KROHNE ALTOFLUX IFM4042K EEx EN - Manual (Page 10)

9
4. REPLACEMENT OF ELECTRONICS UNIT
IMPORTANT !
The following instructions must be followed carefully, when the IFC 040-EEx signal
converter housing has to be opened respectively closed again !
Before opening:
♦
Make absolutely sure that there is no explosion hazard !
♦
If necessary provide a "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 display cover (with the glass window)
can 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.
Then continue as follows:
1. Remove the display cover of the electronics compartment.
2. Unscrew the two screws of the display unit and turn it carefully aside.
3. Carefully disconnect the 12 pin connector (for field coil and electrode circuits connection)
from the electronics unit.
4. Unscrew the two mounting screws of the electronics unit, which fixes the zinc-plated
frame to the back of the signal converter housing. A screwdriver with a long shaft like the
screwdriver type 2 Pt. Phillips is most suitable.
5. Carefully remove the electronics unit of the converter housing (see the Remark below).
6. Reassemble in reverse order with the replacement of the IFC 040-EEx electronics unit.
After opening:
♦
The zinc-plated frame of the IFC 040-EEx electronics unit must be securely screwed to
the housing (back-end of electronics compartment) by the two non-removable fastening
screws. Screw them with a tightening torque of 1.3 Nm. These two screw-connections
also establish the safety-technical connection of the electronics unit to the signal converter
housing and equipotential bonding system. Before the two screws can be accessed, the
display unit must be removed via their two screws.
♦
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 display cover as tight as possible into the housing by hand, so that the gasket
of the cover must be clamped to provide the required Ingress Protection (IP) degree.
♦
Screw the recessed head screw of the interlocking device tight.
Refer to the standard Installation and Operating Instructions for detailed information about
resetting and reprogramming the new electronics unit after replacement.
REMARK !
Carefully keep the connecting cables of the field coil and electrode circuits to the side of
the housing, while removing respectively inserting the electronics unit into the signal
converter housing. This is to prevent damaging of the connecting cables !