in the correct operating state (malfunction).
2.3.2.1
Subassemblies used
Fig. 3: Ex peripherals for MCS300P Ex category 2G
Signal lines
Main power supply
Ex control unit FS850S
Ex power relay SR853
Ex interface
relays
SR852
