KROHNE ALTOFLUX IFM 4080 K EEx EN - Manual (Page 16)

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4.1 Replacement of electronics unit or power fuse(s)
IMPORTANT !
The following instructions must be followed carefully, if the IFC 090/…-EEx signal
converter housing has to be opened respectively closed again !
Before opening:
♦
Make absolutely sure that there is no explosion hazard !
♦
Gas-free certificate !
♦
Make sure that all connecting cables are safely isolated from the power supply !
♦
Allow the prescribed waiting time to elapse before opening the housing:
20 minutes for temperature class T6
11 minutes for temperature class T5
When the instructions above are strictly followed, the cover (with glass window) of the
electronics compartment may be removed. First unscrew the recessed head screw of the
interlocking device by a hollow-head screw wrench size 3, until the cover can rotate freely.
Unscrew the cover with the special plastic wrench (black) that is supplied with the apparatus.
After opening:
♦
The copper earth strip at the back of the electronics unit must be securely screwed to the
housing (back-end of electronics compartment) by screw SE (see figure 9 below). The
electronics unit is screwed into the electronics compartment by two screws D. Before
screws SE and D can be accessed, the display unit must be removed via screws A.
♦
Before the cover is screwed back into the housing, the screw-thread must be clean and
well-greased with an acid and resin-free grease, e.g. silicone grease.
♦
Screw the cover as tight as possible into the housing by hand, until it cannot be opened by
hand anymore. Screw the recessed head screw of the interlocking device tight.
Figure 9: IFC 090-EEx electronics unit after removal of display unit.
A
Power fuse in fuse-holder
D
D
Power supply PC-board
A
Mains transformer
B
Note:
Safe earth
connection SE
Flat cable of display unit
SE
C
Signal converter housing